STRUCTURE magazine | May 2012 by structuremag

May 2012 Masonry

A Joint Publication of NCSEA | CASE | SEI

STRUCTURE ®

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Model, Analyze, Design, Document and Deliver…in an Integrated Workflow Having all the applications you need for the tasks at hand, along with the ability to easily synchronize your work with the rest of the project information, helps you get your job done right, fast and profitably. And when the structural project workflow can be integrated, the whole team benefits. Bentley’s new Passport Subscriptions for structural engineers provide access to the full range of structural software (including upgrades) and training documents and information that most projects require. These options are available as an affordable alternative to traditional licensing. Contact us to learn more.

www.Bentley.com/Structural © 2010 Bentley Systems, Incorporated. Bentley, the “B” Bentley logo, MicroStation, RAM, and STAAD are either registered or unregistered trademarks or service marks of Bentley Systems, Incorporated or one of its direct or indirect wholly-owned subsidiaries. Other brands and product names are trademarks of their respective owners.

With RAM™, STAAD® and Documentation Center, Bentley offers proven applications for: l Steel/Steel Composite l Reinforced Concrete l Wood and Wood Products l Foundation Design l Post-Tensioned Design l Steel Connections l Structural Drawings and Details … all easily coordinated with the Architect and other team members and their design applications – such as AutoCAD, Revit, MicroStation® and more.

FEATURES Tower Stabilization during Buttress Repairs

By David T. Biggs, P.E., S.E.

Masonry towers are the focal point of numerous historic buildings and monuments. They grace most religious structures and many significant civil works. These towers present numerous difficulties for engineers and architects to define the nature of their problems and develop necessary repair interventions. One such tower on a church in Vermont (circa 1892) suffered from water saturating the buttresses and deteriorating the exterior mortar.

Achieving Separate Licensing of Structural Engineers

By Charles J. Tucker, Ph.D., P.E.

By Susan Jorgensen, S.E., P.E.

34 Product Watch Autoclaved Aerated Concrete as a Holistic Building System By Angelo Coduto and Michael McDonough

45 Great Achievements Walter P. Moore, Jr.

By Richard G. Weingardt, P.E.

HL23

Resolution of Deficiencies in Engineering Education

By Stephen V. DeSimone, P.E., and Ahmed M. Osman, P.E.

By Prof. Kevin Dong, P.E., S.E.

38 Business Practices

58 Structural Forum A Structural Engineer’s Manifesto for Growth – Part 2

Adopting New Technologies into Your Business

7 Editorial Raising the Bar

By Craig Barnes, P.E., SECB

9 InFocus Virtue as a Skill

By Jon A. Schmidt, P.E., SECB

10 Building Blocks

14 Codes and Standards Adhered Masonry Veneers By Peter Loughney

18 Structural Practices Building Unit Masonry Specifications By Renee Doktorczyk

20 Just the FAQs Flashing Steel Lintels and Shelf Angles

51 Spotlight

37 Education Issues

COLUMNS

By Fernando S. Fonseca, Ph.D., S.E. and Kurt Siggard

42 Professional Issues

Infilling the Frame with Masonry

May 2012

High Volume Fly Ash Masonry Grout

DEPARTMENTS 27 Code Updates

CONTENTS

By Erik Nelson, P.E., S.E.

By ASCE/SEI-BPAD Business Practice Committee

22 InSights Link Fractures in Eccentrically Braced Steel Frames

By Michel Bruneau, Ph.D., P.Eng., Charles Clifton, Ph.D., Gregory MacRae, Ph.D., P.E., Roberto Leon, Ph.D., P.E. and Alistair Fussell, B.E.(Hons), ME, CP Eng.

24 Structural Design Design Considerations for Sawn Lumber Wood Studs

A Joint Publication of NCSEA | CASE | SEI

STRUCTURE

By Jason A. Partain, P.E.

THE

COVER

The Gothic style tower was completed in 1892 with a wooden spire that was subsequently removed in 1920 after high winds caused it to sway. The masonry tower was restored in 2009. See more about this project in the feature article on page 30.

May 2012 Masonry

Publication of any article, image, or advertisement in STRUCTURE® magazine does not constitute endorsement by NCSEA, CASE, SEI, C 3 Ink, or the Editorial Board. Authors, contributors, and advertisers retain sole responsibility for the content of their submissions.

STRUCTURE magazine

May 2012

IN EVERY ISSUE 8 Advertiser Index 49 Resource Guide (Steel/CFS) 52 NCSEA News 54 SEI Structural Columns 56 CASE in Point

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Editorial

Raising the Bar

new trends, new techniques and current industry issues By Craig Barnes, P.E., SECB Chair, NCSEA Basic Education Committee

ong before structural engineering became a profession, even looking back to the master builder, structural engineers were covered under an umbrella over all trades. Uniqueness was not demonstrated. Somewhere in the planning of the great pyramids of Giza, there were individuals that more than likely did not understand they were structural engineers. Quite possibly, it was the masons of that period who were the structural engineers. Such individuals did not need sophisticated computer programs or an in-depth knowledge of engineering principles. Structures were massive and there was little opportunity for things to go wrong. The pyramids, for example, will deteriorate to a point where they are a pile of sand, while still resembling the original pyramid. They will not “fail” as we use the term today. Their massiveness will simply allow them to deteriorate. However, if we take the concept of the pyramid and move forward in time to structures that have the same image, such as the LUXOR in Las Vegas, we know that project could not have been realized without the application of sophisticated engineering techniques and an in-depth knowledge of engineering principles. Today we recognize the uniqueness of the structural engineer, and honor the profession by rigorously educating our engineers and conferring a diploma as acknowledgement. As long a track as the academic process might seem, it is just the start for the developing engineer. We then subject graduate engineers to a period of hands-on training under one or more mentors, following which we commit them to a demanding examination process. Then, and only then, do we, the stewards of public safety, feel as though we can turn them loose on society as bona fide structural engineers. Schools have been educating engineers as civil engineers for over 100 years. The American Society of Civil Engineers (ASCE), with a membership of over 140,000, has represented civil engineers for 160 years now. Along the way, civil engineers concentrating on structural engineering began to stand up as specialists. Now, schools are beginning to acknowledge structural engineering as a specialty study; and ASCE has done the same, with its Structural Engineering Institute (SEI). Even before SEI, the Council of American Structural Engineers (CASE) started, twenty years ago, to speak loudly for structural engineers; and, about that time, the National Council of Structural Engineers Associations (NCSEA) literally developed overnight from a gathering of less than a hundred like-minded structural engineers. Further acknowledgement that structural engineers are unique has been demonstrated in the long process of code development and even specific code sections. Who but a structural STRUCTURAL engineer understands what IBC ENGINEERING Chapter 16 is all about and how INSTITUTE to apply the contents?

For over ten years, the process of education, the level and amount of education, and the mentoring of structural engineer “wannabes” has been near and dear to me. Ten years ago, structural engineering practitioners felt strongly that schools and universities, students as well as the profession, would benefit by more direct involvement of practicing structural engineers in the academic process; and NCSEA provided me, and a large number of like-minded professionals, the opportunity to raise the bar of structural engineering education. A wide range of professional organizations are now adding their voice to the chorus, chiming in on education. Similarly, practitioners have realized the need for more involvement in the code process and in materials testing and standards development. At the recent meeting of the 2012 Participating Organizations Liaison Council (POLC), the following engineering-related organizations summarized their positive thoughts on the education process: The Architectural Engineering Institute, The American Institute of Chemical Engineers, The American Nuclear Society, The American Society of Agricultural and Biological Engineers, The American Society of Civil Engineers, The American Society for Photogrammetry and Remote Sensing, The Council of Engineering and Scientific Specialty Boards, The Institute of Electrical & Electronic Engineers, The Society of Naval Architects and Marine Engineers, The Structural Engineers Institute of ASCE, The Minerals, Metals and Materials Society, and the National Council of Examiners for Engineering and Surveying. Each one, in their own way, has taken on the mission of improving the education and raising the bar, if you will, of their membership. The process is moving quickly, and professional associations, educational institutions, and practitioners need to be up for the challenge. I, for one, am confident we are and that the challenge will be met.▪ Craig E. Barnes, P.E., SECB is principal and founder of CBI Consulting Inc. Craig currently serves on the Editorial Board for STRUCTURE® magazine.

a member benefit

structurE

The NCSEA Basic Education Committee seeks to determine and promote the core curriculum that should be offered to, and required of, structural engineering students. Integral parts of this mission include working with the Structural Engineering Certification Board to achieve a common objective, working with educational institutions for curriculum content, and working with practitioner employers to ease students from the academic environment into the workplace. Recently, the Basic Education Committee announced the formation of a group called SE Connect. This group is intended to be a personal connection between structural engineers represented by NCSEA and schools and universities. Two members of the Basic Education Committee, Brian Quinn, P.E. and Lisa Willard, P.E., are heading up this activity and sent out a letter to instructors at schools and universities throughout the United States, to verify contact information and inquire as to how NCSEA could benefit their school. If you would like to be part of this effort, contact Craig Barnes at cbarnes@cbiconsultinginc.com.

STRUCTURE magazine

May 2012

Advertiser index

PleAse suPPort these Advertisers

AZZ Galvanizing .................................. 50 Bentley Systems, Inc. ............................... 4 Computers & Structures, Inc. ............... 60 Concrete Masonry Assoc. of CA & NV. 11 CSC Inc. ................................................. 3 CTP Inc. ............................................... 19 CTS Cement Manufacturing Corp........ 15 Design Data .......................................... 33 Digital Canal ........................................... 8

Fyfe ....................................................... 23 Halfen Inc. ............................................ 26 Hayward Baker, Inc. .............................. 21 Hohmann & Barnard, Inc. .................... 36 The IAPMO Group............................... 43 ICC....................................................... 41 Integrated Engineering Software, Inc..... 47 JMC Steel Group .................................. 48 KPFF Consulting Engineers .................. 40

Masonry Institute of America ................ 25 NCEES ................................................. 44 NCSEA ................................................. 13 Polyguard Products, Inc........................... 6 Powers Fasteners, Inc. .............................. 2 RISA Technologies ................................ 59 Simpson Strong-Tie......................... 17, 29 Struware, Inc. ........................................ 46 Valmont Tubing .................................... 39

Structural Engineer Digital Canal is a software developer seeking a structural engineer to design enhancements and direct the implementation of new design codes for its product suite. The successful candidate will have knowledge of the structural engineering industry including steel and concrete design. Software programming capability and/or CAD knowledge is a significant plus. We offer stability, growth opportunity, causal environment and a competitive compensation and benefits package. Please send your resume to: Janet Betts – Structural Engineer, Digital Canal Corporation, 2728 Asbury Road, Suite 400, Dubuque, IA 52001.

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Erratum The Contents page in every issue of STRUCTURE® magazine includes the statement, “Publication of any article, image, or advertisement in STRUCTURE magazine does not constitute endorsement by NCSEA, CASE, SEI, C3 Ink, or the Editorial Board. Authors, contributors, and advertisers retain sole responsibility for the content of their submissions.” Furthermore, it is the Editorial Board’s policy that all Structural Forum articles be accompanied by the statement, “Structural Forum is intended to stimulate thoughtful dialogue and debate among structural engineers and other participants in the design and construction process. Any opinions expressed in Structural Forum are those of the author(s) and do not necessarily reflect the views of NCSEA, CASE, SEI, C3 Ink, or the STRUCTURE magazine Editorial Board.” However, this disclaimer has been inadvertently omitted from recent issues, including the March 2012 piece that advocated licensing engineers and certifying disciplines, contrary to the policies of NCSEA, CASE, and SEI in favor of separate licensure for structural engineers. The Editorial Board believes in publishing all sides of controversial matters within the profession so that our readers can evaluate the arguments for themselves and then reach their own conclusions. We regret any confusion or consternation that the disclaimer’s absence may have caused, especially in this particular case.

Editorial Board Chair

Burns & McDonnell, Kansas City, MO chair@structuremag.org

Brian W. Miller

Richard Hess, S.E., SECB

Mike C. Mota, Ph.D., P.E.

Mark W. Holmberg, P.E.

Evans Mountzouris, P.E.

Davis, CA

CRSI, Williamstown, NJ

Heath & Lineback Engineers, Inc., Marietta, GA

The DiSalvo Ericson Group, Ridgefield, CT

Roger A. LaBoube, Ph.D., P.E.

Greg Schindler, P.E., S.E.

CCFSS, Rolla, MO

KPFF Consulting Engineers, Seattle, WA

Brian J. Leshko, P.E.

Stephen P. Schneider, Ph.D., P.E., S.E.

John A. Mercer, P.E.

John “Buddy” Showalter, P.E.

HDR Engineering, Inc., Pittsburgh, PA

Mercer Engineering, PC, Minot, ND

BergerABAM, Vancouver, WA

American Wood Council, Leesburg, VA

STRUCTURE magazine

execdir@ncsea.com

Editor

Christine M. Sloat, P.E.

publisher@STRUCTUREmag.org

Associate Editor Graphic Designer Web Developer

Nikki Alger

publisher@STRUCTUREmag.org

Rob Fullmer

graphics@STRUCTUREmag.org

William Radig

webmaster@STRUCTUREmag.org

STRUCTURE® (Volume 19, Number 5). ISSN 1536-4283. Publications Agreement No. 40675118. Owned by the National Council of Structural Engineers Associations and published in cooperation with CASE and SEI monthly by C3 Ink. The publication is distributed free of charge to members of NCSEA, CASE and SEI; the non-member subscription rate is $65/yr domestic; $35/yr student; $90/yr Canada; $125/yr foreign. For change of address or duplicate copies, contact your member organization(s). Any opinions expressed in STRUCTURE magazine are those of the author(s) and do not necessarily reflect the views of NCSEA, CASE, SEI, C3 Ink, or the STRUCTURE Editorial Board.

reproduced in whole or in part without the written permission of the publisher.

Craig E. Barnes, P.E., SECB

Hess Engineering Inc., Los Alamitos, CA

Executive Editor Jeanne Vogelzang, JD, CAE

STRUCTURE® is a registered trademark of National Council of Structural Engineers Associations (NCSEA). Articles may not be

Jon A. Schmidt, P.E., SECB

CBI Consulting, Inc., Boston, MA

EditoriAL stAFF

May 2012

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inFocus

new trends, new techniques and current industry issues Virtue as a Skill By Jon A. Schmidt, P.E., SECB

have suggested previously (“Rethinking Engineering Ethics,” November 2010; “Engineering Ethics as Virtue Ethics,” May 2011) that virtue ethics seems like a more appropriate approach for engineering ethics than deontology (based on rules, duties, or obligations) or consequentialism (based on outcomes). I have also argued on multiple occasions that engineering is more of an art, which is all about skill, than a science, which is all about knowledge. This column will attempt to unify these two ideas, drawing from The Skill of Virtue, the 2007 dissertation of Matt Stichter, who was then a doctoral student at Bowling Green State University and is now an assistant professor at the University of Washington. He noted that one of the traditional tenets of virtue ethics, going all the way back to the ancient Greeks, is that virtues are analogous to skills. However, different philosophers have had different ideas of what it means to have a skill, and this has resulted in different applications of the skill analogy to virtue ethics. Most of the recent work in this area has followed Plato’s characterization, which is found primarily in his early Socratic dialogues. In particular, University of Arizona professor Julia Annas holds that “there are three necessary elements of genuine skill: the skill must be teachable, there must be unifying principles underlying the skill that the expert can grasp, and that experts can give an account of skilled actions.” The last item is especially significant – it means that for Plato and Annas, only those who are able to articulate reasons for what they do qualify as legitimate experts. By contrast, according to Isocrates, an early champion of rhetoric, “The three main elements in the acquisition of practical skills were natural talent, training by experience, and education or instruction.” Possessing skills does not necessarily “require a profound understanding of their subject matter”; in fact, it often involves approximations, rules of thumb, and trial and error – i.e., heuristics (“The Engineering Method,” March 2006; “Heuristics and Judgment,” May 2006). Stichter, citing D. S. Hutchinson, calls these two competing models “intellectualist” and “empiricist,” respectively. The “intellectualist” label is noteworthy, since it was the “intellectualist legend” that Gilbert Ryle explicitly sought to debunk once and for all by affirming that knowledge-how cannot be reduced to a form of knowledge-that (“Engineering as Knowledge-How,” November 2011). The mention of Isocrates brings to mind the broader conflict between Plato and the Sophists, to which Steven Goldman has attributed the generally inferior standing of engineering relative to science in Western culture (“The Principle of Insufficient Reason,” May 2008). Stichter disagrees with Annas regarding the views of Aristotle, Plato’s most famous pupil and, in my opinion, the patron philosopher of engineering (“Engineers Are from Aristotle,” July 2010). Annas claims that Aristotle rejected the skill analogy, but Stichter observes that Aristotle frequently invoked skills as examples in his discussions of virtue. Stichter’s conclusion is that Aristotle did not abandon the skill analogy itself, but rather the intellectualist model of skill acquisition, adopting the empiricist one instead. Stichter then discusses Aristotelian

STRUCTURE magazine

and “neo-Aristotelian” versions of the skill analogy in light of modern research – specifically, the Dreyfus model that I summarized in my last column (“The Nature of Competence,” March 2012). Aristotle identified three indispensable attributes of a virtuous person, besides the obvious one of doing that which is virtuous: knowing what one does, intending to do it for its own sake, and acting with certainty and firmness. Doing the right thing accidentally, or for the wrong reason, or only tentatively instead of habitually, is not sufficient to qualify as evidence of genuine expertise in virtue. Based on the Dreyfus model, the same can be said of exercising a skill, except for the stipulation that it be done for its own sake. Hubert and Stuart Dreyfus anticipated this discrepancy in a 2004 paper, “The Ethical Implications of the Five-Stage Skill-Acquisition Model” (Bulletin of Science, Technology & Society, Vol. 24, No. 3, pp. 251-264). As Stichter put it, “They reject this requirement as adding a type of deliberative intention that is at odds with the intuitive response of the expert.” However, according to Stichter, “Deliberation is about discovering the means to an end, and one can deliberate well or badly. The practically wise person is able to deliberate well.” In Aristotle’s words, “deliberative excellence is that sort of rightness in deliberating which leads to the gaining of some good.” Engineering is often portrayed as “discovering the means to an end,” but that end is rarely determined by the engineer and may not always be something inherently good (“The Social Captivity of Engineering,” May 2010). In order to maintain the skill analogy, I would suggest that Alasdair MacIntyre’s concept of an internal good is relevant here – something specific to a practice that can only be fully understood by those who participate in that practice and is generally beneficial to the entire practicing community. Rather than always having to decide consciously on the best course of action, perhaps an instinctive pursuit of internal goods is an aspect of the superior skill of a true expert. I am a proponent of the thesis that engineering is more intentional than rational (“Engineering as Willing,” March 2010). As Dreyfus and Dreyfus wrote, “It is an unsubstantiated assumption of philosophers since Socrates that there must be a theory underlying every skill domain.” Furthermore, “it is precisely this clinging to the demand for rational justification, rather than accepting the nonrationalizability of appropriate intuitive responses, that blocks the development of expertise.” The fact that these statements pertain equally well to competence in virtue and competence in engineering strikes me as further evidence that virtue ethics is uniquely well-suited to engineering ethics.▪ Jon A. Schmidt, P.E., SECB (chair@STRUCTUREmag.org), is an associate structural engineer at Burns & McDonnell in Kansas City, Missouri. He chairs the STRUCTURE magazine Editorial Board and the SEI Engineering Philosophy Committee. To view a copy of Matt Stichter’s 2007 dissertation, visit (http://etd.ohiolink.edu/view.cgi?acc_num=bgsu1181851300).

May 2012

Building Blocks updates and information on structural materials

oncrete masonry has many proven sustainable benefits including low maintenance requirements, long life cycle, high recyclability, high reusability potential, and lower energy cost over life span. The concrete masonry industry could become even more sustainable by reducing the use of Portland cement, whose production generates approximately one ton of carbon dioxide per produced ton. A possible way to achieve such a vision is to increase the substitution levels of fly ash and ground granulated blast furnace slag for Portland cement in masonry grout – low substitution levels have already been used for many years. The high volume replacement of Portland cement will most likely not cause a decrease in cement’s production, but it will cause a better use of available resources. There are several benefits of increasing the substitution levels of fly ash and slag for Portland cement in masonry grout. The benefits include: (a) using 100% recycled materials, (b) reducing their disposal in landfills, ponds, and (in many places around the world) in river systems, (c) making construction more affordable because less expensive materials are used, (d) possible construction industry expansion without increasing green-house gases emission, (e) making the masonry concrete construction more competitive, and (f ) alleviating the demand for Portland cement, especially in developing countries where masonry construction is the preferred construction method. All these benefits, however, can only be achieved if these materials can be used without compromising building code requirements. A research program is being conducted at Brigham Young University to determine if code required minimum masonry strengths, obtained from testing masonry prisms, can be maintained with high levels of fly ash and slag grouts. In case the minimum code strength is not obtained at the specified 28-day age, this research will determine at what age strength tests of masonry prisms can be then performed. Although this research is in its infancy, its impact can be significant and broad, even transcending time by benefitting generations to come.

High Volume Fly Ash Masonry Grout By Fernando S. Fonseca, Ph.D., S.E. and Kurt Siggard

Fernando S. Fonseca, Ph.D., S.E. is an Associate Professor at Brigham Young University, Department of Civil and Environmental Engineering. Fernando may be reached at ffonseca@et.byu.edu. Kurt Siggard is the Executive Director of the Concrete Masonry Association of California and Nevada. Kurt may be reached at kurt@cmacn.org.

Fly Ash and Slag

The online version of this article contains references. Please visit www.STRUCTUREmag.org.

Fly ash is a fine-grained particulate produced during coal combustion. It is a pozzolan which combines with calcium hydroxide in the presence of water to form cementitious compounds. Fly ash for use in concrete products must meet the requirements of ASTM C618, which

10 May 2012

Figure 1: Concrete masonry units prior to casting grout samples.

defines two classes of fly ash: Class F (which requires a source of calcium hydroxide such as cement or lime) and Class C (self-cementing). Class F is typically used in concrete products. Fly ash has been used as a cement replacement in Portland cement concrete for over 70 years. In concrete products, fly ash slows the rate of compressive strength gain and acts as a plasticizer, so it improves the workability of plastic grout. Replacement of up to 15% (typically by weight) of Portland cement by Class F fly ash is currently a common practice in grout mix designs. Blast furnace slag is a by-product of the iron and steel industry. Granulated blast-furnace slag is formed when molten blast furnace slag is quenched in water. Grinding reduces the particle size of the granulated blast-furnace slag to the same fineness as cement, and the resulting product, ground granulated blast furnace slag (GGBFS), is highly cementitious and hydrates like Portland cement. Substitutions of GGBFS for Portland cement in concrete are common and have been used for over 30 years. A 50% GGBFS replacement, a common amount in the concrete industry, reduces carbon dioxide emissions by approximately one-half ton. Furthermore, grinding slag for cement replacement uses about only 25% of the energy needed to manufacture Portland cement. Composition of GGBFS is governed by ASTM Specification C989, and three grades are specified; Grade 120 provides the greatest strength and is the most widely used. Compared to concrete mixes with no cement replacement, mixes incorporating GGBFS have improved workability and slower compressive strength development but equivalent and even higher ultimate strength.

High Volume Substitutions High volume substitution of Portland cement is a somewhat new development. In 1985, the concrete research group from the materials

Figure 3: Grout samples during testing.

Figure 2: Grout samples during casting.

Experimental Program at BYU A research program is being conducted at Brigham Young University (BYU) under the direction of Dr. Fernando Fonseca in collaboration with Mr. Kurt Siggard, Executive Director of CMACN. The first phase of this research program was to test grout mixes with high volumes of fly ash and slag. The second phase is under way and involves testing of

masonry prisms with high volumes of fly ash and slag grouts. Results of the first phase are being reported in this article, and results of the second phase will be reported in a subsequent article. Chapter 3 of the Building Code Requirements for Masonry Structures specifies that the compressive strength of grout, f'g, must be equal or exceed the specified compressive strength of masonry, f'm, which in turn must be equal

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technology laboratory at the Canada Centre for Mineral and Energy Technology (CANMET-MTL) began developing a high volume fly ash concrete (HVFAC). That concrete utilizes proper mixture proportioning and careful selection of materials to minimize the amount of Portland cement while producing high-quality concrete. HVFAC has low Portland cement content, low water-to-cementitious materials ratio (w/cm) and incorporates up to 55% fly ash. Because of low w/cm, however, superplasticizers may be needed to increase fresh concrete workability. Over the years, CANMET-MTL, in partnership with the Electric Power Research Institute (U.S.A.) Canadian Electrical Association, and other public and private partners, has published a large amount of data on the properties of HVFAC. HVFAC has been gradually gaining acceptance among engineers.

Experimental Program at CMACN A pilot testing program was conducted by the Concrete Masonry Association of California and Nevada (CMACN) to determine the feasibility of using higher substitution levels of fly ash and slag for Portland cement. Tests were conducted using grout mixes with 20, 30, 40, 50, and 60% fly ash replacement and mixes with 50, 60, and 70% Class F fly ash and GGBFS replacement; in these latter mixes, the percentage of fly ash was constant at 25 percent. Some of the results of that pilot research are shown herein for comparison.

In this re tion fi construc ood frame w e th , photo n completely has bee d, while the destroye asonry base m concrete ins intact. rema

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May 2012

Figure 4: Grout strength – fly ash replacement set.

or exceed 1,500 psi at 28 days. Chapter 2 of the code, however, does not specify minimum compressive strengths for grout and concrete masonry. According to the Specification for Masonry Structures, however, concrete masonry must: comply with the unit strength method; have a grout compressive strength equal to or exceeding f'm but not less than 2,000 psi at 28 days; or meet ASTM C476 specifications, which require grout to have a minimum compressive strength of 2,000 psi at 28 days. All of this means that grout must have a minimum compressive strength of 2,000 psi or the f'm, whichever is greater. The first research phase evaluated compressive strengths of several grout mixes by comparing results obtained with results of CMACN pilot testing and determining which mixes reached the compressive strength of 2,000 psi at 28-days. The control mix had Portland cement as the only cementitious material. The second set of grout mix had 45, 55, and 65% replacement of Portland cement with Class F fly ash, and the third set of mix had 65, 75, and 85% replacement of Portland cement with both fly ash and GGBFS with the percentage of fly ash being constant at 25 percent. These percentages were chosen to possibly determine the upper volume limit of these materials without modifications to the typical grout manufacturing procedure. Grout mixes were proportioned by weight and the material mixed in a mechanical mixer in accordance with ASTM C476. The ratio of water-cementitious material remained constant at approximately 0.7, but slump varied slightly from mix to mix. Slump testing was conducted according to ASTM C143 and ranged from 8 to 11 inches. Specimens were constructed and tested per ASTM C1019 with one exception: grout was placed into the cores of 8 x 8 x 8 inch CMU to form the specimens, rather than the four CMU mold. This method provided

Figure 5: Grout strength – fly ash-GGBFS replacement set.

the absorptive mold for the grout specimen as required by ASTM C1019. Grout samples were wet-cured in a fog room complying with ASTM C511. Compression specimens meeting the dimensional requirements of ASTM C1019 were saw-cut from the CMU cores using a wet diamond saw and then returned to the curing environment until testing. The saw-cut specimens were capped with capping compound and tested in compression in accordance with ASTM C1019. The testing of the grout samples occurred at 14, 28, 42, and 56 days. Figures 1 (page 10), 2 and 3 (page 11) show the samples prior to casting, during casting, and one sample being tested, respectively.

that 60% fly ash substitution achieves the code minimum required at 56 days. Testing results for the fly ash-GGBFS replacement set are shown in Figure 5. Results for the fly ash-GGBFS replacement set are more consistent than that of the fly-ash alone. There are still some irregularities and discrepancies, which are also most likely due to difference in materials and/or testing equipment and personnel. Nevertheless, results clearly show that 80% fly ash-GGBFS substitution achieves the code minimum required at 28 days and that 85% fly ash-GGBFS substitution achieves the code minimum required at 56 days.

Results and Discussion

Conclusions

Testing results for the fly ash replacement set are shown in Figure 4. Results show some variability and even what appears to be some discrepancies. The capacity of the CMACN 40% and 50% specimens is similar up to 42 days but then there is a decrease in strength for the 50% set, which is atypical since fly ash mixes gain strength with time. The capacity of the BYU 45% set appears to be low; it is much lower than that of the CMACN 40%, which should not have been, and only slightly higher than that of the BYU 55% set. Also, the increase in capacity from the BYU 65% to the BYU 55% is significantly larger than that between the BYU 55% and the BYU 45%. Furthermore, based on results from the CMACN tests, the BYU 45% set was expected to achieve the minimum code requirement at day 28, which did not occur. These discrepancies may be due to the difference in materials and/or testing equipment and personnel. Nevertheless, results clearly show that 40% fly ash substitution achieves the code minimum required at 28 days and

High volume fly ash and GGBFS replacement of Portland cement is a viable alternative to make concrete masonry construction more economical and sustainable. Research presented clearly shows that 40% fly ash and 80% fly ash-GGBFS substitutions achieve the code minimum compressive strength required at 28 days, and that 60% fly ash and 85% fly ash-GGBFS substitutions achieve the code minimum compressive strength required at 56 days. Results, however, appear to be sensitive to regionally available materials used, testing equipment, and technicians conducting the tests; therefore, masonry grout mix designs incorporating high volumes of SCM’s should be evaluated and tested using regionally available materials by masonry grout suppliers. More research to determine the correlation between these factors and the compressive strength of masonry prisms, constructed with grout containing high volumes of supplemental cementitious materials, is necessary to achieve a confidence level before proposing any changes to current codes and standards.▪

STRUCTURE magazine

May 2012

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Codes and standards updates and discussions related to codes and standards

asonry veneers are divided into two major categories, anchored veneers and adhered veneers. Most of us are at least familiar with anchored masonry veneers, defined by the TMS 402-11/ ACI530.1-11/ASCE 5-11 code as: “Masonry veneer secured to and supported laterally by the backing through anchors and supported vertically by the foundation or other structural element.” However, the other method, adhered masonry veneers, defined by TMS 402-11/ACI530.111/ASCE 5-11(TMS402), as: “Masonry veneer secured to and supported by the backing through adhesion”, has a rich history and is broader in application than generally realized. Richard P. Goldberg, Architect AIA,CSI, provides a brief history of thin cladding systems going back to 2700 B.C. when ceramic tiles were used to decorate graves of Egyptian Pharaohs. The oldest known exterior cladding is the Dragon of Marduk sculpture for the Istar Gate in Mesopotamia dating to 604 B.C. By the 13th century, ceramic tile was used extensively on the exteriors of prominent buildings throughout the Middle East. The influence of Islamic architecture spread though Spain and Italy by the 16th century, and has since become a familiar decorative and functional exterior cladding. In the 1950s, the invention of modern stone cutting equipment coupled with the invention of new adhesive products by the newly formed LATICRETE International, made direct adhesive attachment of ceramic tile, natural stone and thin brick to modern building façades practical and economical.

Adhered Masonry Veneers A Modern Approach to Wall Systems By Peter Loughney

Peter Loughney is the Michigan Area Director of Market Development and Technical Services for the International Masonry Institute. Prior to coming to IMI, Peter spent 26 years in higher education, the last 15 as a Construction Management professor at Eastern Michigan University.

The online version of this article contains references. Please visit www.STRUCTUREmag.org.

Design Requirements for the design and construction of adhered masonry veneers can be found in the 2012 International Building Code (IBC) and the TMS 402 code, as well as its companion Specification TMS 602-11/ACI 530.1/ASCE 6-11 (TMS 602). For residential application requirements refer to the International Residential Code (IRC). Many jurisdictions may have local code requirements which should be considered as well. Adhered veneers fall within the scope of Chapter 14 of the IBC which requires compliance with provisions contained in IBC Section 1405.10 and with provisions contained in TMS 402, sections 6.1 and 6.3; and in accordance with manufacturer’s instructions. In addition to the code requirements noted above, all adhered masonry veneers require a backing system. Acceptable options per the IBC include: concrete, masonry, steel framing or wood framing. Structural design requirements for these wall systems are found in IBC Chapters 19 -23.

14 May 2012

Note that the design of metal and wood framing systems may require extra vigilance with respect to allowable deflection limits, stud spacing, and protection requirements for framing in contact with masonry or concrete, sheathing exposure ratings, general fastener requirements and fastener requirements and patterns for sheathing.

Detailing Within Section 1405.3 are directions for vapor retarder requirements for the interior of frame walls for Climate Zones 5,6,7,8 and Marine Zone 4 (defined in Chapter 3 of the International Energy Conservation Code). Designers of frame systems in these zones should carefully review this section, and may wish to consider having a condensation analysis performed before completing the final design. IBC Chapter 14 also contains requirements related to weather protection. While concrete and masonry wall systems are granted an exception to the weather resistant exterior wall envelope requirements, IBC provisions for metal and wood framing systems are quite specific: 1403.2 Exterior walls shall provide the building with a weather-resistant exterior wall envelope. The envelope is required to provide flashing and to be designed in such a manner as to prevent the accumulation of water within the wall assembly by providing a water-resistive barrier behind the exterior veneer and a means of draining water that enters the wall assembly to the exterior. Protection against condensation must be considered as well. A potentially overlooked IBC provision for water- resistive barriers over wood based sheathing is included in Section 2510.6. Although Chapter 25 contains requirements for Gypsum Board and Plaster, Section 2510.6 specifically includes wood-based sheathing. Water-resistive barriers over wood must also be vapor-permeable with a performance at least equivalent to two layers of Grade D paper. The section also states individual layers are further required to be applied independently in such a manner as to provide a separate continuous plane. Any flashing intended to drain to the water-resistive barrier is directed between the layers. Flashing requirements at the foundations are addressed in Section 1405.10. An acceptable flashing material installed from 1 inch below the plate line to 3½ inches above is required. The top of the flashing is to be lapped over by the waterresistive membrane coming down from above. For exterior stud walls, clearances from contact with horizontal exterior surfaces are called out; from earth, 4 inches, from paved areas 2 inches and from exterior walking systems supported by the same foundation ½ inch.

TMS 402 Design & Detailing

Material may require a thorough cleaning to ensure adequate bond between the veneer and backing.

concrete or metal lathe, and Portland cement plaster applied to masonry, concrete steel framing or wood framing. Adhesion is critical in adhered systems and is addressed in TMS 402, Section 6.3.2.4. Shear strength between the adhered units and the backing is critical to the performance of the system and for public safety. Minimum shear strength of 50 psi, based on the gross unit surface area, is required when tested in accordance with ASTM C482. There is an exception to the test. Under the TMS 602 Specification, 1.4C, if the veneer is placed in accordance with Article 3.3C (see the Construction section that follows), the test is not required.

Construction, Inspection & Testing Construction, inspection and testing requirements are included in the TMS 602 Specification which is referenced in the TMS 402, IBC and IRC. continued on next page

Summary of code and specification provisions for adhered veneers.

Design Provisions IBC Section 1405.10 TMS 402 Sections 6.1 and 6.3 Manufacturer’s instructions (in addition to the code requirements) Backing Systems IBC Section 1405.10 – acceptable backing systems IBC Chapters 19 – 23: specific requirements for design of the backing system selected Detailing Flashing – IBC Sections 1403.2, IBC Section 1405.10 Vapor Retarders – IBC Section 1405.3 Weather Resistance, Water-resistive barriers – IBC Section 1403.2, IBC Section 2510.6 (wood only) Construction, Inspection & Testing Requirements TMS 602 STRUCTURE magazine

May 2012

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Design and detailing requirements for masonry veneers, both anchored and adhered, are addressed in Chapter 6 of the TMS 402 code. Provisions in this chapter also cover dimension stone for adhered applications, but not for anchored stone veneer which is considered a Special System. General design requirements include: • design and detailing of a backing system that will resist water penetration, • flashing with weep holes at least 3/16 inches in diameter spaced no less than 33 inches on center, and • the design and detailing must accommodate differential movement. Specific design options are found in TMS 402 Section 6.3. There are two options, alternative design of masonry veneer and prescriptive requirements for adhered masonry veneer. The alternative method allows designer professionals more latitude in material size and thickness, but requires more research and engineering to ensure the backup systems is adequate. Prescriptive requirements include: unit size, wall area limitations and backing. The unit size of adhered masonry veneers is limited to: • 25/8 inches in thickness (maximum), • 36 inches in any face dimension, • no more than 5 square feet in face area, and • the unit weight shall not exceed 15 psf. These requirements are intended to reduce difficulties in handling and installation, and to assure a good bond. Wall area limitations are not restricted in height, length or area, except as necessary to control differential movement stresses between veneer and backing. Permitted backing systems include masonry,

of the International Energy Conservation Code. Insulation layers are generally found attached directly to masonry or concrete backup walls. For frame walls, there is typically a backer sheathing layer, an air/moisture/ vapor barrier and then the continuous insulation. Beyond this, a water-resistive barrier and any drainage mat layers would be installed followed by metal lathe and scratch coat. Substantial differences in thicknesses are found in these two natural stone units, even though they are from the same batch.

Article 3 of the TMS 602 specification covers execution, or installation in the field. Adhered masonry veneer requirements are found in Article 3.3C 1-4. This article describes the installation process: • Apply a neat paste of Portland cement to the back of the unit and to the backing. • Apply a Type S mortar to the back of the unit and to the backing. • Tap the unit into place completely filling the space behind the unit so that a small amount of mortar is forced from behind at the edges. • The mortar on the back of the unit should be no less than 3/8-inch thick nor more than 1¼-inch thick. • Tool when thumbprint hard. In addition, both the TMS 402 Code and the TMS 602 Specification have an accompanying commentary which will prove invaluable to designers and installers alike. The commentary contains narrative, figures and diagrams, and references that will provide additional valuable information and insight into development of specific requirements and how they may be might met. Careful review of the commentary is recommended. The Table (page 15) shows a summary of the code and specification requirements for adhered veneer.

Additional Considerations In many applications, drainage mats will provide improved drainage, a capillary break and may help to prevent deterioration of the backing system. Drainage mats will generally be found outside the water-resistive barriers, but will need to be behind the metal lathe and scratch coats so the adhered veneer has a solid backing. Continuous insulation layers may be desirable or even mandatory to meet requirements

Lessons from the Field

A clear understanding of the manufacturer’s instructions is imperative. Products are constantly being improved and modified, and manufacturer’s instruction are regularly updated and improved. Be sure you have the latest instructions. If questions remain, contact the manufacturer or the technical representative for your area. Original designs do not always survive to the construction phase. Bid day alternates, value engineering and last minute supply issues often result in substantial differences between original designs and built installations. While this often results in cost savings or schedule improvements, care must be taken to ensure that these design modifications still meet the design intent, and that all elements of the systems are compatible and will perform at the required level. Failure of one system component can result in less than satisfactory performance of the building envelope or worse, resulting in a public safety issue. An adhered veneer application is only as good as the bond between the backing and the veneer. Masonry products often have dust on the outer surfaces from cutting or grinding during production or it may accumulate during shipping and handling. Additionally, backer systems can become dust covered or contaminated during installation or from being exposed on a construction site for any significant length of time. Manufacturer’s installation instructions may include cleaning recommendations to remove any release agents that may be present resulting from the production process. In most cases, it is best for the installer to assume at least some cleaning or scarifying will be required in the field Mockup panels are used to demonstrate to the owner, design professional and CM spell out what to expect of the final installation. Mockup panels should represent the full range variances in size, color and shape or any other distinguishing features that might be found in

STRUCTURE magazine

May 2012

In any good masonry design, one must account for movement of the veneer and the backing. Cracks resulting from movement are unsightly and can be both difficult and expensive to repair.

the specified material. Installers may wish to order and inspect enough quantity of material prior to constructing the mockup panel to ensure that an accurate representation of the final installation is provided. All concerns and issues regarding the final appearance should be resolved before approving the mockup panel. Panels showing the full system: structural backing, water-resistive barriers, insulation, drainage mats, flashing, weeps, scratch coats, setting beds, veneers with grouting and tooling; completely cleaned and sealed, if required, will provide the greatest amount of information to all parties concerned. They can also serve as a good training reference when the full installation crew arrives on-site. Movement control is essential in all masonry design, and adhered veneers are no exception. The TMS 402 Code requires that design professionals show, on the project drawings, provisions for dimensional changes resulting from elastic deformation, creep, shrinkage, temperature, and moisture. (1.2.2h) Movement control methods can vary considerably depending on the selected backup structural system and selected veneer. Movement control is particularly important in seismic regions.

Conclusion Adhered masonry veneers have offered a popular alternative to anchored systems for a wide variety of applications. Modern systems date back to the early 1960s and successful examples, both large and small, can be found in nearly any town or city. Considerable direction is provided by both the IBC and the TMS 402 Codes, and by manufacturer’s instructions and product specifications, for design professionals to complete successful designs and detailing. The TMS 602 Specification and manufactures instructions provide direction to contractors and inspectors to guide installation in the field.▪

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Structural PracticeS practical knowledge beyond the textbook

any structural engineers like to submit the masonry specification to architects and their specifiers; however, many specifiers prefer to author the masonry specification for the structural engineer’s review. The reason why is simple. Engineers are concerned with the structural integrity of the specification, including performance requirements, unit compressive strength, ties, and anchors. The structural components of the specification are very important. But with all of the options available within the unit masonry specification, the structural components comprise only a small portion of the entire specification. The components of the unit masonry specification include options for concrete unit masonry, decorative concrete unit masonry, face brick, glazed brick, structural-clay facing tile, firebox brick, and stone trim unit to start. Then the various accessories associated with the unit masonry must be considered, including mortar and grout, embedded flashing, weeps and vents, cavity drainage materials, and insulation. All of these components are options that must be selected by the architect. For the most part, once the engineering has been completed, the structural engineer is done with the specification. As budgeting prices are reviewed, and re-evaluated, the brick selections may change, the insulation types may change, and even the flashing materials may change. Many structural engineers do not want to be involved with these types of changes, whereas architects may make changes regularly. All good unit masonry specifications start at the foundation of specifying: 1) What version of MasterFormat (or another guideline) is to be used? 2) Is the project attempting to attain LEED certification? 3) What is the format for the specifications? 4) Is the terminology consistent between the specifications and the drawings? By now, most engineers and specifiers have converted over to the 2004 version of MasterFormat, the numbering system produced by the Construction Specifications Institute. Although there are still some entities using the 1995 version, the 2004 version has become the standard. One easy way to tell the difference between the versions is by the number of digits used for section numbering. The 1995 version of MasterFormat had 5 digits and the 2004 version has 6 digits. The majority of the

Building Unit Masonry Specifications By Renee Doktorczyk, AIA, CCS, CSI, SCIP

Renee Doktorczyk, AIA, CCS, CSI, SCIP is an architectural specifier and the president of ArchiTech Consulting, Inc. in Mount Prospect, Illinois. She can be reached at rdoktorczyk@architechspec.com.

For prior specification articles by this author, see the August 2011 and January 2012 issues of STRUCTURE® (www.STRUCTUREmag.org).

18 May 2012

engineering sections not only added a digit but moved divisions. Unit masonry remained in Division 4 – Masonry. If an architect has determined a project will attempt to obtain LEED certification, the unit masonry section can help contribute to LEEDS points. Regional materials and recycled content for the masonry units, mortar and grout, and reinforcing materials can be included in the specifications. Staying on top of which points are in or out, which materials are to be regionally sourced, and the percentage of recycled content are not aspects of the unit masonry specification the structural engineers want to constantly edit as a project progresses from design development to construction documents. Formatting a unit specification section to match the correct font, header and footer information, and margins is not a difficult task, but the format does change with each issue of the specification section. Projects have been known to start in schematic design with one name, progress to design development with another name, to finally be issued at 100% construction documents with a third name. Each issue also will have had a different date on the specification section. This is another reason that structural engineers may not wish to author the unit masonry section. Terminology between the drawings and the unit masonry specifications is another easily handled issue. Many times a product such as Mortar Net® will appear on the drawings and be specified as cavity drainage material in the unit masonry specifications. The terminology on the drawings will need to be changed to a non-proprietary term to ensure bidding competition. Many structural engineers may prefer not to perform this task. Building on the foundation of the unit masonry specification, and looking at the wall, structural engineers determine how the unit masonry wall is to be engineered, by either analytical or empirical methods. If an analytical method is used, then the structural engineer can determine compressive strengths either by ACI 530.1 or ASTM C 1314. Although architects can figure this out, they would prefer not to make the determination. The same is true for deciding what the unit compressive strength of concrete unit masonry and brick unit masonry needs to be to in order to support the loads on the wall. Once compressive strengths for the unit masonry are determined, many other factors for the correct and complete specification of unit masonry come into play. For concrete unit masonry, the density classification needs to be specified. Is an integral water repellent

required? Will the concrete unit masonry be part of an exterior single wythe masonry wall requiring additional products for flashing and weep systems? Decorative concrete unit masonry may also require integral water repellents along with patterns, textures, and colors that need to be ascertained from the Architect and then specified. With brick, additional options include brick grade, brick type, sizes, along with color and texture are required. Other less commonly specified unit masonry types include concrete building brick, pre-face concrete masonry units, concrete facing brick, building (common) brick, hollow brick, glazed face brick, glazed hollow brick, structural-clay facing tile, firebox brick, and clay flue lining units. The unit masonry section extends beyond unit masonry to include stone trim units, both natural stone and cast stone products. The products are included in the unit masonry section when they are used in conjunction with masonry walls as base, sills, copings, and other trim piece locations. Since they are installed as the masonry wall construction progresses, they have been included in this section.

Once the various types of unit masonry are specified, the structural engineers can turn their attention to the mortar and grout types required and the locations for the specific project. Inclusion of cold-weather admixtures may or may not be allowed within the specification as determined by the structural engineer. Water-repellent admixtures requirements may also be required if an integral water repellent has been specified for the concrete unit masonry. Structural engineers are important when the masonry reinforcement, ties, and anchors are specified. The current master specifications for unit masonry include several different types of anchors, including anchors for anchoring to structural steel, anchors for anchoring to concrete, adjustable masonry veneer anchors, and seismic masonry veneer anchors. Once the anchors, ties, and reinforcement are specified, the other masonry accessories need to be selected to complete the masonry wall. Over the years, each architectural firm has developed their office standard for their exterior wall assemblies based on their firms’ experience and lessons as the school of hard knocks. Because of that ADVERTISEMENT - For Advertiser Information, visit www.STRUCTUREmag.org

STRUCTURE magazine

May 2012

experience and those lessons, the selection for the unit masonry accessories varies from firm to firm, and from project owner to project owner. One project may allow the use of rubberized asphalt flashing with a stainless steel drip edge while another project requires stainless steel flashing only. Masonry wall flashing materials continue to evolve, bringing new materials and methods to the market every year, challenging even the best specifiers to keep up with the changes. Weep systems and cavity drainage system change just as frequently. Another shift in unit masonry specifications recently seen is the use of air barriers within the wall cavity. The type and location of cavity wall insulation materials have been changing. The trend for unit masonry walls has been moving towards using more rain screens and pressure-equalized systems. Although a structural engineer’s input into a unit masonry specification is essential, thought is required as to whether or not the structural engineer is the best entity to author the specification based on all the additional non-structural specifications items required to build a strong, sturdy unit masonry specification.▪

Just the FAQs

We see many different ways of flashing steel lintels and relieving angles, and would like to know the Brick Industry Association (BIA) recommendations on the following questions: Question: How high above the angle should the first veneer tie be located?

questions we made up about... Masonry

Answer According to TMS 402 Building Code Requirements for Masonry Structures, wall ties should be placed within 12 inches of any opening. However, some general information: flashing and weeps are necessary anytime you have a window or door opening. They are also necessary at SHELF angles (see May 2009 STRUCTURE article Do Relieving Angles Really Relieve?). The minimum requirements are that the flashing comes out to the outside face of the masonry wall; continue back to the backing and up the wall at least 8 inches. This height is recommended to capture as much water as possible if it were to back up due to mortar droppings, so it doesn’t leak into the building. If you are using a mortar collection device (the height of the most popular one is 10 inches) the flashing should extend above that. Of course, that also makes it more difficult to install a wall tie within the first 10 inches or so of the bottom of the veneer. That doesn’t leave much room for the first wall tie to be placed. A shelf angle is not really an opening, but the same recommendations would hold true for that application. Putting a wall tie and flashing in the same mortar bed joint of the CMU backing is not recommended because the wall tie loses some embedment strength. In many cases, that puts the first tie 16 inches above the steel angle. Instead of tucking flashing into a bed joint of the CMU backing mortar joint, the top edge of flashing can be attached to the backing with a termination bar. That may allow the first wall tie to be placed closer to the support.

Flashing Steel Lintels and Shelf Angles Answers provided by Brian E. Trimble, CDT, P.E., LEED AP, FASTM, Regional Vice President, Engineering Services & Architectural Outreach, Midwest/ Northeast Region, Brick Industry Association Besides his long tenure at the BIA, Brian has worked for a brick manufacturer and the International Masonry Institute.

Question: Is it necessary to have a flashing drip? If so, how is it created? Typical flashing detail at steel angle. (from BIA Technical Note 18A Accommodating Expansion of Brickwork)

Answer A drip edge is a beneficial flashing feature that reduces staining by forcing water out away from a wall as it comes out of the weeps. There are other reasons for drip edge use, but they are often trumped by aesthetics. The drip edge at a window or door head doesn’t have masonry below it, so it may not provide as much benefit as at a shelf angle or sill where masonry is constructed below the drip edge. The drip edge will protect the masonry and any sealant beneath it. Although the

20 May 2012

BIA Technical Notes do not require a specific size, the drip edge only has to extend approximately 3/8 inches beyond the wall face and be bent down at a 45 degree angle (see Figure). In many cases using stainless steel or copper flashing is cost prohibitive. However, using a stainless steel drip edge in combination with flexible flashing that is lapped and sealed properly can be a more cost effective means of providing a drip edge. If a drip edge is not used, it may increase the potential for water penetration and staining. Question: Should the course of brick sitting on the flashing of the lintel angle be set in a bed of mortar?

Answer Let’s look at field practice to see what happens when flashing is placed on a steel angle. Using mortar beneath the first course of brick is optional. There is no structural reason that mortar is placed at this location since it is assumed that no bonding occurs, just friction. The mason determines whether to place mortar under the brick or not, and bases this decision on the need to level the brick. Since tolerances on steel erection are large compared to masonry tolerances, there needs to be some mechanism for the mason to start the brickwork at the proper height. It is much easier to lay the flashing on the angle; the mason can then apply a thin bed of mortar if necessary to level the brick. Remember that masons lay to a line and that line is the top edge of the brick, not the bottom. So the mortar helps start things off right. Question: Should membrane flashing be adhered to the top of a steel angle lintel?

Answer Since the flashing is laid directly on the steel, it may make sense to bed the flashing in some form of compatible mastic, but it is not necessary. This decision may depend on whether the steel angle has any type of corrosion protection. Painted steel angles are the norm, with galvanized angles being used more and more. Placing mastic beneath the flashing and adhering it to the angle could eliminate wind-driven rain from blowing underneath. Of course, the weight of the brickwork should keep this location pretty well sealed. At shelf angle locations, the sealant used beneath the angle provides a seal to keep water out. These are common questions that we receive at BIA all the time. Most answers can be found in BIA’s Technical Notes (www.bia.org), but more job-specific questions need to be balanced with the technical knowledge and real world methods used in the field.▪

InSIghtS new trends, new techniques and current industry issues

Figure 1: Fractured EBF in Pacific Tower. Courtesy of Sean Gardiner, CPG New Zealand Ltd.

ith a few notable exceptions, steel structures performed well during the Christchurch series of earthquakes in 2010 to 2011, even when subjected to ground accelerations that exceeded their design basis by a factor of more than 1.5 in the most intense earthquake. Detailed descriptions of this performance can be found in Clifton et al. (2011). It should be noted that most of the steel structures in Christchurch were of recent vintage and thus their performance is a good test of current seismic design provisions. The notable exceptions are fractures discovered in the links of two eccentrically braced frames (EBF), and these failures deserve further discussion. The first of these link fractures was discovered in the 22-storey Pacific Residential Tower (the tallest building in Christchurch, completed in 2010). The building consists of perimeter EBFs up to the sixth floor on the western side and up to the eleventh floor on the north side of the building, shifting to join the other EBFs around the elevator core above that level, with transfer slabs designed to horizontally distribute the seismic loads at those transition points. Several sections of the EBFs at levels below the level 6 transfer slab were visible, as these levels housed a mechanical multilevel parking elevator system. Paint flaking and residual link shear deformations were observed in the EBF links at those levels. Design of the EBFs in that building was governed by the need to limit drift, with a corresponding resulting design ductility factor (µ) of 1.5 (even though up to 4.0 is permitted for EBF systems in New Zealand). This is typical of EBFs in tall buildings in that country’s moderate seismic zones (like Christchurch), and a more typical design ductility factor range for such buildings is 2 to 3. When the initial internal inspections were undertaken, there was an absence of significant damage to architectural and other non-structural finishings, except at level 6 where a few of the hotel room doors along the corridor

Link Fractures in Eccentrically Braced Steel Frames By Michel Bruneau, Ph.D., P. Eng., Charles Clifton, Ph.D., FIPENZ, FNZSEE, Gregory MacRae, Ph.D., P.E., Roberto Leon, P.E., Ph.D. and Alistair Fussell, B.E.(Hons), ME, MIPENZ, CP Eng.

The online version of this article contains references. Please visit www.STRUCTUREmag.org.

22 May 2012

could not be closed, suggesting greater residual deformations at that level. This level was the first in which a detailed evaluation was undertaken. One fractured EBF active link was discovered (Figure 1) at that level. The fracture propagated from one top corner across the active link region and resulted in significant residual deformation. Temporary strap cross-bracing was welded to the active link frame to provide lateral load resistance while a repair strategy was developed. The active links in the top 4 stories of this frame were subjected to higher inelastic demand than any other frame. These 4 links had a link length of only 400mm, half the link length of the other links in the bulding, accounting for the greater magnitude of inelastic demand. The 4 links are being replaced. This replacement will comprise cutting out the active link and a proportion of the collector beam and brace, and site welding new components back in. This method has been used successfully in the second building with fractured links (Figure 2), which is now repaired and back in service. The welding sequence was developed to minimize locked-in residual stresses. The replacement of this fractured link and the three links below are being undertaken in March 2012, and are the only repairs required to the structural system. This type of failure has not been reported in either EBFs tested in the laboratory or from damage reports from other earthquakes; the reasons for this link fracture are not currently clear and all 4 links will be the subject of detailed metallurgical and structural evaluations once they are removed. Fractures were also found in two bays of a low-rise parking garage having eccentrically braced frames (Figure 2). For a number of reasons explained elsewhere (Clifton at al.), this parking garage was not subjected to ground motions as severe as those felt elsewhere in Christchurch. However, because these EBFs were not drift dominated, they were designed for the maximum µ = 4 ductility demand. The cause of failure has been speculated to be due to an unintended offset observed between the brace flange and the link stiffener. As a consequence of this offset, the axial tension force in the brace fed into the active link/collector beam panel zone through a

flexible beam flange rather than directly into the stiffener, severely overloading this junction area, possibly leading to a fracture that spread across the beam flange and through the web. This suggest that load path through the as-constructed detail is particularly important when inelastic demand is required from the system. Note that at least six EBF frames were used at each level in each of the buildings’ principal directions, and that this significant redundancy contributed to maintaining satisfactory seismic performance of the building in spite of those significant failures. Also, residual drifts of the parking structure or damage to the gravity load carrying system were not visually noticeable, which suggests that these fractures would have not have been discovered if hidden by non-structural finishes. As noted above, the fractured active links have been cut out and replaced to bring the building back into service.

Acknowledgments This work was funded in part by the Foundation for Research in Science and Technology of New Zealand, the Universities of Auckland and Canterbury, and MCEER (University at Buffalo). However, opinions presented here are solely those of the authors. Figure 2: Parking garage with fractured link at lower level EBF. Courtesy of Greg MacRae.

Conclusions

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Although steel structures performed well in the February 22, 2011 Christchurch earthquake and in the numerous other similar events that hit the city between September 2010 and June 2011 as noted by Clifton et al., it is instructive to note that even robust systems such as EBFs can be susceptible to failure when the forces are large. It is expected that the ongoing investigations into detailing practices and material properties will shed light on these two unusual, localized failures.▪ Michel Bruneau, Ph.D., P. Eng., Professor, Dept. of Civil, Structural, and Environmental Engineering, University at Buffalo, Buffalo, NY, USA. Charles Clifton, Ph.D., FIPENZ, FNZSEE, Associate Professor in Structural Engineering, Dept. of Civil Engineering, University of Auckland, Auckland, New Zealand. Gregory MacRae, Ph.D., P.E., Associate Professor in Structural Engineering, Dept. of Civil and Natural Resources Engineering, University of Canterbury, Christchurch, New Zealand. Roberto Leon, P.E., Ph.D., Professor, Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, USA. Alistair Fussell, B.E.(Hons), ME, MIPENZ, CP Eng., Senior Structural Engineer, Steel Construction New Zealand, Manukau City, New Zealand. STRUCTURE magazine

May 2012

Structural DeSign design issues for structural engineers

oday’s wood framed structures utilize efficiency and availability of engineered wood products and prefabricated wood systems to supplement sawn lumber framing. A typical wood framed structure may have a prefabricated wood roof truss system, an I-joist or prefabricated wood floor truss system, structural composite lumber beams and headers, and dimensional sawn lumber wall studs. Prefabricated wood systems are designed by specialty engineers and submitted to the engineer of record for review and approval. Engineered wood products are designed using product manufacturer tables, product manufacturer software, or commercial software that includes manufacturer product design data (specifically for beams). Sawn lumber wall stud design may be performed by prescriptive design or by hand calculations, spreadsheet, or commercial software. This article covers design considerations and code required load combinations for sawn lumber wall studs.

Design Considerations for Sawn Lumber Wood Studs By Jason A. Partain, P.E.

Jason A. Partain, P.E. is a Project Manager with Structural Design Group, Inc. in Birmingham, AL. Mr. Partain can be reached at jpartain@sdg-us.com.

The online version on this article contains detailed references. Please visit www.STRUCTUREmag.org.

Adjustment Factors

One of the key considerations when beginning design of a wood frame structure is the adjustment factors which will affect the allowable design stresses for sawn lumber. Under typical design parameters, wall stud allowable stresses will include adjustment factors for duration of load, beam stability, column stability and nominal stud size. Load distribution due to partial composite action and load sharing is accounted for with a repetitive member factor. Design adjustments for factors such as moisture content are not likely to affect typical wood stud wall design and are outside the scope of this article. Duration of load factors are provided in Table 2.3.2 of the ANSI/AWC National Design Specification® for Wood Construction (NDS®) (AWC, 2005). NDS Table 4A provides stud size factors for reference design values for visually graded dimension lumber of all wood species except Southern Pine. NDS Table 4B provides reference design values for Southern Pine that are already tabulated to include adjustments for size effects. Out-of-plane wind loads that induce bending in wall studs require consideration be given to beam stability. Based on conventional wall framing, the NDS prescriptive requirements for stability of bending members up to a nominal 2x8 do not require any lateral bracing to use a beam stability factor of 1.0. While this covers most wall studs used in design, wood sheathing attached to the exterior face of studs provides lateral restraint for studs up to 2x10 to qualify for a beam stability factor of 1.0. Additional beam stability

24 May 2012

requirements are provided in NDS Section 4.4.1 and are outside the scope of this article. Column stability of a rectangular compression member is analyzed for each axis of a member. A column stability factor of 1.0 applies when a member is supported throughout its length to prevent lateral displacement. Preventing weak axis buckling through lateral restraint of a stud is important for achieving full capacity. Building codes leave judgment of what adequately braces a stud for interpretation by engineers, which has led to varying opinions on bracing materials. Attachment of wood sheathing panels to a stud wall is believed to adequately provide lateral restraint to limit weak axis buckling. Drywall, fiberboard and laminated fibrous boards, such as Thermo-Ply®, are less obvious choices to prevent lateral displacement for studs. According to NDS Commentary Section C3.6.7, experience has shown that these sheathing materials “provide adequate lateral support of the stud across its thickness when properly fastened.” Testing also shows that drywall, fiberboard and laminated fibrous boards are capable of resisting weak axis stud buckling when properly attached (Marxhausen, 2009). Test specimens used minimum code requirements to fasten sheathing materials to studs. A repetitive member factor for allowable bending stress of 1.15 is common to sawn lumber framing used in a system such as sheathed floor joists or sheathed rafters. Conventional software, if using the column design feature to design wall studs, may not apply this factor correctly since a repetitive member factor does not apply to axial capacity. When designing wall studs for out-ofplane wind loads, ANSI/AWC Special Design Provisions for Wind & Seismic (SDPWS) (AWC, 2008) allows for an alternative repetitive member factor to calculate allowable bending stress. A repetitive member factor of up to 1.50 can be used, per the SDPWS, when: “Studs are designed for bending, spaced no more than 1-inch on center, covered on the inside with a minimum of ½-inch gypsum wallboard, attached in accordance with minimum building code requirements and sheathed on the exterior with a minimum of 3/8-inch wood structural panel sheathing with all panel joints occurring over studs or blocking and attached using a minimum of 8d common nails spaced at 6-inch on center at panel edges and 12-inch on center at intermediate framing members.” A study of a common 2x4 wall assembly with wood structural panel sheathing and gypsum wallboard sheathing found that partial composite action and load sharing produced wall strengths greater than predicted by traditional single member design (Polensek, 1976). New repetitive

member factors for wood stud wall assemblies were developed for use in the design of wall studs with exterior wood structural panel sheathing and interior gypsum wallboard.

Deflection Requirements

LE ILAB A V A THIS R ME SUM

Load Combinations Local, state, and model building codes include provisions for load combinations for both strength design and allowable stress design. These provisions are derived from ASCE 7 Minimum Design Loads for Buildings and Other Structures (ASCE). Through experience, engineers

elements, such as beams and columns, are not provided for load bearing walls. In typical wood frame construction, the tributary area supported by a wall will not be large enough to allow a reduction in live load.

Computer Analysis Computer software tools, such as Enercalc and TEDDS, usually include wood design calculations for beams and columns. Using the column design calculation may yield an acceptable design but it does not accurately analyze wall studs. The primary difference is the repetitive member factor and the application of combined loading. An Excel spreadsheet or other custom analysis tool designed specifically for wall studs can yield more accurate and efficient results.

Conclusion There are several methods available for designing wood members. Some of these methods are well suited for joist and beam design, but not for wood stud design. Because wood design utilizes adjustment factors for duration of load, the worst case loading may not be obvious. Model building codes require designers to consider each load combination for design of a structural element. Stud walls act as both individual elements and as an assembly of elements that support the overall structure. Using both MWFRS and C&C wind loads with the code required load combinations ensures that sawn lumber wood stud walls will continue to be an efficient and reliable structural system.▪

REINFORCED MASONRY ENGINEERING HANDBOOK, 7th EDITION

he Reinforced Masonry Engineering Handbook, 7th edition, updated to the 2012 International Building Code will be available this summer. Originally published in 1972 and authored by the legendary James Amrhein, this resource has been a valuable tool with practical examples and design aids for decades. The upcoming edition has been updated by a current practicing Structural Engineer and the presentation will be no different.

For notification of publication of the Reinforced Masonry Engineering Handbook, 7th edition, send an email to jc@masonry.pro, or visit www.masonryinstitute.org and add the comment ‘RMEH’ in the Request Information section of the website.

MASONRY INSTITUTE OF AMERICA

STRUCTURE magazine

May 2012

P. O. Box 3905, Torrance, CA 90510-3905 Phone (310) 257-9000 – Fax (310) 257-1942

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The International Building Code (IBC) (ICC 2009) provides deflection requirements for walls with flexible or brittle finishes. The IBC lists deflection limits as l/120 for walls with flexible finishes and l/240 for walls with brittle finishes. Brick veneer anchored to walls is a common exterior finish for many types of structures. There are multiple industry recommendations ranging from l/360 to l/720. The Brick Industry Association recommends that brick veneer/steel stud wall systems be designed for l/600 but does not have similar recommendations for brick veneer/wood stud wall systems. This is, in part, based on the high flexibility and flexural capacity of steel studs in contrast to the rigidity and low flexural strength of brick. Trestain and Rousseau reported findings of research performed at McMaster University that showed excessive leakage from flexural cracking did not increase system vulnerability. Brick veneer begins cracking at l/2000. Deflection limit recommendations do not prevent veneer from cracking, but serve to limit the flexural crack size. Control and management of moisture that enters the system and corrosion resistance of system elements were found to have a more significant impact on system durability than the flexural crack width. Although no definitive source is available for the deflection limit of wood studs supporting brick veneer, there are avenues to choose the best design requirements. When calculating deflection of the wall system, designers should consider using exterior sheathing attached to studs to create a composite system. Designers should also be aware of any manufacturer requirements for deflection limits on other finish systems. A manufacturer may choose to require a specific deflection limit that if not met could void the warranty of an exterior finish.

may decide to take short cuts when applying load combinations to various structural elements, choosing to design for “worst case” scenarios. For wood design, the duration of load adjustments factors affect the design and may skew what is assumed to be the worst load combination. From ASCE 7-05, applicable load cases to design a wall stud for both bending and axial design loads are: 1) D + L 2) D + (Lr or S or R) 3) D + 0.75L + 0.75(Lr or S or R) 4) D + W 5) D + 0.75W + 0.75L + 0.75(Lr or S or R) ASCE 7-05 also includes provisions for wind design of structures and structural elements. Main Wind-Force Resisting System (MWFRS) and Component & Cladding (C&C) wind loads as defined in ASCE 7-05 both apply to stud wall design. When analyzing a stud as a wall element, C&C loads should be applied to the stud to check for axial and bending stresses individually. MWFRS loads apply to wall studs when designing for combined axial and bending loads (Douglas and Weeks, 2000). Wind load in each load combination above will vary depending on the use of MWFRS or C&C wind pressures. Depending on geometry of the structure being analyzed, MWFRS can load a stud in both compression and bending in the same load combination. For multi-story buildings, lower level members supporting multiple floors and a roof see considerable live loads. Live load reductions are allowed based on the supported area of the loaded floor or roof. Reduction factors found in ASCE 7-05 for specific structural

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code developments and announcements

Code Updates

Infilling the Frame with Masonry By Charles J. Tucker, Ph.D., P.E.

s discussed in STRUCTURE® magazine’s February 2012 edition of Just the FAQs, the Building Code Requirements for Masonry Structures (TMS 402-11/ACI 530-11/ASCE 5-11) includes a mandatory language appendix for the design of masonry infills that can be either unreinforced or reinforced using either clay masonry or concrete masonry. Masonry infills can be designed and detailed as part of the lateral force-resisting system (participating infills) or they can be made to only resist out-of-plane loads (non-participating infills). The new appendix of TMS 402 provides the designer with a straightforward method for the design and analysis of masonry infills. Guidelines and consideration are given for both participating infills and non-participating infills, and were developed based on experimental research and performance in the field. Construction of masonry infilled frames is relatively simple. First, the bounding frame is constructed of either reinforced concrete or structural steel. TMS 402 defines the bounding frame as “the columns and upper and lower beams or slabs that surround masonry infill and provide structural support.” After the bounding frame is erected, the masonry infill is constructed in the portal space. This construction sequence allows the roof or floor to be constructed prior to the masonry being laid, allowing for rapid construction of subsequent stories or application of roofing material. All infills (participating and non-participating) require mechanical connectors attached to the bounding frame for support of the masonry against out-of-plane loading. The maximum spacing of the connectors is four feet along the perimeter of the infill. These connectors are not permitted to transfer inplane loads from the bounding frame to the infill. Research shows when connectors transmit in-plane loads they create regions of localized stresses and can cause premature damage to the infill. This damage then reduces the out-of-plane capacity of the infill because arching action is inhibited. The bounding frame must be designed for these out-of-plane loads. In this article, we will discuss masonry infills in greater detail.

In-Plane Shear for Participating Infills For participating infills, the masonry is either mortared tight to the bounding frame so that the infill receives lateral loads immediately as the frame displaces, or the masonry is built with a gap such that the bounding frame deflects slightly before it bears upon the infill. If the gap is less than 3/8 inches or the calculated displacement, the gap does not conform to the requirements of Code Section B.2.1. However, the infill can still be designed as a participating infill provided the calculated strength and stiffness are reduced by half. The maximum height-to-thickness (h/t) ratio of the participating infill must not exceed 30 in order to maintain stability. The maximum thickness allowed is one-eighth of the infill height. From a code perspective, participating infills must fully infill the bounding frame and have no openings. Code Section B.1.5 does not allow partial infills or infills with openings to be considered as part of the lateral force-resisting system because structures with partial infills have typically not performed well during seismic events. The partial infill attracts additional load to the column due to its increased stiffness; typically, this results in shear failure of the column. The limitation of full panels and no openings may be relaxed as the code matures and more research becomes available. The in-plane design is based on a braced frame model, with the masonry infill serving as an equivalent strut. The width of the strut is determined from Equation 1 (TMS 402 Equation B-1). (See Figure 1 in the February 2012 article.) w=

0.3 strutcosstrut

Equation 1

where strut = 4

√ E t4E Isin2h  m netinf

strut

bc bc inf

Equation 2

The term strut, developed by Stafford Smith and Carter in the late 60s, is the characteristic stiffness parameter for the infill and provides a measure of the relative stiffness of the frame and the infill. The numerator under the radical includes the modulus of

STRUCTURE magazine

May 2012

elasticity of the masonry, the net thickness of the masonry, and the angle that the strut makes with the horizontal. The denominator under the radical includes the frame modulus of elasticity, the moment of inertia of the bounding columns, and the height of the infill. Design forces in the equivalent strut are then calculated based on elastic shortening of the compression only strut within the braced frame. The area of the strut used for that analysis is determined by multiplying the strut width from Equation 1 and the specified thickness of the infill. The infill capacity can be limited by shear cracking, compression failure, and flexural cracking. Shear cracking can be divided into cracking along the mortar joints, which includes stepped and horizontal cracks, and diagonal tensile cracking. The compression failure mode consists of either crushing of the masonry in the loaded diagonal corners or failure of the equivalent diagonal strut. The diagonal strut is developed within the panel as a result of diagonal tensile cracking. Flexural cracking failure is rare because separation at the masonry-frame interface usually occurs first; then, the lateral force is resisted by the diagonal strut. As discussed above, the nominal shear capacity is determined as the least of: the capacity infill corner crushing, and the horizontal component of the force in the equivalent strut at a racking displacement of one-inch; or, the smallest nominal shear strength from Code Section 3.2.4, calculated along a bed joint. The displacement limit was found to be a better predictor of infill performance than a drift limit. Generally, the infill strength is reached at lower displacements for stiff bounding columns, while more flexible columns result in the strength being controlled at the one-inch displacement limit. While Code Section 3.2 is for unreinforced masonry, use of equations from that section does not necessarily imply that the infill material must be unreinforced. The equations used in Code Section 3.2 are more clearly related to failure along a bed joint and are therefore more appropriate than equations from Code Section 3.3 for reinforced masonry. The equations used in the code are the result of comparing numerous analytical methods to experimental results. They are strength based.

The experimental results used for comparison were a mixture of steel and reinforced concrete bounding frames with clay and concrete masonry. While some methods presented by various researchers are quite complex, the code equations are relatively simple.

Out-of-Plane Flexure for Participating Infills The out-of-plane design of participating infills is based on arching of the infill within the frame. As out-of-plane forces are applied to the surface of the infill, a two-way arch develops, provided that the infill is constructed tight to the bounding frame. The code equation models this two-way arching action. As previously mentioned, the maximum thickness allowed for calculation for the out-of-plane capacity is one-eighth of the infill height. Gaps between the bounding frame and the sides or top of the infill reduce the arching mechanism to a one-way arch and are considered by the code equations. Bounding frame members that have different cross sectional properties are allowed by averaging their properties for use in the code equations.

Non-Participating Infills Because the non-participating infills only support out-of-plane loadings, Code Section B.2.1 requires these infills must have isolation joints at the sides and the top of the infill. These isolation joints must exceed the larger of 3/8 inches or the expected design displacements of the bounding frame, including inelastic deformation due to a seismic event, so that the infill does not receive any lateral loadings. The isolation joints are allowed to contain filler material as long as the compressibility of the material is taken into consideration when sizing the joint. Non-participating infills support out-of-plane loadings according to Code Section B.2.2. As previously noted, mechanical connectors are required for this support. These connectors are not allowed to transmit in-plane loads. The masonry infill may span vertically, horizontally, or both. The masonry design of the non-participating infill is then carried out based on the applicable sections of TMS 402 for reinforced or unreinforced masonry (Code Section 3.2 for unreinforced infill and Code Section 3.3 for reinforced infill using strength design methods). The choice of unreinforced or reinforced masonry belongs to the designer. However, there are seismic conditions which may limit the use to only reinforced masonry. (See the February 2012 article.)

Masonry infills with concrete frame.

Since they support only out-of-plane loads, non-participating infills can be constructed with full panels, partial height panels, or panels with openings. The effects on the bounding frame must be included by the designer.

Examples The Figure shows a reinforced concrete frame infilled with concrete masonry. Both participating and non-participating infills can be seen in this picture. The infill at the left of the figure is participating due to the fact that the masonry is laid tight to the bounding frame and completely fills the portal space; the mechanical connectors exist but are not visible on the left column. The infill at the right of the figure has a door opening which makes this a non-participating infill. As previously mentioned, each infill’s effect on the bounding beam and columns should be considered in their design or analysis.

Bounding Frame TMS 402 gives guidance on the design loads applied to the bounding frame members; however, the actual member design is governed by the appropriate material codes and is beyond the scope of TMS 402. The presence of infill within the bounding frame places localized forces at the intersection of the frame members. Code Section B.3.5 helps the designer determine the appropriate augmented loads for designing the bounding frame members. Frame members in bays adjacent to an infill, but not in contact with the infill, should be designed for no less than the forces (shear, moment, and axial) from the equivalent strut frame analysis. The shear and moment applied to the bounding column are not to be less than the results from the equivalent strut frame analysis multiplied by a factor of 1.1. The axial loads are not to be less than the results

STRUCTURE magazine

May 2012

of that analysis. Additionally, the horizontal component of the force in the equivalent strut is added to the design shear for the bounding column. In a similar manner, the shear and moment applied to the bounding beam or slab are not to be less than the results from the equivalent strut frame analysis multiplied by a factor of 1.1. Likewise, the axial loads are not to be less than the results of that analysis. Additionally, the vertical component of the force in the equivalent strut is added to the design shear. Design of the frame should also take into consideration the volumetric changes in the masonry infill material that may occur over time due to normal temperature and moisture variations. Expansion of clay masonry infill material will exert additional forces on the bounding frame that must be considered. Shrinkage of concrete masonry infill material may open gaps between the infill and the bounding frame that need to be addressed also. Guidance for these volumetric changes is provided in Code Section 1.7.5.

Conclusion Although masonry infills have been used worldwide for nearly a century, the US structural designer has not had a simple way to take true advantage of their efficiency. The new appendix in TMS 402-11 provides the necessary guidance for the designer to benefit from the inherent lateral strength of masonry infills.▪ Charles J. Tucker, Ph.D., P.E. is an Associate Professor of Engineering at Freed-Hardeman University, Henderson, Tennessee. Dr. Tucker is the Chair of the Masonry Infill subcommittee of the Masonry Standards Joint Committee. He can be reached at ctucker@fhu.edu.

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Tower Stabilization during Buttress Repairs

By David T. Biggs, P.E., S.E., DistM.ASCE, Hon.TMS

asonry towers are the focal point of numerous historic buildings and monuments. They grace most religious structures and many significant civil works. These towers present numerous diﬃculties for engineers and architects to define the nature of their problems and develop necessary repair interventions. Among the most challenging concerns is structural deterioration of the buttresses and walls. Depending upon where it occurs over the height of the tower, such deterioration produces a weakness that can cause local or global instability of the tower, requiring strengthening as a possible intervention. This can vary, from repointing with supplemental reinforcement to in-situ injection with transversal pinning to partial removal and reconstruction. Structural problems with towers can affect either the local or global stability of the tower during restoration and strengthening. Caution must be taken on any invasive intervention to avoid further instability of the tower during implementation of the repairs.

Figure 1: 1892 Church – Vermont, USA.

Problems A church in Vermont with an 80-foot-tall tower (Figure 1) was completed in 1892. The walls are multi-leaf brick and the exterior is faced with limestone that is 6 to 8 inches thick. The corner buttresses have a core of rubble stone. Based upon visual observations, water was saturating the buttresses and deteriorating the exterior mortar. Random cracks were noted in the mortar joints and several stones were displaced outward from the buttresses. Investigations indicated that the face stones of the buttresses were not well connected to the core. While the walls had header stones, there was an inadequate number of header stones to interlock the rubble core with the face stones of the buttresses. This was primarily evident over the mid-height of the buttresses. Both the upper and lower portions of the buttresses were in good condition; only the middle sections were deteriorated. See the oval on Figure 1 that highlights the distressed area. All four buttresses were affected. The lack of interlock of the face stones in combination with freezethaw action caused the exterior leaf stone to shift and crack the mortar joints. Removal of several stones further indicated that water infiltration STRUCTURE magazine

Figure 2: Existing buttress.

May 2012

Figure 4: Tower with proposed cable locations.

Figure 3: Tower with personnel-access scaffolding. Courtesy of Micahel Gnazzo.

and freeze-thaw had deteriorated the binding mortar inside the buttresses. Voids had developed due to the erosion of the interior mortar in both the buttresses and random areas of the walls of the tower. The walls were approximately 22 inches thick; the buttresses were approximately 3 feet thick. Figure 2 shows the section through one of the buttresses.

Restoration Repair The intervention selected for the buttresses was to remove and rebuild them in the damaged areas, inject the voids in the adjacent walls and other buttresses, and pin the face stones of the walls at the injected areas. The buttress reconstruction included stainless steel anchors to bond the stones with the rebuilt masonry core. The reconstruction reused the existing stones. Proportionate to the wall thickness of the tower, the buttresses occupy the majority of the wall corner. If the buttresses were all to be removed simultaneously, the reduced section area of the masonry would cause the stresses in the remaining stones to be excessive. In addition, the tower would be become unbalanced because the buttresses against the building would not be removed to the same degree as the outer buttresses. Since a stability analysis indicated that removing and rebuilding all four corners simultaneously would be detrimental, the work was sequenced to avoid excessive stresses and to maintain stability of the tower. One option was to build a massive scaffolding structure to shore and underpin the removal area. The cost was deemed excessive and alternate methods were considered. After several analyses, the work was planned so that it could be performed on two buttresses at a time by removing opposing corners to balance the load on the tower. The scaffolding that was used was only needed for personnel access and to stage materials. It was not used for tower support (Figure 3).

Tower Stabilization during Buttress Reconstruction

Figure 5: Overhang created by removals.

Figure 6: Upper stones produce eccentricity at overhang.

The tower stabilization scheme was subdivided into both global and local actions. The global action was to wrap the upper portion of the tower with cables to resist overturning of the corners. In addition, the buttresses were removed two at a time, leaving the opposing corners intact. The local stabilization required that the stones immediately above the removal area be held in place to prevent movement.

Global Tower Stabilization The goal of the stabilization procedure was to hold the top of the tower in place so that the buttress removal and reconstruction could occur without heavy shoring. The scheme utilized steel cables wrapped around the top of the tower. Figure 4 shows the tower before reconstruction, with the proposed cables located. The buttresses below the lower cable were to be removed and reconstructed down to above the main door entrance. Figure 5 shows a graphic with the buttress removed below leaving the upper portion overhanging. Figure 6 shows that the removals below would produce an eccentric load on the remaining STRUCTURE magazine

May 2012

Figure 7: Overturning restraint with cables.

Figure 8: Corner protection for cable on stone.

Figure 9a: Pinning upper stones before lower buttress removal.

Figure 9b: Partial buttress removal below the the pinned stones in Figure 9a.

masonry. Figure 7 (page 31) shows that, with very little bearing area remaining below the corners due to the removals, cables were needed to overcome overturning and provide a clamping force that would increase the shear capacity of the upper masonry at the corners. The two cables in Figure 7 were wrapped around the tower and tightened. The corner stones that were clamped by the cables were protected from damage by crush plates made up of a piece of steel pipe with a wooden filler that is formed to the edge of the stones (Figure 8). Alignment tabs were welded to the pipe for the cables. The extra cable shown in the lower portion of the photograph is not stressed.

Local Stone Stabilization Prior to actual buttress removal, the stone just above the area was reanchored using drilled-in pin anchors to provide localized support and stability. Figure 9a shows the stainless steel pins being installed. These 1-inch-diameter steel pins were drilled and adhesive anchored into the backing material. After the restoration was completed, the pins were subsequently cut below the face stone and a patching material was used to cover the hole. Figure 9b shows the area below Figue 9a after the stones of the buttress below were removed. The pins from Figure 9a are shown by the arrow.

Figure 10: Detail of buttress reconstruction.

Buttress Reconstruction Figure 10 shows graphically the reconstruction of the buttress. The core of the buttress was reconstructed and anchored to the brick backing wall using #3 reinforcing bars drilled and adhesive grouted 8 inches into the brick. The reinforcement was installed at 16 inches on center over the height of the buttress. Stainless steel ties were used to provide additional bonding of the face stones to the core of the buttresses by attaching them to the #3 bars (Figure 11).

Conclusion Restoration interventions take many forms. However, the contractor must implement the intervention while maintaining the structure in a stable condition. This article provides some problems observed and methods used to stabilize a church tower during the construction phase. The methods were developed in cooperation with the masonry contractor.▪ David T. Biggs, P.E, S.E, DistM.ASCE, Hon.TMS (biggsconsulting@att.net), is a Principal at Biggs Consulting Engineering in Troy, New York.

STRUCTURE magazine

Figure 11: Stainless steel anchors to bond face stones.

Acknowledgment This project was developed while the author was with Ryan-Biggs Associates, P.C. Matt Yerkey, P.E. is recognized for his significant efforts on the restoration project. Credit also goes to the Gnazzo Company of Connecticut that was the masonry restoration contractor.

May 2012

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Product Watch

updates on emerging technologies, products and services

Autoclaved Aerated Concrete as a Holistic Building System By Angelo Coduto and Michael McDonough, AIA, NCARB

hen Dr. Johan Axel Eriksson, an assistant professor for Building Techniques at the Royal Institute of Technology in Stockholm, developed Autoclaved Aerated Concrete (AAC) in 1923, he could not have anticipated how his work would impact the future of building. AAC, originally conceived as a wood substitute, has become a global industry rooted in one of the most widelyused and economical cellular concrete building systems available. Eriksson‘s product can be tooled like wood, but it is concrete. It is a mass wall product (has high thermal mass) and yet is insulative. It is porous but passively manages moisture. It has superior acoustical attenuation properties, is fire resistive, projectile impact resistive, carveable (as in gargoyles), cost effective, and most charmingly, it floats in water. Because it is structural it can be manufactured–like other concrete products–as block or prefabricated steelreinforced panels. Because it has millions of entrained air bubbles, depending on its manufacturing class for density, volume for volume it can weigh as little as 20% of the weight of conventional concrete. AAC was introduced commercially in Europe in 1939, Asia in the 1960s, and North America in the 1970s, when material was produced in Quebec and exported to the U.S. until manufacturing was established here in 1996. Today it comprises up to 40% of all the buildings systems used in the EU (20 million cubic meters annually), up to 80% in Japan; it is commonly employed in Mexico, and is on the cusp of wide acceptance in the U.S. It is commercially available as reinforced panels for walls, floors, and roof assemblies, masonry blocks from 2 to 14 inches thick, and precast lintels. AAC is available in three densities and strengths: low density AAC2 (non-load bearing infill; approximately 2 MPa or 290 psi); middle density AAC4 (load bearing up to 6 stories of building height; approximately 4 MPA or 590 psi); high density AAC6 (acoustical attenuation; approximately 6MPa or 860 psi). All densities are fire resistive and provide thermal insulation; specifics are listed under ASTM standard C 1693-09 (Standard Specification for Autoclaved Aerated Concrete, AAC). The most common AAC density is AAC 4-500,

Sky Indian Cultural Center at Acoma Pueblo, New Mexico employed AAC structural building systems throughout, including AAC masonry block, prefab vertical reinforced panels and prefab reinforced floor panels.

which is manufactured as masonry blocks and reinforced panels in standard thicknesses of 8, 10 and 12 inches for both load bearing and non load bearing applications. The products are currently available from two plants in the US: Aercon Florida and Xella Aircrete North America, with a third plant, Carolina AAC, coming in fall of 2012. As a specifier, you may see AAC listed under Ytong or Hebel. Ytong is a condensation of Eriksson’s original name for the product, Yxhult Anghardad Betong: “Yxhult” is the small Swedish town where AAC was first licensed and manufactured and “Betong” is the Swedish word for concrete. Hebel is named after Josef Hebel, who developed prefabricated reinforced AAC panels and further mechanized production with various machines for lifting, trimming and packaging the material. Hebel was instrumental in the “German Miracle,” the rapid reconstruction of Germany’s bombed-out cities after World War II using AAC in the 1940s, and the development of a suburban residential home known as the “Hebel Haus” in the 1950s. He also constructed Hebel AAC factories throughout Germany, the Middle East, Asia and Greater Europe, essentially globalizing the

STRUCTURE magazine

May 2012

product before he died in 1972 at the age of 78. Ytong and Hebel are essentially the same. So beyond that, what are the essential facts that an engineer practicing in the American market needs to know about AAC? Extensive research and testing has culminated in the development of ACI standards that comprise engineering reference guides to designing with AAC. SP- 226 – Autoclaved Aerated Concrete – Properties and Structural Design is a good example. AAC masonry complies with the International Building Code (IBC) for structural applications as referenced in “Building Code Requirements for Masonry Structures, ACI 530/ASCE /TMS 402 Reported by the Masonry Standards Joint Committee (MSJC) in “Appendix A.” ACI- 523.4R-09 Guide for Design and Construction with Autoclaved Aerated Concrete Panels is the guide intended for designers, engineers and building officials as a single source reference for construction using factory reinforced AAC panels. AAC has been used successfully in hundreds of building projects in many coastal regions of the Southeastern U.S. such as Florida, Georgia, North Carolina, South Carolina,

Private residence construction showing a block base course and bored cores with vertical steel reinforcement. Cores will be grouted for structural continuity across block.

Alabama, Mississippi, Louisiana, and Texas– areas where structures are required to resist sustained wind speed up to 150 mph. AAC is currently approved by the IBC for seismic zones A and B without restrictions, and in Zone C with a 35-foot height restriction. The AAC industry in the U.S. is working on securing additional Zone D approval in the near future. AAC is implicitly listed under ASHRAE standards for cellular concrete by weight class. Commercial thermal design criteria can be extrapolated under the mass wall listings under ASHRAE 90.1 and IECC. Low rise construction can be extrapolated under ASHRAE 90.2 and industry listed DBMS, or Dynamic Benefit of Mass Wall Systems, developed under Dr. Jan Kosny while he was at Oak Ridge National Laboratories (ORNL) in the 1990s. Kosny and his team developed metrics relating to the advantageous thermal lag factors in AAC assemblies based on ASHRAE Climate Zones–pioneering work that still stands today as ground-breaking in its scope and importance. A significant number of buildings representing a variety of building types and styles have been built in the U.S. These range from gothic churches, to big box store warehouses, to modern, traditional, and transitional style single family homes, to dormitories, schools, hotels, motels, military barracks, museums and advanced energy research facilities. Two of the most important recent energy-related commercial AAC projects in the U.S. are the Department of Energy’s Nicholas Metropolis Center, Strategic Computing Complex at Los Alamos National Laboratory, Los Alamos, New Mexico; and the Department of Energy’s New American Home 2008 in Orlando Florida, built in cooperation with the National Council of the Housing Industry (NCHI) and

Trotwood Middle School, Trotwood Ohio employed an AAC structural wall system comprising prefab steel reinforced AAC wall panels and AAC masonry block load bearing walls.

Builder Magazine. At Los Alamos, AAC was chosen in part for its superior critical construction path impacts. At Orlando, AAC was chosen as a component of the exterior walls in a 6,725 square foot net zero-energy home intended to introduce production builders to advanced insulation, air tightness (0.30 ACH atmospheric), and HVAC strategies. AAC can be an important part of any holistic approach to the design and engineering of a building. If your firm offers structural and MEP/HVAC services, AAC allows you to meaningfully integrate building envelope design metrics with mechanical system design. If you offer software-based building energy modeling, you will be able to make a case for more advanced equipment and technologies, integrate balanced ventilation, advocate for alternative energy sources, and down-size systems based on low to nearzero air leakage and overall energy offsets–all based on modeled results. AAC can also be an important part of moisture management in buildings; it provides passive vapor phase water transport via capillary action under neutral to slightly positive interior air pressure while serving as its own air and liquid phase water barrier. In other words, AAC is a single trade, near perfect structural wall system from a holistic or integrated design engineering point of view. Accordingly, it is not difficult to trace AAC’s advantageous impact on any ultra-low energy or net zero energy design strategy, and an integral part of any Passive House strategy or climate neutral certification.

STRUCTURE magazine

May 2012

At this writing, multiple efforts to facilitate seamless integration of AAC with existing energy and seismic codes via industry standardized reference tables, UL listed ballistics testing, and blast resistance ratings are in progress. Theater projects where AAC integrates acoustical attenuation with whole building energy offsets and structural systems, and net zero energy capable multi-family projects are on the boards. As we enter the second decade of the 21st century, almost 90 years later, Dr. Eriksson’s invention looks more relevant to modern practice than ever.▪ Angelo Coduto is President of AIRCRETE TECHNOLOGIES, LLC, a concrete technologies consulting firm. He is a founding member and former president of the Autoclaved Aerated Concrete Products Association (AACPA), and was a voting member of the ASTM and MSJC committees that developed AAC standards in the U.S. He can be reached at codu1161@bellsouth.net. Michael McDonough, AIA, NCARB is an award-winning architect and designer. A member of the Building Enclosure Committee of AIA/NYC, he is currently working in conjunction with MIT/ Fraunhofer Laboratories and a consortium of universities and manufacturers to promote the use of AAC in the U.S. He can be reached at mail@michaelmcdonough.com.

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core requirements and lifelong learning for structural engineers

Education issuEs

Resolution of Deficiencies in Engineering Education By Prof. Kevin Dong, P.E., S.E.

n earlier articles, the reader was introduced to self-teaching curriculum content for structural steel and concrete (STRUCTURE’s June 2011and January 2012). In this final article of this series, the reader will see a new approach–a split mission. Since the Basic Education program for Structural Engineers was introduced in 2002, NCSEA has been working with practitioners and educators to improve the education program provided by schools to those students looking to Structural Engineering as a profession. Since 2002, for a variety of reasons, schools have not found it easier to equip the student with an appropriate education, but have found it all the more difficult. The cost of attending school has risen much faster than inflation. Schools are under more and more pressure to reduce required credits necessary for graduation. Research dollars that support schools, and which have a definite impact on tuition and instructor salaries, are tougher to come by. Elements of the basic curriculum are still necessary, but the route to the end may be changing. With each of the previous national surveys, three parts of the curriculum have stood out as a deficiency in more schools than any of the other core components; Masonry, Timber, and Technical Writing. Starting with Technical Writing, schools have found ways to accomplish the education requirements by utilizing other in-school opportunities for training the student to become a competent communicator. Northeastern University in Boston, MA, is one of the leading schools in the Technical Writing area. Refer to article by Peter Furth, PhD, titled Embedding Communication Education within the Civil Engineering Curriculum in the April 2007 issue of STRUCTURE®. Using a cram-down approach, the author combines Timber and Masonry instruction in one three-credit course. The course contains the major elements needed for both core Basic Education courses in Timber and Masonry, and provides a sound platform for a student to self-teach. The 2013 survey, which began in October 2011 with the school interview process, acknowledges those schools that have developed a way to address core curriculum deficiencies.

Below, the author adds to the self-teaching curriculum series for Structural Steel, Reinforced Concrete, Masonry, and Timber. The Basic Education Committee of NCSEA appreciates your comments.

Timber and Masonry Design Course Content  Mechanics and assumptions of masonry and wood design o For masonry:  Allowable stress versus strength design  Reinforcement ratios and the balanced condition  Cracked section properties  Typical block dimensions and types (terminology) o For timber  Shrinkage  Allowable stress and the use of service loads  Nomenclature and the use of a non ductile material  Gravity load resisting systems o Column design  Premise of design equations  Un-braced length, slenderness ratio (h/t or l/d), and second order effects o Beam design  Flexural design • For timber: solid sawn versus glue laminated beams and simulated continuity  Shear design  Deflection and serviceability limits • Creep o Beam-column elements  Combined stresses  Second order effects and slenderness o Basic connection principles  Beam seats, tie downs, straps, nails, lag screws, anchor bolts, blocking  Lateral load resisting systems o Understand the failure mechanisms and required detailing to ensure the failure mechanism can be formed. The system proposed for study: special concrete walls o Walls – masonry and wood panel

STRUCTURE magazine

May 2012

o Diaphragms  Sub diaphragms  Diaphragm shear  Drags and chords  Wall ties  Amplified loads and capacity based design  Construction Documentation o General Notes  Relation to project specifications  Content and purpose of general note sheets o Framing Plans and “industry standards” for notation  Line weights, line types, hatching, dimensioning, text work  Information required to build, such as openings, dimensioning, and miscellaneous framing members. o Detailing  Load path and detailing for typical gravity elements  Load path and detailing for diaphragms and shear walls: collectors  The bread and butter of the industry, but again, academia does not adequately cover this topic and this is integral to design and ultimately building performance.  Elective Topics – not necessary to achieve the goal of lifelong learning, but helpful to integrate into practice o Masonry  Shear walls  Retaining walls o Diaphragms  Openings and discontinuities The full Basic Education for Structural Engineers program containing curriculum, course content and desired outcomes can be viewed in the Education section on the STRUCTURE website, www.STRUCTUREmag.org.▪ Kevin Dong, P.E., S.E. is a professor in the Architectural Engineering Department at California Polytechnic State University and a member of the NCSEA Basic Education Committee. He may be contacted at

kdong@calpoly.edu.

Business Practices

business issues

Adopting New Technologies into Your Business By ASCE/SEI-BPAD Business Practice Committee

volving technology is as inevitable as the sunrise and sunset. It is easy to always want “the next best thing.” Firms must have a process in place to define, implement and evaluate their return on investment of any technology before blindly making the leap to adopt it. Effort spent up front can ease new technology integration in terms of time, money and staff acceptance.

Categories of Technologies Given the proliferation of software and hardware available, this article will focus on project production technology within the A/E/C environment. Undoubtedly, there are many ancillary components to project delivery, each with their own universe of technologies, yet the integration process is similar across all technologies. To be clear, the process for office-wide adoption of a new mobility resource such as GoToMyPC is the same as introducing BIM. A short list of categories and associated technology your firm may be considering includes: • Shared/virtual offices and branch offices via Regus or DaVinci • On-line records storage with tools like Google Docs, Newforma, or any private cloud • Online meeting tools such as GotoMeeting or WebEx • Collaboration tools such as Files Anywhere • Paperless shop drawing review using Acrobat or BlueBeam • Email marketing using Constant Contact or iContact • Social media such as LinkedIn, YouTube, Facebook, and Twitter All technology requires adequate background assessment and preparation before adoption. Prior to implementation, appropriate members of the leadership team must understand and agree on the various issues that could impact the firm as a result of the technology. It is impossible to anticipate every possible threat, but the old adage “better safe than sorry” definitely applies here.

Considerations Prior to Moving Forward One of two scenarios usually prompts firms to consider introducing a new technology. The first scenario could be called “the dust”, as in

the place where a firm will be left if the new technology is not adopted. Firms in this position generally know it is not a matter of if a certain technology will be implemented, but when. The best example of a current technology causing firms to be in this situation is BIM. Structural firms know clients and the A/E/C industry are pushing BIM as a project requirement. The second scenario is “early adopters”; these are the firms willing to risk potential setbacks through trial and error. These are also the firms viewed as industry leaders because of their ability to harness technology as a means to further the industry. After acknowledging the scenario applicable to your firm, firm leadership should frame the technology discussion in strategic planning terms, which answers the basic question of “Why are we considering this?” Planning for technology should be no different than the planning process for other business decisions, such as opening a new office or diversifying into other market sectors. Firm leadership should candidly assess whether the firm will be on the cutting edge with the technology, or scrambling to catch up. When a firm is forced into adopting a new technology, there can be a tendency to hold back. From a practical standpoint, the internal technology manager or an external consultant should brief firm leadership on security and privacy issues as well as employee usage policies as part of this strategic evaluation. Think also about the potential for culture clashes as a result of the new technology. This is common because of the multitude of differing knowledge and comfort levels with technology in general. The division may be between staff members of different ages, levels of education, or backgrounds. It could be prudent to consider a mitigation strategy to prevent some group from derailing the implementation. Structural engineering and other professional consulting firms must determine if adopting the new technology could mean production standards might drop below that which another engineer would reasonably provide under similar circumstances in the same locality. For new technologies, Engineering Standard of Care is not always well defined. Answer the following questions in advance: • What are the owner and client expectations? • What is the role of the other participants?

STRUCTURE magazine

May 2012

• What are the deliverables? • Who owns the final work product? For technologies that impact clients or other outside firms, develop an implementation plan; it can have varying degrees of complexity, depending on the need. Anticipating potential setbacks up front can help develop the roadmap and timeline for implementation once the decision to adopt the technology has been made. Once due diligence is complete and the leadership approves the new technology, the hard work of implementation can begin. A four-step adoption process for any new technology includes Planning, Definition, Implementation and Evaluation.

Planning The planning process during implementation is much different from the initial assessment of the technology. Implementation planning needs to be diligent, thoughtful and purposeful. There are many different approaches that range from complete immersion to incremental bridge building. During planning, the firm’s leadership should look at the business case for the technology in specific areas such as start-up costs and return on investment, and how to market new capabilities resulting from the technology. With a solid plan there must also be unwavering commitment in terms of time, money and people. Firm leadership should be unified in their support, and ensure the necessary staff and financial resources are dedicated to successful adoption of the technology. The final piece of the Planning phase is cost evaluation. In addition to the cost of purchase, installation and training, there may be hardware and software costs and, very likely, the cost of lost time and productivity.

Definition The broad definition of the new technology needs to answer three questions: • What are the business drivers for the technology? • What are the merits of adopting the new technology vs. maintaining the status quo? • What does the value potential of the technology depend upon? By example, look at adopting BIM for production in an A/E/C firm. The industry drivers for BIM are Virtual Design and Construction, Integrated Project Delivery,

biggest areas of concern during implementation include: • Infrastructure acquisition & maintenance • Training • Added stress on staff Maintaining infrastructure usually comes down to simply spending money. However, the budget is always limited and budget approvers will expect to see the money is spent wisely. For example, early research into the recommended hardware can eliminate midstream computer retrofits. Likewise, overspending on an unnecessary state-of-the-art item may force

sacrifice of something else potentially more useful. For infrastructure budgeting purposes, keep in mind that one-time and annual costs are known. Commitment to renewing these costs must be firm, and a discretionary budget for miscellaneous expenses should be established to keep the program moving forward. Also be mindful of your current hardware. Is it necessary to change workstation hardware configurations (for example faster processors, dual monitors, new OS, more memory)? Would it be prudent to improve network thru-put speed? What software applications should be used, and,

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and Lean Construction. The merits include drawings linked to the design models, multidisciplinary coordination (clash detection), and the use of an Integrated Practice Model (for fabrication, cost estimating, scheduling and constructability review). The value depends on collaboration opportunities, and team member capabilities and willingness to participate. More specifically, you must also have a clear definition of how existing workflows will change to accommodate the new technology. Again, consider using BIM to improve workflows by way of improved communication among the internal/external team members. Internally, software interoperability allows the model to start in an analytic or graphics platform (engineer or drafter/designer). Who will start and finish the model? Who will check the model? How do you ensure design intent is conveyed? Externally, the structural model is used by the architect and MEP engineer as a reference for their drawings. Detailers use the model to create shop drawings; general contractors use it for cost estimating and scheduling; and, owners use it for facilities management. Additionally, the model allows better interaction among the team members by improved visualization of design intent. How will the information be distributed? Who manages the information and verifies its accuracy? To facilitate all this, one may define strategic partnerships – complementary firms, peers, or professional organizations – that can participate in synergistic relationships. To improve BIM capabilities, the relationships might be with designers (architects, MEP engineers, other peer firms) or with software developers that can add capability to the technology, such as a third party add-in or standalone application. Finally, does the technology offer the chance to provide additional services resulting in new revenue streams? Effective structural BIM creates value by improving the schedule, reducing RFIs, mitigating the risk of change orders and delays, and it improves cost and schedule control. Providing early certainty to the structural system cost estimate reduces waste. What can be added to the consultant’s scope? How will you price your services? Can the consultant partner with a subcontractor or fabricator to produce deliverables?

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what are the software licensing options? How can you maximize utility and investment? Most importantly, is your IT department ready for the new challenges? Training is another fairly straightforward process. However, if not planned properly, and without proper follow-up after the training takes place, it can easily be unproductive. Key elements to consider when planning training are: • A sufficient budget • Time AND money • A clear allocation of Out-of-House vs. In-House training hours There are unknowns with any new initiative, thus a tendency towards doubt. Pro-active communication is one way to reduce the doubt. Make affected staff members aware of the time, money and effort invested to achieve success. If they have to guess how you are handling the process, they may assume you are not considering important factors – such is the nature of contending with unknowns. There can be tension between the “old ways” and “new ways”, which adds stress on the staff. This can be significant as you push people to learn new skills. It may be aligned with experience demographics, since less experienced staff may be more willing to try something new. You should be adaptable by recognizing staff members

who won’t ask for help, but need additional encouragement or training.

Evaluation Especially after a lengthy integration, it may be tempting not to devote adequate time to evaluate the technology and adoption process. This final step is the litmus test when it becomes questionable whether to maintain the technology, change it, or pursue more. The implementation team should discuss basic questions together. Has the firm become more profitable? Has the firm generated new revenue? Are you better positioned for growth? Find out and make any necessary changes. The initial evaluation meeting is the ideal time to identify metrics to be used, the means for gathering the data, and the “Keeper of the Data”. Successful metrics will illustrate how the new technology affected billings and the bottom line. Evaluation meetings held at regular intervals post-implementation can help identify other metrics necessary, or fine-tuning of the measurement process. The simplest approach to gauge differences in old versus new technology is to use your current accounting software to track how much you spent on implementation. One suggestion is to study the shift of hours between higher and lower level personnel. If the man-hours went

down, but the man-hour-dollars did not, you need to be more careful about staffing to ensure you take advantage of the hour savings. Another suggestion is to consider the portion of necessary early design work in order to avoid costly revisions later on. If you find that some of your workload shifts from the detailed design phase to the schematic design phase, should you, and would your clients agree to, put a larger percentage of your fee into earlier phases? It is also critical to discuss lessons learned throughout the process. Be inclusive of the entire project team, but also review this at the management level. Do not be afraid to identify failures. And finally, broadly share the lessons. This is the way to incorporate the data collected in order to help meet your original goals.

Conclusion Evolving technology is a constant business consideration firms cannot ignore. Technology has the ability to truly transform a business. Whether the transformation is positive or negative is in each firms’ hands to determine. Firms must focus on the future. SEI-BPAD’s Business Practices Committee believes strongly that successful firms must be introspective and gain knowledge from the recent past. To this end, the Committee presided over a panel discussion on Lessons Learned from the Recession and Where Do We Go from Here at the SEI 2012 Structures Congress. We hope to pass along some of that discussion in a future article.▪ The ASCE/SEI-BPAD Business Practice Committee’s purpose is to consider the issues that relate to the role of the structural engineer in the greater business environment and within the public at large. The current members of the committee are: Joe DiPompeo, P.E., SECB – Structural Workshop, LLC, joedip@structuralworkshop.com

Seattle

Long Beach

Everett

Pasadena

Tacoma

Irvine

Lacey

San Diego

Portland

Boise

Eugene

Phoenix

Sacramento

St. Louis

San Francisco

Chicago

Walnut Creek

New York

Los Angeles

Abu Dhabi, UAE

Paul Hause, P.E. – Structural Consultants, Inc., paul@sci-denver.com Ron LaMere, P.E. – BKBM Engineers, Inc., rlamere@bkbm.com Pat McCormick, P.E., S.E. – Brander Construction Technology, Inc., Chair, pat@brandercti.com Scott Rosemann, P.E., LEED AP – Rosemann & Associates, P.C., srosemann@rosemann.com Steve Wilkerson, Ph.D., P.E. – Haynes Whaley Associates, Inc., steve.wilkerson@hayneswhaley.com

STRUCTURE magazine

May 2012

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Professional issues

issues affecting the structural engineering profession

Achieving Separate Licensing of Structural Engineers By Susan Jorgensen, S.E., P.E.

“...emphasize the objective: To protect the safety, health and welfare of the public in all that we do.”

he steps to developing separate licensing of structural engineers are the same from one jurisdiction to another; however, the order in which they are achieved differs from state to state. The guidelines presented here provide all the major steps toward separate licensing of structural engineers. Some investigation will be required to determine the order in which these steps should be followed and the manner in which they should be utilized in a particular state to achieve the ultimate goal of licensing of, and practice restrictions for, structural engineers. Determine the Objectives What is the desired end result and what are the reasons behind it? The bottom line should always be to live up to our ethical obligation to hold paramount the safety, health and welfare of the general public. Understanding this, making it clear from the very beginning, and reinforcing it in everything that is done will help increase the chances of success. Identify the Champions All efforts need a leader who keeps everyone on the right track. Often this is a single person (the champion) backed up by a great support team, all of whom are dedicated to the same goals. Everyone else will depend on these people to ensure that their efforts remain on track. Above all else, the group that leads this charge must be fully committed to the cause and trusted to see the effort through. Understand the Process Every state differs in how the laws and rules for licensing structural engineers may be changed. Doing the research to understand this process is imperative, as it will help to determine how best to proceed. A

thorough understanding of the process, including the motivations and drivers of all parties involved, helps keep you on the right course. Determine the Method Implementing change from an active grassroots level can be very effective and requires less funding, but will demand a great deal of time and effort by volunteers. Utilizing the expertise of a lobbyist and other professionals may be more effective in some states, but requires constant funding that may persist over several years. There is no one correct way to go about this; you must determine what will work best in your state.

Reach out to other engineering professionals, as well. The civil engineering community recognizes the benefits of credentialing beyond initial licensing. Separate licensing reduces the risks to architects, building officials and licensing boards as they are assured that the engineer stamping the structural drawings is adequately trained and experienced. Marketing Campaign

A white paper can be very effective in spelling out exactly what the objective is and why it is important. Developing a one-page list of reasons behind the initiative can also be beneficial, keeping everyone focused and moving in the same direction. These types of materials can assist in making sure that the focus and language are always positive when discussing the issues with others, and that the message is clear to all.

Get the word out beyond the professional community. Look for opportunities to get your name and cause in front of the public. Take advantage of every opportunity to differentiate structural engineers from other professionals and deliver the message to the general public. Explain to anyone who will listen what structural engineers do and what sets them apart from other branches of engineering. Ask anyone you meet if they know the credentials of the engineer that designed their school, church, fire station, etc. Be sure the message is always about the positive aspects and avoid phrases that could cause anxiety or fear. This is not ultimately about the structural engineering community; it is about our ethical duty to the public.

Gather Support

Work with the Licensing Board

The more people you enlist in support of the initiative, the more likely you will be to succeed. The first line of defense should be the structural engineers. Objections more often than not stem from a lack of understanding. Once everyone understands that a) the motivation is the safety, health and welfare of the public; b) the cost to the engineering community (and the public in general) will be minimal; and c) the intent is not to exclude engineers currently in practice but to ensure they will be able to continue to practice without additional examination, then garnering support from structural engineers is likely to be relatively straightforward.

Make the licensing board your ally. Having this well-respected group in support of your objectives carries a great deal of weight with the legislature. They understand the process, know the pitfalls and are acquainted with the people who enact change. The board will understand the issues and generally be in support once its members recognize that the primary goal is the safety, health and welfare of the public. Even if the licensing board cannot publicly take a position on the issue, they need to be familiar with the issue and not be in opposition. The easier you make the process for them, the sooner you will get their support.

Develop the Statement of Purpose

STRUCTURE magazine

May 2012

Identify a Legislator

Write the Legislation

An advocate for your cause in the legislature is essential. Do your research to find out who the legislators are (it is all online), where they live and who might be your strongest supporter. Are any of them professionals that are licensed and understand the need for protection of the safety, health and welfare of the public? Understanding what is important to legislators will help you determine how to select your advocate. Primarily, they will support a bill or initiative that will be successful, help make their campaign and image look good, take minimum time and effort and not restrain/restrict business or cost their constituents any money. In many states, enlisting the help of more than one legislator will be beneficial. Once your supporters in the legislature have been identified, they must be educated. They must fully understand the reasons and the purpose behind the Bill, and be willing to stand alone on the floor speaking for the Bill and answering questions.

Take the existing rules and legislation that govern the licensing and practice of engineering and revise them accordingly. Be sure that you understand what you are trying to achieve and write the legislation to reflect it. In many instances, the legislative language regarding the practice of engineering is fairly straightforward. Do not start from scratch; other states have already developed rules and statutes that you can use as a starting point for developing your legislation. Include everything that you think would make the Bill ideal in a perfect world. Asking for everything you want, and then some, will allow room for negotiations so that the end result is something with which you can live. Be careful with the wording to avoid unintended consequences. Watch for terms and phrases with double meanings. Have others read the language, including those not directly involved, and get their perspectives on what you are trying to achieve. Do not forget the most important aspect of this change – the Transition Clause. Make

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STRUCTURE magazine

May 2012

the process whereby structural engineers currently practicing are transitioned into the new practice restrictions as simple and wide-open as possible. This issue can make the difference in getting the support that you need to get this Bill passed. Keep in mind that the intention is to ‘raise the bar’ so that all engineers who come after us will be better qualified to protect the safety, health and welfare of the public. Develop a Writing/PR Campaign Have your talking points and one-page support material ready so that you can start getting the word out. Do not overlook any and every opportunity – newspapers, radio, television, magazines, community functions, etc. Focus on what is in it for the viewer, reader, or listener. Emphasize the reasons why the layperson should care, and be sure that your message is one that everyone can understand – the safety, health and welfare of the public. continued on next page

Be Willing to Negotiate The single best way to get your Bill passed is to be willing to negotiate. Trying to hold the line and refusing to give an inch is a sure way to get the Bill killed. By including everything in the original Bill, you have left room for negotiations so that the Bill still has some meat when it is finally passed. Rally the Troops Take every opportunity to get the entire membership of the Structural Engineers Association and other professional organizations involved – newsletter articles, frequent emails, calling trees, social media, regular meetings, etc. Be specific and direct so that the message is clear and understood. In every communication, emphasize the objective: To protect the safety, health and welfare of the public in all that we do. Identify the Detractors Who are the opponents and why? Determining who is against the issue and understanding what their objections are will make it possible for you to develop arguments to counter their comments. Can any of your opponents be

turned into proponents? Take time to visit with the groups who oppose your measure and fully understand why they object. Will they be a dissenting voice when this Bill comes up for review, or do they just not understand why you are making this change? If they cannot be swayed to support your position, can they be neutralized so that they do not oppose it? Look for support in areas that are not patently obvious. Fight Back There will be shots from all sides: the rule makers (why change something that appears to be working?), the licensing board (why make our job more difficult?), other professionals (why is it necessary to change a process that works?), other engineers (why is it important to separate the practice of structural engineering?). Fully understanding the importance of what you are trying to do, and why, will give you the ammunition that you need to stand up and fight back. The change will never happen unless and until you are willing to defend your position and fight for what you want. Keep in mind that you are doing this for the health, safety and welfare of the public. ADVERTISEMENT - For Advertiser Information, visit www.STRUCTUREmag.org

STRUCTURE magazine

May 2012

Conclusions Separating licensing of structural engineers and restrictions of practice are necessary to help protect the safety, health and welfare of the public. The steps to implement these types of changes are the same from state to state; however, the order and manner in which they are utilized may vary. Whatever it takes to get there, the way to safer structures is the ethical duty of all of us, and it is our responsibility to take the steps to accomplish this goal. Several states have been successful at implementing change and more are currently in the process. The NCSEA Licensing Committee (www.ncsea.com) has a wealth of resources and information that can be beneficial. Reach out for help and guidance to ensure your success.▪ Susan Jorgensen, S.E., P.E. (sajorgensen@leoadaly.com), is a Vice President, Senior Structural Project Engineer, and Director of Operations at Leo A. Daly in Denver, Colorado. She chairs the NCSEA Licensing Committee.

notable structural engineers

Great achievements

Walter P. Moore, Jr. Computer Sophistication and National Prominence By Richard G. Weingardt, P.E., Dist.M.ASCE, F.ACEC, D.Sc.h.c.

hen Rice University presented Walter P. Moore, Jr. with its Distinguished Alumnus Award in 1995, it reported: “From the time he was a child, Walter knew he would be an engineer like his father. What he didn’t know was that someday he would equal his father’s success. Like his father, he has won three of the most prestigious awards a person can win for professional achievements: Rice’s Outstanding Engineering Alumnus, Engineer of the Year Region IV given by the Texas Society of Professional Engineers, and Rice’s Distinguished Alumnus this year.

Hyatt Regency Hotel, Houston, TX. Courtesy of Evelyn Weingardt.

They are the first father and son to win all three awards.” In addition, Walter, Jr. was the recipient of a distinguished alumnus award from the University of Illinois and a member of the National Academy of Engineering. Asked if he had surpassed his father’s success, Walter, Jr., replied, “Hell, no. I am doing well just to match him. He [Walter, Sr.] came out of the Depression and, through a lot of hard work, created a firm that built things like the Rice Stadium. I came along when everyone knew who I was. But by the same token I moved the firm into the computer era and made it a national firm.” Moore took over the leadership of his father’s firm, Walter P Moore (WPM), in 1971 when the 69-year-old founder stepped down as president. At the time, the company was headquartered in Houston with a handful of smaller branch offices scattered around – and a bulging portfolio of impressive Texas projects. As his father’s understudy, Walter, Jr. was involved in many of the major ones, most notably the Miller Outdoor Theater, Six Flags AstroWorld, alterations to the Astrodome, and the Houston Hyatt Hotel, which officially debuted in 1972. At 401 feet, the Hyatt was (and is) Houston’s tallest hotel. For its crown, it has a roof-level revolving restaurant known as “Spindletop.” The hotel’s dramatic 30-story atrium was the backdrop for the 1976 Hollywood movie Logan’s Run. While president and later chairman of the board of WPM, Walter, Jr. was instrumental in leading the firm to national prominence in the design of high-rise buildings, sports facilities and other complex projects. In increasing and broadening the firm’s range of clients and ventures, and greatly improving its computer-design capabilities, he was intimately involved in the engineering of such noteworthy structures as the Pyramid Arena, Memphis, Tennessee; IBM Tower in Atlanta, Georgia; and NationsBank Corporate Plaza in Charlotte, North Carolina. When completed in 1987, the IBM Tower (now known as One Atlantic Center, with Johnson/Burgee as architects) was the tallest building in the Southeast at 825 feet. The NationsBank building (today called the Bank of America

STRUCTURE magazine

Walter P. Moore, Jr. Courtesy of Walter P Moore.

Corporate Center, and designed by architect Cesar Pelli), when topped off at a height of 871 feet in 1992, garnered the title as the highest building in North Carolina. Walter, Jr. was born in Houston on May 6, 1937, to Walter and Zoe (McBride) Moore, the oldest of two boys. Following in his father’s footsteps, Walter, Jr. became a structural engineer while his younger brother, Robert Laurence (“Larry”), became a history professor. The young Moore brothers grew up a few blocks from Rice University and played along the shady tree-lined streets in the area. Walter, Jr. perfected his tennis game on the university’s clay courts and attended college football games at Rice Stadium, which was engineered by his father as were a number of other Rice campus structures. Many years later, when head of WPM, Walter, Jr. also engineered several Rice buildings, including Sewall Hall, Lovett College, the Mudd Computer Building, Anderson Hall, Jake Hess Tennis Facility, Herring Hall and the Duncan Building (Rice’s state-ofthe-art computational engineering facility). The entire Moore family studied at Rice. Walter, Jr.’s father graduated in 1927, while his mother Zoe attended the institution in 1926. His brother Larry graduated in 1962 and Walter, Jr. received a bachelor’s of art in civil engineering in 1959 and a bachelor’s of science in the same field in 1960. Throughout his life, Moore gave generously to his alma mater. He served as president of the Rice Alumni Association and the Rice Engineering Alumni Association, and on the board of the Rice Design Alliance and its Engineering Advisory Council. He was also an adjunct professor of architecture and served on the Architectural Advisory Council. continued on next page

May 2012

Duncan Hall, Rice University, TX. Courtesy of Evelyn Weingardt.

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One Atlantic Center, Atlanta, GA. Courtesy of Wikimedia Commons-Magnus Manske.

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Prior to college, while attending Houston’s Lamar High School, Walter, Jr. began dating Mary Ann Dillingham. She was a cheerleader and he played guard on the school’s basketball team, where his steady and dependable performance earned him the nickname “Rock.” The pair became high school sweethearts and later married, after she spent two years at Texas Christian University before transferring to the University of Houston to complete her degree in English and education. The young couple then moved north to Urbana, Illinois, where Walter, Jr. earned a Master of Science and a Doctor of Philosophy in structural engineering at the University of Illinois. After receiving those advanced degrees, Moore served as a captain in the U.S. Army Corps of Engineers, then moved back to Houston where he joined his father’s thriving consulting engineering business. Moore’s entire career as a consulting structural engineer was spent with his dad’s firm, with all the plusses and minuses that come with being the son of the founder of the company. He began at the bottom and moved up through all the necessary positions until he became president and chairman, just like his role-model father. In 1994, while remaining chairman of the board, Moore relinquished his position as president of WPM and accepted a distinguished professorship in academia, at Texas A&M

STRUCTURE magazine

May 2012

University in the College of Architecture and Department of Civil Engineering. He held the Thomas A. Bullock Endowed Chair in Leadership and Innovation, and was director of both the Center for Building Design and Construction and the Center for Construction Education. Along with his duties as a professor of both architecture and engineering at Texas A&M and as chairman of WPM, Moore also served on the Board of Directors of the CRS Center in Houston. With his extensive background in the design and construction industries, Moore believed that, in addition to theoretical analysis, future structural engineers and architects needed exposure to actual design and construction issues. He said, “What I do is bring real world problems and leadership situations to the students. A&M was founded not to just educate engineers, but to turn out leaders. That spirit seeps through into everything. Our students are immersed in a wide range of outside activities: church groups, engineering societies and the community. In my classes, part of a student’s grade is dependent on his or her presentations skills and how well they can communicate their solutions. They must spend time outside the classroom developing these skills. Their grade depends on it.” Moore also opined that engineering education should be modified to be more in line with that of the schools of architecture, law and medicine – a four-year undergraduate degree (with a

Moore was widely published and a soughtafter speaker. He contributed his time and talent to numerous academic institutions and professional societies, serving on the national board of the American Concrete Institute (ACI), as vice president of the American Council of Engineering Companies (ACEC), and on the Executive Committee of the Council on Tall Buildings and Urban Habitat (CTBUH). Other professional organizations in which Moore was active included the American Society of Civil Engineers (ASCE), the Society of American Military Engineers (SAME), the Consulting Engineers Council/ Texas (CEC/T), the International Association of Bridge and Structural Engineers (IABSE), the National Society of Professional Engineers (NSPE), and the Structural Engineers Association of Texas (SEAoT). Notable among Moore’s numerous awards, honors and recognitions were being named an Honorary Member of AIA, the Master Builder by the Associated General Contractors in 1995, and a Distinguished Member of ASCE. He was also the 1996 recipient of ASCE’s prestigious Edmund Friedman Award. Moore died on June 21, 1998, in Houston, from injuries suffered in a terrible automobile

Bank of America Corporate Center, Charlotte, NC. Courtesy of Wikimedia Commons-Fife Club.

STRUCTURE magazine

Richard G. Weingardt, P.E., Chairman, Richard Weingardt Consultants, Inc., Denver, CO. He is the author of nine books. Two of his latest, Circles in the Sky: The Life and Times of George Ferris and Engineering Legends, both published by ASCE Press, feature the exploits of great American structural engineers who had significant influence on the progress of the nation. His current book nearing completion, Empire Man, is about Homer Balcom, the structural engineer for the Empire State Building. Mr. Weingardt can be reached at rweingardt@weingardt.com.

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diverse collection of subjects) followed by a concentrated two- or three-year master’s (or professional) degree in engineering. He stated, “That type of education would turn out engineers much more in tune to the world around them, which is an advantage young architects and lawyers have over engineers.” In the future, said Moore, “Engineers must take a leadership role, not just an advisory role, in the proper use and development of technology. Engineers need to prepare themselves for this expanded role in society. Decisions are constantly being made by those who have no scientific or engineering backgrounds. Engineers need to become more visible so that ordinary citizens in our society desire, or even demand, that technology decisions come primarily from engineers. It is time for engineers to redirect their effort and energy in order to assume responsibility for our nation’s future – not to leave our society’s destiny totally in the hands of academics, bureaucrats, politicians and others who lack technical expertise.”

accident. He was survived by his wife Mary Ann; his children Walter P. Moore III and his wife Sarah, Melissa (Moore) Magee and her husband Michael, and Matthew D. Moore and his wife Valerie; five grandchildren; and his brother Larry and his wife Lauris. Since Moore’s passing, a number of national awards have been established in his name, among them: SEI’s Walter P. Moore, Jr. Award, SEAoT’s Walter P. Moore, Jr. Merit Scholarship, and ACI’s Walter P. Moore, Jr. Faculty Achievement Award.▪

May 2012

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ClarkDietrich Phone: 513-870-1100 Email: info@clarkdietrich.com Web: www.clarkdietrich.com Product: MaxTrak® Description: MaxTrak Slotted Deflection Track is a head-of-wall deflection track used for framing exterior curtain walls and non-load bearing interior walls where vertical deflection occurs. Allows vertical live load movement of the structure without transferring axial loads to the wall studs. This system provides savings by reducing the components required. Product: RedHeader RO Rough Opening System Description: RedHeader RO is designed for interior and exterior framing applications around non-load bearing doors and windows. Reduces the number of components required for a rough opening. Reduces onsite labor to assemble multiple rough openings by 50 percent. Pre-cut to customer order and painted red for easy identification.

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Product: SUBH Bridging Connector for Cold-Formed Steel Description: The new SUBH wall-stud bridging connector has been extensively lab tested as a system, ensuring the tabulated design values reflect stud web size and thickness. It requires only one screw for most installations and has superior rotational and axial pullthrough resistance to meet AISI S100 Sections D.3.2.1 and D3.3 requirements.

Valmont Industries Phone: 402-359-2201 Email: kyle.debuse@valmont.com Web: www.hsssuperstruct.com Product: HSS Superstruct Description: Now you have the flexibility to design using square and rectangular HSS tubing between 12-inch square and 50-inch square, up to 1-inch thick walls and 55 feet long.

Coatings Atlas Tube Phone: 800-733-5683 Email: sales@atlastube.com Web: www.atlastube.com Product: Epox Z Kote Powder Primed Tubing Description: Epox Z Kote is a high performance, super-tough, super-thin epoxy powder coat primer. Ordinary primers are 2 to 4/1000 of an inch thick (2.0 to 4.0 mil). Our new epoxy powder primer is less than 1/1000 of an inch (0.5 mil) and accepts laser cutting and welding operations.

Software Bentley Systems Phone: 317-664-8890 Email: katherine.flesh@bentley.com Web: www.bentley.com Product: RAM Elements, STAAD.Pro and RAM Structural System Description: The most comprehensive structural products anywhere. Bentley’s flexible and scalable software allow seamless workflow of analysis, design, detailing, documentation and BIM data. Product: RAM, STAAD, ProSteel Description: Analysis and steel design of buildings, bridges, plants, and civil structures, as well as detailing products for structural steel.

CSC, Inc. Phone: 877-710-2053 Email: sales@cscworld.com Web: www.cscworld.com Product: Fastrak Description: The essential design and drafting software for steel buildings. Design simple or complex steel buildings to US codes. Produce clear and concise documentation including drawings and calculations. Design any simple

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Devco Software, Inc. Phone: 541-426-5713 Email: rob@devcosoftware.com Web: www.devcosoftware.com Product: LGBEAMER v8 Description: Analyze and design cold-formed cee, channel and zee sections. Uniform, concentrated, partial span and axial loads. Single and multi-member designs. 2007 NASPEC (2009 IBC) compliant. Pro-Tools include shearwalls, framed openings, X-braces, joists and rafters.

Digital Canal Phone: 800-449-5033 Email: clint@digitalcanal.com Web: www.digitalcanal.com Product: Steel Design Description: NEW Steel Design supports AISC 13th Edition, ASD 9th and LRFD 2nd Editions. Incredibly detailed “hand calculation” reports are a “must have” to learn the new AISC code! Steel Design is available in single member beam/column modules as well as full-featured frame/FEA programs.

Dimensional Solutions, Inc. Phone: 281-497-5991 Email: Info@DimSoln.com Web: www.dimsoln.com Product: Mat3D Description: Mat3D completes soil and pile supported mat/pile cap designs supporting multiple load points, in an integrated environment that takes you from concept to construction in minutes. Enhance your productivity from input to construction drawings and 3D foundation modeling in popular CAD/modeling engines for industrial, commercial, petrochemical foundation design projects. Product: Foundation Design Suite Description: Foundation Design Suite components are integrated, single program solutions that quickly complete soil/pile supported foundation design from concept to construction drawings to modeling in minutes. The suite includes DSAnchor, Shaft3D, Mat3D, Foundation3D, and Combined3D. You can experience significant time savings and increased productivity by visiting our website. continued on next page

May 2012

IES, Inc. Phone: 800-707-0816 Email: sales@iesweb.com Web: www.iesweb.com Product: VisualAnalysis Description: IES VisualAnalysis automates the design of cold-formed, steel, wood, concrete, and aluminum beams, columns, and framing for anything from simple members to complete, complex structures. A modern and intuitive user interface simplifies modeling, analysis, design, and reporting. For more information visit our website.

Nemetschek Scia Phone: 877-808-7242 Email: usa@scia-online.com Web: www.scia-online.com Product: Scia Engineer Description: Scia Engineer links structural modeling, analysis, design, drawings and reports in ONE program, so a change anywhere is reflected everywhere. Centralize design tasks with static, nonlinear, and dynamic analysis. Design to multiple codes and for multiple materials. Plug into BIM with IFC support, and links with Revit, Tekla, and others.

POSTEN Engineering Systems Phone: 510-275-4750 Email: sales@postensoft.com Web: www.postensoft.com Product: TaperSTEEL Description: TaperSTEEL is Steel Design with LEED in mind. Sustainable design and cost saving in steel go hand in hand. Simply get the most out of the steel.

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RISA Technologies Phone: 949-951-5815 Email: info@risatech.com Web: www.risa.com Product: RISAFloor Description: Get the most out of your steel designs with RISAFloor and RISA-3D. The ability to use multiple materials in one FEA model makes these programs your first choice for both hot rolled and cold formed steel. With 16 steel databases and 21 steel codes RISA has all your bases covered.

S-FRAME Software, Inc. Phone: 203-421-4800 Email: info@s-frame.com Web: www.s-frame.com Product: S-PAD™ Description: A steel-member design and optimization application for small consulting engineering firms. Easy to use with advanced code-checking capabilities and auto-design to multiple design codes (AISC, CSA, EU, BS) for both strength and serviceability of columns, beams, and braces without the need to build complete detailed models. Free trials available. All Resource Guides and Updates for the 2012 Editorial Calendar are now available on the website, www.STRUCTUREmag.org. Listings are provided as a courtesy. STRUCTURE® magazine is not responsible for errors.

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StrucSoft Solutions Phone: 514-731-0008 Email: info@strucsoftsolutions.com Web: www.strucsoftsolutions.com Product: MWF Description: Light gauge metal and wood framing application running inside Autodesk Revit. Frames walls, floors and ceilings.

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OK as is

May 2012

OK with changes

award winners and outstanding projects

Spotlight

HL23 Unique Geometry Grows Wider as it Goes Up By Stephen V. DeSimone, P.E., LEED AP and Ahmed M. Osman, P.E. DeSimone Consulting Engineers was an Outstanding Award winner for the HL 23 project in the 2011 NCSEA Annual Excellence in Structural Engineering Awards Program (Category – New Buildings $10M to $30M).

eveloped by one of Manhattan’s most progressive developers, Alf Naman, HL23 is a 14 floor condominium tower that responds to a unique and challenging site directly adjacent to the High Line at 23rd street in New York’s West Chelsea Arts district. Partially impacted by a spur from the elevated tracks that make up the High Line superstructure, the site is 40 x 99 feet at the ground floor. The site and the developer demanded a specific response from the design team, yielding a solution that is a merger between given parameters and architectural ambition. For the team, the most important question was how to expand the possible built floor area, given the impact of the High Line on the site and the restricted zoning envelope. The project architect, Neil Denari responded to the unique site restrictions by reversing the architectural setback for which New York is famous. HL23 rises up from a small footprint adjacent to the High Line and actually grows wider so that portions of the tower lean out over the park itself. This allowed the developer to maximize the amount of floor area built, and resulted in a dramatic sloping of both the South and East façades. In New York City, demand for new luxury residential product continues to be strong. The favored method of construction for most residential buildings is cast-in-place, reinforced concrete slab. However, due to the unique geometry of the building and the desire for large column free spaces, steel was the economical and efficient material of choice. Floor beams are composite and, in order to maximize ceiling height, the intermediate beams were eliminated in favor of implementing shored slab construction. Deep, long span composite metal deck of 6 inches was used and shored until the concrete achieved the desired strength. At the upper floors, the maximum beam/girder span is over 30 feet creating dramatic units. The building slopes east from bottom to top, creating a large, cantilever over the Highline Railway. This cantilever was achieved by utilizing a diagonally braced perimeter frame. The columns on the west side of the structure

are in net tension under gravity loading. The columns are anchored into a 3-footmat foundation system, and further stabilized by (12) – 1⅜-inch diameter, double corrosion protected high-strength steel anchors to rock. In addition to the bending moments due to gravity loads, many of the steel floor beams resist axial loads created by the outward sloping steel columns of the diagonally braced perimeter system. As an added level of redundancy, steel reinforcement bars were placed inside the concrete slab and mechanically spliced at specific locations to hold the columns back and drag the horizontal forces back to the main lateral resisting system. In some cases, where it was difficult to achieve a direct load path, (2) – 1½-inch steel tension rods inside a 2-inch PVC sleeve were anchored from the outward sloping column to the main lateral resisting system and cast within the slab thickness. The building’s main lateral force resisting system is a steel plate shear wall (SPSW) system. While the system has never been used in New York City, it proved to be both structurally effective and economical. The east-west dimension of the building at the base is less than 25 feet wide, and any reduction in structural dimension was beneficial to the floor layouts. Using ⅜-inch thick plates, instead of wide flange diagonal brace members, freed up an extra foot of useable floor area between the columns that made up the ends of the brace frame. In addition, the SPSW system is considerably more stiff then a braced frame. The added stiffness and strength was critical for this building given the demands created by the gravity and lateral overturning forces. A SPSW system typically takes longer to erect than a conventional braced frame. DeSimone worked with TG Nickel and Associates (General Contractor) and Breton Steel (Fabricator) to develop a system of prefabricated shear wall panels, with integral columns and beams. The perimeter of the plate was continuously welded on three sides in the shop. The prefabricated panels were shipped to the site and spliced in the field. This process ultimately saved a considerable amount of time and reduced the construction time over what would have been expected for a conventional braced frame.

STRUCTURE magazine

May 2012

The second component of the lateral system is comprised of diagonally braced brace frames located on each of the building elevations. In addition to lateral loads, the perimeter braced frames are part of the gravity system as well. The braced exoskeleton members are 8-inch diameter double-extra strong pipes at the North, South and part of the East façade; HSS 10x5 tubes on the West façade and 6 x 4 backto-back angles on the remainder of the East façade. DeSimone and project architect, Neil Denari, incorporated the pipe elements into the building architecture and exposed them on the façade and in the residences. The detailing of these elements was heavily scrutinized. In addition to standard AESS (Architecturally Exposed Structural Steel) specifications, the nodes of the system have been designed with an exposed single 1½-inch diameter pin connection. The final building aesthetic embraces the pipe and the connection details both on the façade and in the interior of the units. The HL23 project is a testament to the versatility of steel and showcases the ability of the Owner, Architect, Structural Engineer, and Contractors to work together to achieve inventive solutions to the challenges of a difficult and unique site.▪ Stephen V. DeSimone, P.E., LEED AP is the President and the Chief Executive Officer at DeSimone Consulting Engineers. He served as Principal in Charge for HL23. He can be reached at stephen.desimone@de-simone.com. Ahmed M. Osman, P.E. is an Associate at DeSimone Consulting Engineers. He served as Project Manager for HL23. He can be reached at ahmed.osman@de-simone.com.

NCSEA News

News form the National Council of Structural Engineers Associations

NCSEA Annual Conference and ICC-ES Committee Meeting at the Hilton Frontenac St. Louis, MO

October 1-6, 2012 9:15 – 9:45 a.m. – Strength Design of Masonry Ed Huston, S.E., CAC General Subcommittee Chair and Principal, Smith & Huston, Inc., Consulting engineers, in Seattle, Washington, will provide an update on the new code provisions on Strength Design of Masonry and how they will impact design practice.

Monday – Tuesday, October 1-2

ICC-ES Committee Meetings: Environmental Committee on Monday. Evaluation Committee on Monday/Tuesday. For more information, visit www.icc-es.org/Criteria_Development/deadlines.shtml

Wednesday, October 3

ICC-ES Evaluation Committee Meeting – Structural engineering topics NCSEA Board Meeting NCSEA Committee Meetings Software and Non-Software Vendor Presentations

Wednesday Night, October 3

SECB Reception – Everyone invited. SECB video on Vimeo: http://vimeo.com/39919598

Thursday, October 4

The Spirit of St. Louis…Design Trends for the Future 8:00 – 8:15 a.m. Ronald Hamburger, S.E., SECB, NCSEA Code Advisory Committee (CAC) Chair and Senior Principal at Simpson Gumpertz & Heger in San Francisco, California, will provide an overview of 2012 Codes and Standards. 8:15 – 8:45 a.m. – Where ASCE 7 Wind Provisions Might Go in 2016 Don Scott, S.E., Vice President, CAC Wind Subcommittee Chair and Director of Engineering for PCS Structural Solutions, will summarize the results of last year’s NCSEA membership survey of wind design practices, provide an update on the present ASCE 7 Wind Design Provisions, and speculate on the future direction of these provisions. 8:45 – 9:15 a.m. – Seismic Anchorage and Appendix D Kevin Moore, P.E., S.E., SECB, CAC Seismic Subcommittee Chair and President, Principal and co-founder of Certus Consulting, Inc. in Oakland, California, will provide an update on changes to ACI 318 Appendix D for anchorage to concrete, focusing on the implications to seismic applications. STRUCTURE magazine

9:45 – 10:15 a.m. – ICC-ES Collaboration, Process, and Effect on Structural Engineers Bill Warren, S.E., SECB, CAC Evaluation Services Subcommittee Chair and Principal with SESOL, Inc., in Newport Beach, California, and Jim Collins, Ph.D., P.E., Director of Engineering for ICC Evaluation Service, LLC, in Whittier, CA, will provide a description of how the ICC Evaluation Services (ICC-ES) program works, the effect this program has on Structural Engineering practice, and an ongoing program of collaboration between ICC-ES and NCSEA. 11:00 a.m. – 12:00 noon – Structural Engineering Practice – Instilling “A Culture of Discipline” Keynote Speaker: Lawrence Griffis, P.E. The practice of structuring engineering today involves working on projects with tight budgets, fast-track schedules and dwindling material resources. To achieve success, engineers must learn and practice a certain culture of discipline. Lawrence Griffis, P. E., is a Senior Principal and President of the Structures Division of Walter P Moore and Associates, Inc. He serves on the code committees for both AISC and ACI and also as an on-going member of the ASCE 7 Standards Committee. 1:00 – 2:00 p.m. – Snow Load Provisions in ASCE 7-10 This seminar will provide practicing structural engineers with an understanding of the new snow load provisions and will cover all 12 sections of ASCE 7-10. Michael O’Rourke, P.E., Ph.D., has authored snow load publications for ASCE on ASCE 7-02, ASCE 7-05, and ASCE 7-10, has written numerous snowload-related journal articles, and has been the recipient of several snow-load-related research grants and contracts. 2:00 – 3:00 p.m. – The Performance of New England’s Buildings in the Winter of 2010-2011 Hundreds of buildings in New England suffered structural damage or collapsed during the winter of 2010-2011. Mr. Zona will discuss lessons learned, with emphasis on the primary factors that lead to collapse. Joe Zona, P.E., SECB, is a senior principal with Simpson Gumpertz & Heger Inc. and chairs the Structural Advisory Committee to the Massachusetts Board of Building Regulations and Standards. May 2012

4:30-5:00 p.m. – Speakers’ Forum

Thursday Night, October 4

Friday, October 5 8:00-9:45 a.m. – Roll call and Member Organization Reports 10:30 a.m.–12:30 p.m. – ATC Cliff Notes: What you Should Know but Don’t Have Time to Read This session will present key findings, conclusions, and discoveries from recently completed and ongoing projects funded by the Federal Emergency Management Agency (FEMA) and the National Institute of Standards and Technology (NIST). These projects will include: • ATC-63: Quantification of Building Seismic Performance Factors (FEMA P-695). • ATC-71-1: Seismic Evaluation and Retrofit of Multi-Unit Wood-Frame Buildings With Weak First Stories (FEMA P-807). • ATC-72-1: Modeling and Acceptance Criteria for Seismic Design and Analysis of Tall Buildings (PEER/ATC 72-1). • ATC-82: Selecting and Scaling Earthquake Ground Motions for Performing Response-History Analyses (NIST GCR 11-917-15).

1:30 – 3:00 p.m. – Diaphragms and Wall Anchorage Dr. Timothy Mays will present major components of NCSEA design guides titled Guide to the Design of Diaphragms, Chords and Collectors and Guide to the Design of Out-of-Plane Wall Anchorage. The presentation will focus on example problems and appropriate hand and computer modeling techniques. 3:30 – 5:00 p.m. – Serviceability and Foundation Systems Dr. Timothy Mays will present major components of newly released NCSEA design guides titled Guide to the Design of Building Serviceability and Guide to the Design of Foundation Systems. The presentation will focus on practical example problems, 2012 IBC Chapter 18, ASCE/SEI 7-10, and all areas of building serviceability. Timothy Mays, Ph.D., P.E., is President of SE/ES and an Associate Professor of Civil Engineering at The Citadel in Charleston, SC. Dr. Mays currently serves as NCSEA Publications Committee Chairman. He has received two national teaching awards (ASCE and NSPE) and both national (NSF) and regional (ASEE) awards for outstanding research. He is a prolific speaker who sits on several code writing committees.

Friday night, October 5 6:00 – 7:00 p.m. – NCSEA Awards Banquet Reception 7:00 – 10:00 p.m. – NCSEA Awards Banquet Black tie requested

Saturday, October 6 8:00 – 12:30 p.m. – NCSEA Business Meeting

NCSEA Webinars in May May 3: Specialty Structural Engineering – Façades, Means and Methods, and Repairs William Bast, P.E., S.E., SECB

May 10: Ethics – A Practical Guide for the Practicing Engineer Barry Arnold, P.E., S.E., SECB

Register at www.ncsea.com. Cost: $225 for NCSEA members, $250 for SEI/CASE members, $275 for non-members, FlexPlan option still available. Several people may attend for one connection fee. 1.5 hours of continuing education. Approved for CE credit in all 50 States through the NCSEA Diamond Review Program. Applicable for SECB recertification. No fee for continuing education certificates. Time: 10:00 AM Pacific, 11:00 AM Mountain, 12:00 PM Central, 1:00 PM Eastern. Miss a webinar that you wanted to see? Purchase the recording at www.ncsea.com. STRUCTURE magazine

May 2012

News from the National Council of Structural Engineers Associations

5:30 – 6:30 p.m. – President’s Reception for Delegates 6:30 – 8:30 p.m. – Welcome Reception with Exhibitors

• ATC-83: Soil-Structure Interaction for Building Structures (NIST GCR 11-917-15). The session will also include a detailed overview of the ATC-58 project report, Seismic Performance Assessment of Buildings (FEMA P-58), and associated products such as the Performance Assessment Calculation Tool (PACT). Jon Heintz, P.E., S.E., is Director of Projects at Applied Technology Council in Redwood City, California. Ronald Hamburger, S.E., SECB, is Senior Principal at Simpson Gumpertz & Heger in San Francisco, California. Mr. Hamburger serves as Chair of the ASCE 7 Committee, the AISC Connection Prequalification Review Committee, and the NCSEA Code Advisory Committee.

NCSEA News

3:30 – 4:30 p.m. – The 2011 Joplin Tornado The Joplin Tornado of May 22, 2011 was one of the most damaging events to hit the state of Missouri in regards to casualties and costs. In light of the magnitude of devastation to the built environment, a SEAKM committee was formed to investigate the performance of some of the building types that were damaged by the tornado. As a result of this investigation, the committee found commonalities in damage patterns, regardless of building type. Randall Bernhardt, P.E., S.E., is Chief Structural Engineer for the St. Louis region at Burns & McDonnell Engineering Company, St. Louis, MO. He has served as a member of NEHRP Technical Subcommittee 5, Masonry, and is a member of the NCEES Structural Exam Committee. Malcolm Carter, P.E., S.E., is a consulting structural engineer in Lenexa, Kansas. During his 43 years in the profession, he has been responsible for numerous structures located throughout the world.

The Newsletter of the Structural Engineering Institute of ASCE

Structural Columns

Structures Congress Call for Proposals Structures 2013 Congress will be held in the beautiful and historic city of Pittsburgh, from May 2-4, 2013. You are invited to submit session proposals and/or paper abstracts for the Structures 2013 Congress. Proposals should focus on topics consistent with the list on the SEI website. Visit the SEI website at www.asce.org/SEI for details about abstract and session proposals, as well as suggested topics and subtopics.

KEY DATES: All Session and Abstract Proposals Due: June 12, 2012 Notification of Acceptance: September 18, 2012 All Final Publication Ready Papers: January 15, 2013 (no extensions)

Proceedings: Authors of accepted abstracts are strongly encouraged to submit a 10-12 page final paper for inclusion in the proceedings. The proceedings will be copyrighted and published by ASCE. Questions? Contact Debbie Smith at dsmith@asce.org or 703-295-6095. For information on Sponsoring and Exhibiting, please contact Sean Scully at sscully@asce.org or 703-295-6276.

SEI Logo Available for Local Groups and Committee Chairman

ASCE 7 Committee Call for Proposals for the 2016 Edition The Structural Engineering Institute (SEI) of ASCE is currently accepting proposals to modify the 2010 edition of ASCE 7, Minimum Design Loads for Buildings and Other Structures Standards Committee to prepare the 2016 revision cycle of the standard. Interested parties may download the proposal form from the SEI website at www.asce.org/SEI. The committee will accept proposals until June 30, 2012. For additional information please contact Jennifer Goupil, SEI Director, at jgoupil@asce.org.

Mark your calendars now and plan to attend this forum where transmission and substation engineers can share technical knowledge and explore emerging issues, while bringing new engineers up to speed on core issues. You won’t want to miss: • In-Depth Technical Sessions presented by leading industry experts on topics including Aesthetic Design Principles; Construction Challenges; Emerging Technologies; Foundations; Lifeline Reliability and Performance; Line and Substation Siting; Line Design, Re-rating and Upgrading; Extreme Loading Events; Managing Aging Infrastructure; Project Management; Regulatory Compliance; Structural Analysis and Design; Substation Design and Upgrading. STRUCTURE magazine

How to submit a proposal: For detailed instructions on how to upload a session proposal or paper abstract, visit the SEI website at www.asce.org/SEI.

ASCE Branding Toolkit ASCE’s Collaborative Marketing Department has created a Branding Tool Kit website to help standardize branding across the Society. All institute logos, including SEI’s, were redesigned recently to include the ASCE shield. Please make sure that you use the most up-to-date ASCE and SEI logos when sending out correspondence, creating flyers, or marketing events. The Branding Tool Kit includes logos in black and white, color, horizontal, and vertical versions. The website will walk you through creating a login to access the toolkit. Visit the Branding Toolkit today at: www.ascebrandingtoolkit.com/pages/login.php.

• A dynamic Pre-Conference Workshop on Design Criteria and Load Requirements for Transmission Line Structures. • Networking events where you can exchange ideas with colleagues from around the world. This year the Conference will feature a special 2012 Election Night Reception! • An Exhibit Hall packed with state-of-the-art products and services from leading industry suppliers. • Tours and demonstrations at American Electric Power’s transmission facilities where you can view EMF and Corona demonstrations, EHV hot-line maintenance, and hands-on substation operations all in the same day! For more information visit the ETS conference website at: http://content.asce.org/conferences/ets2012/index.html. May 2012

Third Orthotropic Bridge Conference Three-Day Conference with Workshop and Tours June 25–29, 2013 – Northern California The American Society of Civil Engineers, The Metropolitan Transportation Commission, and the partner organizations invite you to attend and participate in the Third Orthotropic Bridge Conference. The objective of this conference is to present the latest developments in the design and construction of orthotropic deck bridges worldwide, and visit California orthotropic bridges in operation. Many of the world’s leading engineers and researchers from across the USA and more than ten other countries, who contributed to the spectacular advances of orthotropic design and construction, presented their views at the 2004 and 2008 conferences.

Tentative Schedule Attendees may register for all events, or events may be selectively attended, including a one-day registration for any day of the 3-day conference. Tue., June 25 – One-day workshop “Orthotropic Deck Bridges”. Separate registration. Wed., June 26–Fri., June 28 – Orthotropic Bridge Conference Separate registration includes two luncheons and Thursday Bus Night Tour of the San Francisco/Oakland Bay Bridge East Spans, (SAS) Self-Anchoring Suspension Orthotropic spans. Fri., June 28 – Optional Boat Tour of East Spans (SAS) & Golden Gate Bridge. Separate Registration. Sat., June 29 – Tour of nine orthotropic bridges in the San Francisco Bay Area. Separate registration includes bus fare and meals. One page abstract due on or before September 15, 2012; Send to: Abstract_3OBC_ASCE@hotmail.com.

New ASCE Structural Webinars Available Several new webinars are available: Webinar Title Antiquated Structural Systems Damping and Motion Control in Buildings and Bridges Designing for Flood Loads Using ASCE 7 and ASCE 24 Preventing Bridge Damage During Earthquakes Evaluating Damage and Repairing Metal Plate Connected Wood Trusses A General Overview of ASCE 7-10 Changes to Wind Load Provisions Mitigating Effects of Corrosion and Deterioration in Construction Pier and Beam Foundation Design for Wind and Flood Loads Webinars are live interactive learning experiences. All you need is a computer with high-speed internet access and a phone. These events feature an expert speaker on practice-oriented technical and management topics relevant to civil engineers. Pay a single site fee and provide training for an unlimited number of engineers at that site for one low fee, and no cost or lost time for travel and lodging. ASCE’s experienced instructors

Date June 14, 2012 June 18, 2012 June 20, 2012 June 22, 2012 June 25, 2012 June 28, 2012 July 2, 2012 July 23, 2012

Instructor Matthew Stuart Brian Breukelman TBA Mark Yashinsky TBA William L. Coulbourne TBA TBA

deliver the training to your location, with minimal disruption in workflow – ideal for brown-bag lunch training. ASCE Webinars are completed in a short amount of time – generally 60 to 90 minutes – and staff can earn one or more PDHs for each Webinar. Visit the ASCE Continuing Education website for more details and to register: www.asce.org/conted.

SAVE THE DATE ATC & SEI Advances in Hurricane Engineering Conference Miami, Florida

October 24–26, 2012

The Applied Technology Council (ATC) and the Structural Engineering Institute (SEI) of the American Society of Civil Engineers (ASCE) are teaming up to present the Advances in Hurricane Engineering Conference in Miami, October 24-26, 2012. This is the second joint conference of these two organizations in a growing partnership to benefit the engineering community regarding natural hazard issues. The Conference Program will feature presentations on topics such as:

STRUCTURE magazine

• Wind Engineering • Coastal Flooding • Engineering for the Building Envelope • Low-Rise Buildings • High-Rise Buildings • Infrastructure • Meteorology and Oceanography • Risk Modeling and Forensic Engineering For more information visit the ATC & SEI Hurricane conference website at: www.atc-sei.org/.

May 2012

The Newsletter of the Structural Engineering Institute of ASCE

SEI partners with ASCE Continuing Education to present quality live interactive webinars on useful topics in structural engineering.

Structural Columns

Call for Papers

The Newsletter of the Council of American Structural Engineers

CASE 10 Foundations for Risk Management The Ten Foundations for Risk Management are the basis of a risk management program for your firm. The tools are interactive and easily adaptable to your firm’s needs. Most importantly, these tools have been developed by CASE’s members – engineers in private practice whose combined experience and expertise ensure this program’s effectiveness.

Each Foundation has accompanying worksheets, sample documents, case studies, and exercises that build your firm’s Risk Management Toolkit. As a special to NCSEA and SEI members, we are offering a complimentary copy of CASE Tool 1-1: Create a Culture for Managing Risks and Preventing Claims. CASE Tool 1-1 will help you identify your firm culture and offer recommendations to develop a culture of risk management and claims prevention. To get your copy, please visit the CASE Website www.acec.org/case and click on “Getting Involved.” Developed by the CASE Toolkit Committee, the CASE 10 Foundations for Risk Management are available at www.booksforengineers.com. www.booksforengineers.com

The Ten Foundations are: 1. Culture 2. Prevention & Proactivity 3. Planning 4. Communication 5. Education 6. Scope 7. Compensation 8. Contracts 9. Contract Documents 10. Construction Phase

Senior Executives Institute’s Class 18 Filling Fast; Register Now! Since its inception in 1995, ACEC’s prestigious Senior Executives Institute (SEI) has provided the industry’s top leadership program to public and private sector engineers and architects from firms of all sizes, locations and practice specialties. In five separate five-day sessions over 18 months, participants acquire new high-level skills and insights that facilitate

adaptability and foster innovative systems thinking to meet the challenges of the A/E/C business environment. The next SEI Class 18 meets in Washington, D.C. in September 2012 for its first session. A limited number of slots remain. To inquire, contact Deirdre McKenna, 202-682-4328, or dmckenna@acec.org.

CASE in Point

Ray Messer at Structures Congress The CASE Risk Management Convocation was held at this year’s Structures Congress, March 29-31 in Chicago, IL. Kicking off the program was the sold out breakfast with keynote speaker Ray Messer, President of Walter P Moore. Structural engineering is a great profession! The question is how do we make it a great business? A global economy has presented new challenges and created a new world order for the engineering industry. Regardless of these changes, we can control our destiny. It is up to each of us to continue to develop our business and technical skills and manage our clients in order to protect our firms and clients as we serve the public.

STRUCTURE magazine

Ray’s presentation, Structural Engineering is a Good Business, highlighted “ten things to consider” in running a good business: 1) Balance technical proficiency with business acumen. 2) Think proactively. 3) Maintain relationships with fewer, quality clients. 4) Focus on client service. 5) Consciously develop learning organization. 6) Recognize that good, technical engineers don’t necessarily make good project managers. 7) Plan the work. 8) Manage don’t unnecessarily minimize overhead. 9) Manage benefits with focus on healthcare. 10) Have fun in the process. Thanks to Ray for being a great speaker!

May 2012

If you would like more information on the items below, please contact Ed Bajer, ebajer@acec.org.

Unauthorized Changes to Your Plans

Public/Private Partnerships: Why the Public Ownership is Hesitant

Understanding Your Obligations Standard contracts by CASE and others are not intended as a starting point for negotiations with the intent that some of the language will be “bargained away” in favor of some concession elsewhere. Rather, their purpose is to set forth clearly and concisely what services the engineer is and is not obligated to perform. They also recognize that others, particularly the contractor, have their own expertise and skills which the engineer does not possess. It is important that they each respect the other’s expertise. With that understanding, the possibility of ill will, claims and litigation will be lessened.

Public owners are very mindful of their obligation to protect the public interest and hesitant to reduce its role in project management. It could be viewed as relinquishing its responsibilities to the private sector. There is also concern that the private sector partner may not deliver a quality project if they are not watched

You can follow ACEC Coalitions on Twitter – @ACECCoalitions

JOIN CASE! The Council of American Structural Engineers (CASE) is a national association of structural engineering firms. CASE provides a forum for action to improve the business of structural engineering through implementation of best practices, reduced professional liability exposure and increased profitability. Our mission is to improve the practice of structural engineering by providing business practice resources, improving quality, and enhancing management practices to reduce the frequency and severity of claims. Our vision is to be the leading provider of risk management and business practice education, and information for use in the structural engineering practice. Your membership gets you free access to contracts covering various situations, as well as access to guidance on AIA

STRUCTURE magazine

documents, free national guidelines for the Structural Engineer of Record designed to help corporate and municipal clients understand the scope of services structural engineers do and do not provide, free access to tools which are designed to keep you up to date on how much risk your firm is taking on and how to reduce that risk, biannual CASE convocations dedicated to Best Practice structural engineering, bi-monthly Business Practice and Risk Management Newsletter, AND free downloads of all CASE documents 24/7. For more information go to www.acec.org/case or contact Heather Talbert at htalbert@acec.org. You must be an ACEC member to join CASE.

May 2012

CASE is a part of the American Council of Engineering Companies

It is not uncommon for someone (the owner, a contractor, building official) to make changes to construction documents without the knowledge and approval of the engineer. Contractors may make minor and what they think are harmless changes. The engineer may become liable or more likely responsible for the costs of such changes. The obvious solution is to have language in your contract absolving you of responsibility of such changes, and to indemnify and hold you harmless for them. If possible, retain ownership of your plans and specifications. Work closely with your attorney to assure the language used does not conflict with your scope of work.

carefully. However, if the private sector partner is compensated adequately, it has the incentive to minimize disruptions as well as construction costs. A poorly constructed project is not in anyone’s interest, and will result in increased repairs during the operating phase causing lost fees plus the cost of repairs.

CASE in Point

CASE Business Practice Corner

Structural Forum

opinions on topics of current importance to structural engineers

A Structural Engineer’s Manifesto for Growth Part 2 By Erik Nelson, P.E., S.E.

his is the second installment of what I am calling my manifesto, which presents some of my thoughts about our profession and how we can grow as individual designers. For steps 1-7, please see Part 1 in the April 2012 issue of STRUCTURE®.

8: Be Aggressive Design is an incredible process. It is good for you to make the process of design your own. Drive the process, and in so doing, you will grow and become a better engineer. Cooperate, listen, be humble, but do not let that prevent you from being aggressive. You need a love of learning and a pursuit of excellence. Focus on the present and take action now. As the philosopher Immanuel Kant put it, act as though everything you do will become universal law. Your pursuit of well-being will help others, which will in turn come back to yourself. Do not picture yourself as a great engineer, a rich engineer, or a famous engineer. Do great engineering now and you will be great–not the famous type of great, but the non-famous type of great, which is more worthy of the word.

9: Improve the Codes Codes are good and extremely important, but they are getting completely out of control. There is an old Faraday adage, “Make every effort to ensure that the results of your experiment are proportional to the evidence and assumptions that produced them”. The code committees should keep in mind the approximate nature of this enterprise called structural engineering. Not only are there large uncertainties in our loads and material strengths used in design, there are huge uncertainties in construction. Before meeting in a conference room, the code committee members should visit a construction site to remember how reinforcing is placed within a slab on grade. While they

are there, they can see what a true “pinned” base support looks like (a thick base plate with four heavy anchors). They can see the soil and the assumptions used for designing the footings. They can see what shear connections look like that purportedly do not resist moment. They will notice the large non-structural interior and exterior walls that were completely neglected when modeling structural stiffness. In summary, the code committee should ask themselves the following two questions: • Is this provision important to the design of safe structures? • Is the provision too exact? Or in Faraday’s words … “Is the proposed provision proportional to the assumptions and uncertainty inherent in structural design (loads, strengths, construction, etc.)?” If they would ask these questions, then the codes would not balloon to the size they are now. I understand that the codes are becoming more and more sophisticated, and provisions are being improved in an effort to reflect reality better. But there was a time when people understood that code requirements needed to exist to ensure public safety, and that was the only standard that they needed to meet. We need to join code committees and take our profession back.

10: Teach Engineering I never thought being a teacher would make me a better engineer. It is undoubtedly the best decision I have ever made as an engineer. It allows you to reflect on important concepts and theories that you thought you understood, but never really did. In order to teach, you must be able to convey complex ideas into clear language, which requires one to master the material. It also allows you to explore how best to communicate to people with different learning styles. It is a constant challenge and highly rewarding.

11: Become a Material Talk to materials. You can ask a brick if it likes to take compression. Feel a brick (or bolt, concrete sample, etc.) in your hand and discuss with it what it wants and where it wants to be in the building. (For more, see my article, Participation Mystique, in the May 2007 issue of STRUCTURE.) You can gain a better understanding of structures by becoming the thing itself, by manifesting yourself in the building, beam, connection, or bolt. I remember visiting a project where I designed all the connections for a large box truss spanning 100 feet supporting four stories of concrete. The erector was proud to show me his work and described the installation, weld and details as craftsmen often do. He and I both knew that the architect was going to cover it all up for no one else to see. He was still deeply satisfied, as was I. I realized much later that the satisfaction was not really about the truss or even the workmanship. What he was really showing me was himself, a manifestation of himself in the steel connection; he was quality just like the connection. He was the inanimate object, and it was beautiful. We can learn a great deal about ourselves in the same way. In his book, Zen and the Art of Motorcycle Maintenance, Robert Pirsig suggests: You want to know how to paint a perfect painting? It’s easy. Make yourself perfect and then just paint naturally. That’s the way all the experts do it. The making of a painting or the fixing of a motorcycle isn’t separate from the rest of your existence… The machine that appears to be “out there” and the person that appears to be “in here” are not two separate things. Therefore, according to Pirsig, if you want to become an expert structural engineer, make yourself an expert structural engineer, then engineer.▪ Erik Anders Nelson, P.E., S.E. (ean@structuresworkshop.com), is owner of Structures Workshop, Inc. in Providence, RI. He teaches one class per semester at the Rhode Island School of Design and Massachusetts Institute of Technology. Please visit and comment on his blog at www.structuresworkshop.com/blog.

Structural Forum is intended to stimulate thoughtful dialogue and debate among structural engineers and other participants in the design and construction process. Any opinions expressed in Structural Forum are those of the author(s) and do not necessarily reflect the views of NCSEA, ® CASE, SEI, C 3 Ink, or the STRUCTURE magazine Editorial Board. STRUCTURE magazine

May 2012

Integrated Connection Design RISAConnection now integrates directly into RISA-3D and RISAFloor. The integration of RISAConnection into RISA-3D and RISAFloor gives you the power to design and detail your connections as you optimize your structure. As you modify loads and structural conﬁgurations in RISA-3D and RISAFloor your connection designs are updated and recalculated automatically. An extensive library of connection types (including vertical brace connections) enables you to use RISAConnection to handle all your connection design needs. Try the RISA suite of fully integrated design products and see how productive you can be!

STRUCTURE magazine | May 2012

Articles inside

Structural Forum

Great Achievements

Professional Issues

Education Issues

Product Watch

Codes and Standards

Structural Practices

Just the FAQs

Code Updates

Building Blocks

InFocus

Structural Design

InSights