STRUCTURE magazine May 2019 by structuremag

STRUCTURE MAY 2019

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Mortar Compressive Strength Post-Installed Adhesive Anchors Temple Sherith Israel

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LeMessurier Calls on Tekla Structural Designer for Complex Projects Interoperability and Time Saving Tools

Tekla Structural Designer was developed specifically to maximize collaboration with other project parties, including technicians, fabricators and architects. Its unique functionality enables engineers to integrate the physical design model seamlessly with Tekla Structures or Autodesk Revit, and to round-trip without compromising vital design data. “We’re able to import geometry from Revit, design in Tekla Structural Designer and export that information for import back into Revit. If an architect makes geometry updates or changes a slab edge, we’ll send those changes back into Tekla Structural Designer, rerun the analysis and design, and push updated design information back into Revit.”

Tekla Structural Design at Work: The Hub on Causeway

For over 55 years, LeMessurier has provided structural engineering services to architects, owners, contractors, developers and artists. Led by the example of legendary structural engineer and founder William LeMessurier, LeMessurier provides the expertise for some of the world’s most elegant and sophisticated designs while remaining true to the enduring laws of science and engineering. Known for pushing the envelope of the latest technologies and even inventing new ones, LeMessurier engineers solutions responsive to their clients’ visions and reflective of their experience. An early adopter of technology to improve their designs and workflow, LeMessurier put its own talent to work in the eighties to develop a software solution that did not exist commercially at the time. Their early application adopted the concept of Building Information Modeling (BIM) long before it emerged decades later. While LeMessurier’s proprietary tool had evolved over three decades into a powerhouse of capability, the decision to evaluate commercial structural design tools was predicated on the looming effort required to modernize its software to leverage emerging platforms, support normalized data structure integration and keep up with code changes. After a lengthy and thorough comparison of commercial tools that would “fill the shoes” and stack up to the company’s proprietary tool, LeMessurier chose Tekla Structural Designer for its rich capabilities that addressed all of their workflow needs. According to Derek Barnes, Associate at LeMessurier, ” Tekla Structural Designer offered the most features and the best integration of all the products we tested. They also offered us the ability to work closely with their development group to ensure we were getting the most out of the software.”

One Model for Structural Analysis & Design

From Schematic Design through Construction Documents, Tekla Structural Designer allows LeMessurier engineers to work from one single model for structural analysis and design, improving efficiency, workflow, and ultimately saving time. “Our engineers are working more efficiently because they don’t need to switch between multiple software packages for concrete and steel design. Tekla Structural Designer offers better integration of multiple materials than we have seen in any other product,” said Barnes. LeMessurier engineers use Tekla Structural Designer to create physical, information-rich models that contain the intelligence they need to automate the design of significant portions of their structures and efficiently manage project changes. TRANSFORMING THE WAY THE WORLD WORKS

“Tekla Structural Designer has streamlined our design process,” said Craig Blanchet, P.E., Vice President of LeMessurier. “Because some of our engineers are no longer doubling as software developers, it allows us to focus their talents on leveraging the features of the software to our advantage. Had we not chosen to adopt Tekla Structural Designer, we would have needed to bring on new staff to update and maintain our in-house software. So Tekla Structural Designer is not just saving us time on projects, it is also saving us overhead.

Efficient, Accurate Loading and Analysis

Tekla Structural Designer automatically generates an underlying and highly sophisticated analytical model from the physical model, allowing LeMessurier engineers to focus more on design than on analytical model management. Regardless of a model’s size or complexity, Tekla Structural Designer’s analytical engine accurately computes forces and displacements for use in design and the assessment of building performance.

“Tekla Structural Designer offers better integration of multiple materials than we have seen in any other product.”

Positioning a large scale mixed-use development next to an active arena, a below grade parking garage, and an interstate highway, and bridging it over two active subway tunnels makes planning, phasing and engineering paramount. Currently under construction, The Hub on Causeway Project will be the final piece in the puzzle that is the site of the original Boston Garden. Despite being new to the software, LeMessurier decided to use Tekla Structural Designer for significant portions of the project. “Relying on a new program for such a big project was obviously a risk for us, but with the potential for time savings and other efficiencies, we jumped right in with Tekla Structural Designer. It forced us to get familiar the software very quickly.” “Tekla Structural Designer allowed us to design the bulk of Phase 1 in a single model,” said Barnes. The project incorporates both concrete flat slabs and composite concrete and steel floor framing. “Tekla Structural Designer has the ability to calculate effective widths based on the physical model which is a big time saver,” said Barnes. “On this project, the integration with Revit, along with the composite steel design features enabled us to work more efficiently. Adding the ability to do concrete design in the same model was a bonus because we had both construction types in the same building.” “Tekla Structural Designer helped this project run more efficiently, and in the end it was a positive experience,” said Blanchet.

“Tekla Structural Designer gives us multiple analysis sets to pull from, which gives us lots of control. Most programs don’t have the capability to do FE and grillage chase-down. For the design of beam supported concrete slabs, Tekla Structural Designer allows us to separate the slab stiffness from the beam stiffness, so if we choose to we can design the beams without considering the influence of the slab. In the same model we can use a separate analysis set to review the floor system with the beams and slab engaged,” said Barnes. Barnes also shared similar benefits with concrete column design. “Tekla Structural Designer does grillage take-downs floor-by-floor, finds the reactions and applies them to the next floor. This allows us to view column results both for the 3-dimensional effects of the structure as a whole and from the more traditional floor-by-floor load take-down point of view. Doing both has always required significant manual intervention, but Tekla Structural Designer puts it all in one place.” “We reduce the possibility for human error because with Tekla Structural Designer less user input is required,” said Barnes. “Tekla Structural Designer automatically computes many of the design parameters, such as column unbraced lengths. The assumptions made by the software are typically correct, but we can easily review and override them when necessary.”

“Tekla Structural Designer provided the best fit for our workflow compared to other commercially available software.”

Want to Evaluate Tekla Structural Designer? tekla.com/TryTekla

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STRUCTURE ® magazine (ISSN 1536 4283) is published monthly by The National Council of Structural Engineers Associations (a nonprofit Association), 645 N. Michigan Ave, Suite 540, Chicago, IL 60611 312.649.4600. Application to Mail at Periodicals Postage Prices is Pending at Chicago, IL and additional mailing offices. STRUCTURE magazine, Volume 26, Number 5, C 2019 by The National Council of Structural Engineers Associations, all rights reserved. Subscription services, back issues and subscription information tel: 312-649-4600, or write to STRUCTURE magazine Circulation, 645 N. Michigan Avenue, Suite 540, Chicago, IL 60611. The publication is distributed to members of The National Council of Structural Engineers Associations through a resolution to its bylaws, and to members of CASE and SEI paid by each organization as nominal price subscription for its members as a benefit of their membership. Yearly Subscription in USA $75; $40 For Students; Canada $90; $60 for Canadian Students; Foreign $135, $90 for foreign students. Editorial Office: Send editorial mail to: STRUCTURE magazine, Attn: Editorial, 645 N. Michigan Avenue, Suite 540, Chicago, IL 60611. POSTMASTER: Send Address changes to STRUCTURE magazine, 645 N. Michigan Avenue, Suite 540, Chicago, IL 60611. STRUCTURE is a registered trademark of the National Council of Structural Engineers Associations (NCSEA). Articles may not be reproduced in whole or in part without the written permission of the publisher.

Contents M AY 2019

22 THE SEISMIC Feature STRENGTHENING OF TEMPLE SHERITH ISRAEL By Terrence F. Paret, Gwenyth R. Searer, and Sigmund A. Freeman

Temple Sherith Israel was subject to the City of San Francisco’s ordinance regarding assessment and upgrade of all unreinforced masonry buildings found to be seismically deficient. Structural engineers employed a host of new technologies, in concert with traditional ones, to surmount technical challenges.

Columns and Departments 6

Editorial What’s the Plan?

David R. Horos, P.E., S.E.

Building Blocks Mortar Compressive Strength

Insights Horizontal End Wall Hooks By Craig Baltimore, Ph.D., S.E., and Rachel Chandler

Spotlight University of Connecticut Downtown Hartford Campus

By Michael Reynolds, Fernando S. Fonseca, Ph.D., S.E., Theodore Moffett

By David Adler, P.E.

Structural Forensics Reinforced Masonry Construction By Michael Schuller, P.E.

Structural Practices Post-Installed Adhesive Anchors in Masonry By Mark Ziegler, P.E.

Structural Performance Resiliency of Reinforced Structural Clay Unit Masonry Construction By Steven G. Judd, S.E

In Every Issue 4 68 70 72 74

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Historic Structures The Brooklyn Bridge Masonry ~1860-2019

On the Cover

By Alice Oviatt-Lawrence

See Historic Structures on page 19 for the article on this iconic Bridge.

Brooklyn Bridge in New York City lit up at night.

Publication of any article, image, or advertisement in STRUCTURE® magazine does not constitute endorsement by NCSEA, CASE, SEI, the Publisher, or the Editorial Board, Authors, contributors, and advertisers retain sole responsibility for the content of their submissions.

M AY 2 019

EDITORIAL What’s the Plan? By David R. Horos, P.E., S.E., LEED AP

“What’s the Plan?” ~Anonymous “Make no small plans; they have no magic to stir men’s blood.” ~Daniel Burnham “Plan the work and work the plan.” ~Jeff McCarthy, former Skidmore, Owings & Merrill LLP (SOM) Managing Partner “Plans are of little importance, but planning is essential.” ~Winston Churchill

hese are a few sayings and quotes that we have probably all heard over the years. Some of us love planning, while others despise it, and still others oscillate between the two. Either way, the time has come for NCSEA to refresh our strategic plan. We undertook the most recent effort at the end of 2014, producing a plan in 2015; we created the plan before that in 2011. This recent four-year pattern suggests that now is the time. During my tenure on the SEAOI (Illinois) and NCSEA Boards of Directors, I have had the fortune (or not) of participating in what will now be a third strategic planning effort for a structural engineering organization. I have attempted to learn about vision and mission statements and found myself confused multiple times by the varieties of jargon and formats associated with strategic plans. While this by no means makes me an expert, my experience leads me to approach our upcoming effort in ways that are markedly different from my previous efforts. I now enter with cautious rather than unbridled optimism, and I am more aware of how much work can be required to navigate the process successfully. This includes honest self-reflection, thorough engagement of diverse stakeholders, creative and visionary thinking, clear documentation and communication of the results, and – most importantly – execution moving forward. I am also aware that the best intentions can fall short if even just one of the above is lacking. That is not to say that a plan will not emerge, but rather that a plan may not be what it otherwise could be. Most of all, I will stick with the adage, “you get out of it what you put into it.” While not involved in NCSEA’s 2015 effort, I was encouraged to see that it included a mission statement focused on “representing and strengthening its Member Organizations.” This may seem obvious, and maybe even trivial, but it properly reflects NCSEA’s unique structure. Comprised of 44 associations, NCSEA serves as an umbrella organization for this diverse group which represents states as large as California or Texas and as small as Wyoming or Rhode Island. Thus, NCSEA will always present unique challenges for developing a strategic plan. I have observed the 2015 mission statement in action over the last few years at the annual Summit Delegate sessions, NCSEA’s periodic visits to MOs, and ongoing activities such as the free monthly MO webinars. For these reasons alone, I would call the results of the 2015 plan a success. Now is the time to continue to build on that success. Last year, three board members worked with Al Spada, our Executive Director, to identify, solicit proposals and qualifications, interview, and select 6 STRUCTURE magazine

a facilitator to help guide us through the effort. After presentations to and discussions with the full board, we selected and engaged Association Laboratory, Inc. We were interested in, and excited by, their focus on “fact-based advice, critical thinking, and creative insights” as well as “peer-based industry research”; after all, what engineer would not be attracted to such research and data? We then formed a steering committee and started collecting data, both on our peer organizations through Association Laboratory’s research, and through an initial survey of the steering committee itself. This information will be used to create a survey to be sent to a broader audience. All such preparation leads to a retreat in July, which will end with a draft strategic plan to be followed by the final plan. Association Laboratory will provide support for a year following the retreat to help, as needed, with decisions related to the implementation of the plan. At a little over 25 years old, NCSEA is still a relatively young organization. A number of member organizations (MO’s) predate our formation, and ASCE was founded in 1852. NCSEA is continuing to mature and grow. We have attempted to select participants for the retreat that include a healthy mix of constituents, from a variety of MO’s, a variety of roles within NCSEA and MO’s, and related non-members, including NCSEA staff, an MO Executive Director, and a vendor representative. We expect this group to provide the creativity, vision, and diversity of viewpoints necessary to identify both shortcomings and opportunities, as well as help to develop strategies and tactics – explaining the difference between those two would require another article – to continue to move NCSEA forward. However, we are also looking forward to receiving input from you as part of the upcoming survey process. Please look for more information on the timing of the survey, once we finish developing it and make it available. “Life is what happens to us while we are making other plans.” (Alan Saunders, newspaper comic strip writer; not John Lennon, although a similar version is in his 1980 song, “Beautiful Boy”) I hope that this upcoming process will be my most successful involvement in strategic planning to date. If only I would make the time for such a rigorous personal strategic plan. Maybe I can tackle that four years from now. “If you don’t know where you are going, you’ll end up someplace else.” (Yogi Berra)■ David R. Horos is Director of the Structural Engineering Studio at SOM and also a member of the NCSEA Board of Directors.

building BLOCKS Mortar Compressive Strength By Michael Reynolds, Fernando S. Fonseca, Ph.D., S.E., Theodore Moffett

ortar is specified by proportions or by properties. The proportion method is simply a mortar recipe or certain volumes of cementitious materials and aggregate combined with water that gives a workable mix. Experience shows that if a specified recipe is followed, mortar with certain performance characteristics is consistently obtained. Sampling, testing, or measurement of properties in the laboratory or in the field is not required of a proportion-specified mortar. The property method of specifying mortar allows for construction flexibility but requires the mortar to have minimum average values of certain mechanical properties, including compressive strength. The values of the mortarâ&#x20AC;&#x2122;s mechanical properties, to be compared with the minimum specified values, are determined through laboratory testing according to the requirement prescribed in ASTM C270, Standard Specification for Mortar for Unit Masonry. Once the minimum average values of the mechanical properties are obtained, the quantities of cementitious materials and aggregates used in the preparation of the laboratory mortar are converted to volumetric proportions for making the mortar at the construction site.

Compressive Strength A property-specified mortar needs first to be developed in the laboratory, through a trial-and-error procedure, to determine a mix that meets the property specification of ASTM C270. Trial mixes must be made from the materials to be used at the construction site as specified in the project specifications and be prepared according to the strict specifications outlined in ASTM C270. One of these strict specifications is that water is added to obtain a flow of only 110 Âą 5%. The amount of water to obtain such a flow is significantly smaller than that used in the preparation of the mortar at the construction site. Before construction begins, the mortar mix must go through preconstruction testing evaluation. For preconstruction testing, the mortar is mixed using the volumetric quantities of the materials to be used in construction and must have a consistency similar to that of the field mortar. To achieve such a field consistency, the amount of water added is significantly greater than that used during the laboratory trial-and-error procedure to develop a suitable mortar mix. During the preconstruction evaluation, the mortar is tested to establish baseline values for comparative evaluation of the field mortar. The values obtained during the mortar preconstruction evaluation shall not be compared to the values obtained during the development of the mix because, most importantly, during the mix development, the mortar is mixed to a drier consistency. During construction evaluation, mortar is tested to obtain values for comparison to the baseline values established during the preconstruction evaluation and to determine batch-to-batch mortar uniformity. A property-specified mortar typically has three different values of average compressive strengths: one obtained during the trial-and-error development of the mix according to ASTM C270, one obtained during preconstruction evaluation, and one obtained during construction evaluation. The values obtained during preconstruction and construction evaluations are expected to be similar to each other

Figure 1. Cube vs. cylinder compressive strength.

but significantly lower than that obtained during the trial-and-error mix development. Compressive strength testing of mortar specimens, such as that used during the trial-and-error development of the mix and preconstruction and construction evaluations, establishes one of the characteristics of hardened mortar. Field mortar compressive strength test values are not representative of the actual compressive strength of mortar in the masonry wall and are not appropriate for use in predicting the compressive strength that would be attained by the mortar in the masonry. The measured compressive strength of a molded mortar specimen is lower than that of the same mortar in the masonry, primarily due to differences in mortar water content and specimen shape. Mortar compressive strength is influenced by mortar water content at the time of set. Because molded mortar specimens are not in contact with absorptive masonry units and are not subjected to other mechanisms of water loss, they have a higher water content than mortar in the masonry. Higher water content results in lower compressive strength. Specimen size and shape also affect compressive M AY 2 019

Figure 2. Double punch test results.

strength. Cylinders and cubes exhibit different strengths even when made from the same mortar mix, and the use of either specimen configurations yields lower strengths than what would be attained if a specimen having the same size and configuration of a typical mortar joint could be reliably tested. In addition, the mortar in a masonry joint is in a state of stress different from that of the cylinder or cube specimen tested for their unconfined compressive strength.

Previous Research As described above, the measured compressive strength of a molded mortar specimen is lower than the strength of the same mortar in the masonry. Research has been conducted to try to determine the compressive strength of in-situ mortar. In most of the cases, however, research was done to determine the compressive strength of the mortar in existing historical structures, which typically were constructed with weak mortars with very low compressive strength. To the knowledge of the authors, no attempt has been made to determine a correlation between the compressive strengths of a laboratory mortar and an in-situ mortar because of the difficulties associated with obtaining undisturbed specimens from masonry and the lack of a standardized procedure for testing such specimens.

A Pilot Research Program The objective of the research presented herein was to determine a correlation between the compressive strengths of mortar made from the same mix but using different specimen configurations. Several batches of mortars with different water content were mixed, and molded specimens of different configurations were made for compressive strength testing.

Materials Both Type N and Type S mortar were used in this research. Preblended mortar mix was used to make all mortar to mitigate ingredient variability. Water has an integral role in the compressive strength of mortar and is the sole determinant of fluidity. ASTM C1437, Standard Test Method for Flow of Hydraulic Cement Mortar, establishes a mortar flow test as the means of measuring the amount of water present in mortar paste. However, flow is seldom paired to a specific water content. In the field, masons add water until a desired workable consistency is achieved. Different preferences of mortar fluidity may even exist 8 STRUCTURE magazine

among different masons. Variable water contents were therefore used in this research to determine the degree to which the compressive strength of the mortar was affected.

Mixing Procedures The mortar utilized was prepared using the procedures listed in ASTM C305, Standard Practice for Mechanical Mixing of Hydraulic Cement Pastes and Mortars of Plastic Consistency. This standard specifies the apparatus to be used for mixing the mortar, as well as the temperature and humidity, and provides a step-by-step procedure. The introduction of the material into the mixing bowl, however, was modified slightly to accommodate the use of bagged mortar mix instead of raw materials. After mixing the components of the mortar for the specified amount of time, a small mortar sample was used to perform a mortar flow test in accordance with ASTM C1437.

Specimen Shapes and Sizes Standard 2-inch mortar cubes and 2- × 4-inch cylinder specimens were used for compressive strength testing. According to ASTM C780, Standard Test Method for Preconstruction and Construction Evaluation of Mortars for Plain and Reinforced Unit Masonry, when the compressive strengths from cube and cylinder test specimens from the same mix are compared, the cylinder compressive strength is approximately 85% of the cube compressive strength. The first phase of testing was organized to verify the compressive strength disparity between cube and cylinder specimens. In addition, cured cubes were cut to thicknesses of approximately ¼, 3⁄8, ½, 5⁄8, and 7⁄8 inch. These mortar slices were also used for compressive strength testing. The thicknesses used in this research were selected to provide a wider range, even though bed mortar joint thickness is typically specified as 3⁄8 inch with an allowable tolerance of plus or minus 1⁄8 inch.

Compressive Strength of Cubes vs. Cylinders Mortars with six water content variations were made and a minimum of seven specimens were cast from each mortar batch to compare the compressive strength of cubes and cylinders. The compressive strength of the specimens was obtained according to the requirement and methodology outlined in ASTM C109, Standard Test Methods for Compressive Strength of Hydraulic Cement Mortars. The results of the compressive strength testing of the cubes and cylinders are presented in Figure 1 (page 7).

Table of compressive strengths and corresponding compressive strength increase.

Flow (in)

Compressive Strength (psi) Type N Mortar Cube

⁄8-inch-Thick Specimen

Strength Increase (%)

Flow (in)

Compressive Strength (psi) Type S Mortar Cube

⁄8-inch-Thick Specimen

Strength Increase (%)

5.1

3541

4731

4.8

3073

7481

143

5.8

2111

4316

104

6.3

2056

5539

169

6.6

1419

4337

206

7.5

1794

4310

141

7.1

1304

3408

161

The results show small discrepancies as the expected compressive strength of the Type N mortar with 5.6-inch flow appears to be slightly lower, the compressive strength of the Type S mortar with 5-inch flow appears to be slightly higher, and the cube compressive strength of the Type S mortar with 5-inch flow appears to be slightly higher. In general, the results indicate that as the flow increases, attributable to water content increases, the compressive strength decreases. Average test results indicate that the cylinder compressive strength is approximately 73% and 65% of the cube compressive strength for Type S and Type N mortar, respectively. The smaller compressive strength of the cylinders was expected due to their higher slenderness ratio and the probability of a greater number of flaws and failure planes due to their greater size. Although the ratios are slightly smaller than that given in ASTM C780, the values are similar to that obtained by other researchers (Elwell and Fu 1995, Parsekian et al. 2014).

Compressive Strength of Thin Mortar Specimens There is no ASTM standard to determine the compressive strength of mortar specimens extracted from a masonry assembly. The Double Punch Test (DPT), however, has been used to determine the compressive strength of thin mortar specimens. The DPT determines the compressive strength of thin mortar specimens by means of compressing the center area of the specimen with steel rods. The DPT allows for some simulation of mortar joint confinement. The DPT involves the use of two steel rods tapered at the ends to create a circular loading surface with a ¾-inch diameter. The rods or punches compress both sides of a layer of mortar. Each type of mortar used three variations of water content, and two batches were made for each water content. In most cases, the two batches with the same water content yielded nearly identical mortar flows, and they were simply combined. However, in one instance, despite careful measurements, a batch of the Type N mortar did not produce similar flows, so they were kept separate. Several 2-inch mortar cubes were cast: some tested according to ASTM C109 and some sliced to thicknesses of approximately ¼, 3⁄8, ½, 5⁄8, and 7⁄8 inch for double punch testing. Results of the Double Punch tests are shown in Figure 2. The results clearly show that the thickness of the specimen affects the compressive strength of the mortar and, for the results presented herein, the compressive strength increased with decreased thickness. There is a small increase in compressive strength from the 5⁄8-inch to the 7⁄8-inch specimens since the 7⁄8-inch specimens are thicker than the diameter of the puncher. Another general observation is that compressive strength increases with the decrease of mortar flow, or decreased water content. The small discrepancies observed for Type N are due to normal variations of mortar testing (Jessop and Langan 1979). The Table shows the compressive strengths of the cubes that were tested for comparisons to the DPT results. Also presented are the approximate compressive strengths of a 3⁄8-inch-thick specimen for

each mortar flow; these values were obtained from the interpolation of the values presented in Figure 2. The Table also shows the percentage increase in compressive strengths for cube mortar specimens compared to a 3⁄8-inch specimen. For all cases, except for Type N mortar with a 5.1-inch flow, the compressive strength more than doubled when comparing cube strength to the typical mortar joint 3⁄8-inch-thick specimen strength. These results have significant implications related to the compressive strength of mortar in a masonry assembly. During construction evaluation, the mortar is tested and a compressive strength value is determined. The obtained value should, however, not be used to make any judgment of the mortar compressive strength in the masonry assembly. If, however, the mortar compressive strength in the masonry assembly is erroneously compared to that of the mortar tested during construction evaluation, the research results presented herein confirm that the compressive strength of the standard mortar cube will be significantly lower than the compressive strength of the in-situ mortar. The reasons are (a) the cubes are thicker yielding lower compressive strengths; (b) the cubes are cured in non-absorbent molds having higher water content and therefore lower compressive strength; and (c) the cubes are tested under unconfined compression which results in lower compressive strength.

Conclusions The following conclusions are made from the research presented: 1) Water content affects the compressive strength of mortar. 2) Specimen shape influences the compressive strength of mortar. 3) Specimen thickness influences the compressive strength of mortar. The results presented show that a 3⁄8-inch in-situ mortar joint will have significantly greater compressive strength over a cube specimen made of the same mortar and tested according to prescribed ASTM standards.■ The online version of this article contains references. Please visit www.STRUCTUREmag.org. Michael Reynolds is a Graduate Student at Brigham Young University, Department of Civil and Environmental Engineering. He participated in the mortar research project. (michael.reynolds457@gmail.com) Fernando S. Fonseca is a Professor at Brigham Young University, Department of Civil and Environmental Engineering. Dr. Fonseca supervised the mortar research project. (fonseca@byu.edu) Theodore Moffett is a Graduate Student at Brigham Young University, Department of Civil and Environmental Engineering. He participated in the mortar research project. (tedadora@gmail.com)

M AY 2 019

structural FORENSICS Reinforced Masonry Construction Nondestructive Evaluation Methods By Michael Schuller, P.E., FTMS, FAPTI

einforced masonry is used throughout the United States as a cost-effective and desirable building form for commercial, residential, institutional, and industrial

construction. Reinforced masonry is a form of composite construction where the masonry units resist compressive stress and internal reinforcement resists tensile stress developing primarily from flexure and shear actions. Vertical and horizontal reinforcement is placed in hollow cells of concrete or clay masonry units (Figure 1), or within internal spaces of multiwythe masonry wall systems. The reinforced masonry system relies on cementitious grout, encapsulating reinforcement for bond, to transfer stresses as a composite system. Masonry walls may be fully grouted with all internal spaces filled. In many parts of the U.S., it is more common to have partially-grouted construction with grout placed only at reinforced cells. Nondestructive evaluation (NDE) methods are based on the concept of interpreting how different forms of energy interact with the material being evaluated. NDE techniques use energy from many parts of the electromagnetic spectrum to evaluate masonry materials, including visible light, x-ray radiation, infrared emissions, and microwaves. Stress wave energy is also used for some nondestructive methods, introduced into masonry as a mechanical hammer tap or an energy pulse from an ultrasonic transducer. Energy is reflected, absorbed, or otherwise altered as it passes into, through, or out of a masonry wall, and interpreting the material’s effect on that energy gives an indication of masonry properties, geometry, and condition. Reinforced masonry construction is evaluated for several reasons. • Determining construction geometry, wall thickness, and thickness of individual wythes • Locating internal metals including horizontal and vertical reinforcement, anchors, pipes, and conduit • Identifying solid-grouted areas and voids • Determining grouted areas for locating post-installed anchors • Evaluating distress such as cracks or spalls Evaluation information is used for structural analysis, to guide repairs, and to help understand the causes of distress.

construction. Methods range from localized measurements to global techniques. Some approaches are non-contact, but most require close-up access to the wall surface for rolling antennae or coupling small transducers to the masonry.

Sounding Sounding methods introduce sonic stress waves by tapping with a hammer and listening to the sound generated (Figure 2). The method is effective for locating near-surface spalls and hollow areas and, if the correct sounding hammer is used, grouted masonry cells. Sounding over voids gives off a dull, low-frequency sound, whereas a higherpitched ringing is heard at solid areas. Different sized hammers are used depending on the substrate hardness and density, and the depth of the expected void space. For concrete masonry construction, a mason’s hammer, ball-peen hammer, or ball bearing welded to a metal rod work well for locating grouted and hollow cells (Figure 2).

Diagnostic Methods In its simplest form, existing construction can be evaluated by opening destructive probes to visually examine internal conditions. Fiber optic borescopes and videoscopes, inserted into small-diameter holes drilled into mortar joints, provide a less destructive approach for visually observing internal wall conditions. Nondestructive methods are attractive because they do not disfigure or otherwise harm masonry 10 STRUCTURE magazine

Figure 1. Reinforced concrete masonry construction.

Figure 2. Sounding hammer used to locate hollow and grouted cells in concrete masonry construction.

X-Ray Imaging For decades, x-ray imaging was the nondestructive method of choice for evaluating internal conditions of masonry and other construction. Two-dimensional x-ray images provide a snapshot of internal conditions, showing reinforcement, unit cross webs, grout, and internal voids. Highpower x-ray sources required to penetrate massive masonry wall sections are hazardous to humans, and the method has mostly fallen out of favor in recent years for other, safer, methods.

Ultrasonic Pulse Velocity The speed at which high-frequency ultrasonic stress waves travel through walls provides a direct

Figure 3. Ultrasonic waves travel through grouted cells and around hollow cells, altering the apparent wave velocity (left). With the impact-echo method (right) waves reflect off the back wall face at solid-grouted areas and reflect off the face shell at empty cells.

indication of material density and dynamic modulus, and may be correlated with compressive strength. Waves travelling around internal voids and cracks give an apparent change to straight-line velocity, thereby indicating internal anomalies (Figure 3). The approach for locating internal voids or solid-grouted cells involves placing ultrasonic transmitters and receivers on opposite wall faces, coupled to the wall with low impedance gel or rubber pads. Greater measured velocities indicate solid, high-density material, whereas low velocities are recorded at areas with internal voids, cracks, or delaminations. Pulse velocity techniques provide a local measure and require access to both wall faces to acquire a series of point-bypoint velocity measurements.

Ultrasonic Imaging Imaging systems developed for use with concrete construction are also used to identify solid grouted construction (Figure 4), internal cracks, voids, spalls, and delaminations in masonry construction. The method uses an ultrasonic array system with an external processor to develop a 2-dimensional representation of internal conditions based on arrival times of reflected pulses. The system is automated and provides for assessment, in a matter of seconds, of areas approximately 4 inches by 8 inches.

Impact-Echo Low-frequency stress waves, generated with an impactor, travel into masonry and are reflected at internal discontinuities (Figure 3). Knowing the characteristic stress wave velocity, the depth to a discontinuity is calculated based on the time and frequency of reflected waveforms. The method is useful for locating voids in grouted masonry construction and member thickness. Originally developed for use with concrete construction, equipment can be used for masonry evaluation, but the interpretation is complicated by stress wave reflections off nearby mortar joints.

Figure 4. Ultrasonic imaging equipment used here to determine solidity of a reinforced clay masonry column.

for use with concrete, and most devices have a maximum detection depth of 4 to 6 inches for common reinforcement sizes.

Surface Penetrating Radar More commonly known as â&#x20AC;&#x153;ground penetrating radarâ&#x20AC;? for its use with archeological investigations, surface penetrating radar used for masonry NDE uses an antenna mounted in a small, hand-held cart that is rolled over the wall surface (Figure 6). Electromagnetic waves in the microwave frequency range are generated thousands of times each second; these waves propagate into the wall and are reflected at interfaces between materials with varying electrical properties. Waveforms are displayed on the processor screen for analysis and interpretation. The method is highly sensitive to internal metals and voids and is commonly used to map reinforcement, wall thickness, grouted cells, void spaces, and separations within masonry walls. Lower frequency antennae provide greater penetration depth to locate reinforcement at 16 inches or greater; high-frequency antennae provide better resolution of internal conditions. Microwave energy is absorbed (attenuated) by internal moisture and salts, limiting the usefulness of the method in these conditions.

Infrared Thermography Infrared images are acquired by special cameras that measure heat energy emitted from wall surfaces in the infrared range. The method is a noncontact, global approach permitting rapid evaluation of large regions. In a state of heat flux, differences in surface temperature represent materials with different emittance values, density, heat capacity, and/or thermal

Pachometer A pachometer, sometimes called a cover meter or metal detector, generates an electromagnetic field with a hand-held search head (Figure 5). Ferrous and non-ferrous conductive materials in the vicinity interact with the electromagnetic field to indicate the location, depth, and size of the embedded metal. These devices are most commonly used to locate reinforcement in concrete construction and are also used to locate structural reinforcement, joint reinforcement, and veneer anchors in masonry walls. Equipment sensitivity is optimized

Figure 5. Locating vertical and horizontal masonry reinforcement with a pachometer.

Figure 6. Surface-penetrating radar equipment in use to locate reinforcement and grout in clay masonry construction.

M AY 2 019

Figure 7. Concrete masonry construction: reinforcement located with pachometer scanning is shown as dashed lines in the left image; infrared image (right) shows internal grouted cells as cooler zones.

conductivities. Thus, wall surface temperature is affected by internal voids, spalls and cracks, and varying material density. Heat energy must be traveling into or out of wall surfaces for successful imaging. Good images are generated when internal building temperature is regulated to provide a minimum temperature differential of 20 to 30ºF across the wall section. Alternatively, active heating using solar radiation or a bank of infrared lights is used to provide a state of heat flux. The infrared image in Figure 7 was taken after 3 hours of direct sunlight. Hollow areas heat rapidly and show as high-temperature zones; grouted cells have greater thermal mass and show as cooler areas. Infrared images are also used to detect wall moisture; damp walls transmit heat energy at a greater rate than dry walls, and moisture evaporation at the wall face tends to have a localized cooling effect.

Verification and Validation Interpreting NDE data requires experience and professional judgment, and some level of verification and proof testing is necessary to validate results. Multiple techniques are often used in the same area as a form of verification, and conditions requiring expensive repairs should always be confirmed. For example, voids detected using radar scans could be verified using ultrasonic or infrared imaging and evaluated visually using a videoscope inserted into the void space.■ Michael Schuller is President of Atkinson-Noland & Associates, a consulting engineering firm specializing in masonry materials and structures. (mschuller@ana-usa.com)

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structural PRACTICES Post-Installed Adhesive Anchors in Masonry Practical Installation Considerations By Mark Ziegler, P.E.

he use of adhesive anchors is a common method of forming attachments in both existing concrete and masonry base materials. They are widely used for structural connections, including steel reinforcement embedments, mounting non-structural components, equipment anchorage, and other miscellaneous hardware. The popularity of adhesive anchors in construction practice necessitates an opportunity to discuss, encourage, and promote good installation practice when these products are utilized. There are important aspects that can directly influence proper installation practice of adhesive anchor systems in masonry and minimize potential issues that may arise surrounding their use and service in the field. Key considerations include: • Masonry base material type and installation location • Anchor system selection and preparation • Hole drilling and drilled hole cleaning • Adhesive system, installation, and curing • Special inspections and proof loading on site

Base Materials and Installation Adhesive anchors rely on the bond formed to the inside of a drilled hole and the transfer of loads locally into the masonry base material. Understanding the type, condition, and capability of masonry relative to the anchorage is significant. Installers and users should have a working knowledge of the material prior to any physical anchorage. Site testing may be appropriate where the wall strength at planned anchorage locations is unknown. Masonry block and brick are found in a variety of sizes and shapes (depending upon the age and location of a building) and both hollow and solid styles. Mortar strength, consistency, and conditions can vary significantly in existing structures, especially in older walls exposed to the elements. The combination of masonry components, including grout for solid filled Concrete Masonry Unit (CMU) members, is critical to the behavior of the composite member and ultimately has a significant influence on the anchorage strength. Installation of adhesive anchors, common in solid block or brick, may be in the face, end, or top of the wall. In hollow base materials, anchors may be installed through the face of material into the cavity section provided the adhesive is suitable for use with screen tubes. The screen tubes hold the adhesive in place before installation of the steel anchor element (i.e., threaded rod or rebar). Anchoring locations in the mortar joint are also possible; however, additional care should be taken depending on the masonry wall type. Mortar joints of hollow CMU walls and most vertical joints of CMU walls are only required to be mortared the depth of the face shell. Consequently, these locations should generally not be used for anchoring unless the product manufacturer has specific data and installation instructions for these locations. Similarly, joint locations in the top of masonry walls can be problematic and should be approached with caution if considered for anchorage.

Injecting adhesive into drilled holes in masonry to make an anchor connection.

Anchor System Selection and Preparation For any adhesive anchoring application, product selection that is suitable for the masonry base material type and environment is critical. For example, some products are not suitable for both solid and hollow masonry applications because they may not work effectively in conjunction with screen tubes in locations with open cells, cavities, or significant voids. Select a product with a current product evaluation report from a recognized approval body (e.g., the International Code Council’s Evaluation Service, ICC-ES) for the masonry base material whenever possible. This provides an additional level of product testing and qualification, ongoing third-party quality control inspections, and a requirement for the manufacturer to provide installation instructions with each adhesive unit package. Consider the temperature impact of base material and adhesive during installation. Epoxy based formulas typically have a minimum application temperature of 40°F to 50°F while ‘acrylic’ or hybrid formulas can be used in colder weather with lower temperature limits. Masonry base materials that are too cold for the adhesive will prevent the adhesive anchors from curing properly or not curing at all. Practical limits of the dispensing and mixing of the adhesive should be clearly understood at both low and high temperatures. Adhesive products that are too cold or not conditioned to a minimum temperature will be difficult or impossible to dispense/mix. Very warm environments can cause adhesive products to have short working times and cause some products to become runny unless they are specifically formulated to have good standing behavior at high temperatures. Most current adhesive anchor systems have a maximum shelf life between 9 months and 2 years, depending on manufacturer and chemistry. Expired product should never be used unless the manufacturer is willing to provide proof or certify the material is still acceptable for use. In any case, the product manufacturer should be consulted concerning the capabilities and limitations of the adhesive anchor product if the available information is not clear. continued on next page M AY 2 019

Hole Drilling and Cleaning

Installation and Curing

The drilling method can have an influence The selected manufacturer’s adhesive anchor when drilling holes in masonry materisystem is essential to the success of the instalals. Installers most commonly will use a lation. System components typically include rotary hammer drill (i.e., percussion drillthe following: ing) to create holes in the base material. • The adhesive: multiple use cartridges For solid base materials, this is standard or foil packs; single-use-capsules are practice and does not introduce any issues. less common but available However, in hollow base materials or very • Mixing nozzles/Dispensing tools weak substrates, rotary-only drilling may (for injection type systems) be considered or required to limit any • Hole cleaning equipment potential damage to the masonry from • Injection and/or placement accessories percussion drilling (e.g., unreinforced Today's most popular adhesive anchor sysmasonry [URM] walls undergoing seistems are injection systems. These systems mic retrofits). Drilling that causes excessive allow for flexibility in anchor sizes, embedspalling on the backside of hollow cavities ments, and allow for multiple uses. can reduce the effectiveness of the adheA supplied mixing nozzle for the adhesive sive anchor connection due to the reduced must be used and attached to the cartridge or material thickness. foil pack before use. These nozzles proportion The masonry drill bit size must meet the adhesive and provide a simple delivery ANSI requirements and follow the recmethod into the drilled holes. Although Bonding rebars into grouted concrete masonry walls. ommendations and requirements of the mixing nozzles for these injection systems manufacturer’s published installation can look very similar, they should only be instructions (MPII). Adhesive anchor used with the recommended system (e.g., do diameters generally range from 3⁄8 inch to ¾ inch in masonry. not use Brand X mixing nozzle with Brand Y adhesive). The installer Corresponding drill bit diameters can range from 7⁄16 inch to 1 inch should make sure mixing elements are inside the nozzle before using. depending on the product and whether or not adhesive anchors are If the mixed adhesive hardens in the mixing nozzle (when the workbeing used in conjunction with screen tubes (which require larger ing time of the product is exceeded), a new mixing nozzle will be holes to accommodate the screens in hollow materials). Typical necessary. A new mixing nozzle should be used with every cartridge embedments into masonry wall faces range from approximately 3 change. Mixing nozzles should not be modified unless directed by to 6½ inches in solid materials depending on the width of the wall, the product manufacturer. although deeper embedments are possible for top of wall anchorages. Before inserting a threaded rod or rebar into the drilled hole, the Embedments into hollow materials can vary greatly depending on embedment depth should be marked on the anchor. This practice the material, geometry, and availability of screen tube lengths in helps the installer verify that the steel element was installed to the the selected diameter. necessary embedment during and following installation. The threaded Prior to adhesive installation, it is critical that the holes be clean rod or rebar must be clean, straight, and free of mill scale, rust, oil, and free of dust, debris, ice, grease, oil, or other foreign material. and other coatings (other than zinc) that may impair the bond with Traditionally, holes are cleaned following drilling using a method of the adhesive. blowing or vacuuming the holes, then using an appropriately sized Cartridges or foil packs should be used with and properly loaded brush to scour the sides of the hole, and then blowing or vacuuming into the recommended dispensing tools. Adhesives must be properly the holes again (a.k.a., blow, brush, blow). More recently, hollow drill mixed to cure and achieve the manufacturer’s published properties. bit systems have been introduced that allow installers to automati- For new cartridges and nozzles (and prior to dispensing adhesive cally clean the holes during the drilling process with no further hole into the drilled hole), separately dispense some adhesive through the cleaning required. However, these systems should be monitored for mixing nozzle and verify that the adhesive is a consistent mixed color effectiveness, especially in conditions where the masonry drilling (reference published product instructions for specifics). locations are wet or saturated because drill bits can clog during use During the adhesive injection, cleaned holes are typically filled in these conditions. approximately one-half to two-thirds full of the mixed adhesive

Adhesive anchor system (dispensing tool, cartridge adhesive and mixing nozzle components shown).

14 STRUCTURE magazine

for installations in solid masonry materials. Start the injection from the bottom or back of the anchor hole and slowly withdraw the mixing nozzle as the hole fills to avoid creating air pockets or voids. Screen tubes are completely filled in hollow materials. Use a nozzle extension with the mixing nozzle if the bottom or back of the anchor hole/screen tube is not reached with the mixing nozzle only. Following this, the clean threaded rod or reinforcing bar is pushed into the anchor hole, while turning slightly to ensure positive distribution of the adhesive, until reaching the embedment depth. Completely fill the annular gap at the masonry surface following the insertion of the steel element. Remove any excess adhesive at the masonry surface and wipe clean any exposed threads that have been fouled with adhesive. The excess adhesive on the masonry surface or threads may hamper installation after the adhesive hardens. Adhesives must be allowed to cure for the full specified curing time prior to applying any load (reference published curing times for the selected product). Anchors should not be disturbed, torqued, or loaded until the adhesive is fully cured. After full curing of the adhesive anchor, a fixture or attachment can be made to the anchor. For torqued anchors, the maximum torque allowed for the diameter and embedment into the masonry substrate must not be exceeded. This can vary considerably depending on the product and whether the masonry application is solid or hollow. Applying excess torque can damage or cause bond failure of the adhesive to the substrate.

Screen tubes for hollow masonry base materials (e.g. open cells, cavities).

and size, and general requirements of acceptance. Proof loading requirements should be determined by the design professional responsible for the anchorage and may vary depending upon the specifics of location and connection detail. Also, if proof loading is used, the possible consequences should be considered for cases where an anchor fails during the proof load test, especially since a large percentage of anchors are installed horizontally into masonry walls.

Conclusion

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Installation issues with adhesive anchor systems in masonry can be avoided with sufficient knowledge, proper training, and good practice. Understanding and following the manufacturer’s published installation Special Inspections and Proof Loading instructions, as well as using recommended equipment and accessories Special inspections have been used for years to help ensure a basic for the application, is critical. Special inspections are an effective quallevel of knowledge and competence by the actual installation person- ity control tool and should be strongly considered, even if not required. nel. Section 1704 of the International Realizing the practical application and Building Code (IBC) requires periodic limitations of adhesive anchor systems special inspections for adhesive anchors can improve the user experience, make in masonry building construction. The the installation process more efficient, special inspector is expected to be on the and improve the long-term job site initially during anchor instalperformance of the conneclation and must verify that the anchor Threaded rod and reinforcing bars (typical steel anchor elements). tion during service.■ installation complies with the manufacturer’s published installation instructions and code evaluation report, Mark Ziegler is Technical Director for DEWALT anchoring and fastening as applicable, by the local authority having jurisdiction (AHJ). systems. He has served as a Past President of the Concrete and Masonry Special inspectors need to verify and document important inforAnchor Manufacturer’s Association and is actively involved with several mation such as anchor type, size and dimension, masonry type working groups which address connections and fastening systems in and strength, drill bit size, anchor spacing and edge distances, construction. (mark.ziegler@sbdinc.com) embedment, and adherence to the manufacturer’s published installation instructions. For any significant change in site conditions, installation personnel, adhesive anchor system, etc., or for ongoing installations over an extended period of time, the special inspector should make supplemental periodic inspecDemos at www.struware.com tions to reconfirm the correct handling and installation of the Wind, Seismic, Snow, etc. Struware’s Code Search program calculates these and selected product. other loadings for all codes based on the IBC or ASCE7 in just minutes (see online Proof loading can also be considered for use as a supplemenvideo). Also calculates wind loads on rooftop equipment, signs, walls, chimneys, tal tool to help verify proper adhesive anchor installations in trussed towers, tanks and more. ($250.00). masonry. This is especially true if the existing base material is CMU or Tilt-up Concrete Walls Analyze solid walls for out of plane loading and questionable in materials or strength, or if it varies significantly panel legs next to or between openings by automatically calculating loads to the wall depending on location. Proof loading involves the application leg from vertical and horizontal loads at the opening. ($75.00 ea) of a predetermined amount of tension to an installed anchor Floor Vibration Program to analyze floors with steel beams and/or steel joist. without causing any damage to it or the surrounding base mateCompare up to 4 systems side by side ($75.00). rial. The essential components of a proof load requirement are Concrete beam/slab Program to provide bending, shear and/or torsional reinforcing. Quick and easy to use ($45.00). size and type of anchors to be tested, the percentage of each type and size to be tested, proof loads to be applied for each type

M AY 2 019

structural PERFORMANCE

Resiliency of Reinforced Structural Clay Unit Masonry Construction By Steven G. Judd, S.E.

t is common to overlook Structural Clay Units (SCU) as a viable, and often more desirable, solution during discussions

of structural masonry. It seems that the default solution to most structural masonry design challenges is Concrete Masonry Units (CMU). Unfortunately, in many instances, this is due to lack of information. There are some areas of the U.S. and Canada, and some individual practitioners, who are unfamiliar with SCU as a viable structural solution. If properly evaluated, practitioners may find that SCU is the best structural masonry solution to satisfy the design criteria/demand.

History Reinforced clay masonry use dates to the 1800s where it was typically used to hold large ornate Terra Cotta pieces onto masonry buildings. In 1813, reinforcement was proposed by Mark Isambard Brunel to reinforce a masonry chimney which was under construction in England at the time. Its first significant use was the Brunel-designed Thames Tunnel which began in 1825 – a successful construction of a 30-inch-thick (762 mm), 50-foot-diameter (15.24 m) tube buried 70 feet deep (21 m) under the famous river that bisects London, England. Another early use came in 1875 with the construction of the seven-story Palace Hotel in San Francisco, California. The hotel was comprised of three-foot-thick solid brick walls with iron bands spaced every few feet, forming a “basket” that completely encircled the facility. The hotel is one of the very few large buildings that survived the 7.9 (Richter) magnitude (est.) 1906 San Francisco earthquake. It was not until the 1920s and 1930s that serious research was performed (initially in India, and later in the United States) on the properties of loadbearing, grouted, and reinforced clay brick masonry and engineering procedures were developed to create thinner masonry elements. The first reinforced clay brick systems used reinforced cavity construction; two wythes separated by a grouted and reinforced cavity space (Figure 1). The international use of reinforced masonry in the early 20th century was initially driven by the lack of suitable (ductile) structural steel and the cost of wood (for forming reinforced concrete). Reinforced masonry became the standard material for construction of public and important private buildings, plus bridges, retaining walls, storage bins, and chimneys (back to the original proposed use). In 1952, the Structural Clay Products Institute (SCPI) developed the “Structural Clay Research” (SCR) brick. This brick was intended to be used as a loadbearing wall replacement to wood framing. This was unreinforced clay masonry, common before the introduction 16 STRUCTURE magazine

Figure 1. Reinforced cavity wall.

of seismic codes in the 1970s. In response to many large west coast seismic events up through the 1970s, building codes in California and the western United States changed to mandate that all loadbearing masonry buildings be reinforced and tied to the foundation and the roof. The concept of a two-wythe reinforced cavity wall coupled with SCR brick led to the development of hollow reinforceable brick, which is the principal reinforced SCU used today: two brick faces separated by reinforced grout cells – a scaled-down version of the grouted cavity wall (Figure 2).

Resiliency To understand the resiliency provided by reinforced SCU masonry, one must understand the manufacturing process of the clay units. Brick is a natural product principally comprised of clay, shale, and sand in various proportions. Other minerals (barium, chromate, manganese) are added to modify/broaden the color palette and which also, consequently, modify the strength. Water is added to the pulverized dry clay mix to create a stiff plastic consistency, similar to modeling clay, so that the clay mix can be pushed through dies or pressed into molds. After the clay is extruded through the die and trimmed to size, the column of brick is cut to the pre-fired size. In some facilities, the clay is dried in a separate process to help reduce stress cracking from the firing process. Whether pre-dried or not, the clay units are then fired in kilns at temperatures around 2100°F (1149° C), near the vitrification temperature of clay, creating a very hard, strong, durable, mostly inert product. As fired, the net unit compressive strength ranges from 9,000 psi (62 MPa) upwards of 18,000 psi (124 MPa), depending on the clay mix, the unit profile, and the firing process. As one can see, the clay units are many times stronger than CMU units that are generally around 2,500 psi (17.2 MPa) to 3,500 psi (24.1 MPa), perhaps up to 6000 psi (41.4 MPa) for high strength CMU concrete mixes.

The high strength of the clay units used in grouted and reinforced walls produce a very high-strength, resilient wall system. This SCU wall system can accomplish many goals and accommodate many design challenges, including resistance to fire exposure, extreme wind, winddriven projectiles, ballistic impact, and seismic forces.

Fire Resilience The kiln temperatures used to fire the Figure 2. Structural Clay Unit. brick are higher than the temperature used to fire-test reinforced SCU wall assemblies for fire resistance. The UL-935 rating requires wall assemblies to be preloaded in compression and held at a temperature of 2000° F (1093° C) for four hours, then sprayed with water at 45 psi (2.16 kPa) for 5 minutes. Eight-inch (203 mm) reinforced SCU walls (unreinforced vertical cells filled with grout or insulation) are UL 935 rated for 4-hour fire resistance. Thinner walls, or partially unfilled walls, meet shorter fire duration ratings. Fire-rated walls used for safe rooms, property-line walls, fire-rated demising walls, and building separation walls are ideal uses for reinforced SCU. In the past several years, two different multi-family, multi-story apartment buildings caught fire in Winnipeg, Manitoba. In the first case, the building was a typical multi-level wood framed facility. The fire started in one unit and spread to all the units, displacing around a dozen families. In the second case, the multi-story apartment facility was constructed of SCU and the fire was contained in one unit, displacing only one tenant. Homes and other residential buildings have a distinct advantage in consideration of accidental fires and wildfires. According to an article written by Christopher Williams for THE NEST website, houses with brick or masonry construction are often less expensive to insure than wood-framed houses, due, in part, to their increased capacity to resist fire.

Extreme Wind Resilience

Projectile Resilience Tests have shown that 6-inch (152 mm) and 8-inch (203 mm) solid grouted SCU walls effectively resist penetration of projectiles, unlike typical brick veneer walls. The standard tornado projectile test – a 15-pound (6.8 kg), 10-foot-long (3.0 m) 2x4 (51mm x 102mm) traveling at 100 mph (161 kph) – results in the projectile shattering when striking the face of a reinforced and grouted SCU wall, leaving no discernable damage (Figure 3, page 18). This projectile resistance capacity complies with the prescribed criteria for tornado shelters for community and residential safe rooms as contained in FEMA P-361, Safe Rooms for Tornadoes and Hurricanes. An added benefit is that the high strength, reinforced SCU wall system can more easily develop high capacities for fasteners used to secure window frames, door frames, and louvers. Due to these two factors, tornado shelters, hurricane shelters, and hardened rooms are good uses for reinforced SCU.

Ballistic Impact Resilience The high kiln-firing temperatures of the clay produce materials that come close to becoming an impermeable fused mass, like igneous rock. continued on next page

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Large areas of the United States can have tornado driven winds as high as 250 mph (402 kph). This equates to servicelevel-design wall pressures of around 117 psf (5.6 kPa) for single-story facilities. Reinforced SCU walls can efficiently resist this intensity of direct pressure. As an example: a 6-inch-thick (152 mm), 12-foot-tall (3.6 m) reinforced SCU wall, supporting 1500 plf (2232 kg/m) roof loads at a 1.5-inch (38 mm) eccentricity, can resist the 117 psf (5.6 kPa) direct wind design pressure perpendicular-toface. A similar height CMU wall would have to be 8 inches (204 mm) thick to provide the equivalent axial and bending wall capacity. This example shows that reinforced SCU walls save space and use less grout (due to smaller grout cells), which can save construction cost and increase leasable space. FEMA grants are often used by small communities to fund construction of

storm shelters. FEMA grants will not cover the cost of aesthetic enhancements, like brick veneer, but FEMA will cover the cost of reinforced SCU used as the primary structure. This approach maintains the brick aesthetics with costs covered by the FEMA storm shelter grant (75% FEMA/25% local jurisdiction). SCU walls can solve design challenges in tornado and hurricane-prone areas. Potential SCU uses include essential facilities, hospitals, schools, fire stations, police stations, emergency generator enclosures, hardened spaces, and tornado and hurricane shelters as good uses for reinforced SCU.

M AY 2 019

The Los Angeles Police Department, Devonshire Station, is a reinforced SCU facility that survived the 6.7 (Richter) magnitude 1994 Northridge California Earthquake intact and was reportedly used as an emergency service coordination center immediately after the temblor. The facility is located 3.0 miles (4.8 km) from the epicenter of that event.

Blast Resilience

Figure 3. Shattered projectile after hitting SCU wall.

Self-performed preliminary ballistic testing proves grouted SCU is an effective barrier to ballistic impact. In general, typical handgun munitions only pock the surface of the brick. Rifle munitions can do more damage, but, up to certain large calibers, do not penetrate the wall. This capability to resist ballistic impact can be effective in protecting occupants in schools, libraries, workspaces, and many other at-risk facilities.

Seismic Resilience

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Typical high-strength clay units can produce a very strong and resilient wall for resistance to high in-plane shear loads and high axial loads, at a higher capacity than the same thickness CMU wall systems. Typical design prism strengths for CMU range from 1900 psi to 2500 psi; typical design prism strengths for SCU range from 3500 psi to 4000 psi. This higher prism strength means thinner walls of SCU can be used to generate the capacities/resistance needed as compared to CMU. This capability makes reinforced SCU a good choice for primary lateral force resisting masonry systems – bearing wall and shear wall buildings. In some ways, reinforced SCU can be considered as “left-in-place concrete formwork,” providing high in-plane wall strength with a durable, classic finished surface. Unlike structural clay tile, which is restricted for use in some high seismic areas, structural clay brick can be used in any seismically active region.

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Blast resistant reinforced SCU exterior walls were used for the United States Federal Courthouse in Covington, Kentucky. Reinforced SCU walls produce almost infinite redundant load paths, which is essential for providing the capacity to withstand blast damage without total collapse. Reinforced structural walls tend to arch over openings and redistribute load paths as a natural consequence of their construction. The high strength associated with reinforced SCU allows embedded items (connections) to develop high strength in the wall system, which is essential for blast resistant connection design of the wall to the primary structure. These characteristics make reinforced SCU an excellent choice for facilities that require blast resistance, such as judicial facilities, embassies, emergency response facilities, high-value diplomat residences, and military facilities.

Other Considerations

When compared to reinforced CMU, a reinforced SCU wall can be constructed higher for any given wall thickness and applied load, or can generally be thinner for a given wall height and applied load. Thus, reinforced SCU provides for more efficient space use; less space is devoted to the wall system. Interior 10-inch (254 mm) SCU bearing walls (f´m = 4000 psi [27.58 MPa]) have been designed with heights up to 44 feet [13.4 m] (without bracing or pilasters). A CMU wall (f´m = 2500 psi [17.24 MPa]) would have to be 12 inches [305mm] thick to work with the same amount of reinforcement as that 10-inch [254 mm] SCU wall. Consequently, less interior space may be required for the structural wall using SCU, making it a good choice for large volume spaces such as garages, pools, auditoriums, ballrooms, and water treatment plants. The firing process drives out all latent moisture from the clay, so clay masonry does not shrink after it is fired. Clay masonry will expand over time, to a small Post-Tensioning.org degree, as the clay absorbs ambient atmospheric moisture. Clay masonry wall systems tend to “tighten up,” enhancing moisture impermeability over time. In addition to the resiliency discussed above, grouted SCU provides: good sound transmission control; the benefits of thermal mass (thermal dampening and temperature lag); and a finished brick face without the need for adding brick veneer. Reinforced SCU should be considered a versatile, resilient, and high performing structural wall system to apply to many structural design challenges.■ Steven G. Judd is Technical Director at Interstate Brick/H.C. Muddox. (steven.judd@interstatebrick.com)

18 STRUCTURE magazine

historic STRUCTURES The Brooklyn Bridge Masonry ~1860-2019 By Alice Oviatt-Lawrence

he landmark Gothic-Revival massive granite towers of the Brooklyn Bridge, with their arrays of cable-and-stay structural scheme, developed in the usual way for its era. Commercial East River shipping and ferry operators in the 1860s protested when they foresaw that if the East River Bridge in New York City, proposed by John Roebling (b.1806), was built, it would undercut their highly profitable river businesses. The flourishing river interests organized and put political pressure on the War Department to thwart the proposal. Concurrently, a hard freeze of the East River in 1866-7 shut down all waterway transport, demonstrating the economic advantages of a bridge. In resolving the case in 1869, a Federal ruling stipulated that any future East River bridge constructed could not interfere with surface river traffic, no pier components could extend beyond pier vertical edges, and the deck must be raised to 135 feet above mean high water. The Roebling office, aided by architect William Hildenbrand, made the required minor design changes to proceed with the nearly 6,000- foot-long suspension bridge. The 1597-foot-long center span is flanked by two 930-foot-long side-spans, with the approaches making up the difference in length. Roebling died in mid-1869, leaving design drawings complete for the world’s longest span bridge (completed 1883) with its great tonnages of granite and limestone, and the nation’s first use of nascent galvanized crucible steel cable wire in a bridge (SEAoNY. org\publications V22, N3. 2017). His son, Washington Roebling (b.1837), was appointed later that year as Engineer-in-Chief to build the bridge.

Collingwood Transverse Plan Section 1877.

Cradling: Ammann DWG (left); Author’s photo today as built (right).

Soils, Masonry Tower Foundations The stable sub-foundations are of high bearingquality on solid strata. At the Brooklyn tower, 1860s borings established gneiss at elevation -97 feet, topped by 45 feet of solid-enough strata on which to establish the tower foundation (bottom of the caisson). On the New York side, the concrete-filled caisson rests on hard materials over bedrock encountered at variable elevations of -75 to -90 feet below mean high water. Early post-construction reports noted no discernable settlement over the years, and Othmar Ammann, in a 1945 technical report, noted that the towers at their tops were only 5 ⁄8 inch out of plumb. Caisson technology in the United States advanced from placing airlocks outside the air chamber to placing the airlock inside the air chamber – an idea James B. Eads patented in 1869 for the St. Louis Bridge, after visits to England and France to study foundation construction advancements there. Roebling learned of the new technology, but only in time to apply it to the Manhattan-side caisson construction in 1871. The caisson-foundations, built by Webb & Bell Construction and weighing 7000 tons each,

are 102 feet by about 170 feet surmounted by a 15-foot-thick grillage (Brooklyn) or a 22-foot-thick grillage (New York), comprised of nine courses of 12- by 12-inch yellow-pine timber (48 pounds per cubic foot); all are encased in several-feet-thick, well-compacted Rosendale-cement concrete. These components support the solid masonry tower-base pedestals, measuring about 59 feet by 140 feet by 20 feet high (Brooklyn), and 47 feet high (New York), measured from the water line to the top of the timber grillages. The pressure at the bottom of the foundation is 5½ tons per square foot (t/sf ) (Brooklyn) and 6¾ t/sf (New York). Masonry base (pedestal) pressure on the timber grillage is 9¼ t/sf (Brooklyn) and 10½ t/sf (New York). This pressure is increased 8 percent by the superstructure weight. Concrete is 1: 2: 3 (cement-sand-gravel) (Brooklyn) and 1: 2: 4 for New York.

Towers and Stone Details Above the deck rise the buttressed doublearches. The buttresses are additive elements to the three-shafts-with-pointed-arch tower structure. The towers ascend to a reentrant spandrel, water table, and entablature under the summits of 316 feet (Brooklyn) and 350 feet (New York). The New York tower is slightly larger than the Brooklyn tower. The towers above the floor are rock-face, random-ashlar granite [153 pounds per cubic foot (pcf )], whereas below the water line they are limestone (calcium carbonate) protected M AY 2 019

ranging from 17 feet thick at the grillage to 10½ feet thick at high water.

Engineering Theory and Design Assumptions

Etching of anchorage under construction.

from rainwater dissolving the carbonates. Granite is a textured, granular, igneous, and anisotropic rock. Roebling carefully specified a natural rock face surface on fine-granite set off by a 1½-inch chisel or ax-crafted draftcut perimeters, a light color and no flaws. Thousands of loads were shipped by sea from the quarries after being split by drill holes and wedges, and the corners, ends, and roughaxed beds well squared by pitching chisels. Rosendale cement was applied in all of the ½-inch flush mortar joints. The Roebling office provided templates for each stone. The best quarry and stone-cutting workers were required for the precise squared bed and sides handwork; emerging early machine technology for hammer and chisel tooling was not high quality until c. 1900. The towers at the arch faces, arch intrados, and spandrels are smooth peen-hammered or pecked to contrast with the rusticated surfaces of the adjacent buttresses. The arch surround on each transverse face displays a complex and striking saw-tooth stonework design, set in relief. The pointed arches have a radius of about 46 feet measured from the springing plane, with the extrados and intrados non-concentric. The towers are slightly battered from the water line to the tower top. Tower tops of 53 x 106 feet are 271 feet above mean high water and 159 feet high above the roadway. The keystones, of about 11 tons weight each, are also smooth pointed with three-inch drafts cut to a depth of three inches. The tops of the pointed arches are 117 feet above the roadway. The towers have a factor of safety of 2½; the cable’s safety factor is 6. Current live loads include at least 120,000 vehicles, 4000 pedestrians, and 3000 bicycles per day. Towers weigh about 79,000 tons (Brooklyn) and 97,000 tons (New York) with wall thicknesses 20 STRUCTURE magazine

Theoretical engineering analysis was far from understood in the 19th century. Engineers at the time continued to strongly favor testing by loading, rather than by the emerging elastic limit calculations which were considered by most, if not all, contemporary engineers to be unreliable “complications.” Graduating from Berlin’s Royal Polytechnic School in 1826, John Roebling benefited from the advanced German engineering schools, first established in the early 19th century. While engineering work was largely empirical, he likely studied with or under many of the leading contributors to the pool of knowledge on strength of materials and very early theory of structures, while also knowing of progress made in France’s Ecole Polytechnique, which would have included Louis Marie Henri Navier’s (b.1785) and others’ calculations on the thrust of arches. Arch theory was understood via geometric solutions since c.1700. In Roebling’s era, engineers and mathematicians proved graphically that the pressure line and the resistance line are two different curves. With this background, John Roebling devised several interesting structural innovations:

Ammann DWG underfloor at tower masonry-wire nexus.

Cable Cradling for Arch Equilibrium To attain equilibrium, compressive loads such as statically indeterminate arches must contain the line of thrust within the masonry section. However, the Brooklyn Bridge tower’s arch line of thrust would be 2½ feet outside of the outer shafts except that, as Washington Roebling commented in 1877 of his father’s design: “The main outer cables, when drawn in laterally, modify its position to such an extent as to throw its position six inches inside of that point, a condition of the utmost stability.” John Roebling had conceived of a mechanism to “cradle” the main cables. Additionally, in the days of empirical design, Roebling assumed that cradling the four main 15¾-inch-diameter cables, along with the over-floor and underfloor trusses and the tremendous weight of the cables (3600 tons, 53% of superstructure dead weight), would help to resist lateral forces.

Lateral Force Resistance Mechanism Iron bars are embedded flat across each tower’s transverse face near the top of the tower to reinforce tower resistance to various forces. Also, just below the floor at 119 feet above mean high water, Roebling inserted 2- by

Author’s photo today as built.

10-inch steel or heavy iron bars longitudinally into and through the tower masonry, terminating in eye-bars exterior to each tower near the corner where adjustments to wires in plane with the main and land-span’s underdeck lateral-resistance truss are made.

Cable Ends to Anchorage Attachments The massive anchorages weigh 60,000 tons each and rest on sandy strata which, after construction, settled into a stable state. The limestone blocks, with a bearing capacity of about 625 t/sf, are trimmed in white granite at corner quoins, arch voussoirs, and cornices. John Roebling specified high-quality limestone with a bold rock-face surface and a maximum 3-inch projection, the same as for the towers above the deck. The anchorages, which rise over a four-footdeep timber grillage, were bolted and grouted

Ammann DWG-anchorage mechanism, chains, anchor plate (left); HAER 1982 pix as built (right).

for a tight seal, then filled with the same Rosendale cement-concrete as the towers. From both anchorage bases of about 129 x 119 feet, there is a straight batter of ½-inch per foot rise over about 85 feet elevation to 114 x 117 feet at the top. John Roebling used his 1846 patent for Rows of Anchoring Suspension Chains to Cables, invented for the Cincinnati Bridge over the Ohio River and enlarged for the Brooklyn Bridge. On the interior floor, four cast iron anchor plates, at 23 tons each and well weighted down by 650 cubic yards of granite stone, secure chains of parallel rows of pin-connected wrought iron anchor bars. The bars rise in a curved quadrant to attach to the cable ends at about eight feet under the deck level. Wrought iron was selected, after testing of that era’s early steel exhibited no physical advantages over that of iron.

Construction Rail tracks conveyed bridge components to sites from the waterfront. To build the arches,

stone beds for the saddles, and tower tops, steam-powered hoists raised granite stones weighing nine tons or more, each, by way of lewising each stone. Each stone would have 4½-inch-deep mortises drilled into it, into which the counterpart tenon in the lewis device would fit, to grip the stone for lifting. Three hundred and fifty feet of 1½-inch steel hoisting ropes, powered by steam (sometimes dangerously oscillating from engine cycles), raised the stones for derricks to place into position. The stones of the anchorages, weighing up to six tons each, were hoisted and set by balance derricks; over that weight, derricks were tied to lewis holes and gaps in the completed stonework. The cast iron saddles and saddle plates by themselves weighed 182 tons.

Arch Blocks Arcades of arched construction, with exterior faces of rusticated stonework trimmed with voussoirs of contrasting stone, run longitudinally under the floor of the long approaches landside of both anchorages. Here, John Roebling devised income-producing interior spaces intended for housing, shops, or offices within the arch blocks. Today, mostly vacant, all are under rehabilitation, managed by a collaboration of state and federal agencies, after vault cracking discovered in 2010 affected installation of a remote monitoring system. Fiber-optic sensors tracked structural movement, vibrations, and thermal data, after which a safety program was initiated.

Ongoing Condition and Rehabilitation Arch block interior with vault transverse and longitudinal symmetrical and asymmetrical through-cracks, revealing various forces acting on the load bearing structure.

The original approach-decking used in the superstructure – the nation’s second use of rolled structural steel sections in a bridge superstructure,

according to HAER (Historic American Engineering Record) – was recently replaced with pre-cast, concrete-filled steel grid panels. Some approach under-deck arch block exterior walls are undergoing reinforced concrete infill rehabilitation. Parts of the east-facing wall-element of the original unreinforced load-bearing limestone Brooklyn anchorage, which contained continuous vertical through-cracks, are also being infilled with reinforced concrete to improve structural strength. Similar cracks exist in the south wall of the longitudinal stairwell from the over-floor pedestrian walk to the street below. The use of modern materials and methods to replace original construction in flagship historic structures requires careful scrutiny and consideration of preservation principles. Another modern action is the application of sealant, which is sprayed periodically on the piers and tower parapets. Considering that the Roeblings, with their wire manufacturing business, likely intended to celebrate – or at least emphasize – the inherent engineered applicability of the wire elements over the masonry itself, the combination of the tower’s basic, hardy, base-shaft-capital scheme, juxtaposed with the network of delicate-appearing structurally-interlaced wire, produced the powerful, continuing presence of the Brooklyn Bridge today.■ The online version of this article contains references. Please visit www.STRUCTUREmag.org. Alice Oviatt-Lawrence is Principal of Preservation Enterprises – an international architectural-engineering research and historicbuilding analysis organization. She serves on the SEAoNY Publications Committee. (strucBridge@aol.co.uk)

M AY 2 019

Figure 1. Sherith Israel exterior. Courtesy of David Wakely.

Figure 2. The sanctuary of Sherith Israel. Courtesy of Bruce Schneider.

the Seismic Strengthening of

Temple SheriTh iSrael

By Terrence F. Paret, Gwenyth R. Searer, and Sigmund A. Freeman

arthquake engineering professionals generally recognize that unreinforced masonry buildings of most vintages pose a significant risk of collapse in strong earthquakes. Cognizant of this, the City of San Francisco enacted an ordinance that required assessment, and either upgrade or demolition, of any such building within the jurisdiction found to be deficient

regardless of its historic, cultural, or aesthetic significance. Sherith Israel was one such building. The story of how it was literally saved from the wrecking ball by diligently treating seismic safety and historic preservation objectives with equal priority, and by employing a host of new technologies in concert with traditional ones to surmount technical challenges, is described herein.

Temple Sherith Israel Constructed in 1904, Temple Sherith Israel was designed by Albert Pissis, a prominent San Francisco engineer/architect trained at Ecole des Beaux-Arts, and is on the National Register of Historic Places (Figure 1). The ornately painted interior of its vast sanctuary is one of the last surviving mural interiors by turn-of-the-century artist Attilio Moretti. The sanctuary space is framed by large opalescent stained-glass windows designed by Albert Pissis’s brother, Emile (Figure 2). The building also houses one of the last surviving Murray Harris organs. The vast sanctuary and the room in which the machinery and pipes for the organ are housed together occupy more than 90 percent of the plan area of the building, which created a significant challenge for establishing seismic improvements. The building shell consists of thick, multi-wythe brick masonry bearing walls that rise to roughly 75 feet at the gables and are clad with Colusa sandstone. The east, west, and south walls are articulated in plan and incorporate large corbelled arch substructures that span over large openings and provide out-of-plane stability. The north wall is nearly planar, without significant openings or ornamentation. The sanctuary 22 STRUCTURE magazine

is capped by a steel-framed, zinc-clad, 60-foot-diameter drum and a dome that rises to roughly 100 feet above the sanctuary floor and naturally lights the sanctuary interior. Surviving the “Great 1906 Earthquake” with only modest damage to cornices, gable end wall masonry, and interior plaster, Sherith Israel temporarily served as the Hall of Justice following the collapse of San Francisco City Hall in that event. Archival records indicate that the south gable end wall detached from the roof framing, sufficient to require rebuilding of the masonry in that area. Also, existing conditions indicated that out-of-plane movement of two other gable end walls resulted in permanent relative displacement between the steel “outrigger” beams and the end walls, resulting in local cracking and partially dislodged brick where the beams were partially withdrawn from their bearing. Thus, the ground shaking during 1906 was apparently strong enough to initiate, but not complete, a failure sequence commonly observed in masonry buildings with gable end walls. Nonetheless, the comparison between its behavior and that of other large URM buildings in the neighborhood at the time suggests that Sherith Israel is a more competent building than many of its unreinforced brethren.

Design Philosophy Subject to San Francisco’s ordinance, and having an assembly usage, Sherith Israel was required to meet more stringent seismic upgrade requirements than ordinary structures. The congregation solicited engineering concepts to satisfy the ordinance; however, the concepts relied on brute force interventions that supplanted rather than supplemented the inherent strengths of the existing structure and did not defer at all to the historic character of the building. The proposed massive concrete shear walls, heavy structural steel bracing, and replacement of existing wood diaphragms with concrete and metal deck systems would have largely destroyed the very historic characteristics of the property that the congregation cherished. Employing these strengthening techniques in this structure was counterproductive in another important respect: they would have destroyed the beneficial dynamic separation between in-plane and out-of-plane modes of the masonry walls that was key to the structure’s superior performance during the 1906 earthquake. That separation resulted from the very flexible diaphragms and open sanctuary interior that allowed the seismic mass associated with out-of-plane wall behavior to respond at spectral accelerations well off the spectral plateau. Elimination of that separation would have required more lateral resistance than the extant masonry walls could provide without supplementation. Although these commonly employed strengthening concepts all could have been engineered to satisfy the ordinance, by discounting the inherent strengths of the existing structure, radically altering its original dynamic characteristics, and needlessly disrupting historic integrity, the concepts were all rendered infeasible with respect to preservation, cost, and the desires of the congregants. In contrast, preservation of this behavior would eliminate the need for supplementation of story shear strength and was made a design priority, second only to the goals of preserving the historic fabric of the building and complying with the City’s seismic requirements. In California, the California Historical Building Code (CHBC) is permitted to be used for qualified historic properties. In recognition of the special conditions encountered in dealing with archaic materials and construction, the CHBC contains fewer prescriptive requirements and provides broad discretion for the use of alternate materials and methods of construction. Based on the provisions in the CHBC, the prior performance during the 1906 earthquake was used to benchmark the strengths and weaknesses of the structure. A number of alternate strengthening methods were identified which, as part of the overarching “do no harm” project philosophy, could be installed with little or no disruption to the structure’s character-defining features. In the end, the sanctuary was left undisturbed, despite it occupying the vast majority of the building plan. Everything visible in Figure 2 is original; other than some localized repairs to correct prior water damage, this post-retrofit photo is indistinguishable from the preretrofit condition of the sanctuary.

Seismic Strengthening Techniques Avoiding disruption to the extraordinary historic character of Sherith Israel required a creative approach that utilized state-of-the-art measures, in concert with more traditional interventions like a roof level bond beam and floor-to-wall ties that could be surgically installed.

Center Cores To improve the overall integrity of the bearing walls, center-cored reinforcement – which the designers viewed as “integrity steel” – was added to the unreinforced masonry. The center core technique generally involves coring a hole within the unreinforced masonry, installing

Figure 3. Stress-strain curves developed from testing of nitinol subassemblies.

Figure 4. View of nitinol fuses as installed in the attic of Sherith Israel

a steel reinforcing bar in the hole, and filling the hole with grout – in effect reinforcing the unreinforced masonry. The reinforcement was not numerically relied on to provide supplemental masonry shear strength. The primary goal of the center cores was to preclude uncontrolled cracking and separation of the masonry, thereby reducing the likelihood of large blocks of masonry dislodging and increasing the toughness of the bearing wall system. Due to the sensitivity of the historic finishes, the coring was accomplished without water, primarily from the roof, which required threading cores as long as 75 feet down through the masonry and also anchoring the reinforcement into a new perimeter bond beam at the roof. In the case of Sherith Israel, roughly 20 percent of the more than 6,000 linear feet of cores that were installed were horizontally-oriented. These cores were used to stitch masonry corners together and to control “unfolding” of the walls at plan articulations. A polymer grout was engineered specifically for the project to match the stiffness of the masonry, reduce shrinkage, reduce thermal cracking, reduce cost, and prevent damage to water-sensitive interior plaster finishes. The polymer binder in the grout also impregnates the adjacent porous masonry materials as it bleeds, improving integrity in the process.

Octagonal Tension Ring Gable end walls are known to be susceptible to out-of-plane failures in relatively modest ground motions and, in the 1906 event, out-ofplane gable end wall failure at the south wall was underway. To reduce the vulnerability of the gable end walls, an octagonally-configured tension tie system with super-elastic nitinol “fuses” was added in the attic to promote re-centering and control out-of-phase, out-of-plane behavior of the gable end walls and the main arches that support them. Nitinol is a super-elastic, temperature-dependent, shape memory/ nickel-titanium alloy. Its use on this project is believed to be the first use of nitinol for seismic resistance in North America. Nitinol’s primary use is in medical devices for which it can be engineered to provide precisely specified properties, depending on the device. The project’s M AY 2 019

structural engineers selected an off-the-shelf product that provided the desired properties within the normal temperature range of the attic – fully recoverable strain to roughly five percent to assist in re-centering and a “yield stress” of approximately 80 ksi at a strain of 1 percent – and identified a technology for installing it within the balance of the tension tie system. Prototypes of the nitinol subassembly were subjected to testing in laboratories to confirm that these “fuses” would perform as intended. Figure 3 shows the stress-strain curve of the nitinol. In many ancient houses of Figure 5. Pilaster end supported on worship around the world, tenrocking block in north alley. Courtesy sion ties traverse the sanctuary of Charley Stern. interior. However, in this case, passage of the tension ties through the murals on the interior dome and across the sanctuary interior was judged to be too disruptive. To circumvent the sanctuary interior completely, a “tension ring” concept was implemented using steel Dywidag rods that run parallel to and hang from each of the eight original riveted plan-octagonal structural steel trusses that support the main drum and dome. The structural steel nodes of the octagonal tension ring are the reaction points for loading by the nitinol fuse assemblies, which are comprised of smalldiameter nitinol wires in a loom-like support structure (Figure 4) that was designed to be lightweight, easy to fabricate and install, and easy to anchor to the masonry.

Compression-Only Concrete Pilasters The north elevation of Sherith Israel, hardly visible from the street and facing a narrow walkway that is required for emergency exiting, is a mostly solid, mostly planar, four-wythe thick masonry wall. Without

significant folds, this wall is far more prone to out-of-plane instability than the other perimeter walls, as evidenced by the inclined cracks that were caused by the 1906 earthquake and remain visible in several adjacent perpendicular plaster walls. Four reinforced concrete pilasters with unusual capabilities and geometries were designed for the north wall (Figure 5) to supplement its stability. The pilasters were necessary to preclude the north wall falling outward from the building toward the north, but a typical pilaster designed to preclude northward instability would also stiffen the wall against southward displacement. Restraint against southward displacement was judged to be undesirable because, when the building displaces toward the south during an earthquake, the stiffened north wall could be torn free from the structure. To provide the necessary support against northward instability while permitting southward movement, the pilasters, dimensioned to approximate the plan articulations in the other three exterior walls, were designed to uplift when the building moves to the south and the base of each pilaster was designed to freely translate by supporting it on a “rocking block”.

Fiber-Reinforced Polymer Catenary To address a portion of the north wall masonry with an excessive spanto-thickness ratio between the above-described rocking pilasters that was not accessible for center-coring, a horizontal strip of sandstone veneer was temporarily removed to install a “catenary” of fiberreinforced polymer (FRP). This FRP catenary was anchored to the nearby compression-only pilasters and concealed within the veneer’s mortar bed, thus reinforcing the masonry out-of-plane and allowing it to span horizontally between pilasters.

Backup Support for Plaster Ceiling Framing To reduce the likelihood of collapse of the heavy plaster vaulted and domed ceilings over the sanctuary, backup support for the ceilings was achieved by conversion of gable roof rafters into trusses. This was accomplished via the addition of threaded rod tension members in the attic, across the gables, and by addition of secondary suspension wires that connect the ceiling framing to the newly formed roof trusses. Relative to the incremental safety they provided, these additions were incredibly cost-effective with respect to both materials and labor required to convert the gables to trusses and to add the hanger wires. Figure 6 shows a schematic cut-away diagram highlighting some of the strengthening measures that were taken during the project.

Conclusions More than one hundred years after the Temple Sherith Israel resisted the 1906 earthquake with relatively minor structural damage, the building has undergone an extensive historic renovation and seismic strengthening, meeting San Francisco’s upgrade requirements for unreinforced masonry buildings and precluding the need to abandon and demolish the structure. Key, from a structural standpoint, were the efforts taken to understand the inherent positive seismic characteristics of the building and the framework of the California Historical Building Code, which permits legal recognition of alternate materials and construction in historic preservation projects. ■ All authors are employed by Wiss, Janney, Elstner Associates, Inc. in the San Francisco office.

Figure 6. Schematic cut-away diagram showing some of the strengthening measures that were implemented. Courtesy of ELS Architecture and Urban Design.

24 STRUCTURE magazine

Terrence F. Paret is a Senior Principal. (tparet@wje.com) Gwenyth R. Searer is a Principal. (gsearer@wje.com) Sigmund A. Freeman is a Senior Principal. (sfreeman@wje.com)

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SIMPSON STRONG-TIE Choosing Resiliency: Lessons from Hurricane Michael

By Doug Allen, P.E.

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energy use or environmental impact. Expected life is often approximated for the water heater, furnace, AC unit or shingles, but rarely is the structural soundness discussed as an area of value. This is likely because of the buyer’s implicit trust that the structure has been built to the latest building codes and that the codes will suffice to ensure the occupants’ safety in the event of a natural disaster. However, building codes are intended merely to provide life safety in the event of a design-level natural disaster; this does not imply that the structure and its furnishings will survive the disaster in usable condition. Additionally, older buildings designed and built to superseded codes are typically less resilient because they have not benefited from later code provisions developed in response to the lessons of more recent catastrophes or the latest research. Just as we have instituted a 5-star crash rating system for vehicles, many people think it’s time for estimated performance metrics or ratings for what is usually the largest investment of our lives. As we build the communities of our future generations, city planners and engineers are trying to find the perfect balance between cost and resiliency. Too often, however, the focus is on the short-term versus the life cycle of the building. One example of this added measure of resiliency is provided by the IBHS through their FORTIFIED Home™ program. Would you pay an additional $5,000 to level up the resiliency of one of your biggest investments? What if, due to the increased resiliency, you also received reduced insurance premiums to help offset the additional costs? Habitat for Humanity often builds their structures to the FORTIFIED Home standards. A small cluster of Habitat homes that were located in the path of Michael performed very well, proving that the effort and minimal added cost make the difference. As we rebuild our communities and recognize the value of resiliency, we can make choices that have lasting effects. In the coming years, I expect to start hearing from realtors about the genetic makeup, the skeleton, the structure of the homes and businesses they are selling. I expect the marketplace to start allowing more room for resiliency decisions, along with metrics that quantify resiliency to the consumer of new construction or retrofit options. As an engineering community, we have the responsibility and opportunity to continue to evolve, educate, and support the built environment – comprising our homes, schools and workplaces, and the supporting infrastructure alike. Whether you are an engineer, builder, or homeowner, our HighWind Solutions page has resources to help you protect structures against high-wind events. Visit strongtie.com/highwind.

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esilience, or resiliency: The capacity to recover quickly from difficulties; toughness. The ability of a substance or object to spring back into shape; elasticity. In the wake of recent hurricane seasons, the theme of structural resiliency has resurfaced with renewed urgency. Hurricanes pose a triple threat of high winds, substantial rain, and storm surge. Extreme weather cost the nation nearly $100 billion in damage during 2018. Accordingly, awareness has risen within affected and surrounding coastal regions regarding their communities’ existing structural resilience ratings. In the days after Hurricane Michael made landfall, survey teams began to quantify the destruction as a first step to recovery. News reporters gravitated toward the stark contrast between the structures still standing and the surrounding devastation. One such example is the much-publicized Sand Palace on Mexico Beach. This juxtaposition raised many questions: What made this structure so resilient? What were the differences between this structure and the others? How much did those differences cost? Were they differences in design, in construction, or both? Was this added measure of resilience known prior to the storm? Structural Extreme Events Reconnaissance (StEER) Network, a group focused on research of structural performance in extreme events, deployed prior to Hurricane Michael making landfall and were very instrumental in the damage assessment process. StEER was strategic in setting up towers to measure the storm’s wind speed along its forecasted trajectory, and they used color-coded maps identifying the different demographic of houses by their year of construction and their implied vulnerability. It quickly became obvious that many of the structures were in older communities and were built in the 1960s and 1970s. Consistent with the havoc caused by Hurricane Harvey in 2017, many older structures exposed to high wind were significantly, if not totally, damaged or destroyed. Considering the devastation wrought upon families that lost their homes or business, I wonder how such a catastrophe would affect me. So often when we are buying homes, realtors speak to the aspects of the house that are associated with value, aesthetic features such as granite countertops or hardwood flooring, or features that reduce the building’s

The only clip proven to perform in full-scale testing.

The new SCS seismic clip doubles the in-plane capacity of other bypass clips. The innovative SCS seismic bypass framing connector from Simpson Strong-Tie is engineered for either slide-clip or fixed-clip applications in high-seismic areas. Backed by our real-world, full-scale cyclic testing, the SCS seismic clip delivers the highest seismic loads in the industry. Trust the value-engineered SCS seismic connector for your next project. Visit go.strongtie.com/scs or call (800) 999-5099.

ÂŠ 2019

Simpson Strong-Tie Company Inc. SCS18-E

STRUCTURE solutions

PROFILE

ADHESIVES TECHNOLOGY CORPORATION A New Future for Code Compliant Anchoring Adhesives A Legacy of Innovation Adhesives Technology Corporation (ATC) was founded in 1978 and, within 10 years of its inception, changed the commercial anchoring adhesives industry with its introduction of ULTRABOND 1, the first ever dual component epoxy system to fit in a standard caulking tool. This cartridge-based delivery system was often imitated and remains a staple in the anchoring adhesive industry to this day. In the decades to follow, ATC’s continued dedication to strategic innovation has allowed for sustained growth, culminating in its 2018 alliance with Meridian Adhesives Group. A calculated approach to an evolving industry has provided ATC with a unique perspective, and the result is likely to change the industry yet again.

What’s Changing?

Speaking of Bridges… According to the most recent Report Card issued by American Society of Civil Engineers (ASCE) in 2017, America’s infrastructure rates a D+ on a scale from A-F. Almost 40% of the nation’s bridges are at least 50 years old and, in 2016, over 56,000 were deemed structurally deficient. Estimates to repair these bridges top $120 billion. In 2015, ATC began exploring the role its products could play in addressing the needs of designers and contractors as they carry out this immense scope of work. Traditionally, the highest performing adhesive anchoring products have been manufactured primarily by European companies. They have produced them almost solely in cartridges, neglecting the bulk application needs of contractors and designers focused on higher volume infrastructure work common in the U.S. This forced these designers and contractors to choose between performance and ease of use and, in many cases, between domestic and foreign adhesives. Taking all of this into consideration and foreseeing an inevitable

merger of the two construction sectors, ATC began a 4-year development effort to create the adhesive anchoring epoxy known today as ULTRABOND HS-1CC, a high-performance anchoring epoxy that would satisfy the requirements of both commercial construction and infrastructure specifiers. In 2017, ATC began independent and statewide testing of its new, domestically produced flagship product, and in 2018 received a structural building code compliant approval report (ICC ESR-4094). Through this printing, HS-1CC is included on authorized materials lists in 31 of the 40 states that maintain such lists, and remaining states are pending.

Finally, a Solution ULTRABOND HS-1CC’s patent-pending technology makes it the first and only anchoring adhesive approved by ICC in both cartridge and bulk dispensing systems. It boasts the highest average bond strength of any anchoring epoxy on the market today and is made in the USA. This is why, shortly after receiving its ICC report, HS-1CC was specified as the anchoring epoxy for the Lake Pontchartrain Causeway bridge project in Louisiana (targeted to begin in mid-2019), making it the first project ever to utilize a code approved anchoring epoxy delivered via bulk dispensing pumps for better economy, speed, and lower environmental impact. Whether the need is for high volume bulk dispensing for roadway dowels, higher performance for critical structural connections, high short-term temperature resistance (up to 205°F), or underwater installation, a single product can be specified. For projects where environmental concerns require a product which is drinking water safe, nonylphenol and lead-free, and packaged in bulk for reduced environmental impact, ULTRABOND HS-1CC will meet those requirements as well. After 40 years, Adhesives Technology continues to innovate, and its latest creation promises to be the new standard on jobsites into the foreseeable future. 800-892-1880 | atcinfo@atcepoxy.com | www.atcepoxy.com

www.whitehouse.gov/presidential-actions/executive-order-strengthening-buy-american-preferences-infrastructure-projects

28-SS STRUCTURE solutions

ADVERTORIAL

Historically, individual states have maintained their own approval lists for adhesive anchoring materials for use on infrastructure projects, while structural projects have been regulated according to IBC/IRC guidelines and require anchoring products certified by ICC or IAPMO, ensuring higher performance and quality standards as defined in ACI 355.4. In January 2018, however, the FHWA announced that all post-installed adhesive anchors used in Federal-Aid projects must be tested to ACI 355.4 and designed to ACI 318. This is a critical regulatory change that has effected significant change in DOT regulations across the country. Add to that the executive order signed in January 2019 that mandates, “the use of goods, products, and materials produced in the United States,”1 on infrastructure projects utilizing federal funds, and suddenly designers and contractors are faced with the necessity to find a domestically manufactured product that meets or exceeds IBC/IRC requirements, whether they are designing a high-rise building, a tunnel, or a bridge.

ULTRABOND HS-1CC, first-ever code approved anchoring epoxy in bulk, specified by GEC Engineering for use in critical infrastructure applications by JB James Construction to repair the Lake Pontchartrain Causeway Bridge in Louisiana. Courtesy of Navin75 via Flickr.com.

WHY SPECIFY ANYTHING LESS THAN

THE WORLD’S STRONGEST ANCHORING EPOXY

NEW ULTRABOND HS-1CC DELIVERS SUPERIOR VALUE AND PERFORMANCE TO HILTI RE 500 V3 ULTRABOND HS-1CC is the world’s first and only anchoring epoxy formulated to be IBC/IRC code compliant in both bulk and cartridge dispensing systems. It also happens to be the world’s strongest anchoring epoxy for use in dry, damp, water-filled and submerged holes.

ESR-4094

MH61032

ULTRABOND HS-1CC is the preferred choice for infrastructure and construction projects all across the country. Not only is it made in the USA, it is included on Departments of Transportation authorized materials lists in 31 of the 40 states that maintain such lists, and remaining states are pending. For more information, visit atcepoxy.com/HS-1CC.

450 EAST COPANS ROAD POMPANO BEACH, FLORIDA 33064 USA | 1.800.892.1880 | WWW.ATCEPOXY.COM HILTI IS A REGISTERED TRADEMARK OF HILTI AKTIENGESELLSCHAFT CORPORATION.

STRUCTURE solutions

PROFILE

STRONGWELL

trongwell has been developing pultruded structural composites for over 60 years. These composite products are used in more than 30 market sectors and in a broad range of applications, including: industrial platforms, skyscrapers, architectural façades, industrial flooring and decking, security barriers, telecommunications shielding and screening, architectural and industrial handrail and guardrail, fencing, walkway grating, wastewater separation, pedestrian footbridges, and aquatic structures. The company’s industry-leading, proprietary Design Manual and Corrosion Resistance Guide provide a powerful, versatile, and intuitive structural design solution ready to tackle any new-build or refurbishment challenge in place of, or in harmony with, traditional materials. The following case studies illustrate the versatility of some of Strongwell’s exclusively Made in the USA products. Project: Architectural Adornment and Awning Supports using EXTREN® Fiberglass I-Beams, Wide Flange Beams, and Channels

Project: HS Armor Fiberglass Ballistic Panels Secure a School Waiting Area School districts nationwide are taking proactive steps to ensure school safety and security. In addition to training, schools have begun to implement smart technology and materials to combat security threats. Strongwell’s HS Armor panels began as a military product application, installed and tested throughout the world to protect high value government assets. With proven applications, and successful use in the commercial building and vehicular markets as well, an educational institution in Tennessee installed HS Armor, during a recent renovation, as a part of its overall plan to secure entry points. Because it was a full renovation, the school district installed Strongwell’s HS Armor panels onto metal studwork prior to installing a finish layer of drywall to conceal the UL 752 Level 8 (NIJ Level III) 30-SS STRUCTURE solutions

Project: Pultruded Stairs Eliminate Corrosion Cycle for Oceanfront Lodging An oceanfront lodge on the Isle of Palms, South Carolina, has a main lobby on the structure’s first floor, which is elevated 12 feet above ground level due to its proximity to the ocean. For years, the steel and concrete access stairs to the lobby continually rusted and degraded. Eventually, the stairs deteriorated beyond repair. The management company reported that it spent over $2,500 annually to have the stairs sandblasted, rust treated, and repainted in their attempt to slow the degradation. The overall annual process would create inaccessibility for almost two weeks with no significant improvement to aesthetics. Rust began to quickly reappear within 60 days of treatment. To further complicate accessibility, the 54-inch front staircase for the lodge shared the same corrosion cycle as the 96-inch access stairs to the service elevators adjacent to the front of the facility, which meant that, for several weeks each year, there was construction going on simply to try and maintain the stairs. The associated ongoing corrosion costs began to worry the lodge’s HOA board, so they began to look at ownership costs over a 15-year period and calculated that almost $20,000 of maintenance expenses had been spent just on maintaining the stairs. Under the advisement of a structural engineer and several general contractors, the board learned that steel, cast-in-place concrete, or structural FRP were the three viable options for replacing the failing stairs. Upon consideration of the three options, the board chose EXTREN structural FRP, as it offered the possibility of as many as 75 years or more of life expectancy. This option also provided the lowest 10-year overall ownership costs compared to the steel (32% less) and cast-in-place concrete (57% less) options. As the stairs remain one of two access points for check-ins, using EXTREN also provided a significant reduction in downtime compared to steel (88%) and cast-in-place concrete (98%) without the need for special permits or traffic rerouting. These recent case studies are just three of many that illustrate Strongwell’s Structural Fiberglass as an intuitive struc276-645-8000 tural design solution for your next building info@strongwell.com project. Visit www.strongwell.com/ www.strongwell.com structure to learn more.

ADVERTORIAL

Near Glendale, California, sits a brand-new multi-story housing complex which blends outdoor living with industrial style. The complex provides studio, one-, two-, and three-bedroom floorplans. EXTREN 525 series pultruded fiberglass structural shapes offer the industrial look of steel, which fits well with the desired fascia aesthetics and structural support needs of the housing complex, but with a much lighter weight, higher corrosion resistance, and improved UV and thermal performance. To welcome new renters with an industrial motif, the leasing office requested an exposed subtle beam threshold. Three EXTREN I-Beams (12- x 6- x ½-inch) were utilized for this application, and lend continuity with the exterior façade, which is made up of EXTREN Fiberglass Beams as well. EXTREN Wide Flanges with channels serve as side supports for awnings and balconies. On the top floor of this housing complex, residents are treated to a communal area, which houses an entertainment venue complete with kegerator, foosball, table tennis, and a well-equipped bar. The Skydeck is supported with a series of connections of wide flanges and channels, also from EXTREN 525 series fiberglass structural shapes, to bring the entire theme together.

protection. A small work crew completed the entire renovation in less than four weeks, including the installation of all HS Armor panels, drywall, paint, trim, new entryways, and updated electrical wiring.

PowerfUl · Versatile · intUitiVe structural Design solutions

Architectural Adornment Project (Opposite)

visit www.strongwell.com/strUctUre to learn more STEEL

FIBERGLASS

strongwell ProDUcts ProUDlY

ISO 9001 Quality Certified Manufacturing Plants

the World leader in Pultrusion and Pultruded Fiberglass structures & shapes 276-645-8000 • info@strongwell.com www.strongwell.com

STRUCTURE solutions

PROFILE

CAST CONNEX

ifteen years ago, a research group at the University of Toronto set out to explore how steel casting manufacturing could be leveraged to simplify and improve complex structural steel connections. Through a full-scale destructive testing of castings that they designed, those researchers saw firsthand how castings could provide dramatically improved structural performance and resilience over conventionally fabricated steel connections. They also recognized the architectural potential of the geometric freedom afforded by casting manufacturing.

Elegance in Design

A Variety of Solutions Universal Pin Connectors™ (UPC) are sleek, clevis-type standardized fittings designed to connect to round hollow structural section (HSS) elements for use in AESS applications. The connectors are carefully sculpted to provide smooth transitional geometry that is otherwise unachievable using standard fabrication practices. Architectural Tapers™ (ART) are hollowed, cast structural steel conical tapers also designed to connect to round HSS for use in AESS applications. Both UPCs and ARTs can be used on their own at the ends of steel columns, braces, struts, and ties, or used together, lending a slenderer overall appearance to structural elements fitted with the connectors.

32-SS STRUCTURE solutions

ADVERTORIAL

Fueled by a passion to improve safety and enhance the beauty of the built environment, two graduate students from that research group made it their life’s work to enable structural engineers to leverage castings in their building and bridge designs. And thus, in 2007, CAST CONNEX was born. Since then, the company has put thousands of steel castings into service in hundreds of structures, establishing itself as an enabler of its collaborators’ innovative designs as well as an innovator in its own right. Today, CAST CONNEX is a rapidly growing multinational organization, and elegance in design remains one of the company’s core values. To CAST CONNEX, elegance encompasses everything from utility to aesthetics to manufacturability. “All of our solutions are developed with the aim to improve overall structural performance and safety, to simplify steel fabrication and field installation, and to beautify the spaces in which our components are used,” says company President and CEO, Carlos de Oliveira. Company co-founder and Vice President, Dr. Michael Gray is equally motivated. “In my ideal world, there would be more incentive to push buildings to higher levels of performance,” says Gray. “As an industry, we ought to move beyond code minimum; we need to elevate our standards. And not just for structural performance, but for aesthetics in design, too.” CAST CONNEX offers pre-engineered steel connection solutions ranging in applicability from strictly functional to products ideal for use in architecturally exposed structural steel (AESS). The company also engineers and supplies custom designed cast steel components.

Diablo™ Bolted Splices (DBS) are cast steel fittings that enable unobtrusive field bolted splices in round HSS members. The fittings are designed such that the bolted connection is inboard of the outer diameter of the HSS. Splices made with DBSs can be sheathed in thin-gauge plate to conceal the splice completely or can be left uncovered to provide a more technical aesthetic. Timber End Connectors™ (TEC) are clevis-type fittings designed to connect to the ends of heavy timber or glue-laminated structural elements loaded in predominately tension or compression for use in architecturally exposed applications. High Strength Connectors™ (HSC) and Cast Bolted Brackets (CBB) are capacity designed connectors for use in Special and Ordinary Concentrically Braced Frames and Special and Ordinary Moment Frames, respectively. Both connector types eliminate the need for field welding, thereby reducing the total installed cost of the structural steel frame while improving quality. High Strength Connectors are also commonly used in AESS, as their use results in smaller gusset plates and because the connectors’ curvaceous appearance is often preferred over slotted-HSS connections that require net section reinforcement. Scorpion™ Yielding Connectors (SYC) are modular, replaceable, standardized hysteretic fuses that provide enhanced ductility and improved performance in the retrofit of seismically deficient structures or for use in the Seismic Force Resisting System of new structures. The system exhibits a full, symmetric hysteresis characterized by an increase in stiffness at deformations above design level. In multistory structures, this post-yield stiffening can decrease the likelihood of the formation of a soft story and results in a more uniform distribution of inelastic demand over the building’s height when compared to other yielding devices that exhibit a low postyield stiffness. High Integrity Blocks® (HIB) are ultra-heavy weldable solid steel components that exhibit a minimum 50 ksi yield strength and elevated notch toughness in all three directions of loading and through the full cross-section of the section. HIBs are ideal for use at the Disturbed Regions of Connections where lamellar defects in conventional rolled plate may compromise quality and strength of the connection, or where the lamination of multiple steel plates to build up a section is not advisable due to the need to transmit forces in multiple directions or orthogonal to the laminations. CAST CONNEX also provides design-build services for Custom Cast Steel Components. Custom castings are designed to address project-specific needs and can provide economy in shop fabrication and field erection as well as create connection details that enable iconic architecture. The company’s turnkey services related to custom casting supply typically include industrial design and 3-dimensional modeling, engineering including 416-806-3521 finite element stress analysis, casting info@castconnex.com detailing , and manufacturing www.castconnex.com including oversight.

THE EXCEPTIONAL IS IN THE DETAILS

Emory University Hospital J-Wing Expansion by SmithGroup JJR with Walter P Moore

Photography by Robbins Photography, Inc

We provide an array of Cast Steel Solutions: From Pre-engineered to Custom Castings, We are expert in working with Architects to produce exceptional results.

UNIVERSAL PIN CONNECTORâ&#x201E;¢ www.castconnex.com

PROFILE

STRUCTURE solutions

NATIONAL CONCRETE MASONRY ASSOCIATION

Direct Design Software v3 The next generation of structural masonry analysis

• Ease of use with a low learning curve DDS includes an intuitive user interface. Buildings are created by defining plan dimensions, number of stories and story heights, diaphragm properties, roof configuration, and locations of openings. Based on the building geometry and loading criteria, DDS calculates the lateral loads resulting from the main wind force, components and cladding, and seismic loads. Gravity loads resulting from user-defined dead, live, and snow loads are distributed using conventional engineering mechanics. The software generates structural concrete masonry designs in compliance with the 2015 edition of the International Building Code, which references the 2013 TMS 402, Building Code Requirements for Masonry Structures. The basis for the design loading requirements is the 2010 ASCE 7, Minimum Design Loads for Buildings and Other Structures. One of the primary goals for DDS is the complete transparency of all design calculations. Users can verify design loads and material resistance at any stage of design by checking the design report. Design results are shown in detail to allow for anything from a quick, at-a-glance overview of status to an in-depth calculation review. Direct Design Software truly is the next generation of structural masonry analysis. A trial version is available for free download at www.directdesignsoftware.com.

ADVERTORIAL

irect Design Software (DDS) is a structural analysis program for designing single and multi-story, reinforced concrete masonry buildings. The software provides a streamlined procedure for determining loads, analyzing load paths, performing design checks, and creating drawings, resulting in an economical structural masonry design with little effort. Structural software packages tend to come in two forms: simple, member-based analysis platforms for designing discrete elements or systems, and complex software, capable of analyzing exotic geometries and arbitrary loading scenarios. The gap between these extremes is software that can analyze a full 3-D masonry structure but does not require a high level of computing power, training investment, and effort. That gap has remained largely unfilled – until now. To provide engineers and designers with a best-of-both-worlds tool to safely and economically design masonry, Direct Design Software Version 3.0 is now available. The core goals for this application include: • Automation of the full structural workflow, from loads to analysis to design checks to drawings • Support for most common masonry building configurations • Transparency of calculations, design assumptions, and methodology • A masonry-specific application, rather than a general-purpose application adapted for masonry

703-713-1900 | info@ncma.org | www.ncma.org

DIRECT DESIGN SOFTWARE v3 Masonry: Clear. Precise. Direct. Design Pressures

Out-Of-Plane Wall Checks

LOADS

Pressure values from Equation 28.4-1:

CHECKS

Check Summary

DRAWINGS

For each check, this shows whether it passed or failed, the index of the critical load combination, and the ratio of th M ). A ratio greater than 1.0 is failing. Load combinations are listed beneath the table.

e.g. Mᵘ/ p = q (GC -GC ) = (145.49 psf)(0.61--0.18) = 114.94 psf (Windward surface,provided, edge zone

All Length Pass?

Axial Stress Check

Axial Force Check

P-M Intr Check @ top

P-M Intr Check @ mid

PFlex Check

Yes

10.00 ft

0.073 (1) Pass

0.061 (1) Pass

0.000 (1) Pass

0.668 (16) Pass

0.642 (16) Pass

Yes

2.00 ft

0.131 (1) Pass

0.060 (1) Pass

0.000 (1) Pass

0.312 (16) Pass

0.298 (16) Pass

Segment 3 in Wall along grid 1 from A to B, Story 1

Yes

11.33 ft

0.068 (1) Pass

0.059 (1) Pass

0.000 (1) Pass

0.719 (16) Pass

0.695 (16) Pass

Segment 1 in Wall along grid 2 from A to B, Story 1

Yes

4.00 ft

0.090 (1) Pass

0.057 (1) Pass

0.000 (1) Pass

0.328 (16) Pass

0.316 (16) Pass

Segment 2 in Wall along grid 2 from A to B, Story 1

Yes

2.67 ft

0.106 (1) Pass

0.057 (1) Pass

0.000 (1) Pass

0.227 (16) Pass

0.218 (16) Pass

Segment 3 in Wall along grid 2 from A to B, Story 1

Yes

10.00 ft

0.058 (1) Pass

0.048 (1) Pass

0.000 (1) Pass

0.476 (16) Pass

0.461 (16) Pass

p = q (GC -GC ) = (145.49 psf)(0.40--0.18) = 84.38 psf (Windward surface, field zone p = q (GC -GC ) = (145.49 psf)(-0.43-0.18) = -88.75 psf (Leeward surface, edge zone Segment 1 in Wall along grid 1 from A to B, Story 1

Segment p = q (GC -GC ) = (145.49 psf)(-0.29-0.18) = -68.38 psf (Leeward surface, field zone2 in Wall along

grid 1 from A to B, Story 1

1 A B

88.75 psf psf 2

88.7 88 .75 .7 5 ps psff 88.75 psf psf 68.38 psf ps psf 114.94 psff 114.94 ps psff

68.38 psf psf

114.94 94 ps psff

88.7 88 .75 .7 5 psf ps 3f

88.75 88. 75 ps psff 88.75 psf psf 68.3 .38 psff 88.7568 ps.3 psf f 8 ps 88.75 ps psf 88

Try it FREE TODAY!

COMPLIANCE SUMMARY Code Compliance Status

Wall Segments (In-Plane Loading): All 30 are passing Wall Segments (Out-of-Plane Loading): All 30 are passing

Wall Header & Sill Panels (Out-of-Plane Loading): All 28 are passing Lintels: All 16 are passing

Diaphragm Levels (Chord Reinforcement): All levels pass

Structure has one or more irregularities, but the relevant provisions do not trigger anything th

Direct Design Software enables design of an entire masonry structure in minutes, with just a few simple inputs in the intuitive user

interface. This easy to learn software generates code-compliant structural masonry analyses per TMS 402 with design load calculations per ASCE 7.

The powerful program is fully automated, detailing every block and reinforcing bar and displaying the full text of every calculation for easy verification. Fully-detailed wall elevation drawings quickly communicate the design.

www.directdesignsoftware.com 34-SS STRUCTURE solutions

Direct Design Software saves time and cuts costs by doing the tedious work for you and letting you focus on your clients and project workflow. Start your free trial today and unlock the power of Direct Design!

STRUCTURE solutions

PROFILE

SIDEPLATE SYSTEMS

Optimized. Minimized. Simplified.

as compared to conventional moment frame packages. Even more savings come during the erection phase as SidePlate connections are field-bolted, requiring no on-site welding – or welding inspections. With a field-bolted connection, erectors can stay on schedule in almost any weather. There is no question that the SidePlate design process is very technical – with a number of pre-approvals and prequalifications – but the fabrication process is incredibly simplified. Any fabrication shop can build a SidePlate design with no special or proprietary tools required. SidePlate’s detailed drawings and calculations are included directly in the construction documents, helping to eliminate deferred submittals. The simplified approach carries into erection as field-bolted connections help keep a project on schedule. Beams can be installed in virtually any weather, and bolting requires no preheating or UT inspections. A design process that specializes in optimized lateral systems, focusing on providing benefits to the entire project, SidePlate has a 25-year history of proven results in offering structural engineers an alternative to the same old thing.

ADVERTORIAL

idePlate Systems is entering its 25th year of serving the structural engineering world with experience extending across 750-plus projects totaling over 115M square feet of building area. A design optimization process, SidePlate looks at the lateral structure for a building and finds the most efficient way to build it by engineering a system that puts steel where it is actually needed. Working as an extension of the design team, SidePlate engineers will implement their connection technology to resist wind, seismic, or progressive collapse situations. The stiffness of the SidePlatedesigned connections offers incredible design opportunities. From elongated cantilevers to vast open showrooms to utilizing all the available space in a building by eliminating the need to hide vertical braces, a SidePlate engineered building helps an Engineer of Record fulfill almost any architectural requirement. Inherent in the SidePlate designs are multiple opportunities for owners and general contractors to see significant cost reductions in a project. The stiffness of the SidePlate moment frames often minimizes the required number of connections by 20-30% as compared to conventional moment frame buildings. More savings are found in steel costs, as the inherent connection design stiffness allows the lateral system to reduce column and beam weights by 15-20%

949-238-8900 | info@sideplate.com | www.sideplate.com

OPTIMIZED. MINIMIZED. SIMPLIFIED. SIDEPLATE BENEFITS: • • • • • • • •

Schedule efficiency Field-bolted construction No field-welding Reduced required connections Minimized crane time Increased design flexibility Reduced steel package costs Increased useable square footage

www.sideplate.com 949-238-8900 info@sideplate.com

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STRUCTURE solutions

PROFILE

NEW MILLENNIUM

ADVERTORIAL

ew Millennium Building Systems is in the business of solutions. Solutions involving a range of structural steel building systems. Solutions providing dramatic cost savings. Solutions utilizing pioneering BIM-based design capabilities. Solutions achieving your architectural vision. Solutions exceeding expectations. New Millennium engineers and manufactures a breadth of steel building systems, from standard steel joists and deck to architecturally unique steel joist and deck solutions. • Steel roofing and flooring systems • Ceiling and cladding systems • Multi-story, long-span composite slab floor systems • Stay-in-place steel and concrete form systems for bridges Each New Millennium steel solution is custom-engineered to streamline the design-build process and reduce total project costs. New Millennium specialists use their expertise to help customers evaluate and determine the best solution for their application. The result is a tailored building system that lowers costs, shortens project timelines, and is visually stunning. We do not get there alone, however. New Millennium experts collaborate with design teams, builders, and building owners from the concept phase through project completion.

With engineering, manufacturing, and service facilities throughout the country, New Millennium is perfectly positioned to support and respond to customers quickly and efficiently. Together, let’s meet the growing demand for advancements in aesthetic design, functional spaces, positive environmental outcomes, and cost containment. Together, let’s build a better www.newmill.com steel experience.

OPTIMIZE YOUR MULTI-STORY DESIGN AND CONSTRUCTION

Advanced long-span composite floor systems Create open spans up to 36 feet with solutions that can be 40% lighter than cast in place. Reduce installation costs and improve field safety. Achieve your vision with architecturally exposed deck-ceiling and acoustical options. Fire, sound and vibration code compliant. • Efficient Construction • Aesthetics and Performance • Two Distinct Profiles

YOUR N AT IO N W ID E RES O U RC E F O R C U STO M - E N GI N E E R E D ST RU C T U R A L ST E E L B UI L D I N G SYST E M S

www.newmill.com

18-NMBS-2_structure-MSR.indd 1

36-SS STRUCTURE solutions

12/7/18 4:56 PM

STRUCTURE solutions

PROFILE

GEOPIER FOUNDATION COMPANY

settlements. Geopier’s rigid inclusion systems are used in very poor soils (e.g. variable fill or soft, organic soil) to support heavy building loads and provide an advantage over pile foundations because no structural pile caps are required. Geopier’s Rammed Aggregate Pier® systems have also been successful at mitigating total and differential liquefaction settlements beneath structures in highly seismic areas, as measurably demonstrated during large earthquakes in New Zealand and Ecuador. Geopier has licensed installers in all of North America, as well as in Central and South America, Europe, New Zealand, Australia, the Philippines, South Korea, and the Middle East. The designbuild model allows local Geopier engineers to work directly with structural engineers to develop a ground improvement solution for project-specific soil conditions and building loads. The 30-year old company has worked on some high-profile projects, such as NASA’s Stennis Space Center in Mississippi, Assembly Row, and a 5-block mixed-use development in Massachusetts, Grand Condominiums (12-story structure with 2-levels of below grade parking) in Ontario. Through dedicated research and develop800-371-7470 ment, Geopier continues to expand system info@geopier.com capabilities to meet virtually all foundation www.geopier.com design challenges.

ADVERTORIAL

tructural engineers choose Geopier ground improvement systems for a variety of good reasons. Geopier GP3®, Impact®, Rampact®, X1®, Armorpact®, GeoConcrete®, and Densipact® systems have supported thousands of structures around the world. These ground improvement systems can often replace the need for deep foundations, such as driven piles, drilled shafts, or augered cast-in-place piles, effectively allowing structural engineers to convert to less expensive shallow foundation systems. Geopier ground improvement allows shallow foundations to be designed for high soil bearing pressures, sometimes up to 10 ksf, while controlling

GEOPIER GROUND IMPROVEMENT CONTROLS STRUCTURE SETTLEMENT GIVE YOUR STRUCTURE STABILITY Work with Geopier’s geotechnical engineers to solve your ground improvement challenges. Submit your project specifications to receive a customized feasibility assessment and preliminary cost estimate at geopier.com/feasibilityrequest.

GEOPIER IS GROUND IMPROVEMENT®

800-371-7470 • geopier.com info@geopier.com

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STRUCTURE solutions

PROFILE

STRUCTUREPOINT Concrete Software Solutions

StructurePoint Software Overview spColumn • With newly introduced sp2D/3D View Module and powered by the advanced and flexible graphical interface of the new model editor for creating and modifying irregular sections, spColumn v6.50 is widely used for design and investigation of columns, shear walls, bridge piers, as well as typical framing elements in buildings and other structures. • spColumn v6.50 also features an improved spReporter module with new features for generating, viewing, and exporting reports. spMats • Powered by a sophisticated FEM Solver, increasing capacity and substantially speeding up solutions for large and complex models, spMats v8.50 is widely used for analysis, design, and investigation of concrete mat foundations, footings, and slabs on grade. • spMats v8.50 provides integration with spColumn via exporting of CTI files spSlab/spBeam • Powered by the Equivalent Frame Method of analysis and design, spSlab v5.50 (formerly ADOSS) is widely used for analysis, design, and investigation of two-way slab systems (including waffle and slab bands), beams and one-way slab systems (including standard and wide module joist systems). • With capacity to integrate up to 20 spans and two cantilevers of a wide variety of floor system types, spSlab is equipped to provide cost-effective, accurate, and fast solutions to engineering challenges.

spWall • From shear walls and retaining walls to precast, ICF, and tilt-up walls, engineers worldwide use spWall v5.01 to optimize complicated wall design, reinforcing, and deflections. • spWall’s graphical interface easily generates complex wall models. Wall geometry (including any number of openings and stiffeners), material properties, loads (point, line, and area), and support conditions are assigned graphically by the user

StructurePoint Launches spLearn We have developed our spLearn service program to extend our knowledge and support via training and consulting engineering services. Call us at 847-966-4357 to set up a customized training session, or select a topic from our website for one of the options below: Design Examples include detailed hand solutions of reinforced concrete structural members based on building design codes ACI 318 and CSA A23.3. The examples are selected from the most commonly used references by practicing engineers. A model for each example is created using the corresponding StructurePoint software program; then, results are compared in detail with results obtained from the reference and hand solution. The goal of the detailed design examples is to provide the user with a detailed reference to better understand how StructurePoint software works and to prevent the uninformed use of the software. Samples: • Two-Way Flat Slab (Drop Panels) Concrete Floor Analysis and Design • Two-Way Joist (Waffle Slab) Concrete Floor System Analysis and Design Video Tutorials describe theories and applications of StructurePoint software. The videos related to each application help engineers to better understand the situation where each software can be used and the considerations needed in the process of creating the models. The videos regarding theories help users to understand how the program works and which methodologies are adapted by StructurePoint software. Some of the available videos assist users in getting familiar with the software interface and optimize their time and effort to use the programs quickly, simply, and accurately. Samples: • StructurePoint Suite Overview • Two-Way Floor Systems Technical Articles discuss advanced topics that engineers might encounter while designing reinforced concrete structural members. These articles help engineers in making engineering judgments that would lead to a safe yet economical design using StructurePoint software. Samples: • Comparison of Concrete Two-way Slab Analysis Methods • Flexural Effective Stiffness for Individual Columns Related to our spLearn service, our spAcademic service program focuses on providing tools and resources to educators and academic institutions in order to prepare students to join the engineering industry. If you are an educator and would like additional information, please request a toolkit from structurepoint.org/spAcademic

info@structurepoint.com | www.structurepoint.org

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ADVERTORIAL

tructurePoint originated in 1957 as the Engineering Software Group of the Portland Cement Association (PCA). The group created software to provide design aids and automatic calculations for structural engineers to analyze and design reinforced concrete structures. As software became a widely-used tool in the engineering industry, the group pursued better aesthetics, faster development, and skilled employees. In 2007, under the direction of a trusted PCA employee, the group reorganized as StructurePoint, an independent entity with the complete support of its legacy organization. As stewards and enhancers of PCA software, StructurePoint engineers focus on developing and maintaining a simplified suite of software for analysis and design of reinforced concrete buildings, bridges, and structures. We provide uniquely focused programs to facilitate efficient and cost-effective completion of demanding projects. As our global market expands, we retain important relationships with established clients (some dating back to our software’s inception in the 1960s), while gaining the trust of new engineers, academics, and firms. In recognition of our emphasis on excellent service and researchbased development in our niche market, engineers everywhere value StructurePoint as the gateway to the vast resources of the concrete industry.

STRUCTURE solutions

PROFILE

ALL WEATHER INSULATED PANELS

Providing Solutions for Your Construction Project

Significant Labor Savings AWIP wall and roof panels virtually slide together with tongueand-groove joinery or with an overlapping edge. IMPs install quickly and easily with concealed fastening and provide a complete weatherproof building envelope, offering the best value for insulation. At an approximate R-value of 8 per inch, an AWIP 4-inch wall or roof panel has an R-value of 32, easily exceeding the new R-value standard of 30 prescribed for roofs in most metro areas. On large, low-slope projects, the OneDek roof system encapsulates all IMP benefits: • Less construction time • Fewer components to install • Safer work platform during installation • Significant savings in labor and equipment costs Mark Munley, product manager for OneDek, has more than three decades in commercial roofing. Munley calls OneDek “the most significant development within the commercial roofing space during [his] career.” “The advantage is that the OneDek system can be installed by any trained trade, in all types of weather conditions, for any low-slope (2-degrees or less) roofing project,” Munley says. “It can be done in phases, meaning significant savings for contractors and owners to consider. Getting the building ‘dried in’ faster with less consequential damage is a game-changer in terms of construction costs.”

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OneDek: 2 Is Better Than 3 Traditional low-slope roof systems are assembled in three steps. First, metal decking is secured to the building’s roof supports. Then, the rigid insulation board is layered, staggered, and fastened atop the decking, after which (Step 3) a waterproof membrane is added. The costly, time-consuming second step of adding rigid board insulation is eliminated with AWIP’s OneDek roof system. On a 100,000-square-foot roof typically found on cold storage and warehouse buildings, up to 20,000 fasteners and plates can be required to secure the insulation, which may take two crews of five up to two weeks to complete. It is common for large projects to carry costs up to $1 million a week, so two weeks’ worth of savings on labor and equipment goes a long way to making the project a success. The roll-formed tongue-and-groove joinery of the RD1 panels enables long length panels to slide together and be mechanically attached to the roof ’s structural supports using specific fastening systems to meet project requirements. Then, a white PVC or TPO waterproofing membrane is either installed mechanically onto the 22 ga RD1 deck surface or adhered to the factory-primed surface. OneDek requires less than half of the fasteners, cutting hundreds of labor hours out of installation time as well as reducing equipment rental costs. Our RDl insulated roof deck panel is at the center of the OneDek system. The RD1 has an exterior and interior steel liner which is vapor and water tight. Unlike traditional assemblies, there is little fear of walking on our RDl deck, making for a safer, damage-free working platform. “The greater benefit is that the robust RD1 panel in the OneDek system will virtually eliminate callbacks regarding damages by other trades and third parties,” Munley points out. The OneDek roof system is the cost-competitive solution to meet the performance needs of design professionals while also providing the installation community with an efficient, safe, and durable commercial roofing system that will last multiple roof generations. sales@awipanels.com | www.awipanels.com

ADVERTORIAL

s the construction industry becomes more cognizant about sustainability and green design, architects and structural engineers face daunting challenges – design a building that is energy-efficient, can offer savings, and have fewer obstacles during construction, and yet, over the life of the building, continue to meet, if not exceed, environmental and energy standards. That’s where insulated metal panels (IMPs) come in. Founded in 2004, All Weather Insulated Panels (AWIP) is an innovator in the design, construction, and advancement of insulated metal panels. These unique composites consist of closed-cell polyisocyanurate foam encased by two sheets of light gauge factory-coated steel. The combination of these components results in lightweight, high-strength building modules with exceptional thermal characteristics compared with antiquated field-assembled walls and roofs. For years, IMPs have been used as non-load bearing exterior wall and roof cladding materials, and act as the insulation and primary weather barrier. However, recent studies show that these composite panels are also capable as structural components of building design. With proper attachment methods and design, insulated metal roof deck panels can provide diaphragm shear resistance similar to traditional wide rib (Type B) roof decks. AWIP’s OneDek™ roof deck solution provides the industry with long-term energy efficiency while bringing significant savings during installation.

ONEDEK

™

THE FUTURE OF ROOF DECK CONSTRUCTION

OneDek™ from All Weather Insulated Panels is a superior alternative to traditional roof deck systems. Requiring fewer steps to install, OneDek™ saves construction time in providing exceptional energy efficiency for your low-slope roofing project, and an industry exclusive 20-year top-to-bottom “System Warranty” is available. MULTI-STEP TRADITIONAL BUILT UP DECK SYSTEM Multiple layers of rigid board

Membrane Smooth flat exterior steel substrate



Field-applied Membrane 10”-14”

Steel decking Requires numerous long deck screws attached through multi-layer system

Composite Insulated Roof Deck Panel R values up to 50 (6” thick)

 Commercial / Industrial / Cold Storage

THE

ONEDEK

SYSTEM

OneDek™ is the revolutionary insulated roof deck with insulation and substrate formed at the factory so it arrives on the job site more secure and stronger than components of traditional built-up roof applications.

is better than

OneDek™ Step 1: Composite Insulated Deck Step 2: Waterproofing Other Multi-Layer System

• Incredibly fast installation, no on-site application of rigid foam insulation Step 1: Steel Decking Step 2: Multi Layer Rigid Insulation • Steel substrate provides exceptional damage & fire resistance Step 3: Waterproofing • Tested for diaphragm shear resistance and wind uplift • TPO or PVC membranes easily fastened mechanically or fully adhered • Interior factory white painted steel in clean washable finish reduces lighting needs • “System Warranty” covers membrane through to structural steel, including insulation and fastening applications

www.awipanels.com Contact: Sales@awipanels.com 888-970-AWIP (2947)

STRUCTURE solutions

PROFILE

NUCOR TUBULAR PRODUCTS

ndependence Tube, Southland Tube, and Republic Conduit have merged with Nucor Corporation to form its newest division. Nucor Tubular Products will be your first choice when it comes to purchasing Hollow Structural Sections (HSS), ASTM A513, ASTM A53 pipe, ASTM A135/ASTM A795 fire protection sprinkler pipe and conduit. Nucor Tubular Products are used in a broad array of structural and mechanical applications including non-residential construction, infrastructure and agricultural, and construction equipment and end use markets. Nucor Tubular products sells its products primarily through service centers. As part of our tubular family, Republic Conduit continues to offer its electrical conduit products designed to reduce installation costs and jobsite delays. Nucor Tubular produces steel tubing in the following sizes. 840” x .109” wall . . . . . . . . . . . .through . . . . . . . . . . 16”OD x .625” wall 1½” SQ x .125” wall . . . . . . . . .through . . . . . . . . . . 12” SQ x .625” wall 2½” x 1½” x .125” wall . . . . . . .through . . . . . . . . . . 16” x 8” x .625” wall

ASTM A513 ROUNDS SQUARES RECTANGLES

1”OD x .065” wall . . . . . . . . . .through . . . . . . . . . . .5”OD x .120” wall ½” SQ x .065” wall . . . . . . . . . .through . . . . . . . . . . .3½” SQ x .120” wall 1½” x 1”x .065” wall . . . . . . . . .through . . . . . . . . . . .5” x 2” x .120” wall

ASTM A53 INDEPENDENCE TUBE also manufactures ASTM A53 Type E Grade B pipe in Trinity Alabama in sizes from: Schedule 40 – 2” NPS through 8” NPS | Schedule 80 – 2” NPS through 4” NPS ASTM A135 /ASTM A795 Schedule 10 2” NPS through 8” NPS Schedule 40 2” NPS through 8” NPS UL and C-UL listed, and FM approved. All of the schedule 10 has ITC MIC Guard applied and is CPVC compatible. Rolling Schedule With a yearly-published on–time rolling schedule second to none in the industry, you can manage your inventory more closely, knowing that material will be ready when promised. Nucor Tubular Products also offers Vendor Managed Inventory (VMI), Electronic Data Interchange (EDI), and bar coding, all of which have become very important services in the management of inventory and communications. Value Added Services include: • I.D. flash removal • HSLA grades • Charpy V-notch testing • Pickled and oiled • Weld on the short side

• Special tolerances • Flux leakage • A252 Pipe beveling • Band saw cutting • Mitre cutting

www.ntpportal.com is our 24/7 online customer secure Portal which will allow you to view inventory, place orders and inquiries, release loads, and view and download open order reports and test reports. Nucor Tubular Products is an active member of the American Institute of Steel Construction (AISC), the Metals Service Center Institute (MSCI), the Farm Equipment Manufacturers Association (FEMA), the Pile Driving Contractors Association (PDCA), and the National Association of Pipe Distributors (NASPD). Its products can be purchased at steel service centers across North America. www.nucortubular.com

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ADVERTORIAL

ASTM A500 ROUNDS SQUARES RECTANGLES

THE ULTIMATE RESOURCE IN TUBULAR PRODUCTS

IS HERE Independence Tube Corporation, Southland Tube, and Republic Conduit are now Nucor Tubular Products. As we come together as part of Nucor, North America’s leading steel company, we remain dedicated to working with you, our customer. As a result, our HSS line now boasts a wider product range. But one thing hasn’t changed, our quality and service continues to be among the best in the industry. We pioneered on-line ordering with our 24/7 customer secure portal and our on time rolling schedule is considered to be second to none among our customers. As part of our tubular family, Republic Conduit continues to offer its electrical conduit products designed to reduce installation costs and jobsite delays. This winning combination of products and innovation continues to support the reason why we have been so successful: working together and dedicated to providing our customers with the best products and services in the industry. Our locations include: Birmingham, AL; Cedar Springs, GA; Chicago, IL; Decatur, AL; Louisville, KY; Marseilles, IL; and Trinity, AL.

NTP Grades include: • ASTM A500 • ASTM A252 • ASTM A1085 • ASTM A513 • A53 grade B Type E ERW • ASTM A135 and ASTM A795 Sprinkler Pipe

HSS Sizes include: Squares: ½" x 16" gauge through 12" x .625" wall Rectangles: 1 ½" x 1" x 16 gauge through 16" x .625" wall Rounds: .840" OD x .109" wall through 16" OD x .688" wall

Learn more at www.nucortubular.com

STRUCTURE solutions

PIERESEARCH®

PROFILE

Deep Foundation and Earth Retention Alignment Products

Deep Foundations Our products are made of top-quality durable plastic. These include snap-on wheels, reinforcing cage bottom boots and bar boosters for drilled shafts, as well as centralizing and alignment products for single element reinforcing used in augercast piles and micropiles construction.

Earth Retention Pieresearch’s line of patented UNIBARS® has become the leading alignment aid for the installation of tiebacks and soil nails. Our revolutionary UNIBARS are available in a wide variety of dimensions that accommodate all standard rebar sizes. The brand new, adjustable UNIBAR, coming in mid-July, is easy to install and meets every design need.

What Users Say About Our Products “We specify Pieresearch because, in our opinion, they’ve got the best product on the market for stabilizing the reinforcing cage as it is being placed in the drilled shaft.” Steve Campbell, PE, SE, SECB “We specify Pieresearch products because they are high quality and they add significant value to the project.” Charles Grossman, PE “We’ve been specifying Pieresearch Products for more than 18 years because we look for the most economical and most reliable systems that keep us current with the best methods available.” Salvador Nunez, PE, BSCE/AE

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The Best, So You Can Rest Our website, www.pieresearch.com, is a working resource for engineers and specifiers. The site provides specification guidance, a handy quantity calculator, How-To installation videos, and technical design and management articles from leading engineers and industry management professionals. Visit our site to find information that you can use every day. Having excellent products are all well and good but, in the topsy-turvy, schedule-driven world of geoconstuction, having the product you need when and where you need it is critical. To this end, Pieresearch provides a Service Hotline to accommodate our customers. In most cases, and depending on availability, we will ship your order to a location of choice within 24 hours of receiving your request. We are pleased to report that our products have been and are being used on major construction projects throughout the United States. A representative sample includes: Goethals Bridge NY/NJ, New York Wittpenn Bridge, NJ Kosciuszko Bridge, New York, NY Tappan Zee Bridge, New York, NY Globe Park Texas Rangers Baseball Stadium, Arlington, TX Sky Harbor Bridge, Corpus Christi, TX University of Chicago, WERC Project, Chicago, IL Exxon Corporate Headquarters, Irving TX Winspear Opera House, Dallas, TX Capitol Crossing, Washington DC Cowboys Stadium, Arlington, TX Northgate Project, Seattle, WA Red Rock Hydroelectric Project, Pella, IA Texas Motor Speedway, Northlake, TX Baylor University Commons Building, Waco, TX TCC Football Stadium, Ft. Worth, TX American Airlines Center, Dallas/Ft. Worth, TX For an extended listing of major projects visit our website, Homepage/Projects. When it comes to centralizer and alignment aids, you need to go no further than Pieresearch. Contact us today; we’ll be there to meet your every alignment need. For detailed information about Pieresearch’s wide variety of alignment products for earth retention, drilled shafts, micropiles, augercast piles, and other deep foundation applications, visit our website or call Stan Agee at 817-277-3738.

ADVERTORIAL

t is widely accepted that, when it comes to designing and constructing deep foundations and anchored earth retention systems, one of the main concerns facing structural engineers, geotechnical professionals, and specialty geo-constructors is quality control and quality assurance. Engineers seek confidence that the support systems and deep foundations they design are built as intended. Geo-constructor’s strive to deliver a reliable product. The correct placement of concrete and/or grout are key ingredients of successful construction. The use of centralizers, spacers and related alignment tools help insure that foundation and earth support reinforcing elements perform as intended. For over 30 decades, Pieresearch, Arlington, TX, has been designing and manufacturing cuttingedge products that address QA/QC concerns. Long considered an industry leader, Pieresearch has developed innovative products for every reinforcing steel alignment need. Whether it is for drilled shafts, augercast piles, micropiles, tieback anchors, or soil nails, Pieresearch is the go-to company for field-proven, high quality, easy-to-install alignment aids.

DETAILS MATTER, DON’T PUT YOUR PROJECTS AT RISK.

BUILD WITH ESTABLISHED RELIABILITY – SPECIFY PIERESEARCH FOR ALL YOUR REBAR AND REBAR CAGE ALIGNMENT COMPONENTS.

Unique one-piece designs, made of noncorrosive plastic, install in seconds and are built tough!

DURABLE. ECONOMICAL. RELIABLE. PROVEN.

Quick - Lock HD ® Pier Wheel

Quick - Lock® Pier Wheel

Quick - Lock Pier Boot ®

Quick - Zip ® Bar Booster

INTRODUCING THE REVOLUTIONARY NEW QUICK-LOCK UNIBAR CENTRALIZER ®

Patent No. 10,151,113

SEE OUR INFORMATIVE DRILLED SHAFT, WHEELS & BOOTS, AND UNIBAR VIDEOS.

Visit pieresearch.com to see our full line of alignment products, download spec kits, watch how-to videos and request free samples.

pieresearch.com • stanagee@pieresearch.com 817.277.3738 • 817.275.2335 Fax New York Office contact Herb Engler 718.786.8814 • herbengler@pieresearch.com ®

Manufacturer of Quality Concrete te Accessories Proudly Made in the USA! EST. 1986

STRUCTURE solutions

RISA

PROFILE

ISA believes structural engineering software should be powerful, accurate, and user-friendly. The RISA Building System designs steel, concrete, timber, masonry, aluminum and cold-formed steel all in a single, seamlessly integrated model. The following recent case studies illustrate the versatility of our software.

Project: Binghamton University Smart Energy Building

Project: Center for Naval Aviation Technical Training Complex Building Client: Naval Facilities Engineering Command Structural Engineer: SMR-ISD Consulting Structural Engineers, San Diego, CA The Center for Naval Aviation Technical Training Complex is a 131,000-square-foot facility which houses all aviation mechanics responsible for the maintenance of Huey and Cobra helicopters stationed at Camp Pendleton Marine Corps base, as well as space for administrative and training activities. SMR-ISD Consulting Structural Engineers utilized BIM models in order to work collaboratively with the architect; these models were then exchanged with RISA-3D using the RISA-Revit Link. Once the models were available in RISA-3D, the engineer could focus on the design challenges that existed. One such challenge was the hangar 46-SS STRUCTURE solutions

Project: Splash Lagoon Indoor Waterpark Resort Building Client: Scott Enterprises, Erie, PA Structural Engineer: Urban Engineers, Inc., Philadelphia, PA Splash Lagoon Indoor Waterpark Resort, located in Erie, PA, allows visitors to enjoy summer activities year-round and was recently ranked as the #4 indoor waterpark by USAToday. The 80,000-square-foot facility includes 12 waterslides, numerous pools, interactive treehouse, ropes course, arcade, laser tag facility, and wave pool for guests to enjoy year-round. The main structure includes a large, clear span for the attractions, and glulam timber columns were used to support the exposed framing system designed for the Splash Lagoon’s roof. In total, the Splash Lagoon Indoor Waterpark Resort main structure only required 10 interior columns as a result of the 84-foot glulam girders. Another unique structural feature is that of the tree-shaped columns, which made specifying narrower girders and trusses easier. More recently, the waterpark expanded to include a 200,000-gallon wave pool, which is the largest in the Eastern United States. The addition includes the use of 120-foot clear span glulam trusses supported by circular concrete columns. As with many projects, Dave Steele, Vice President of Urban Engineers (Philadelphia, PA), faced the dilemma of how to best deal with changes and, as a result, required a software that could save him the most time. His choice of RISA-3D and RISAFoundation allowed for the modeling of both the gravity and lateral systems as well as the structure’s foundations. The features that saved Steele the most time were RISA-3D’s “physical members” which allows for fixity to be applied to all joints that occur along the length of the member, without breaking the member up 949-951-5815 risa.com into multiple smaller members.

ADVERTORIAL

Building Client: Binghamton University Structural Engineer: Ryan Biggs | Clark Davis, Engineering and Surveying P.C., Skaneateles Falls, NY The new 105,000-square-foot Smart Energy Building at Binghamton University is part of a series of laboratory research facilities being built on campus. The $45 million building consists of several separate programmatic spaces including two laboratory “pods,” the atrium that connects them, and a rotunda structure that links the building with the adjacent Center for Excellence. The main structural system consists of steel framing on a concrete basement and concrete spread foundations. Moment frames are used in each direction within the laboratory pods to resist Binghamton University Smart Energy Building lateral forces. Additionally, the first floor of each pod was designed for floor vibrations due to human activity according to AISC Design Guide #11. Overall, the building’s use of curved, round HSS members serves as one of its primary visual features and achieves the architect’s vision of creating visual interest from both the interior and exterior of the structure. The more ornate elements of the structure, including the atrium roof trusses, link rotunda, tree stair as well as various canopies were designed using RISA. For the trusses, AutoCAD geometry was imported into RISA-3D to perform a 2-D analysis and obtain initial member sizes. These design elements were then included with the entire roof structure, including the columns, in order to verify the full design. Additionally, the plate analysis features of RISA-3D were used in the design of the 40-foot-diameter link rotunda in order to determine stress concentrations at the locations where members were welded together.

structure that features a 10-foot-wide by 16-foot-deep space truss which weighs 250 tons and spans 320 feet, providing unobstructed entry for up to 9 helicopCenter for Naval Aviation Technical Training Complex ters. The overall depth of the truss was governed by the 29-foot clear height that was required for the operation and maintenance of the helicopters. This required the engineer to use RISA-3D to evaluate the truss iteratively in order to determine the most optimal design while minimizing overall steel tonnage. The hangar also includes two, 5-ton bridge cranes that serve the entire hangar area and are attached to the bottom chord of the trusses spanning in the direction opposite the hangar opening. These transverse trusses were also included in the same RISA-3D model and necessitated special consideration due to the L/600 deflection limit required for proper operation of the crane. Overall, the entire hanger structure was modeled, analyzed, and designed in RISA-3D.

STRUCTURE solutions

PROFILE

HOHMANN & BARNARD, INC. Pushing the Envelope since 1933

ohmann & Barnard, Inc., serves both the commercial and residential markets as the leading developer and distributor of reinforcement, anchoring, and moisture protection systems for masonry. An exciting part of Hohmann & Barnard’s product line is our thermal products. Our TBS Thermal Brick Support System, a groundbreaking brick veneer support system, offers many benefits. It reduces thermal bridging in relief angles and also allows for the installation of continuous insulation behind the support angle. A recent study showed attached shelf angles will create an effective reduction of the R-Value by between 46 percent and 63 percent. The same study shows that offset angles minimize that reduction to between 15 percent and 16.5 percent. Each job is designed and engineered in-house to meet your specific project needs. Among Hohmann & Barnard’s thermal offerings is our Thermal Wingnut – the only functional wingnut anchor in the industry. As the wingnut tightens, it presses the insulation tight against the backup wall, maximizing its R-Value. Single-barrel means a single

penetration, as opposed to anchors that typically require two fasteners. This means the number of thermal bridges is reduced by half. Using a wall configuration with 4 inches of XPS insulation, at 16- x 16-inch spacings, typical masonry anchors can lead to an R-Value reduction of upward of 20 percent or greater. This anchor limits that effective R-Value reduction to 7.4 percent or operating at 92.6 percent efficiency. The steel-reinforced wing maintains integrity during NFPA 285 testing. Hohmann & Barnard’s line of Thermal 2-SEALTM anchors uses a proprietary UL-94 coating to create a thermal break at the insulation, and a stainless-steel barrel that transfers 1/7th the thermal energy of a standard zinc barrel. The dual-diameter barrel with EPDM washers makes our 2-SEAL line the only anchors on the market to seal both the insulation and the air barrier. In fact, we make the only anchors to seal the air barrier. 800-645-0616 | weanchor@h-b.com | www.h-b.com

REDUCE THERMAL TRANSFER

CONCRETE THERMAL 2-SEAL™ WING NUT

With Hohmann & Barnard’s Thermal Products VISIT

STEEL REINFORCED WING MAINTAINS INTEGRITY DURING NFPA 285 TESTING.

www.h-b.com/thermal

for more information

TBS

Thermal Brick Support System

48-SS STRUCTURE solutions

ADVERTORIAL

STRUCTURE solutions

NCEES

Discover more.

PROFILE to complete the licensure process. An established NCEES Record will include most – if not all – of the materials you need to apply for comity licensure in additional states and territories. Credentials Evaluations: The service is intended primarily for candidates who have earned degrees outside the United States and are pursuing licensure. CPC Tracking: Most state licensing boards require licensed engineers and surveyors to meet a continuing professional competency (CPC) requirement to renew a license. You can track and report your CPC requirements for free through your MyNCEES account. Engineering Education Award: The annual award has a $25,000 grand prize and recognizes college engineering programs for engaging their students in collaborative projects with licensed professional engineers.

ADVERTORIAL

he National Council of Examiners for Engineering and Surveying (NCEES) is a nonprofit organization made up of engineering and surveying licensing boards from all U.S. states and territories and the District of Columbia. Since its founding in 1920, NCEES has been committed to advancing licensure for engineers and surveyors in order to safeguard the health, safety, and welfare of the U.S. public. NCEES develops, administers, and scores the exams used for engineering and surveying licensure in the United States. It also facilitates professional mobility and promotes uniformity of the U.S. licensure processes through services for its member licensing boards and licensees. These services include the following: Engineering Exams: The FE exam is generally the first step to becoming a professional licensed engineer. The PE exam is designed to test for a minimum level of competency in a particular engineering discipline. It is intended for engineers who have gained a minimum of four years of work experience in a discipline. The SE exam is designed for engineers who practice in jurisdictions that license structural engineers separately from other professional engineers. Exam Prep Materials: NCEES exam preparation materials are developed by the same people who create the licensing exam. Records Program: The program is designed for currently licensed engineers and surveyors who are looking for an easier and faster way

outreach@ncees.org | www.ncees.org

RECORDS “An NCEES Record makes it fast, easy, and convenient to apply for additional P.E. licenses in other states.” Alexander Zuendt, P.E. Zuendt Engineering Record holder since 2011

National Council of Examiners for Engineering and Surveying® P.O. Box 1686, Clemson, S.C. 29633 864.654.6824

Build your NCEES Record today. ncees.org/records

M AY 2 019

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STRUCTURE solutions

PROFILE

AMERICAN CONCRETE INSTITUTE

ACI monthly webinars and ACI’s 175+ on-demand courses. Some topics include Admixtures, Codes, Cracking, Design, Durability, and much more. The ACI University subscription allows individuals to access each course one time during the subscription period. The access period for each course is 30 or 90 days, depending on the course (see course details). Additional quantities or repeat access to a course during the subscription period may be purchased separately. ACI publishes Symposium Publications in conjunction with many ACI-sponsored symposia and convention sessions on various

50-SS STRUCTURE solutions

industry hot topics. These publications often include more than a dozen papers authored and compiled by leading industry designers, practitioners, researchers, and academicians. ACI now provides unlimited access to new and archived papers from all Symposium Publications. The Symposium Papers Subscription provides 12 months of digital access to over 6,000 papers published since 1962, plus any new papers that are published. The most recent subscription launched by ACI in January 2019 is the Concrete Repair Subscription. This online subscription includes digital access to the American Concrete Institute’s technical and educational content on concrete assessment, repair, rehabilitation, and more. Subscribers will receive twelve months of access to ACI’s existing concrete repair-specific code requirements/commentary, specifications, guides, reports, symposium volumes, and ACI University on-demand courses, plus new materials as they are published/developed. Specific contents include: • 65+ codes, specifications, guides, and reports, including ACI 562-16: Code Requirements for Assessment, Repair, and Rehabilitation of Existing Concrete Structures and Commentary, ACI 563-18: Specifications for Repair of Concrete in Buildings, ACI 364.1R-07: Guide for Evaluation of Concrete Structures Before Rehabilitation, and more; • 16+ educational publications and documents, including Guide to the Code for Assessment, Repair, and Rehabilitation of Existing Concrete Structures and the Repair Application Procedures series; • 33+ on-demand courses through ACI University, including all courses required to earn the “ACI Repair Application Procedures” certificate, plus recorded webinars and self-paced courses featuring ACI 562 design examples, guidance for incorporating ACI 563 into concrete repair projects, materials selection for concrete repair, and more; and • 25+ symposium volumes containing 500 total papers on a diverse range of concrete repair topics. For more information regarding ACI subscriptions, please visit www.concrete.org. 248-848-3700 acicustomerservice@concrete.org

ADVERTORIAL

ounded in 1904 and headquartered in Farmington Hills, MI, the American Concrete Institute (ACI) is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensus-based standards, technical resources, educational & training programs, certification programs, and proven expertise for individuals and organizations involved in concrete design, construction, and materials, who share a commitment to pursuing the best use of concrete. ACI has over 95 chapters, 110 student chapters, and nearly 30,000 members spanning over 120 countries. ACI is the premiere, global community dedicated to the best use of concrete. Over the past year, ACI has built up its subscription platform to give users the ability to gain digital access to a large portion of ACI’s concrete resources in one central location. The online ACI Collection of Concrete Codes, Specifications, and Practices contains nearly 50 codes and specifications plus 200+ practices (including all guides and reports) and is the most comprehensive, always updated, and largest single source of information on concrete design, construction, and materials. Featuring ACI 318: Building Code Requirements for Structural Concrete, ACI 301: Specifications for Structural Concrete, and ACI 562: Code Requirements for Assessment, Repair, and Rehabilitation of Existing Concrete Structures and Commentary, additional categories in the ACI Collection include concrete materials, properties, design, construction, reinforcement, specialized applications, repair, structural analysis, and innovation, plus popular topics such as slabs, formwork, and masonry. ACI also offers an all-access subscription to ACI University webinars and on-demand courses. This 12-month subscription includes all

ACI Convention

Grow industry knowledge & connect with the brightest leaders in concrete at 120+ sessions & events.

STRUCTURE solutions

PROFILE

DLUBAL SOFTWARE

The add-on modules for steel and concrete design apply code provisions per the AISC and ACI to determine unity checks and reinforcement layout. Result output in these modules is among the most transparent any software can provide. Complete with listed variables and code references for all equations used, engineers have little doubt on how the program is ultimately determining final code checks.

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Do not discount Dlubal when it comes to steel and concrete design, as they do it well; however, they also recognize this is the most competitive material design when it comes to structural analysis software. Where RFEM continues to thrive are the niche markets where other software has yet to explore. RFEM single-handedly stands out with additional design modules for aluminum (ADM), timber (NDS), cross-laminated timber (NDS), glass (stress design), and the fabric and form-finding procedure. Engineers do not have an efficient solution for the design of these various materials. As projects become increasingly more complex and deadlines become increasingly shorter, a more advanced structural analysis program such as RFEM is needed to move forward and stay ahead of the competition. One of Dlubal’s most valuable clients, Moses Structural Engineers located in Toronto, Canada, utilized Dlubal Software for the analysis and design of a timber veil structure over the TD Place Stadium in Ottawa, Canada. The veil consisted of 24 curved, glued-laminated members. The curved beams are further connected horizontally with multiple, smaller glued-laminated beams with additional steel diagonals to provide lateral stiffness. The elegant timber veil has received numerous awards throughout Canada. Another valued client, Bensonwood located in Walpole, NH, utilized RFEM’s cross-laminated timber design to complete the unique and functional art installation, Conversation Plinth, in front of the Cleo Rogers Memorial Library in Columbus, IN. Conversation Plinth was designed to generate conversation around the use of hardwood CLTs in U.S. construction, as only softwoods have primarily been used thus far. Custom CLT compositions were assigned to 84 curved surfaces in order to carry out a stress and deflection analysis utilizing Dlubal Software’s RFEM. In summary, Dlubal Software aims to integrate the most powerful yet user-friendly FEA program with today’s engineers to meet the challenges of modern-day structural engineering. Building heights are increasing, materials are no longer limited to steel and concrete, and structure designs now include complex curvatures and asymmetric layouts. Structural engineers need software that can not only keep up with the demand but far exceed it. 267-702-2815 | info-us@dlubal.com | www.dlubal.com

ADVERTORIAL

n 1987, Dlubal Software was founded by George Dlubal in the remote town of Harsewinkel, Germany. Over the last 30 years, the company has grown to more than 200 employees in six different office locations. In July of 2015, the Philadelphia, PA, office was established to emerge as a competitive player in the North American structural engineering software market. The 3-D finite element program, RFEM, is the main attraction among the Dlubal Software lineup, a nonlinear program capable of not only 1-D member analysis but also 2-D and 3-D elements such as plates, shells, and solids. In a market full of similar programs and other competitors, Dlubal knew that RFEM had to stand out among the crowd. The company takes extreme pride in its user-friendly and intuitive programs. Although the capabilities of the software can explore the extreme depths of nonlinear structural analysis, the modeling ease, workflow, and organized data input and results won’t leave engineers in need of endless training to learn the program. Rather, in a matter of hours, along with the technical guidance of Dlubal’s technical support engineers and online resources, users will have a firm grasp on how to generate and analyze a structural model. RFEM works with the modular concept system. Any design or advanced capabilities beyond the static analysis provided in RFEM are available with the vast array of add-on modules. The add-on module RF-MAT NL, for example, allows for consideration of nonlinear material behavior in RFEM. This includes isotropic plastic, isotropic nonlinear elastic, isotropic thermal elastic, and many more for 1-D, 2-D, and 3-D elements. The module RF-STABILITY analyzes the stability of the structure and calculates critical load factors and corresponding stability modes. When many other programs cannot take into consideration buckling behavior of member, plate, and shell elements, RFEM steps up.

Powerful, Easy, and Intuitive

FREE 90-DAY TRIAL FREE TECHNICAL SUPPORT

RFEM 5 The 3D FEA Structural Analysis Software The 3D FEA structural analysis software RFEM is the basis of a modular software system. The main program RFEM is used to define structures, materials, and loads for planar and spatial structural systems consisting of members, plates, walls, shells, solids, and contact elements. The add-on modules perform design per the USA, Canadian, and other international standards for various materials and applications. Create a software package specific to your design needs.

Dlubal Software, Inc. 30 South 15th Street, 15th Floor Philadelphia, PA 19102

Phone: E-mail:

(267) 702-2815 info-us@dlubal.com

Nonlinear Analysis Steel Concrete Timber Aluminum

CLT Glass Form-Finding Dynamic Analysis BIM Integration

www.dlubal.com

STRUCTURE solutions

PROFILE

LNA SOLUTIONS A KEE SAFETY COMPANY

erving the structural design-build industry since 1995, LNA Solutions is North America’s leading provider of strong, safe, steelwork connections. The company offers a complete line of steel-to-steel connection components backed by free technical design and engineering support. As a Kee Safety Company, LNA Solutions brings to market the strength and resources of a global manufacturing and customer service organization.

a seismic solution for engineers, architects, and specifiers where uncompromising steel-to-steel connections are critical.

First in Service and Support

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ADVERTORIAL

LNA Solutions provides technical design solutions for any industrial, commercial, institutional, or municipal steel connection challenge. A team of experienced engineers and sales support professionals ensure that every customer receives a design to meet their specific construction Install without project needs. Welding or Drilling Products are manufactured to the highest The hallmark of the standards. Every order LNA Solutions line of BeamClamp®, BoxBolt® BoxBolt attaching curtain wall brackets to hollow tube steel structure. undergoes rigorous quality expansion anchors and control to ensure full comselection of floor fasteners is that they connect steel-to-steel without pliance with specifications and codes. There is added emphasis on the need for welding or drilling and bolting. These conventional meeting the customer’s delivery schedule and supporting installation. methods require expensive equipment, skilled labor, and often Product Line additional work permits. They do not allow for onsite adjustments like the LNA Solutions product line does. • BoxBolt blind steel connectors to connect to Hollow With LNA Solutions, builders can achieve significant savings in Structural Sections (HSS) where access to the back of the connection is restricted. time and cost while installing component-based steel connectors • BoxSok® specially designed tool to expedite the installation that have a Safe Working Load with a published Factor of Safety. of BoxBolt. Seismic Solutions • BeamClamp line of engineered steel-to-steel clamping systems for permanent or temporary connections that allow for In 2012, BoxBolt became the first blind bolt to receive an easy on-site adjustment. International Code Council (ICC) Evaluation Service Report • FastFit® steel-to-steel fastening products that provide a secure for use as ICC-ES ESR-3217. ICC is an accrediting association clamping method for structural steel. dedicated to developing model codes and standards used in the • GrateFix floor fasteners that secure open floor grating the design, build, and compliance process to construct safe, sustainsupporting steel from the top. able, affordable and resilient structures. • Grating Clip fasteners – galvanized for corrosion resistance In 2018, BoxBolt received subsequent Type C accreditation for – to clamp down open steel flooring. seismic design categories A through F by ICC-ES as published in • FloorFix to clamp flooring plates to supporting steel from ESR-3217. In addition to seismic approval, the type C BoxBolt the top is now hot dip galvanized to BS EN ISO 1461 for extra corrosion protection. This enables BoxBolt to comply with demanding seismic stan888-724-2323 | tziccardi@lnasolutions.com dards for building construction in volatile earthquake regions. This www.lnasolutions.com approval provides confidence in the dependability of BoxBolt as

STRUCTURE solutions

PROFILE

LARSEN PRODUCTS

beds for ceramic tile, for bonding Portland Cement plaster and stucco mixes, and to bond to such surfaces as brick, block, tile, marble, metal, glass block, soundly adhered paint (non-soluble in water), and silicone. Our original chemical, concrete bonding agent incorporates polyvinyl acetate homopolymer in a patented formulation and has been specified in major construction projects around the globe. If you have not yet specified Weld-Crete, we encourage you to reach out to us directly to learn more. We will answer any questions you may have so that you feel completely confident spec’ing our product. To our current engineers and architects who consistently specify Weld-Crete, we thank you for your loyalty and look forward to seeing Weld-Crete specified in your projects for years to come. For over sixty years we have set the standard for bonding agents and take great pride in the reliability, consistency, and overall product quality that Weld-Crete offers. This, along with our unparalleled customer service and support, and our desire for every customer to be completely satisfied, is why Larsen Products Corp. has been an industry-trusted source by architects 800-633-6668 and engineers worldwide since 1952. claire@larsenproducts.com For more information, visit our www.larsenproducts.com website or contact us directly.

Weld-Crete®—The pale blue bonding agent with over 60 years of superior performance in the field.

Simply brush, roll or spray Weld-Crete® on to concrete or any structurally sound surface. Then come back hours, days or a week later and finish with new concrete, stucco, tile, terrazzo, other cement mixes or portland cement plaster. Plus Weld-Crete’s® low VOC content significantly reduces airborne pollutants that affect health and the environment.

Originators of leading chemical bonding agents… worldwide since 1952

800.633.6668 www.larsenproducts.com

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ADVERTORIAL

high-performance, low VOC concrete bonding agent, Weld-Crete® bonds new concrete, stucco, tile setting beds, and terrazzo to any structurally-sound surface, be it on the interior or exterior. Weld-Crete’s open time lets you bond to concrete shear walls when needing a time lapse between the application of the bonding agent, the placement of reinforcement steel, placement of formwork, or the placement of concrete. Conveniently, Weld-Crete can be “painted on” in a single application for a wide range of time-lapses. You can save time on the job by painting on Weld-Crete in a single application, prior to concrete placement. Use Weld-Crete’s broad open time (1 hour to 10 days after applied) to your advantage in bonding to concrete shear walls; when you need a time lapse between application of bonding agent; placement of reinforcing steel; placement of formwork; and placement of concrete. Weld-Crete is also used for bonding setting

STRUCTURE solutions

PROFILE

WILLIAMS FORM ENGINEERING

illiams Form Engineering Corporation has been providing threaded steel bars and accessories for rock, soil and concrete anchors, post tensioning systems, and concrete forming hardware systems in the construction industry for over 95 years. Williams’ pre-stressing / post tensioning 150 KSI All-ThreadBars are high tensile steel bars available in seven diameters from 1 inch (26 mm) to 3 inches (75 mm), with guaranteed tensile strengths to 969 kips (4311 kN). Bars are cold rolled threaded to close tolerances under continuous monitoring procedures for quality control. Threads for Williams 150 KSI bar are specially designed with a rugged thread pitch wide enough to be fast under job site conditions and easy to assemble. They also have a smooth, wide, concentric surface suitable for torque tensioning.

This combination offers tremendous installation savings over inefficient, hot rolled, non-concentric thread forms. The 360° continuous thread deformation pattern has the ideal relative rib area configuration to provide excellent bond strength capability to grout or concrete, far better than traditional reinforcing deformation patterns. Threads are available in both right- and left-hand in all diameters. All 150 KSI All-Thread-Bar fasteners are machine threaded (no cast threads) to specific tolerances for precision adjustments. All fasteners are designed to develop 100% of the bar’s ultimate strength, meeting all criteria set forth for anchorages by the Post- 616-866-0815 williams@williamsform.com Tensioning Institute and ASTM www.williamsform.com A-722 specifications.

ADVERTORIAL

one source FOR MICROPILE

QUALITY SYSTEMS LARGE BAR . HOLLOW BAR . MULTI-BAR

reliable | durable | versatile

Large Bar Micropiles: • Excellent choice for underpinning or emergency repairs All-Thread Bar — can be installed in virtually any ground condition with with Steel Casing minimal vibration and disturbance to existing structures. Geo-Drill Injection Bar • Right-handed threaded Grade 75 All-Thread Rebar in #14 – #28 along with a selection of reducer couplers that can adapt to space together any larger size bar to any small size. • Grade 80 to 100 All-Thread Rebar, as well as 150 ksi All-Thread Bar (as alternative for micropile design application upon request).

Williams Multi-Bar Micropile System

Hollow Bar Micropiles: • Accepted by the FHWA in the Micropile Design and Construction Guidelines Manual, Hollow Bars are being used increasingly for micropile applications as the reinforcement bar choice in collapsing soil conditions because of their increased bond stress resultant from the simultaneous drilling and grouting operation. • Using sizes from 32mm – 76mm, these bars offer up to 407 kips of strength, up to 3.88in2 of cross sectional reinforcement area, and their selection modulus provides considerable bending resistance.

Multi-Bar Micropiles: Construction photos courtesy of Williams Form Engineering Corp.

• Used for attaining ultra-high load carrying capacity. High-rise office buildings and condos are construction examples where such high load carrying micropiles (mini-caissons) are used. • Designed to specific contractor specifications and shipped to the jobsite fabricated in durable cages for quick installation. Williams Form Engineering Corp. has been a leader in manufacturing quality products for the customer service for over 80 years.

Belmont, MI 616.866.0815

Lithia Springs, GA 770.949.8300

Kent, WA 253.854.2268

San Diego, CA 858.320.0330

Portland, OR 503.285.4548

London, ON 515.659.9444

Golden, CO 303.216.9300

Collegeville, PA 610.489.0624

18104_WILLIAMS_Micropile_Structures_half_page_ad.indd 1

System illustrations courtesy of Williams Form Engineering Corp.

For More Information Visit:

williamsform.com 3/15/18 11:00 AM

M A Y 2 019

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STRUCTURE solutions

PROFILE

INTEGRATED ENGINEERING SOFTWARE, INC

ince our start, 25 years ago this month, IES empowers thousands of structural engineers and related professionals, people just like you, with innovative analysis and design tools. We are experienced engineers with licenses and advanced degrees, and a passion for software development. A History of Serving Customers IES ShapeBuilder calculates structural properties for any cross section, including the torsion constant, warping constant, and warping normal function. The latest release also calculates shear flow at any location.

Easy to Use Software

IES VisualAnalysis performs finite element analysis on just about any structure. Find static, dynamic, p-delta, and time history results quickly and easily.

At IES, our goal is to create reliable tools that are engineer friendly. Our software tools stay out of your way. We deliver products that speak your language as a structural engineer. Whenever possible, we present intermediate data, display actual equations or specification-references, and make it easy to double-check your answers. We also perform extensive and automated validation to provide you with the highest quality software. Tools for Practicing Engineers IES software helps you solve very complex problems with confidence while streamlining small day-today jobs. You will meet your deadlines and improve your profits using tools like VisualAnalysis, ShapeBuilder, and others. With over 4,000 engineers using multiple products across 80 countries, we still provide free email support with one engineer in less than two hours per day. The benefit for you is that IES software is extremely easy to use and as reliable as anything available.

IES VisualAnalysis lets you solve frame and truss design problems in all materials. Optimize member sizes to meet demands according to the latest codes and your

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800-707-0816 www.iesweb.com

ADVERTORIAL

When we started, engineering software was a black-box tool that required you to write scripts in arcane formats and interpret tables of numbers. You also needed low-level knowledge of the finite element method and how it was implemented. Today, engineers expect excellent graphics, the ability to enter data using any physical unit system, and friendly error-checking with helpful messages when things go wrong, and IES delivers! For you to be competitive, we provide BIM integration, nonlinear analysis capabilities, multiple material design checks, and a host of convenience features!

“ Confidently Meet Your Deadlines ” Structural Software Easy. Versatile. Productive. Get the tools that will help you succeed:

Download your free trial today:

iesweb.com

800.707.0816

STRUCTURE solutions

MITEK

PROFILE

BREAKTHROUGHS IN BUILDING™ MiTek Integrated Solutions for more affordable, healthy, sustainable, safe, efficient, and resilient homes.

iTek is a diversified global supplier of building products, collaborative software, engineering services, and manufacturing equipment. With solutions that optimize and control costs, shorten cycle times, and eliminate waste, builders achieve more profitable, higher-volume business results and deliver more affordable, legacy-quality homes. Solving Industry Challenges with Innovation

A Better Way to Build We see an urgent and acute need across the globe to produce housing more efficiently and more affordably. Entry-level housing must be more affordable to meet the needs of first-time homebuyers and renters. The shortage of skilled labor is now a permanent problem. Rising, volatile material costs require processes to optimize and accurately predict their usage. We know there are better ways to build and that better technology exists – 3-D modeling technology and automated manufacturing for prefabrication can immediately improve the productivity of new home construction. But, a better process is required to be able to leverage the precision and the optimization of these solutions. We have learned that a better process requires a different discipline of decision-making. Traditional construction methods leave much of the detailed decision-making, and even the actual design and material usage, in the hands of skilled labor at the jobsite. 3-D modeling technology requires strong collaboration and decision-making up front – essentially building the home virtually before it is physically constructed. It requires the participation and ownership of everyone – from the structure, to the MEP design, to the finishes. From what we see, this discipline change may be the most difficult transformation. The future of housing will emerge through the technology that enables it, the processes that discipline it, and the bold leaders that envision and achieve it. Software MiTek’s Enterprise Software systems optimize the business workflow, including the costing, design, and production of homes. Our SAPPHIRE® 3D Structural Modeling Software also expands the 60-SS STRUCTURE solutions

Engineered Products With constant R&D and new products developed every year, MiTek has crafted thousands of code-compliant engineered solutions that waste less time, material, labor, steps, and cost. MiTek Hardy Frame® Lateral Load Solutions is the only complete line of lateral force resisting products for residential homes – from single family to multi-story, multifamily complexes. Solve better architecturally, design with new possibilities, and utilize a more economical solution. USP® Structural Connectors is a complete line of innovative codecompliant construction hardware backed by robust design and placement software, training, and technical support. The line includes Fire Wall Hangers for face mount applications designed to be installed before the drywall is attached, allowing your project to be completely framed-up and weather-tight before the drywall sheathing shows up on site. Services MiTek provides a range of services to support the efficient growth, capability, and profitability of our customers. Our Plans Services team allow our customers to improve their scalability without adding overhead. Our software consulting and implementation team enable efficient and effective transformation of current business processes. Off-Site Manufacturing Conquer the labor shortage with roof trusses, prefabricated walls, and floor trusses. Off-site design and prefabrication technology reduce cycle times and offer predictable costs, resulting in higher throughput for you and consistent, high-quality homes for your customers. Our Core Purpose MiTek exists to create breakthroughs in building that accelerate the genius of our customers. Our standard of doing business sets the bar for what you should expect from a company; a new standard of service – not just in the way of products, software, and machinery, but more importantly in partnering with you to achieve continuous improvement and success. www.mitek-us.com/specify

ADVERTORIAL

MiTek is helping our customers address an unprecedented level of challenges (and opportunity) in the residential construction environment, including: • Labor shortages in nearly every developed country • Poor communication between trades at the jobsite • Shortage of developable land in major population centers • Rapidly escalating material costs, driven in part by tariffs and global supply chain disruption • Lack of affordable homes and changing buying patterns • Environmental and sustainability concerns • Access to technology and the speed of technological change Homebuilders can overcome these challenges and experience historic breakthroughs in their business through higher-performance processes from MiTek. Our family of integrated solutions will permanently reduce design and construction cycles, optimize and control costs, and significantly reduce waste on every project.

information helpful in having a successful project by creating an optimized, buildable, structural frame in a virtual world. Designed to bring home builders and building material suppliers together in a virtual jobsite, MiTek’s SAPPHIRE® Viewer is a free tool for zooming, measuring, and creating the perfect 3-D BIM design and the well-built home. From ridge line to foundation, SAPPHIRE Viewer delivers great collaboration for design, approval, and on-site construction of your structural framing. Designed for Engineers and Estimators, MiTek Specifier™ software simplifies access to information on thousands of MiTek USP Structural Connectors. Looking up connector capacities, viewing code evaluation reports, and mapping from referenced products to USP products is free, quick, and easy to use. This versatile tool assists with the design, specification, and quoting processes for steel connections in wood frame structures of all sizes.

BREAKTHROUGHS IN BUILDING

™

MITEK INTEGR ATED SOLUTIONS FOR MORE AFFORDABLE, SUSTAINABLE, SAFE, HE ALTHY, EFFICIENT AND RESILIENT HOMES. ENGINEERED STRUCTURAL CONNECTIONS

SOFTWARE

MiTek Integrated Solutions

SERVICES

OFF-SITE MANUFACTURING

Our family of integrated solutions will permanently: → reduce design and construction cycles → optimize and control costs → significantly reduce waste on every project.

Learn more at MiTek-us.com/Specify C O P Y R I G H T © 2 0 19 M I T E K I N D U S T R I E S , I N C . A L L R I G H T S R E S E R V E D

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PROFILE

NUCOR VULCRAFT GROUP – REDICOR How RediCor’s ‘ready-to-set’ core erection system helped get Homewood Suites under roof as winter loomed.

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each upper floor. They can immediately start framing as they go, virtually eliminating fall hazards. “When a stair module goes in place, and the stair railing is bolted to the stringer,” says Freiberg, “the core is functional, and the subcontractors can go up and down in that building almost immediately. It keeps them off ladders and makes for much more efficient construction… and much safer.” The modules also come with preinstalled connections, which are compatible with steel, concrete, and wood framing, and can support limited construction loads prior to concrete placement, resulting in no waiting on core curing. Freiberg said the RediCor System works particularly well in conjunction with Building Information Models (BIM) “because it is a fabricated module as opposed to a field installed component such as reinforced concrete block or cast-in-place concrete.” Using the BIM approach, the general contractor can coordinate with the architect, the steel fabricator, the erector, and a host of subcontractors to have the customized RediCor modules fit with all the major framing components. “That kind of coordination sounds simple, and that’s how it’s supposed to work,” says Freiberg. “But it rarely does. And when connections don’t fit on a large project, somebody sends an RFI (Request for Information) back to the general contractor. . . and then the affected parties have to wait for the fix.” Freiberg explains that the RFI process often contributes to a break in the workflow. “And when you break workflow, you have a cascading detrimental effect on a construction schedule.” In contrast, Vulcraft’s pre-fabricated RediCor System, working in tandem with the BIM approach, reduces the occurrence of RFIs, which reduces workflow interruptions and helps keep projects on schedule. “RediCor’s modular form system simplified and fast-tracked the core construction process, which saved us time and the owner money,” said Brown. “And more importantly, we dodged a major snowstorm that could have added weeks to the construction schedule. It’s hard to put a price on that.” www.redicor.com

ADVERTORIAL

estled quaintly in the shadow of the Rocky Mountains, you will find the valley of Steamboat Springs, Colorado – worldrenowned for its hiking and biking in the summer months and its exquisite skiing in winter. The locals will tell you that Steamboat’s year-round recreational opportunities attract throngs of visitors annually – and that, in turn, has fueled a building frenzy in the area’s hospitality industry. Local building contractors are celebrating Steamboat’s robust construction boom, but at the same time facing its challenges – particularly in the wintertime. For that reason, most building projects are scheduled during the spring and summer – when the days are longer, and the weather is more predictable. Builders avoid starting projects in the fall because the impending winter brings with it the probability of snowstorms – and nothing plays more havoc on a construction project’s schedule than a surprise blizzard. Such was the case with Michael Brown, CEO of Brown Contractors, Inc. of nearby Westminster, Colorado, who did not have the luxury of building when the weather was, well, more accommodating. Commissioned in early fall 2017 to begin construction on 74,000-square-foot Homewood Suites hotel in Steamboat, Brown knew that he would be on a tight schedule to get the project under roof before the first big snowfall. Time was of the essence and he could not chance using conventional methods of construction, which almost always guarantees delays. “When you’re in the mountains of Colorado, you can expect snow at about the same time every year,” says Brown. “We knew that if we were going to stay on schedule, we had to get the roof on before the snow started falling.” Brown reached out to Jim Freiberg, sales representative at Vulcraft, a division of Nucor that manufactures steel joists, deck, and a host of building products. Freiberg has years of experience working with contractors facing mountain-range weather, and he knew that Brown needed a building system that reduced delays – especially with winter bearing down. After reviewing the scope of the project, Freiberg recommended Vulcraft’s RediCor System – a pre-fabricated, ready-to-set, steel modular form system that is engineered to simplify and accelerate the construction of reinforced concrete stair and elevator cores. The RediCor System incorporates custom-designed core modules that can be stacked quickly and easily, enabling the framing phase – often the phase most susceptible to delays – to begin almost immediately. And that can reduce the job site schedule by weeks or even months on most building projects. “The RediCor system made sense to Brown Contractors because this job was starting in the fall,” said Freiberg. “And if his schedule slipped at all because of snow, Brown would get punished on the back end.” The RediCor System is ideal for time-sensitive projects because the stair cores are pre-fabricated at the Vulcraft factory and shipped in the modules, with only the railings to install. Hoisted by crane off the trailer, the cores are stacked like building blocks then secured with welds, one on each corner. Once the core modules are stacked and the stair rails fastened, the building trades have safe access to

Redi. Set. Go.

REDICOR SIMPLIFIES AND ACCELERATES THE CONSTRUCTION OF REINFORCED CONCRETE CORES. Conventional methods of constructing reinforced concrete shear cores can be a challenge. Unpredictable onsite construction timelines frequently delay framing, and unacceptable concrete tolerances or improperly located steel embed plates often bring production schedules to a halt. Now there’s a better way. RediCor is a pre-fabricated, ready-to-set modular steel form system that simplifies and accelerates the construction of reinforced concrete stair and elevator cores. Our steel modules are factory builtto-spec with structurally true, load-bearing vertical and horizontal structural connections pre-engineered to ensure that framing fits perfectly – saving time, energy and money. VISIT US AT REDICOR.COM FOR THE REDICOR STORY. www.redicor.com

Powerful Partnerships. Powerful Results.

STRUCTURE solutions

MAPEI

PROFILE

Meeting More Construction Needs

APEI is the world-leading manufacturer of mortars, grouts, Concrete Admixtures Add Strength and Flexibility. MAPEI adhesives, and products for floor and wall covering installa- Americas moved into the concrete admixture market in the United tion. MAPEI manufactures chemical products for building, including States through the acquisition of General Resource Technology, Inc. waterproofing products, admixtures for concrete and repair products, (GRT) in 2014. A regional admixtures manufacturer founded in decorative and protective exterior coatings, and more. 1993, GRT marketed concrete admixtures and auxiliary products Cement Additives Optimize Manufacturers’ Processes. Starting for the concrete industry in the central United States. With MAPEI’s INFO SPECS at the beginning of the concrete cycle, MAPEI’s cement additives resources and innovation, this new North American subsidiary will File Name: 18-2650 Ad_Structure_Mar_CRS Corporate Page Size: 5w" x 7.5h" provide innovative solutionsPR#: fornocement including grindto incorporate the latest product technology available to Job#:producers, 18-2605 Number of continue Pages: 1 Artist: Georginareducers Morra Email: gmorra@mapei.com Bleed: Yes meet Amount: .125" ing1 1aids, pack-set and CR(VI)-reducing customer needs and focus on continuing the development of 4 4 E . strength N e w p o r t C eenhancers, nter Dr. Deerfield Beach, FL 33442 Date: February 1, 2019 11:09 AM Colors: CMYK Process, 4/0 next-generation concrete admixture products. additives for all types of cement, as well as air-entraining agents for N O T E : C O L O R S V I E W E D O N - S C R E E N A R E I N T E N D E D F O R V I S U A L R E F E R E N C E O N L Y A N D M A Y N O T M A T C H T H E F I N A L P R I N T E D P R O D U C T. masonry cement. Underground Construction Team Offers Technology and Products. MAPEI has entered the underground technology arena in North America with a team of specialists who are working with contractors, engineers, and owners’ representatives for tunneling, hard-rock mining, and other large underground projects. MAPEI’s product solutions for underground construction cover admixtures, alkali-free accelerators, • Concrete Repair Mortars • Epoxy Adhesives soil-conditioning systems, injection, sprayable • Corrosion Protection • Decorative Toppings membranes, ancillary products for waterproof• Construction Grouts • Cure and Seals ing, and more. • Waterproofing • Densifiers Waterproofing Systems Excel at Keeping • Sealants and Joint Fillers • Structural Strengthening Projects Dry. MAPEI has been heavily engaged • Coatings and Sealers Products and very successful in above- and below-grade waterproofing markets around the world for some time, and has introduced two belowgrade waterproofing systems to the Americas – the Mapeproof ™ sodium bentonite, geotextile waterproofing membranes for blindside waterproofing and the Mapethene™ self-adhering, rubberized-asphalt sheet waterproofing membranes for positive-sized waterproofing. Supporting these waterproofing products is a complete line of detailing and accessories, including the new Planiseal® CR1, a cold-fluid-applied structural waterproofing membrane that provides a fast cure and is VOC-compliant. Elastomeric Coatings Provide the Perfect Finish. The Elastocolor® product line of wall coatings is the latest extension to MAPEI’s Concrete Restoration Systems (CRS) category and showcases MAPEI’s creativity and innovation. Ideally suited for the concrete restoration and waterproofing market, Elastocolor Primer, Elastocolor Texture, Elastocolor Flex, Elastocolor Coat, and Elastocolor provide decorative and protective finishes for vertical, above-grade building facades and structures. MAPEI is growing. Wherever construction is underway, MAPEI has products and systems for builders.

MAPEI provides a world of Concrete Restoration Systems

www.mapei.com 18-2650 Ad_Structure_Mar_CRS Corporate.indd 1

64-SS STRUCTURE solutions

2/6/19 2:03 PM

ADVERTORIAL

MAPEI USA

STRUCTURE solutions

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PROFILE Celebrating 85 years of innovation.

prescribed in AISC 360 and are used in structural steel connections. The report also confirms that Girder Clamps may be used to resist axial tension and slip due to load combinations that include wind load or seismic load for steel structures in Seismic Design Categories A to C. Reasons to use Lindapter Girder Clamps: • No drilling or welding in the field • Cost effective and time saving • For structural steel sections including W and S beams, channels, and angles • High tensile and slip resistance capacitates • Adjustable • Safer connections • Free connection detailing service

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For information and design data, call 866 566-2658 or visit www.LindapterUSA.com M A Y 2 019

65-SS

INSIGHTS Horizontal End Wall Hooks

Practical Construction Detailing for 8-inch CMU Special Shear Walls By Craig Baltimore, Ph.D., S.E., and Rachel Chandler

ertain types of special masonry shear walls require reinforcement hooks, typically 180 degrees, at the end of a masonry wall, but the cell dimension and grout clearance requirements can make installation problematic. When this happens, using a three-dimensional (3-D) technique allows for practical detailing and construction of horizontal reinforcement end hooks to vertical reinforcement as required by code for special shear walls (The Masonry Society, TMS 40216, Section 7.3.2.6(d)). This 3-D technique twists the horizontal reinforcement so that the hook angles instead of lying flat. The twisting delivers code required grout space while providing a proper end hook. The hook is necessary for wall continuity allowing for ductile behavior. This article refers to 8-inch concrete masonry unit (CMU) walls with #4 reinforcement and coarse grout. The flat 180-degree hook dimension is 4 inches overall (TMS 402-16, Table 6.1.8). For load-bearing CMU, standards require a minimum face shell thickness of 1¼ inches (ASTM C90). The flat dimension directly impacts the side clearance requirements (TMS 402-16, Section 6.1.3.5). With 7.625 inches overall width, 2.5 inches of face shell thickness, and a 4-inch hook flat dimension, it appears there is no issue (that is if #5 reinforcement, or larger, is not being

Figure 2. 3-Dimension reinforcement hook twisted.

66 STRUCTURE magazine

Figure 1. Hooked reinforcement dimensional requirements.

used). Considering the minimum face shell dimension and perfect placement, the code requirements can be met with ⅛-inch tolerance as depicted in Figure 1. However, TMS 602, Article 3.4 B.11.a, allows for ½-inch tolerance in reinforcement placement. As presented in two-dimensional (2-D) construction drawing format when considering material and installation tolerances, the reinforcement does not fit.

The 3-D Solution The hook orientation does not require flat horizontal placement in the wall. The Concrete Reinforcing Steel Institute (CRSI) Research Note on the “tilt” angle of end hooks (RN-2009-2) concluded: “hook tilt angle did not appear to have an effect on the maximum stress or displacement of the reinforcing bar.” Since the horizontal reinforcement hook is not required to lay flat, a 3-D solution, i.e., twisting the hook, becomes an option and the 2-D issue disappears (Figure 2). The orientation of the hook does not affect the structural integrity; however, the apex of the hook must surround the vertical reinforcement to achieve a proper hook.

The hook prevents buckling of vertical reinforcement should spalling occur under high lateral loading. Research conducted by the Technical Coordinating Committee on Masonry Research (TCCMAR) on shear wall performance, and results assessed by Greg Baenziger and Max L. Porter (Iowa State University, 2010), showed that horizontal reinforcement not hooked to vertical reinforcement (i.e., there is slack) caused excessive spalling resulting in a negative impact on the ductility of the wall. Their recommendation was to assure there was no slack or there was a properly installed hook. The Concrete Masonry Association of California and Nevada reports this issue is a common question. With today’s computer drafting software, the 3-D solution is easy to represent on construction drawings. Since special shear walls are performance-based, adequate structural performance requires a proper hook while maintaining proper side clearances for adequate grouting.■ Craig Baltimore is a Professor of Architectural Engineering at Cal Poly, San Luis Obispo. One of Baltimore’s specialization and research areas is masonry, and he has been active with The Masonry Society for two decades. (cbaltimo@calpoly.edu) Rachel Chandler is a Master’s student in Architectural Engineering at Cal Poly, San Luis Obispo. She is studying sustainable self-consolidating grout for concrete masonry construction. (rgchandl@calpoly.edu)

SPOTLIGHT The Face-Mounted Solution By David Adler, P.E.

fter enduring over a decade of disuse, the iconic front of the Hartford Times Building (HTB) has been restored and reborn as the face of the University of Connecticut’s new downtown satellite campus. UConn Hartford, designed by Robert A. M. Stern Architects, is part of a larger development effort to revitalize the area. The Beaux-Arts facade of the historic former newspaper headquarters features a muraled arcade and green granite pillars. Don Barber, the building’s original architect, salvaged the pillars from Stanford White’s Madison Square Presbyterian Church prior to its demolition in 1919. The original HTB is steel framed with 5-inch-thick cinder concrete draped mesh slabs. There is no discernable lateral system other than the inherent stiffness of the old riveted steel connection and the thick (but unreinforced) perimeter brick masonry walls. The entire 160-foot western-facing building facade remains, along with half of the original 60-foot-deep massing. The restored historic structure ties into the new 5-story addition, including a 50-foot-by-80-foot atrium and a courtyard between the three buildings that is open to the public. Because the story elevations of the original building do not align with those of the rest of the Hartford campus, the interface between old and new, a maze of overlapping spaces, is full of hanging and transferred columns. This left no room for a lateral frame along the cutaway back of the old building. This was one of the factors that drove two decisions regarding the existing masonry: to utilize it as the main lateral load resisting system in one direction and to seismically isolate it in the other. Though both decisions presented challenges, the reinforcement required the design team to develop a more innovative structural solution. Due to the heavy stone at the facade, the design seismic load for this project was massive. Unlike a typical steel framed building, the original walls of the HTB are completely unreinforced, meaning any inherent ductility they might possess could not be relied on to reduce seismic loads. This resulted in a far larger tensile demand than the original brick mortar could withstand. However, using these design loads, it was possible to calculate the amount of steel reinforcement that would be required. The challenge, then, was how to get that steel into the existing wall. STRUCTURE magazine

Silman was an Outstanding Award Winner for its University of Connecticut Downtown Hartford Campus project in the 2018 Annual Excellence in Structural Engineering Awards Program in the Category – Forensic/ Renovation/Retrofit/Rehabilitation Structures over $20M.

The most straightforward solution – hiring a company that specializes in post-installed reinforcement of unreinforced brick walls – was rejected as being too costly and too late in the schedule. Thus began an exploration of “the face-mounted solution:” applying steel to the face of the brick wall to act as conventional reinforcement. With this face-mounted premise, the first draft of the solution involved anchoring a continuous steel plate to the wall with epoxy anchors, which posed the immediately obvious questions. How many anchors would be required to develop the load into the wall? How many to anchor it to the foundation? Would the brick crush, locally, at the more heavily loaded anchors? Would the eccentricity of that tension load cause any problems? The answers to those questions turned out to be, respectively: too many, also too many, absolutely, and very likely. Thus, the face-mounted steel must somehow load the wall with no eccentricity. Moreover, if the inherently eccentric face-mounted steel was not loaded along its own center, then it would have to resist bending moment along with the wall’s tension. This conclusion eliminated this first face-mounted draft as a viable option, as neither a plate nor anchors would be able to transfer that bending. A superior solution, as it turned out, was tubes. Each end of each pier is reinforced with a single, continuous, thick-walled, wide and shallow steel tube along the face of the wall, with smaller tubes periodically cantilevering

into brick pockets. There are also bearing plates and incompressible filler to ensure the centricity of the load. At the connection of each stub, the shear loads the primary tube in tension, while the fixed end moment transfers into its weak axis. This moment is then resolved at each stub through epoxy anchors into the wall, which does load the wall with some out-of-plane moment. However, the net load on the wall is centered, and the local moments are effectively negligible. The final question: how to anchor the load into the foundation? The solution lay in turning the problem on its side, transforming it into the more familiar shear lug from a steel base plate into a concrete footing. Resolving it this way involved a 3-inch-thick plate completejoint-penetration welded to the bottom of the primary tube, which is reinforced to be able to withstand the bending moment from the entire eccentric tensile force. This unique structural detail allows the project to not only preserve HTB’s history alongside the future of the UConn satellite campus but also to preserve the original function of the facade. The new building relies on these walls as the original building did, a truer restoration than if they had merely been braced. While ultimately hidden behind furred out walls, this detail serves as a metaphor for the project as well as for the greater revitalization effort in Hartford.■ David Adler is a Senior Engineer with Silman in New York, NY. (adler@silman.com)

M AY 2 019

NCSEA

NCSEA News

National Council of Structural Engineers Associations

NCSEA Education Director Jan Diepstra Retires After 14 years of service, NCSEA Education Director Jan Diepstra retired this month. Jan was instrumental at NCSEA in developing and growing the Council’s education and webinar programs, working in conjunction with the Continuing Education Committee to establish leading resources for structural engineers. Jan joined NCSEA after working with the Structural Engineers Association of Illinois (SEAOI), where she also led education efforts. A key to Jan’s success has been her tireless efforts to foster relationships with hundreds of speakers to better the education available to the practicing structural engineer. Jan is excited to join her husband in retirement and to spend more time traveling. Jan also is looking forward to spending more time with her children and grandchildren. NCSEA staff and the Board of Directors thank Jan for her years of service to the profession and wish her the best of Jan Diepstra luck moving forward. Replacing Jan is Katherine (Kat) Ort, who joins NCSEA from the American Society for Surgery of the Hand. Kat will serve as NCSEA’s Education and Conference Manager. She has a Master’s in Education from Middle Tennessee State University and has spent her career in associations assisting them in enhancing their education initiatives. “NCSEA was fortunate to have Jan Diepstra lead its education programs. Jan was an amazing ambassador for the Council and had a first-rate approach to continuing education. She will be missed,” said Al Spada, NCSEA Executive Director. “Katherine Ort brings a great set of skills to help NCSEA move toward the future. We are excited to have her on our team.” Katherine Ort

REGISTRATION IS OPEN: 2019 STRUCTURAL ENGINEERING SUMMIT We’re going to Disneyland! Join us November 12th to 15th for the 2019 Structural Engineering Summit taking place at the Disneyland® Hotel in Anaheim, California. The Summit draws the best of the structural engineering field together for high-quality education by expert speakers, a dynamic trade show with over 60 exhibitors, and compelling peer-to-peer networking at a variety of events and receptions.

What's new to the 2019 Summit? • New Format! Beginning on Tuesday & ending Friday afternoon, the program will offer more education (over 16 hours) and less overlap. • NCSEA has partnered with the American Wood Council, APA–The Engineered Wood Association, and Simpson Strong-Tie to bring the Timber-Strong Design Build™ Competition to the Summit for student teams from across the country to compete. • Four Keynotes Presentations from Stacy Bartoletti, P.E., S.E., Melissa Marshall, Avery Bang, and Ashraf Habibullah, S.E.

Secure Training to Become a Second Responder

Register for the next NCSEA CalOES Safety Assessment Program on Wednesday, June 12, 2019 The California Office of Emergency Services (CalOES) Safety Assessment Program (SAP), hosted by NCSEA, is highly regarded as a standard throughout the country for engineer emergency responders. It is one of only two post-disaster assessment programs that will be compliant with the requirements of the Federal Resource Typing Standards for engineer emergency responders, and has been reviewed and approved by FEMA's Office of Domestic Preparedness. Based on ATC-20/45 methodologies and forms, the SAP training course provides engineers, architects, and code-enforcement professionals with the basic skills required to perform safety assessments of structures following disasters. Register by visiting www.ncsea.com. This course is not included in the Live & Recorded Webinar Subscription. DOUG FELL, P.E. Doug Fell is a CalOES Assessor, Coordinator, and Instructor. He is a licensed professional engineer (structural) in his home state of Minnesota as well as several others. Doug is the managing principal of Structural Resource Center LLC. His practice includes structural engineering design and analysis for new and existing structures, structural assessments, forensic engineering, emergency response, development and review of safety programs, and project management services. Doug has responded to all types of emergencies and performed assessments all over the U.S. He was the lead structural engineer for the Minneapolis Metrodome roof collapse stabilization and return to service. 68 STRUCTURE magazine

News from the National Council of Structural Engineers Associations

MO Public Outreach Competition

Can structural engineers improve the public visibility and recognition of the profession? The NCSEA Communications Committee thinks so, and wants to encourage you and your SEA to participate. Through the creation and distribution of information and content via news articles, videos, blogs, and a multitude of other methods, SEAs can spread the message about our profession and its critical role in society. The NCSEA Communications Committee invites NCSEA Member Organizations to participate in the very first Member Organization Public Outreach Challenge. The goal is to inform and educate other industries, professions, and the general public about Structural Engineering. The process is simple, SEAs and SEA members are already creating content; compile it, submit to NCSEA by September 8, 2019, and, after review, a winner will be chosen! NCSEA will be hosting an information webinar on June 20th; register for the webinar and learn more about the challenge by visiting www.ncsea.com/challenge.

2019 NCSEA Grant Program Subscribe to Knowledge The NCSEA Grant Program was developed in 2015 to award SEAs funding for projects that grow and promote their SEA and the structural engineering field in accordance with the NCSEA Mission Statement: NCSEA advances the practice of structural engineering by representing and strengthening its Member Organizations. Any NCSEA Member Organization or member of a Member Organization is eligible to submit a grant application, as long as the application has been reviewed and approved by the Member Organization. Past Grant recipients have used their funds to support endeavors as hosting symposiums and networking events for members, enhancing mentoring programs, setting up Engineering for the Arts initiatives, and renew dated studies. Some SEAs used their grants to purchase items that could be used to enhance their outreach efforts. Visit www.ncsea.com for more information about the 2019 Grant Program and to submit your proposal

NCSEA Webinars

NCSEA's Live & Recorded Webinar Subscription is the most userand wallet-friendly plan to date! This Live & Recorded Webinar Subscription offers all the same benefits as before, but now includes even more. With this annual plan, you get: • 25+ live webinars a year featuring the highest-quality speakers available. • Receive an unlimited number of free CE certificates for each webinar so multiple viewers at the same location can receive credit for every live webinar with no additional costs. • Unlimited 24/7/365 access to NCSEA's Recorded Webinar Library–more than 120 relevant & high-quality webinars. NCSEA's Education Portal provides easy access to all of your education content. NCSEA Members can subscribe today on www.ncsea.com!

May 16, 2019

Bridge Design – Seismic Design of Bridges (Session III) Tony Shkurti, Ph.D., S.E., P.E.

This third session will be geared to assist exam takers and practicing bridge engineers that must deal with bridge design in their dayto-day activities. It will explain the art of seismic analysis and design in common sense engineering jargon with hands on application of how to apply the proper structural stiffness, demand calculations based on AASHTO methodology for single mode analyses using both the Single Mode and the Uniform Load Method of analyses. May 21, 2019

Insidious Thermal Forces in Steel Structures: What You Need to Know Barry Arnold, P.E., S.E.

This course will expand the attendee’s knowledge of how changes in temperatures and poor detailing of structural members and systems adversely affect individual members as well as entire buildings. June 4, 2019

Wind Tunnel Testing for Structural Engineers Dr. Roy Denoon, Ph.D.

This webinar will cover the basics of boundary layer wind tunnel testing and how it is used to aid structural design. The different testing approaches used for a range of structures will be described. Courses award 1.5 hours of continuing education after the completion of a quiz. Diamond Review approved in all 50 states. M AY 2 019

SEI Update Learning / Networking SAVE THE DATE STRUCTURAL ENGINEERING INSTITUTE

STRUCTURES CONGRESS 2020 St. Louis, Missouri I April 5-8

Interact with and learn from academic/practice experts on innovative topics: • Blast & Structural Response • Bridge & Transportation Structures • Building • Business & Professional • Career Development

• • • • • •

CALL FOR PROPOSALS Be part of the program - Submit an Abstract or Session Proposal Deadline: June 5, 2019

The Premier Event in Structural Engineering

Education Forensic Natural Disaster Special Structures Nonstructural Research

Students & Young Professionals: Apply for Scholarship to Participate. Learn more www.structurescongress.org

Joint International Conference:

Collaboration Efficiency Safety •

•

Dubai, UAE | 29-30 September 2019

Iconic Global Structures:

what can we learn?

Join structural engineers and project stakeholders to explore the successes and challenges of constructing nine complex structures across the world. Keynote speakers will share their experience of high volume occupancy, unusual structures where typical codes do not apply, and performance based design (PBD) of tall buildings. Register now to receive early booking discount: https://structuresdubai2019.cvent.com

SEI Online

ASCE 7-16 Supplement SEI News Member experiences #1 – Now Available at ASCE Fly-In in https://bit.ly/2I8S4Li contains important provisions for seismic and tsunami design as well as commentary changes. The Errata are also available for download via the ASCE Library https://bit.ly/2Zc97l8.

Errata 70 STRUCTURE magazine

Washington, DC www.asce.org/SEI.

SEI on Twitter

SEI Standards Supplements and Errata including ASCE 7. See www.asce.org/SEI-Errata. If you would like to submit errata, contact Jon Esslinger at jesslinger@asce.org.

News of the Structural Engineering Institute of ASCE Membership

SEI Annual Report 2018

New SEI Member Benefit Connect and access resources via ASCE Collaborate: Integrated Buildings and Structures. Use your SEI/ ASCE member login to engage in member discussions, access career opportunities, and view presentations including ASCE 7-16 Overview and Wind Loads, made possible by the SEI Futures Fund.

Review past achievements and future plans.

Join or Renew SEI/ASCE

ASCE/SEI Member Benefits

For innovative solutions and learning, to connect with leaders and colleagues, and to enjoy member benefits such as SEI Member Update monthly e-news opportunities and resources – visit www.asce.org/myprofile or call ASCE Customer Service at 800-548-ASCE (2723).

Advancing the Profession

2019 ASCE Structural and SEI Award Recipients

Congratulations to the 2019 ASCE Structural and SEI Award Recipients recognized April 27 at Structures Congress in Orlando.

Walter L. Huber Civil Engineering Research Prize: Dimitrios Lignos, Ph.D., A.M.ASCE

Shortridge Hardesty Award: Amit H. Varma, Ph.D., M.ASCE

Walter P. Moore, Jr. Award: Robert T. Ratay, Ph.D., P.E., F.SEI, F.ASCE

Dennis L. Tewksbury Award: Glenn R. Bell, P.E., S.E., C.Eng., SECB, F.SEI, F.ASCE

George Winter Associate Editor Award: Award: Thomas E. Boothby, Sriram Narasimhan, Ph.D., P.E., Ph.D., P.Eng., F.ASCE M.ASCE

Moisseiff Award: Gilberto Mosqueda, Ph.D., A. M.ASCE

Raymond C. Reese Raymond C. Reese Raymond C. Reese Research Prize: Research Prize: Research Prize: Sherif El-Tawil, Jason McCormick, Tung-Yu Wu, S.E., Ph.D., P.E., F. SEI, S.M.ASCE Ph.D., P.E. F.ASCE M.ASCE

Moisseiff Award: Michael Pollino, Ph.D., S.E., P.E., M.ASCE

2018 Alfredo Ang Award: Bilal M. Ayyub, Ph.D., P.E., F.SEI, Dist.M.ASCE

SEI President’s Award: David J. Odeh, P.E., S.E., SECB, F.SEI, F.ASCE

Nathan M. Newmark Medal: Bojan Guzina, Ph.D., A.M.ASCE

W. Gene Corley Award: Gregg E. Brandow, Ph.D., P.E., S.E., M.ASCE

Moisseiff Award: Bing Qu, Ph.D., P.E., M.ASCE

Moisseiff Award: Derek Slovenec, S.M.ASCE

2018 Ernest E. Howard Award: Zoubir Lounis, M.ASCE

2018 Ernest E. Howard Award: Therese P. McAllister, P.E., F.SEI, M.ASCE

SEI Graduate Student Chapter of the Year Award: SEI Graduate Student Chapter (GSC) at the University of Texas, Arlington

SEI Chapter of the Year Award: SEI San Francisco Chapter

View recognition and nominate a colleague for the 2020 SEI/ASCE Awards at www.asce.org/SEI. M AY 2 019

CASE in Point Did you know? CASE has tools and practice guidelines to help deal with a wide variety of business scenarios that structural engineering firms face daily. Whether your firm needs to establish a new Quality Assurance Program, update its risk management program, or keep track of the skills young engineers are learning at each level of experience, CASE has the tools you need! The following documents/templates are recommended to review/use if your firm needs to update its current Quality Assurance Program, or incorporate a new program into the firm culture: 962: National Practice Guidelines for the Structural Engineer of Record (2018) 962-B: National Practice Guideline for Specialty Structural Engineers 962-C: Guidelines for International Building Code Mandated Special Inspections and Tests and Quality Assurance 962-D: Guideline addressing Coordination and Completeness of Structural Construction Documents Tool 1-2: Tool 2-1: Tool 2-4: Tool 4-1: Tool 4-2: Tool 4-3:

Developing a Culture of Quality Risk Evaluation Checklist Project Risk Management Plan Status Report Template Project Kick-off Meeting Agenda Sample Correspondence Letters

Tool 4-4: Tool 4-5: Tool 9-2: Tool 10-1: Tool 10-2:

Phone Conversation Log Project Communication Matrix Quality Assurance Plan Site Visit Cards Construction Administration Log

You can purchase these and the other Risk Management Tools at www.acec.org/bookstore.

CASE Winter Planning Meeting Update

CASE does two planning meetings a year to allow their committees to meet face-to-face and interact across all CASE activities. Over 30 CASE committee members and guests attended the recent planning meeting in Tampa, FL, February 7-8, making this another well attended and productive meeting. During the meeting, break-out sessions were held by the CASE Contracts, Guidelines, Toolkit, and Programs & Communications Committees. Members also heard from Sabrina Duk from the NCSEA SE3 Committee, reporting on the results from their recent engagement and equity survey. • Flood-Resistant Design for the Structural Engineer Current initiatives include: • Beyond the Code – Understanding Client Expectations I. Contracts Committee – Brent Wright (brent@wrighteng.net) and Strategies for Managing Them • All Contract Documents are currently undergoing review by III. Programs and Communications Committee – Nils Ericson outside legal counsel (nericson@m2structural.com) • Updated Commentary on AIA C-401 to reflect the updated • Submitted session topics for the 2020 NASCC Steel AIA contract document for 2017 Conference II. Guidelines Committee – Kevin Chamberlain • Discussed options for sessions to submit for the 2019 (kevinc@dcstructural.com) NCSEA Summit in November • Revising the following current Practice Guideline Documents: • Discussed options for sessions at the 2019 ACEC Fall • CASE 962-A: National Practice Guidelines for the Conference Preparation of Structural Engineering • Discussed options for sessions to submit for the 2020 SEI Reports for Buildings Structures Congress • CASE 962-D: Guideline Addressing Coordination and • Finalized session at the 2019 ACEC Annual Convention Completeness of Structural Construction • Discussed program topics for summer meeting that would Documents either be on the Mercedes Benz stadium or the canopies at • CASE 962-G: Guidelines for Performing Project Specific the Hartsfield Int’l Airport in Atlanta, GA Peer Reviews on Structural Projects IV. Toolkit Committee – Brent White (brentw@arwengineers.com) • CASE 962-H: National Practice Guideline on Project and • Working on the following updates to current tools: Business Risk Management • Tool 5-1: Guide to the Practice of Structural Engineering • CASE 976-C: Commentary on Code of Standard Practice • Tool 9-2: Coordination and Completeness of Contract for Steel Buildings and Bridges Documents • Structural Engineer’s Guide to Fire Protection • Working on the following new documents: • Working on the following new documents: • Tool 5-6: Lessons Learned • Introduction to Seismic Engineering for the Practicing • Tool 6-3: Project Scoping Tool Structural Engineer • Structural Engineer’s Guide to the Procurement, Use, and Implementation of Geotechnical Engineering

Follow ACEC Coalitions on Twitter – @ACECCoalitions. 72 STRUCTURE magazine

News of the Council of American Structural Engineers CASE Tool 4-3: Sample Correspondence Guidelines – UPDATED

The intent of CASE Tool 4-3, Sample Correspondence Guidelines, is to make it faster and easier to access correspondence with appropriate verbiage addressing some commonly encountered situations that can increase your risk. The sample correspondence contained within this tool is intended to be sent to the Client, Owner, Sub-consultant, Building Official, Employee, etc., to keep them informed about a certain facet of a project or their employment. The committee did an all-inclusive update to this document, plus added the following new sample letters: • Collections Correspondence / Billing Policies Letter • Human Resources Correspondence / Employee Performance Improvement Plan • Project Acquisition and Contract Correspondence / Scope Change Letter and Additional Services Form

You can purchase these and the other Risk Management Tools at www.acec.org/bookstore.

Donate to the CASE Scholarship Fund!

The ACEC Council of American Structural Engineers (CASE) is currently seeking contributions to help make the structural engineering scholarship program a success. The CASE scholarship, administered by the ACEC College of Fellows, is awarded to a student seeking a Bachelor’s degree, at a minimum, in an ABET-accredited engineering program. Since 2009, the CASE Scholarship program has given $29,000 to help engineering students pave their way to a bright future in structural engineering. We have all witnessed the stiff competition from other disciplines and professions eager to obtain the best and brightest young talent from a dwindling pool of engineering graduates. One way to enhance the ability of students in pursuing their dreams to become professional engineers is to offer incentives in educational support. Your monetary support is vital in helping CASE and ACEC increase scholarships to those students who are the future of our industry. All donations toward the program may be eligible for tax deduction, and you don’t have to be an ACEC member to donate! Contact Heather Talbert at htalbert@acec.org to donate.

Fresh EJCDC Contracts to Meet Modern Market Demands EJCDC’s newly released 2018 Construction (C-Series) Documents are a significant modernization, revision, and expansion of the 2013 C-series and now the state-of-the-art in construction contract documents. The updated edition comprises 25 integrated documents including: • Fundamental contract documents such as the Standard General Conditions, the Small Project agreement, and Supplementary Conditions • Forms for gathering information needed to draft bidding documents • Instructions for bidders and a standard bid form • Bonds including bid, performance, warranty (new for 2018), and payment bonds • Administrative forms, such as change orders and a certificate of substantial completion EJCDC C-700, Standard General Conditions of the Construction Contract has been extensively refreshed and updated, too. The new EJCDC 2018 C-Series also includes expanded and updated “Notes to Users” and “Guidelines for Use” to provide more specific instructions, and it eliminates the need for notary and corporate seals.

You can purchase these and the other EJCDC documents at www.acec.org/bookstore.

Manual for New Consulting Engineers An HR Favorite for New Hires

ACEC’s best-seller, “Can I Borrow Your Watch?” A Beginner’s Guide to Succeeding in a Professional Consulting Organization offers new engineers a head start in the business of professional consulting. This essential guide is tailored to the unique needs of engineering firms, and the skills and experiences rookie consultants need to be successful in a large organization, including: • Proposal Preparation • Project Management • Financial Management • Staff Management • Client Relationships With over 140 pages of consulting expertise, this resource is the perfect addition to any new staffer’s welcome pack or in-house orientation. It can even be a useful resource for more seasoned engineers looking to refine their skills. To order this book, go to www.acec.org/bookstore. Bulk ordering is available, for more information contact Maureen Brown (mbrown@acec.org). M AY 2 019

STEEL/COLD-FORMED STEEL products guide Adhesives Technology Corporation Phone: 800-892-1880 Email: atcinfo@atcepoxy.com Web: www.atcepoxy.com Product: ULTRABOND® Anchoring and Doweling Products Description: A leading manufacturer of construction and industry related adhesives in epoxies, urethanes, acrylics, ester blends and polyureas. ULTRABOND®, CRACKBOND®, and MIRACLE BOND® are some of the most recognized products in North America. ULTRABOND HS-1CC is currently the industry’s highest performing anchoring epoxy.

Alpine TrusSteel Phone: 863-307-9895 Email: ddunbar@alpineitw.com Web: www.trussteel.com Product: TrusSteel Description: The commercial framing industry’s premier cold-formed steel truss system. Our innovative Double-Shear fastening technology combines with our patented symmetrical profile to efficiently transfer structural loads. The unique system provides more overall stability, making TrusSteel easier to handle and easier to install, with less need for additional installation of external restraints.

ClarkDietrich Phone: 800-543-7140 Email: info@clarkdietrich.com Web: www.clarkdietrich.com Product: BlazeFrame Firestop Framing System Description: One-of-its-kind steel framing firestop system that simultaneously frames and seals both dynamic and static joints from air and smoke. Featuring an integrated intumescent strip – expands to 35 times its size when exposed to heat above 375° Fahrenheit, BlazeFrame provides protection from heat and flame passage during a fire event.

Dlubal Software, Inc. Phone: 267-702-2815 Email: info-us@dlubal.com Web: www.dlubal.com Product: RFEM Description: Non-linear FEA software with LRFD and ASD design of hot-rolled steel according to AISC, CSA, and other international standards. Features include warping torsion, deflection checks, tapered and curved beam design, and automatic cross-section optimization. Stress analysis and design of steel surface and shell elements available, including nonlinear plastic analysis.

Listings are provided as a courtesy, STRUCTURE is not responsible for errors.

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ENERCALC, Inc. Phone: 800-424-2252 Email: info@enercalc.com Web: http://enercalc.com Product: Structural Engineering Library/ ENERCALC SE Cloud Description: Steel design is a breeze with ENERCALC’s Structural Engineering Library (SEL). Beams, columns, 2-D frames, force distribution in bolt groups…SEL handles it all. The clear user interface’s new 3-D sketches make it fast and easy to setup, confirm and “what-if ” calculations. Member optimization improves efficiency and saves time!

RISA Phone: 949-951-5815 Email: benf@risa.com Web: risa.com Product: RISA-3D and RISAFloor Description: Get the most out of steel designs with RISAFloor and RISA-3D. Ability to use multiple materials in one FEA model makes these programs your first choice for both hot rolled and cold formed steel. Up-to-date AISC, AISI and Canadian codes included, RISA has all your bases covered.

Heckmann Building Products Phone: 203-857-2200 Email: julien@toggler.com Web: www.heckmannbuildingprods.com Product: Pos-I-Tie® Description: The Pos-I-Tie brand is synonymous with acceptance and longevity in the masonry construction industry and is the #1 most specified veneer anchor. Heckmann Building Products continues to add new and innovative products to the Pos-I-Tie family. The newest additions include: The Pos-I-Tie ThermalClip® and the Pos-I-Tie KeyBolt.

Hexagon PPM Phone: 281-671-1528 Email: geoffrey.blumber@hexagon.com Web: https://hexagonppm.com Product: BricsCAD® BIM Description: Create and manage building designs – from concept to construction documentation – in one familiar environment. With BricsCAD BIM, you can use your current CAD skills to smoothly move to create real Building Information Models in record time.

Simpson Strong-Tie® Phone: 800-925-5099 Email: web@strongtie.com Web: www.strongtie.com Product: CFS Designer™ Software Description: Design CFS beam-column members according to AISI specifications and analyze complex beam loading and span conditions. Intuitive design tools automate common CFS systems such as wall openings, shearwalls, floor joists, and up to eight stories of load-bearing studs. Product: Simpson Strong-Tie Ready Products Description: Accomplish any curved framing job quickly and efficiently with Ready Products and portable Ready Bender framing tools. Ready Products come field ready to hand bend in place, and Ready Bender™ tools easily curve straight tracks and angles. Together, this versatile system makes it easy to create curved drywall designs.

Lindapter Phone: 866-566-2658 Email: inquiries@lindapter.com Web: www.LindapterUSA.com Product: Girder Clamp Description: The world’s first and only structural steel clamping system that is approved by ICC and compliant with the International Building Code. A high strength, permanent connection is quickly achieved by clamping two steel sections together, resulting in a faster, cost-effective alternative to drilling or welding in the field.

Trimble Phone: 678-737-7379 Email: jodi.hendrixson@trimble.com Web: www.tekla.com Product: Tekla Structuress Description: Create a detailed, constructible 3-D model of any steel structure from industrial and commercial buildings to stadiums and high rise buildings. Enables collaboration and sharing of project information among architects, engineers, and contractors. Links with major AEC, MEP and plant design software solutions with Open BIM approach and IFC compliance.

Qnect, LLC Phone: 512-814-5611 Email: Christian@Qnect.com Web: www.Qnect.com Product: QuickQnect Description: Delivers fast, engineered and 3-D modeled connections with significant cost and schedule savings. Qnect will optimize 60-90% of joints for maximum efficiency in minutes.

Not listed?

All 2019 Resource Guide forms, including the 2019 TRADE SHOW IN PRINT, are now available on our website. STRUCTUREmag.org.

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