STRUCTURE magazine | September 2012 by structuremag

A Joint Publication of NCSEA | CASE | SEI

STRUCTURE

September 2012 Concrete Special Section NCSEA 20 Annual Conference St. Louis, Missouri th

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FEATURES Bridge Service Life Extension Study

By Christopher A. Ligozio, S.E., P.E., Scott T. Wyatt, S.E., P.E. and Ernst H. Petzold, P.E.

Service life evaluation methodologies and other diagnostic tools were applied to the 50-year-old concrete substructures of the Blanchette Bridge in St. Charles, Missouri.

26 Special Section

NCSEA 2012 Conference Section The National Council of Structural Engineers Associations will host its 20th Annual Conference at the Hilton Frontenac in St. Louis, MO, on October 3rd through the 6th.

STRUCTURE

IN EVERY ISSUE ON

THE

COVER

A Joint Publication of NCSEA | CASE | SEI

James Buchanan Eads designed and built the bridge that bears his name across the Mississippi River at St. Louis. The bridge is featured on the cover of this issue of STRUCTURE® magazine in recognition of NCSEA’s 20th Annual Conference. Photo courtesy of Paula Bernhardt. September 2012 Concrete Special Section

NCSEA 20 th Annual Conference St. Louis, Missouri

8 Advertiser Index 37 Noteworthy 41 Resource Guide (Anchoring) 44 NCSEA News 46 SEI Structural Columns 48 CASE in Point

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.

CONTENTS September 2012

COLUMNS 7 Editorial Professional Scholarships to Structures 2012 Congress By Taka Kimura, P.E.

9 InFocus The Rationality of Practice

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

11 Guest Column ACI Resources for Concrete Buildings of Moderate Size and Height By Mike Mota, Ph.D., P.E.

15 Structural Practices Strawbale Construction – Part 1 By Martin Hammer, Architect, Mark Aschheim P.E. and Kevin Donahue P.E., S.E.

31 Construction Issues Modular Stay-In-Place Formwork By James L. Ryan, P.E., Neha Gidwani, P.E. and Luis M. Moreschi, Ph.D., P.E.

DEPARTMENTS 20 InSights ADVERTISEMENT - For Advertiser Information, visit www.STRUCTUREmag.org

Construction Quality Management

By Richard L. Hess, S.E., SECB

35 Great Achievements William LeMessurier

By Richard G. Weingardt, D.Sc. (h.c.), P.E.

38 CASE Business Practices Too Many Codes Spoil the Design?

By Kirk A. Haverland, P.E., SECB

43 Spotlight The Case of the Sagging Floors – What Engineers Should Know By Craig A. Copelan, P.E. and Joyce E. Copelan, P.E.

50 Structural Forum Developing the Next Generation of Structural Engineers – Part 1

By Glenn R. Bell, P.E., S.E., SECB

STRUCTURE magazine

September 2012

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Editorial

Professional Scholarships to Structures new trends, new techniques and current industry issues 2012 Congress By Taka Kimura, P.E., M. ASCE, F. SEI

ustainability is a buzzword applied to a variety of practices from recycling to smart forestry – but have you ever thought about how the term applies to our profession? Like the lumber in smart forestry, engineering expertise is a resource that must continually be replenished and nurtured. While a good engineering education provides a solid base of knowledge, an engineer must continually keep abreast of the current state of practice and have a wide network of colleagues to be truly effective. Developing these traits is a daunting task, especially for those who are new to the profession. To assist young structural engineers in their efforts to continually progress beyond book knowledge, the Structural Engineering Institute’s (SEI) Young Professionals Committee has developed a scholarship program for attendance at the annual Structures Congress. Through the scholarship program, SEI granted eight recipients financial assistance – five recipients received complimentary registration and three received partial travel assistance in addition to complimentary registration. The scholarships were awarded based on financial need, professional involvement, and an essay. This was the program’s pilot year, with scholarships awarded to Andy Coughlin, Rafael Gomes de Oliveira, Emily Guglielmo, Linda Kaplan, Chad Schrand, Ashley Thrall, Laura Whitehurst, and Frances Yang. In addition to providing scholarships to the 2012 Structures Congress, the Congress planners placed an emphasis on increasing the involvement of all young professionals and students in attendance by offering the following programs and events directly aimed at engaging them: • Welcome and Walking Tour – After a brief overview of the conference, students participated on a walking tour of two local structural engineering offices. • Meet the Leaders Breakfast – SEI leaders introduced themselves and joined the students and young professionals for breakfast. • School to World 101 Session – Experienced engineers gave real world advice and answered questions for students through an engaging and fun “speed dating” format. • Young Professionals Mixer – A cocktail hour provided the students and young professionals an opportunity to network with SEI leaders. • Student Structural Design Competition Presentations – Winning teams from the annual SEI Student Structural Design Competition presented their award-winning projects. • Panel discussion on Creative, Collaborative, and Communicative: Perspectives on Developing a Future Generation of Engineering Leaders – A panel of young professionals discussed the leadership challenges for the next generation of structural engineers. The scholarships and the targeted events were a resounding success, with record numbers of students and young professionals attending this year’s Congress. I had the pleasure of participating in most of the above Congress activities and was impressed with the insightfulness, ambition, and overall caliber of the young professionals and students with whom I interacted. They wanted to gain knowledge, build their networks, and learn from others; and they wasted no time in making the most of their opportunity. Feedback from the scholarship recipients was overwhelmingly positive, and included the following: STRUCTURE magazine

I feel that my participation at Structures Congress was a potentially career altering experience for me. My involvement with other professionals and on ASCE committees would never have evolved without the Young Professional Scholarship. – Emily Guglielmo, Martin/Martin, Inc. I hope that this involvement will allow me to continue to attend conferences in the future with the support of my company, but I also plan to petition our leadership to allow other young engineers the chance to experience national conferences early in their careers. I truly believe that this is an important facet of a young engineer’s career development. – Laura Whitehurst, Walter P Moore The Meet the Leaders Breakfast and Young Professionals Mixer on Thursday made the Congress much more approachable for those new to the profession and will make it more likely for them to return. – Chad Schrand, CCS Group With this year’s success, SEI intends to continue the Structures Congress Scholarship Program, and to improve it for future Congresses. (If you are a young professional interested in applying for the Structures 2013 Congress scholarship, visit www.asce.org/sei for details.) In fact, I was glad to discover that Linda Kaplan, one of the scholarship recipients and an ambitious bridge designer with Gannett Fleming, will be chairing the committee planning the student and young professional events for the 2013 Structures Congress in Pittsburgh. Her experiences at this year’s Congress provided her with good insight toward improving the program for next year. So the next time you’re at the Structures Congress – or any other conference for that matter – do yourself and the profession a favor. If you’re just starting out as a structural engineer, do more than just attend sessions and listen to presentations. Gaining technical information is important, but you can always read the conference proceedings when you get home. The real benefit of any conference lies in the industry leaders with their wealth of experience, who are there in the same room. Take the extra step to meet these people. If you enjoyed a presentation, talk to the presenter during one of the breaks. At meals and receptions, sit with people you don’t know and get to know them. Attend a committee meeting that deals with a topic of interest. Make the effort to meet people and get actively involved in the host organization. If you are a seasoned structural engineer, do more than just reconnect with old colleagues. Search out young, talented individuals looking for a foothold in the profession. Make time for those who approach you. If you don’t have the time to spare at the moment, give them your contact information or offer to contact them later – and be sure to follow through. Whether you’re a seasoned veteran or new to the profession, the contacts you make will be invaluable. It takes time and effort, but it’s well worth it!▪ Taka Kimura, P.E., M. ASCE, F. SEI is a Senior Principal Engineer at Parsons Brinckerhoff. Taka currently serves as Vice President of the Structural Engineering Institute.

September 2012

ADVERTISER INDEX

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Editorial Board

Chair

Jon A. Schmidt, P.E., SECB

Craig E. Barnes, P.E., SECB

Brian W. Miller

Richard Hess, S.E., SECB

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

Davis, CA

Hess Engineering Inc., Los Alamitos, CA

AdvErtising Account MAnAgEr Interactive Sales Associates

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

CBI Consulting, Inc., Boston, MA

NCEES ................................................. 14 Polyguard Products, Inc........................... 6 Powers Fasteners, Inc. .............................. 2 RISA Technologies ................................ 51 Structural Engineers Assoc. of Illinois .... 42 Simpson Strong-Tie............................... 19 StructurePoint ....................................... 10 Struware, Inc. ........................................ 43 Unbonded Brace ................................... 25

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STRUCTURE® (Volume 19, Number 9). 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. STRUCTURE® is a registered trademark of National Council of Structural Engineers Associations (NCSEA). Articles may not be

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inFocus

The new trends, Rationality new techniques and ofcurrent Practice industry issues By Jon A. Schmidt, P.E., SECB

n the July issue, I introduced the concepts of theoretical knowledge (episteme), technical rationality (techne), and practical judgment (phronesis) as identified by Aristotle, along with the thesis that Western culture has largely abandoned the first and third in favor of the second. This month, I would like to focus on the last two categories and how they bear on practice in the sense specified by Alasdair MacIntyre (“Rethinking Engineering Ethics,” November 2010). Joseph Dunne paraphrases it as follows in a 2005 paper (“An Intricate Fabric: Understanding the Rationality of Practice,” Pedagogy, Culture and Society, Vol. 3, No. 3, pp. 367-389):

knowledge) with character, its need to embrace the particulars of relevant action-situations within its grasp of universals, and its ability to engage in the kind of deliberative process that can yield concrete, context-sensitive judgements. Practical judgment is manifested as “the cultivated capacity to make [particular judgment ‘calls’] resourcefully and reliably in all the complex situations that they address,” as well as “an ability to recognise situations, cases or problems . . . and to deal with them adequately and appropriately.” Dunne does not deny that technical rationality has a rightful place within practices; in fact, he affirms that “one can grant the validity and indeed the desirability of technicising – even in practical domains – everything that can without loss be technicised.” Why, then, is practical judgment necessary? Because practices “often present us with a problematic situation where there is no discrete problem already clearly labelled as such, so that we might better speak of a difficulty or predicament rather than a problem.” When confronting such circumstances,

…a coherent, complex set of activities that has evolved cooperatively and cumulatively over time, that is alive in the community who are its practitioners, and that remains alive only so long as they remain committed to sustaining – and creatively developing and extending – its internal goods and its proper standards of excellence (this commitment constituting them as a community). Dunne helpfully clarifies that the internal goods of practices are those “whose intended achievement defines them as the particular practices that they are,” including “both competencies proper to each practice and virtues of character that transcend any particular practice.” The latter are necessary to ensure that the former are not treated merely as means for acquiring external goods, such that “the practice [is] made instrumental to the point that violation of its internal fabric is allowed.” A practice is thus “something that can succeed or fail in being true to its own proper purpose.” With this in mind, Dunne draws attention to the “hegemony” that technical rationality has established in modern societies. Its allure comes from its perceived objectivity and the apparent mastery over matter that humans have accomplished by employing it, as exemplified by today’s technology. As a result, “it is no longer seen as a form of rationality, with its own limited sphere of validity, but as coincident with rationality as such.” (Dunne and others resist this by contending that practices like engineering have their own legitimate form of rationality, which deserves to be acknowledged accordingly, but I still prefer to emphasize intentionality for the sake of maintaining a sharp distinction; see “Engineering as Willing,” May 2010.) The effect on practices is pressure to conform by “disembedding the knowledge implicit in the skillful performance of the characteristic tasks of the practice,” so that “what is essential in the knowledge and skill can be abstracted for encapsulation in explicit, generalisable formulae, procedures, or rules . . . The ideal to which technical rationality aspires, one might say, is a practitioner-proof mode of practice.” (This is evident from the trend toward ever more detailed and prescriptive codes and standards, a well-meaning but misguided attempt to ensure competent engineering by providing an increasingly elaborate set of instructions; see “The Nature of Competence,” March 2012.) By contrast, the key features of practical judgment include:

one is not calculating the efficiency of different possible means towards an already determined end. Rather, one is often deliberating about the end itself: about what would count as a satisfactory, or at least not entirely unacceptable, outcome to a particular ‘case’. At first glance, engineering might seem like the kind of practice that almost exclusively utilizes technical rationality. To a casual observer, it appears that managers and clients generally specify the ends, and engineers are charged primarily with selecting the means (“The Social Captivity of Engineering,” May 2010). What profession, other than perhaps accounting, is more closely associated with calculation? Anyone familiar with my previous writings on this subject should know better. Technical rationality is only operative when the assignment at hand consists of following a detailed series of steps in order to achieve an already specified outcome. Engineering certainly includes some tasks that conform to this pattern – structural analysis is an obvious example, hence its suitability for execution by a computer – but it also routinely involves making choices from among multiple viable options despite considerable uncertainty. Furthermore, these decisions pertain not only to means, but also to ends. While the ultimate product or project that results from an engineer’s work may be dictated by someone else, it is up to the engineer to ascertain what exactly will be accomplished within the range of his or her direct responsibility. In other words, engineering should be treated as an end in itself – a form of action or doing (praxis), which requires practical judgment; not just production or making (poiesis), for which technical rationality is sufficient.▪ 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.

its role as an action-orientating form of knowledge, its irreducibly experiential nature, its non-confinement to generalised propositional knowledge, its entanglement (beyond mere

STRUCTURE magazine

September 2012

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he goal of this article is to highlight several technical resources developed by American Concrete Institute (ACI) Committee 314 “Simplified Design of Concrete Buildings”. This committee was formed in 2004 with a specific mission to, “develop and report information on the simplified design and economical construction of concrete buildings of limited height.” The resources discussed in this article include a) Newly released ACI 314.R11 Guide to a Simplified Design for Reinforced Concrete Buildings, and b) Case studies for three projects (16-story hotel in Illinois, and two multi-story post-tensioned parking garages located in California and Maryland).

information has been modified or reorganized to be more conservative, to match design process flow, or better support the holistic and simplified design approach. It should be clear to the reader that the manuscript is a guide and not a standard; therefore, it cannot be adopted by the Building Code. The information is presented in such a manner that a structure designed using this document will, in principle, comply with the minimum requirements of the Codes and Standards on which the Guide to a Simplified Design for Reinforced Concrete Buildings was based. The Guide is a self-contained document and must be applied in its entirety. Because the simplified provisions are interdependent, it would be unsafe to employ only a portion of the document and disregard the rest. As the Guide is intended to be used as a design aid, it is the licensed design professional’s responsibility to ensure the requirements of the applicable Building Code are satisfied.

ACI 314.R11 This is intended to provide the more salient features of the newly published ACI document ACI 314.R11 Guide to a Simplified Design for Reinforced Concrete Buildings (referenced as the Guide) available through the ACI website. In short, this document presents simplified methods and design techniques that facilitate and expedite the design of low-rise reinforced concrete buildings of moderate size and height. The Guide meets the minimum requirements of ACI 318-11; however, it is not a “deem to comply” document. The chapters have been organized to follow the typical design process, with procedures introduced to follow the typical course of a building design. As presented, the information is derived from the following documents: Building Code Requirements for Structural Concrete (ACI 31811) and Commentary (ACI 318R-11); Minimum Design Loads for Buildings and Other Structures (ASCE 7-10) by the American Society of Civil Engineers; and International Building Code (IBC 2009) by the International Code Council. Although many of the tables, charts, and values are based on the referenced documents, the

ℓn1/4

ACI Resources for Concrete Buildings of Moderate Size and Height

The Guide was preceeded in 2002 by the first International Publication from ACI, known as IPS-1 (International Publication Series-1), Essential Requirements for Reinforced Concrete Buildings. IPS-1 was the result of an agreement between ACI and two Colombian Institutions: the Instituto Colombiano de Normas Técnicas y Certificación (Colombian Institute for Technical Standards and Certification) and the Asociación Colombiana de Ingeniería Sísmica (Colombian Association for Earthquake Engineering). The motivation of ACI 314.R11 and the parent document IPS-1 was a result of frequent discussions with design professionals that reinforced concrete codes might be unnecessarily complicated for most types of applications, such as small

negative moment reinf. interior support ℓn1/3

splice according to 5.8.2

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By Mike Mota, Ph.D., P.E., F. ASCE

Mike Mota, Ph.D., P.E., F. ASCE is the Atlantic Region Manager for the Concrete Reinforcing Steel Institute (CRSI). He is an Adjunct Professor at Drexel University, an active member of several ACI and ASCE committees, and Chair of ACI Committee 314 on Simplified Design of Concrete Buildings. He also serves on the Board of Directors of the Concrete Industry Board of New York City/NYC ACI Chapter and is a member of the editorial board of STRUCTURE magazine.

0 in. ℓn1/8

ℓn1

greater of cantilever negative moment reinf. or required for internal support

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0 in. positive moment reinf. end span

dedicated to the dissemination of information from other organizations

Background

negative moment reinf. cutoff points based on greater of the adjacent spans negative moment reinf. at interior face of external support

Guest Column

ℓn1/8 positive moment reinf. interior span

ℓn1/8 ℓn2

ℓn3

splice according to 5.8.2

Figure 1: Reinforcement for beams and joists supported by beams or girders.

STRUCTURE magazine

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

extremely useful as a design aid in the completion of homework assignments. To properly use the Guide, it is important to understand the limitations associated with scope. Low-rise buildings within this scope are expected to have a normal rectangular footprint, with simple geometries and member dimensions in both the plan and vertical directions. Other limitations include: • Maximum number of stories must be five or less above ground and no more than one basement level.

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low-rise buildings. A survey of the construction industry conducted by the Portland Cement Association in the early 1990s showed that approximately 90% of structures in the U.S. are five stories or less and, as a result, the design can be simplified through a small amount of conservatism without impacting the overall economy of the structure. The design guidelines in IPS-1 were tested in Latin America where reinforced concrete is the framing system most commonly used. IPS-1 was also successfully tested at Purdue University, where the students found it

STRUCTURE magazine

September 2012

• Maximum area per floor not to exceed 10,000 square feet (1000 square meters). • Story height, measured from floor finish to floor finish, should not exceed 13 feet (4 m). • The span length for girders, beams, and slab-column systems, measured from center-to-center of the supports, should not exceed 30 feet (10 m). • Spans should be approximately equal, and the shorter of two adjacent spans should be at least 80% of the larger span, except in elevator and stair cores. • There should be at least two spans in each of the two principal directions of the building in plan. Single spans may be permitted in one- and two-story buildings if the span length does not exceed 15 feet (5 m). • For girders, beams, and slabs with overhangs, the length of the overhang should not exceed 1/3 of the length of the first interior span of the member. • Buildings with offsets, reentrant corners, and vertical and/ or horizontal irregularities are considered outside the scope of this Guide. • Additional limitations, including use and occupancy, can be found in Chapter 1 of the Guide. Simplicity in the design process, along with practical construction considerations, have been implemented throughout the Guide. An example of this is the limitations of bar sizes from #3 to #8 (3/8-inch to 1-inch nominal diameter) for both ASTM A615 and A706 (weldable reinforcement) grades. In addition, issues such as minimum development lengths and lap-splices are simplified to consist of one value equal to 50db. Given the simple types of structures considered in the Guide, this simplification also facilitates field installation without significantly impacting overall economy. One of the main features displayed throughout the document is the ability to convey the guidelines through wellconceived graphics. A sample graphic (Figure 1) shows that short descriptions have been inserted to explain the reasoning behind the drawing. Although this may be viewed as redundant to seasoned engineers, this information has been found extremely useful by young engineers and students.

prescribed floor lateral loads floor diaphragm lateral-forceresisting structural walls

Figure 2: Lateral-force-resisting structural system.

Brief Overview of Lateral-Force Resisting System Guidelines Within the scope of the Guide and in zones of low and no seismic risk, the total lateral story shear at any story should be distributed to the frames through the columns, and reinforced concrete walls are not required to resist lateral forces. In Moderate or High seismic risk zones, the Guide requires that 100% of factored lateral loads are resisted by reinforced concrete walls. These elements are proportioned through simple design guidelines that preclude the need for special analyses, including

slenderness and second order effects. Additionally, frames should be proportioned to resist a minimum lateral force equal to 25% of the factored lateral force in each direction in plan, to account for effects such as base rotation of the walls or a decrease in stiffness and strength due to inelastic response (Figure 2). Brief Overview of Floor Systems Guidelines

Several types of common concrete floor systems are covered in the Guide. These include both one and two-way systems as follow: • Flat plate and Flat slab, • Slab-on-girder system with and without intermediate beams, • One-way joist systems, and • Waffle slab system. Guidelines are also included for structural integrity for both perimeter and non-perimeter beams. Guidelines for minimum member thicknesses are included for deflection sensitive elements associated with the different types of floor systems mentioned above. ADVERTISEMENT - For Advertiser Information, visit www.STRUCTUREmag.org

STRUCTURE magazine

September 2012

Design Case Studies Developed By ACI 314 In order to assist engineers in the design of typical structures, ACI 314 developed three case studies based on actual designs. The case studies include a 16-level hotel in Illinois, a post-tensioned 6-level parking garage in California, and a 5-level posttensioned parking garage located in Maryland. The case studies consist of five sections that discuss: project information, structural analysis, member design and detailing, miscellaneous design and detailing, and sample drawings. The information presented in these sections is referenced to the provisions of ACI 318-05, and is organized to include detailed calculations with explanations intended to offer designers insight into the design of the particular structure. The case studies can be found in the Concrete Knowledge Center of the ACI website (www.concrete.org) where many other excellent technical resources on a variety of topics can be found. As current Chair of ACI Committee 314, I would like to thank the many volunteer members of this committee that have helped create and review the design aids produced to date. I would also like to recognize prior Committee Chairs, Luis Garcia and JoAnn Browning, for their leadership.▪

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This is the first of a two-part series examining the engineering and design of strawbale buildings. This part provides an overview of the structural system and best practices for the design and detailing of strawbale walls to resist in-plane lateral loads. The second part will address out-of-plane response, uplift, and support of gravity loads.

What is Strawbale Construction? Strawbale construction uses baled straw as stackable blocks in wall systems. Plaster is typically applied to the interior and exterior surfaces of the bales (Figure 1). Clay, lime, or cement-lime plasters may be used, often with reinforcing mesh. The bales, plaster, and mesh can work together to create a composite structural system, similar in concept and performance to a structural insulated panel (SIP). The plaster and its reinforcement form a skin that is strong, stiff, and durable, bonding to the softer bales and protecting them from moisture, fire, and wear. The bales brace the plaster skins against buckling and tie them together, forming a composite section capable of resisting out-of-plane loads. Strawbale wall systems are used as load-bearing walls and as infill in post and beam framing.

History Strawbale construction originated in Nebraska (Figure 2) in the late 1800s, shortly after the invention of baling machines. Some of these early buildings, over 100 years old, are still in service. The practice was abandoned in the 1940s, but enjoyed a rebirth in the American southwest in the 1980s. Interest spread rapidly in this rediscovered building method, valued for its resource and energy efficiency, and aesthetic qualities. Plastered strawbale walls have substantial structural capacity when properly detailed, both as load-bearing and lateral load resisting systems. Strawbale buildings now exist in 49 States, and variations of strawbale construction are practiced in

Structural PracticeS practical knowledge beyond the textbook

Figure 1: The essential components of a strawbale wall. Courtesy of David Mar.

Strawbale Construction

over 45 countries, in virtually every climate. There are over 500 strawbale buildings in California alone. U.S. strawbale buildings include residences, schools, office buildings, wineries (Figure 3, page 16), multi-story buildings, and large buildings (over 10,000 square feet in floor area). In many of these structures, strawbale walls are used as load-bearing elements or shear walls, even in areas of high seismic risk.

Testing and Research The testing of strawbale construction goes back to the early 1990s, and includes structural, moisture, fire, and thermal tests. Plastered strawbale

Part 1: Overview and In-plane Behavior and Design By Martin Hammer, Architect, Mark Aschheim P.E. and Kevin Donahue P.E., S.E.

Martin Hammer, Architect, and Kevin Donahue, Structural Engineer, have practices in Berkeley, California. Mark Aschheim is Professor and Chair of the Department of Civil Engineering at Santa Clara University.

An expanded version of this article, including references, is available online at www.STRUCTUREmag.org. The proposed code provisions along with an archive of important tests, research reports, and analyses of system behavior is available at www.ecobuildnetwork.org.

Figure 2: Simonton house, Nebraska, 1908.

STRUCTURE magazine

two-story limit for structural use of strawbale construction. The IBC review process continues through its final action hearings, scheduled for October 24-28, 2012.

Materials

Figure 3: A contemporary strawbale building. Ridge Winery, CA. Interior before plaster. Exterior finished. Courtesy of FreebairnSmith & Crane Architects.

walls have high thermal resistance (R-30 for a typical wall) and are very resistant to fire (full scale walls passed 1-hour and 2-hour ASTM E-119 tests). Moisture is the notable challenge for strawbale walls, but with good design, detailing, and maintenance, strawbale buildings can last indefinitely. Since 1993, wall specimen and component structural tests have been performed. These tests include vertical load-bearing, reversed in-plane cyclic, monotonic, and out-of-plane wall specimen tests, as well as component tests on bales, plasters, and mesh anchorage. A fullscale shake table test of a small building using a system tailored to post-earthquake Pakistan was conducted in 2009 at the University of Nevada, Reno.

Strawbale Construction and Building Codes Over the last 20 years, most strawbale buildings have been permitted under the alternative materials and methods section of the building code. Only New Mexico (1996) and Oregon (2000) have adopted statewide strawbale codes. In 1995, California legislated strawbale construction guidelines for voluntary adoption by local jurisdictions. Since 1997, nine cities or counties in four other states have adopted strawbale building codes. Most strawbale building codes are derived from the first such code, created for and adopted by the City of Tucson and Pima County, Arizona in 1996. Subsequent experience, testing, and

research have shown these codes to be greatly deficient. They are often too restrictive or not restrictive enough, and are silent on many important issues. In 2009, a strawbale code proposal was submitted by strawbale building practitioners to the International Code Council (ICC) in response to its request for alternative materials provisions to be considered for the International Green Construction Code (IgCC). The proposed section was included in the Second Draft of the IgCC but was subsequently disapproved in 2011, with opponents advising that strawbale construction belongs instead in the International Building Code (IBC) and International Residential Code (IRC). In January, 2012, a further developed proposal was submitted for consideration for the 2015 IBC. The proposal is based on testing results and 20 years of field experience by strawbale design and building professionals. The proposal includes a

Straw is an agricultural waste product remaining after the harvest of grains such as rice, wheat, barley and oat. Straw is baled after harvest, using mechanical baling equipment, at moisture contents less than 20%. Twostring bales are typically 14 x 18 x 36 inches. Three-string bales are typically 15 x 23 x 46 inches. Consequently, bale size, density and moisture content are fairly consistent. Typical densities are 7-8 pcf, resulting in a three-string bale weighing 75-80 pounds. A prescribed set of plasters are addressed in the proposed 2015 IBC chapter. Critical details (e.g. reinforcement, lap splices, anchorage, and sill plates) and design values are based on behavior observed in testing. So-called “hard” plasters use a binder of Portland cement with lime or with soil, or a binder of lime alone, while “soft” plasters use clay as a binder. Typical compositions of these plasters are described in Table 1 along with typical cube compressive strengths. Baseline compressive strengths relied upon for the development of allowable gravity loads and allowable shears are also shown in Table 1. Different types of mesh are recognized as plaster reinforcement in the proposed provisions. A high-density polypropylene mesh (e.g. Cintoflex® C) may be used to reinforce the soft plasters. A welded wire mesh (2-inch x 2-inch x 14 gauge) is recognized for use in both soft and hard plasters.

Behavior of Walls Under In-plane Shear In-plane shear tests were conducted to establish the reversed cyclic load-deformation behavior of strawbale walls designed and detailed for

Table 1: Plaster types and typical cube compressive strengths.

Plaster Type

Typical Composition (parts by volume)

Clay

1 clay: 1 sand: 1 straw 1 cement: 9 soil-sand

Soil-cement

Typical Range of Baseline Strength Compressive Strengths in Proposed (psi) Provisions (psi) 80–250

100

600–1500

1000

Lime

1 hydraulic lime: 3 sand

600 – 1400

600

Cement-lime

1 cement: 1 lime: 6 sand

1000–1600

1000

Cement

6 cement: 1 lime: 21 sand

1400–2400

1400

minimum cement: soil-sand ratio

STRUCTURE magazine

September 2012

(a)

(b)

lateral load resistance. Details were established using a capacity design philosophy to encourage ductile behavior in the field of the plaster. Walls made with reinforced clay and cement plasters were tested at full scale; a superimposed gravity load of 200 plf was applied. Figure 4a shows the recorded load-displacement response of Wall E, having cement-plaster skins, while Figure 4b shows the condition of this wall at a drift of 2.5%. The tests demonstrated that moderate ductility could be obtained without risk of loss of gravity support. The reinforced plasters provide a stiff load path on par with that available from wood shear panels. However, hold-downs are not needed because the reinforced plasters provide both flexural and shear resistance. Well-anchored, robust sills carry these loads to the foundation. In this way, the reinforced plasters act much like thin reinforced concrete walls, which are braced laterally by the straw. At low displacement amplitudes, flexural behavior was dominant, with tensile and compressive zones present on either side of a neutral axis. As imposed drift levels increased, the individual wires of

Design Parameters for In-plane Loading Allowable shears and seismic design parameters (R, Ωo, and Cd) were developed for use in wind and seismic design. Proposed allowable shears are provided in Table 2 (page 18). The allowable shears are for walls composed of two- or three-string bales having reinforced plaster on both sides of the wall. The derivation of allowable shears was constrained by the need to obtain elastic behavior under wind loading and to achieve seismic performance on par with other structural systems. The derivation accounts for differences in the ductility capacity of clay and cement plaster walls, limitations in the number of test specimens, the use of plasters having compressive strengths conforming to the proposed code minimums, and the use of different mesh reinforcement. R-factors for use in seismic design were developed by three approaches: a conventional approach that considers overstrength

STRUCTURE magazine

September 2012

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Figure 4: Behavior observed in a full-scale test of a strawbale wall built with reinforced cement plaster skins. (a) Load-displacement response. (b) Flexural cracks at a displacement of 2.40 inches (2.5% drift).

the mesh or their connections gradually failed, leading to a reduction in strength and the gradual development of rocking. At larger drifts, visible gaps between the individual bale courses opened and closed. Because the walls are relatively stocky (height to thickness ratios between 4 and 6 are common), and because the plaster skins help to maintain the vertical alignment of the bales, the soft strawbale core provides a redundant mechanism to support gravity loads as the skins fail. No sign of instability was apparent even through two cycles of drift to ±7%. Longer walls would be governed by shear failure rather than flexural failure. An 8-foot high by 8-foot 7-inch long strawbale wall was tested at Cal Poly San Luis Obispo. The plaster was restrained along its edges, forcing deformation predominantly in shear. Just as would be expected for a longer wall, the cement plaster skins failed in shear. Following the Vn = Vs + Vc formulation defined for reinforced concrete walls indicates Vc = 3.4√ƒ'c bw d, just above the nominal 3√ƒ'c bw d that would be accorded walls of this aspect ratio in ACI 318. This reference strength level is used to ensure that the proposed allowable shears, derived based on flexural behavior, are well below the true shear strengths.

VERTICAL LOAD TRANSFER INTO PLASTER SKINS BOX BEAM STAPLE MESH TO BOX BEAM

PLASTER APPLIED DIRECTLY TO BALES

MESH

Detailing for In-plane Loading A schematic wall section for a one-story loadbearing shear wall is shown in Figure 5. Along the base of the wall are 4x4 sill plates attached to the foundation with 5/8-inch diameter anchor bolts at relatively close spacing (as little as 2 feet). A gravel bed is used at the base of the wall, in between the sill plates, to provide both a capillary break and a vapor-permeable support surface for the bales. Along the top of the wall is typically a wood box beam, composed of plywood skins sandwiching horizontal 4x4s. The box beam provides for attachment of roof or floor framing and transfer of lateral loads into the wall. The mesh reinforcement is anchored at the top and bottom of the wall by stapling into the horizontal wood members. Typically, 16-gauge staples are applied diagonally over every wire intersection. Stainless steel staples are used when stapling into pressure-treated lumber; electro-galvanized staples may be used in untreated lumber. Alternatively, plastered straw bale walls may be used as infill within a post and beam system. In this application, lateral loads may be transferred

STRAW BALES

GRAVEL SUPPORT

4X4 PLATES WITH ANCHOR BOLTS

VAPOR BARRIER

PLASTER SUPPORT

STAPLE MESH TO PLATES

and ductility, a comparison with established materials (e.g. light-framed walls with wood shear panels), and initial FEMA P-695 analysis results. On the basis of available results, the authors recommend R = 3.5 for bearing wall systems and R = 4.0 for building frame systems. These can be used together with Ωo = 3 and Cd = 3 for bearing wall and Cd = 3.5 for building frame systems. Similar to other instances of allowable stress design, seismic forces should be multiplied by 0.7 while allowable design values should be increased by 40% for resisting wind loads.

DSA Architects - 7/2012 www.dsaarch.com

Figure 5: Schematic section of a loadbearing shear wall.

(a) STAPLE MESH TO BEAM AND BLOCKING

STAPLE MESH TO BLOCKING

PLASTER APPLIED DIRECTLY TO BALES

MESH

PLASTER

STRAW BALES

POST AS OCCURS

GRAVEL SUPPORT VAPOR BARRIER STAPLE MESH TO PLATES

DSA Architects - 7/2012 www.dsaarch.com

Plaster Thickness (min)

Plaster Reinforcement

Clay

1.5”

none

1.27

2.78

Clay

1.5”

2 in. by 2 in. high-density polypropylene

3.05

2.78

140

Clay

1.5”

2”x2”x14 ga.

4.10

2.78

180

1”

2”x2”x14 ga.

16.26

3.87

520

/8”

17ga. woven wire

10.18

3.87

330

/8”

2”x2”x14 ga.

13.97

3.87

450

/8”

17ga. woven wire

11.71

3.87

380

/8”

2”x2”x14 ga.

16.07

3.87

520

/8”

2”x2”x14 ga.

16.70

3.87

540

1.5”

2”x2”x14 ga.

17.45

3.22

680

Lime Lime

Cement-lime

Cement

PLASTER SUPPORT

APPLIED $

" S "

Plaster Type

4X4 PLATES WITH ANCHOR BOLTS

(b)

Table 2: Development of allowable shears.

Soil-cement

BEAM PER STRUCTURAL PLANS

Shear Strength Factor of (kips) Safety

STRUCTURE magazine

Proposed Allowable Shear (plf)

September 2012

Figure 6: Schematic infill shear wall sections. (a) One-story shear wall. (b) Detail at second floor. ! !

# "

into the wall as shown in Figure 6a. For two story construction, connections are designed and detailed to provide for load transfer from the upper level wall to the lower level wall via the first floor. In Figure 6b, blocking between the joists provides a load path between the -&)*/(&/.

000 '.%%-&) &,+ plaster skins, where the joists are perpendicular to the wall. Where the joists are parallel to the wall, a joist is provided under each 4x4 plate. Load transfer across the floor assembly must be provided. Plaster and mesh reinforcement on the exterior may be made continuous across the floor assembly with the mesh stapled to the rim joist and lapped as necessary.▪

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Construction Quality Management By Richard L. Hess, S.E., SECB, F. ASCE, F. SEAOC

efore construction physically begins, quality in construction depends on the architectural, structural and mechanical, electrical, and plumbing drawings that accurately convey the client’s intention to a contractor who is capable of constructing what is required. When a Mechanical Engineer designs an automobile, an airplane or a toaster, the cost for design will not have to be recovered in one unit. When a Structural Engineer designs a building or an industrial support structure, usually it will be only one of a kind. It has to solve a unique need of a client, based on site and time consideration that will not be duplicated. When the design involves an automobile, airplane, or a toaster, it will be fabricated or constructed under controlled conditions by people who are probably trained and supervised by the same people who employ the engineer. In the type of construction that we are involved with, the Structural Engineer usually does not know who will construct the item that was designed, or their ability to understand the plans. In addition, will they be supervised? Will they have access to the engineer on site when conditions change during construction or when something is unclear or missing on the plans? In many cases, there is a budgeted amount for structural engineering site visits and consultation with the contractor that is negotiated by the Architect with the owner. The Structural Engineer will not be paid for work with the contractor unless it is approved in advance by the Architect. I know this. I have lost work on jobs involving unknown site and existing construction conditions because I would not agree with some of these limitations. I have also witnessed large, difficult-to-resolve lawsuits that have resulted from the contractor proceeding because of a tight schedule, without input from the Structural Engineer to resolve unplanned-for problems. Construction quality, therefore, depends on many things that may be unforeseen and outside of the control of the engineer during design. However, the following question must also be raised: Does the engineer even want to understand the construction or the application of his or her design to the finished

product? Or does the engineer believe that responsibility extends only to the mathematical accuracy of his or her calculations, and that the drawings need only extend to the capacity of the CAD program used to produce them? Without understanding their role in construction quality, engineers will do nothing to assure it. Technology in all fields of engineering has advanced dramatically in the past two centuries; and it is advancing at an accelerated pace. While building and manufacturing performed in 1800 could be comprehended and performed by ancient Roman engineers, now it depends on scientific discoveries, mathematical developments, new synthetic materials, and precision tools, as well as enormous quantities of available energy that could not be foreseen even a few decades ago. This increase in the level of technology has created the need for specialization in design based on years of intense education. When the implementation of that design is performed in a controlled environment, such as a manufacturing assembly line, then there is a direct link for quality assurance to take place in the same process. In our case, however, the “implementation” consists of construction at an outdoor site, which is served by a unique set of utilities, weather, and existing traffic conditions, using material obtained by an independent contractor. The contractor may have never worked with these designers before, and his workforce may consist of individuals of varying experience and education. Then, quality assurance is more complex because it involves the actions of different parties who are not under the control of the design engineer; and then it depends on something more from the designer than specialized knowledge in structural analysis. In structural engineering, construction quality assurance requires a design based on constructability as well as structural analysis. It also requires the involvement of the Structural Engineer during construction. “Constructability” can be defined as the integration of construction knowledge and experience by the design engineer into the construction of the project. This is why mandatory Structural Observation site visits and reports by the

STRUCTURE magazine

September 2012

responsible Structural Engineer are necessary. Structural Observation does not take the place of regular inspection by the applicable governmental jurisdiction, nor of the other special inspection and testing personnel involved in Quality Control. Its purpose is to ensure proper interpretation of the construction documents and to detect and resolve questions of constructability before they become a costly problem. To summarize, what is necessary for obtaining quality in construction is an understanding of construction and implementation of constructability in design and the involvement of the Structural Engineer at the site during construction. Without both of these, there is no way to prevent or to control questions at the site before they become problems.▪ Richard L. Hess, S.E., SECB, F. ASCE, F. SEAOC is a consulting structural engineer in Southern California. Richard is a Past President of the Structural Engineers Association of Southern California and Chair, Existing Buildings Committee. He is a member the STRUCTURE magazine Editorial Board. He can be reached at RLHess@HessEng.com.

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Bridge Service Life Extension Study I-70 Blanchette Bridge Concrete Substructures By Christopher A. Ligozio, S.E., P.E., Scott T. Wyatt, S.E., P.E. and Ernst H. Petzold, P.E.

ridge rehabilitation vs. replacement decisions are more challenging when highway funding is scarce. For older, critical highway corridors, decisions are influenced by structural condition and capacity, durability of components, safety standards, future traffic projections, effects on environment, construction-related traffic disruption, and economic considerations. Service life evaluation methodology and diagnostic tools were applied to the 50-year-old concrete substructures of the westbound Blanchette Bridge, carrying I-70 across the Missouri River in St. Charles, Missouri. This article summarizes the substructure service life model and rehabilitation plan developed through a program of hands-on inspection, nondestructive testing, and methodical material sampling and testing. The plan provided a basis for achieving adequate performance for the rehabilitated westbound bridge over an additional 50 years of service life, meeting Missouri DOT project objectives.

Overview Traditional bridge management practice is often reactive to the needs of aging bridges. When routine inspection identifies that structural and durability conditions have degraded sufficiently, a more detailed inspection and study is sought and performed, to correct observed deficiencies. This reactive inspection/maintenance approach rarely addresses latent durability issues in a rational, cost-effective manner, and when applied in a rehabilitation context, tends to favor lower initial capital investment over lower life cycle cost options. When durability concerns are addressed, the method tends to favor full replacement over rehabilitation following extended periods of neglect. The 4,083-foot long, westbound I-70 Blanchette Bridge (Figure 1), consists of 23 steel girder and truss spans, supported on reinforced concrete piers. The structure was originally constructed in 1958 and underwent a significant rehabilitation in the 1980s, including deck replacement, substructure repairs, and strengthening. The bridge presently carries 70,000 vehicles daily. STRUCTURE magazine

Figure 1: I-70 Blanchette Bridge.

The reinforced concrete piers are comprised of a cap beam supported on two columns. Pier geometry varies along the length of the bridge. The substructure service life extension study was conducted by the authors, under contract with Jacobs Engineering Group, Inc. of St. Louis, MO, from July 2009 to March 2010. The Jacobs’ scope of work included inspection, preliminary and final design, and consultation during construction. The project will restore the condition of the older westbound bridge and develop a maintenance plan to provide a 50-year extension to its service life.

Inspection & Testing The field investigation consisted of a hands-on detailed inspection, nondestructive testing, concrete cover profiling, and concrete sampling and testing to document the condition of the concrete piers above ground, and above water. Inspection access to the piers was provided using a combination of aerial lifts, under-bridge inspection vehicles and work boats. Inspection revealed the condition of the piers was highly dependent on their location with respect to deck joints. Piers beneath continuous deck sections were generally in good condition, with minor, localized deterioration and isolated areas of delaminated concrete. Piers beneath or adjacent to deck joints had been subjected to deck runoff and were in poor condition (Figure 2). Significant cracking, localized to widespread spalling, and widespread areas of delaminated concrete (as much as 50% of area) were evident in these latter piers. Corrosion potential measurements were used to evaluate the likelihood of active corrosion (Figure 3). Measured potential values were in general agreement with the inspection results: piers away from deck joints indicated a high probability that no corrosion was occurring at the time of testing; measurements of sound areas of piers under or adjacent to deck joints indicated significant areas of active corrosion, signifying a strong potential for additional delaminations and accelerated deterioration in these piers.

September 2012

Figure 3: Measuring corrosion potential.

Figure 2: Pier Deterioration beneath deck joint.

During inspections, concrete cores were extracted from areas representative of sound concrete. In the laboratory, chloride ion concentration analyses of concrete samples indicated that in piers under or adjacent to deck joints, chloride ion levels at the depth of the reinforcing steel were higher than the threshold at which corrosion of embedded steel is known to initiate. Petrographic examination and compressive strength testing of the concrete cores demonstrated that outside of areas of observed damage, the concrete appeared sound and generally of good quality, with no additional durability concerns.

Service Life Evaluation Based on the project scope and plan, bridge operating environment and results of the inspection and testing program, the following parameters were candidates to pose potential vulnerabilities, which could impair the piers’ remaining service life (these were addressed during the service life study): • Concrete deterioration due to expansive reaction of siliceous aggregate with cement paste in concrete (ASR). • Concrete deterioration due to repeated cycles of freezing and thawing while concrete is wet. • Corrosion of steel reinforcement due to carbonation of concrete, which alters the protective qualities of concrete paste. • Corrosion of steel reinforcement due to the presence of chlorides. Of these factors, corrosion of steel reinforcement due to the presence of chlorides was found to be the controlling vulnerability. Remaining service life was estimated based on a statistical evaluation of measured cover depth and chloride content profiles. STRUCTURE magazine

High levels of chloride ion, in the presence of moisture and oxygen, result in corrosion of reinforcement, even in the highly alkaline conditions of non-carbonated concrete. The American Concrete Institute (ACI) Committee 201 specifies that water soluble chloride contents greater than 0.15% by weight of cement are likely to result in corrosion of reinforcement. Due to the observed differences in environmental exposure among substructure elements and variation in concrete cover, chloride content and reinforcement cover data were subdivided into 4 categories, based on statistical evaluation of results. Chloride content was evaluated for piers under joints separately from piers without joints, since chloride levels were an order of magnitude greater for piers under joints. Within each group of piers, critical cover depth (Figure 4, page 24) was determined separately for the cap beams and columns, as average cover in the columns was generally an inch greater than in the cap beams. Chloride migration and resulting service life was modeled from the normalized data using Fick’s second law of diffusion. Measured chloride profiles were used to calculate the diffusion coefficient, D, for each substructure element evaluated. The element-specific D value was used to calculate the time needed for chloride ions to reach the corrosion initiation threshold for the assumed concrete cover. Results of the evaluation demonstrated that chloride levels have reached critical values at the level of the reinforcement for both columns and cap beams of piers under joints. In these areas, it was inferred that the resulting corrosion of the reinforcement has reached critical levels. These piers had reached the end of their service life and require a significant rehabilitation to extend service life and maintain structural capacity. Estimated remaining service life of piers away from deck joints was better, requiring only minor to moderate rehabilitation, to achieve an additional 50 years of service life. Rehabilitation Options Given the difficulty and cost of full pier replacement and the adequate strength and durability qualities of core concrete, rehabilitation was recommended. For piers under continuous deck sections, rehabilitation recommendations include repair of observed damage, sealing of cracks, and application of a penetrating sealer to the full surface of the piers. Continued on next page

September 2012

The authors conducted a study and identified several PCP systems suitable for protection of reinforcement in existing structures. The team recommended use of a thermal spray zinc anode, applied to the full surface of the piers following repair of delaminated areas. It was determined that this PCP system could be used to save sound, but chloride contaminated concrete, with approximately $2 or 3 million in initial cost savings when compared to Option 1. The savings were offset by a reduction in likely service life, to approximately 20 years before the next rehabilitation. Selected Alternative

Figure 4: Collecting concrete cover profile data.

This approach would slow chloride contamination and result in an additional 50 years of service life for all elements. To achieve an additional 50 years of service life in piers under deck joints, a more extensive rehabilitation was necessary. Two rehabilitation options were evaluated, based on cost, constructability, and risk. Option 1–This alternative included removing all delaminated and chloride contaminated concrete to a specified depth behind the innermost bar level, replacing corroded reinforcement, and repairing with low permeability concrete. Chloride diffusion models were used to determine the required depth of removal beneath the innermost bar to protect reinforcement from the potential for migration of chlorides remaining in core concrete. The benefits of this approach are its practicality within the context of standard bridge concrete construction procedures, i.e., no need for advanced concrete additives, including corrosion inhibitors, resulting in low permeable concrete that is known to reliably provide good protection. This alternative’s principal drawback is the difficulty/cost of removing concrete below the innermost reinforcing bar level. Option 2–This alternative was developed as a lower initial cost option and involved removal and replacement of all delaminated concrete followed by implementation of an impressed current cathodic protection system. Cathodic protection can prevent corrosion in the presence of chloride contaminated concrete. This option provided a 50% reduction in the volume of concrete to be removed and replaced, but some chloride contaminated concrete would remain. Unfortunately, this option requires continuous maintenance of the active cathodic protection system for the life of the structure, to provide ongoing corrosion protection.

The DOT selected a combination rehabilitation approach that included both removal and replacement of the full concrete surface of chloride contaminated piers, including all chloride contaminated and deteriorated concrete to a depth of 1 inch below the rebar (consistent with DOT standards), along with the use of PCP consisting of anodes embedded in repaired concrete to provide added protection. Primary protection will be provided by the high-performance, low permeability concrete specified for replacement concrete. The use of PCP with a low permeability replacement concrete will result in low initial anode consumption rates as the concrete has a high electrical resistance. As chloride content increase over time, due to ongoing exposure to deicing solutions, the electrical resistance of the concrete will be reduced, resulting in increased effectiveness of the PCP. It is anticipated that the rehabilitated piers will provide an additional 50 years of service life, with minimal maintenance, exceeding the target established by the DOT.

Conclusion With proper modeling and application of statistical principles, service life-based evaluation techniques permit engineers to perform life cycle cost analysis, and reduce the cost of repairs and the overall life cycle cost of a structure. For the Blanchette Bridge, the service life evaluation resulted in a forecast of performance for the re-habilitated structure, looking ahead 50 years. By evaluating particular vulnerabilities in conjunction with potential rehabilitation alternatives, it was possible to more confidently project additional service life and tailor the rehabilitation to the needs of the piers, based on observed conditions. For piers in good condition, the team was able to justify minor rehabilitation. For piers at joints with significant levels of existing deterioration, the ability to evaluate the durability of rehabilitation options provided the State with critical information for selecting a rehabilitation scheme. This helped the owner effectively reuse the substructure, accumulating considerable bridge life cycle savings.▪

Value Engineering Study Alternatives Following review of the proposed alternatives, the DOT commissioned a value engineering study of the project, which identified passive cathodic protection (PCP) as a means to reduce costs by providing corrosion protection to the reinforcement in sound but chloride contaminated areas thus allowing this concrete to remain and reducing the amount of concrete to be removed and replaced by approximately 50%, compared to option 1.

STRUCTURE magazine

Christopher A. Ligozio, P.E., S.E. (chris.liqozio@kpff.com), is a Senior Engineer with KPFF’s Chicago Office. Scott T. Wyatt, P.E., S.E. (scott.wyatt@kpff.com), is a Senior Engineer with KPFF’s Chicago Office. He is an agency-certified bridge inspector, including fracture critical assessment, and an inspection team leader. Ernst H. Petzold, P.E. (ernest.petzold@jacobs.com), is a Senior Project Manager, Bridge Structures, in the St. Louis, MO office of Jacobs Engineering Group.

September 2012

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

October 1-6, 2012

Monday – Tuesday, October 1-2

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.

ICC-ES Committee Meetings: Environmental Committee on Monday. Evaluation Committee on Tuesday. NCSEA Board Meeting on Tuesday afternoon.

Wednesday, October 3

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.

Concurrent Sessions Committee Meetings 8:00 – 12:00 NCSEA Board 8:00 – 12:00 CAC General Engineering 9:00 – 1:00 SECB Board 11:00 – 1:00 SEAKM Licensing 1:00 – 5:00 Advocacy 1:00 – 5:00 Basic Education 1:00 – 5:00 Structural Engineering Licensing Coalition (SELC) 1:00 – 4:00 CAC Wind Engineering 11:30 – 1:30 AZZ Plant Tour – Includes Lunch Vendor Presentations 1:40 – 2:10 2:20 – 2:50 3:20 – 3:50 4:00 – 4:30 4:40 – 5:10

Software Bentley Systems Fabreeka Internat. CSC World STRAND7 Pty Ltd RISA Tech.

Non-Software AZZ Galvanizing Services Fyfe Co. Inc. Vector Corrosion Tech. SidePlate Systems Hayward Baker

5:30 – 6:30 Kaplan/NCSEA SE Exam Review Course Social Hour 6:30 – 8:30 SECB Reception

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., 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

11:00 – 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 snow-load-related journal articles, and has been the recipient of several snow-loadrelated 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. 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 September 2012

4:30-5:00 p.m. – Speakers’ Forum

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.

Thursday Night, October 4

Friday night, October 5

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

2012 NCSEA Awards Banquet

Friday, October 5

7:00 – 10:00 p.m. – Banquet and Award Presentations The National Council of Structural Engineers Associations (NCSEA) will be announcing the 2012 Excellence in Structural Engineering Awards on Friday evening, October 5, during the 20th NCSEA Annual Conference in St. Louis, Missouri. Three awards will be given in eight categories, with one project in each category being named the Outstanding Project. Categories for 2012 were as follows: • New Buildings under $10 Million • New Buildings $10 Million to $30 Million • New Buildings $30 Million to $100 Million • New Buildings over $100 Million • New Bridge and Transportation Structures • International Structures • Forensic / Renovation / Retrofit / Rehabilitation Structures • Other Structures

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.

6:00 – 7:00 p.m. – Reception

8:00 – 9:45 a.m. – Roll call and Member Organization Reports 10:30 – 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 WoodFrame 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). • 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. 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.

Delegate Meeting – Saturday, October 6, 2012 7:00 am 8:00 am 8:15 am 8:30 am 8:55 am 9:10 am 9:25 am 9:40 am 10:05 am 10:20 am 10:35 am 10:50 am 11:05 am 11:15 am 11:30 am 12:00 pm 1:30 pm 2:00 pm

Breakfast and Presentation by Sponsor MO Roll Call Code Advisory Committee Report, Ronald Hamburger, Chair Advocacy Committee Update, Brian Dekker, Co-Chair Basic Education Update, Craig Barnes & Brent Perkins, Co-Chairs Continuing Education Update, Mike Tylk and Carrie Johnson, Co-Chairs SEER Committee Report, Scott Nacheman, Chair Licensing Committee Report, Susan Jorgensen, Chair Morning Break Publications Committee Report, Tim Mays, Chair YMG Scholarship Award Winner, Heather Anesta Executive Director Report, Jeanne Vogelzang SECB Report, Bill Warren, Vice Chairman Treasurer’s Report, Barry Arnold, Treasurer Communication and Partnering Ad Hoc Committee, Jim Malley, Chair Lunch and Discussion of Ad Hoc Committee w/ brief summaries Adjourn NCSEA Board Meeting

September 2012

49 50

COMSLAB®

Exhibitors

Food Station

Hercules Bolt

Pasta Station

NCSEA Twentieth Annual Conference

Food Station

35 Bar

American Institute of Steel Construction www.aisc.org

The AISC Steel Solutions Center (SSC) is the one-stop shop for the structural steel industry. The SSC answers technical questions and provides complimentary conceptual studies in structural steel for buildings and bridges. The SSC facilitates a file sharing and networking site (www.steelTOOLS.org) for the design and construction community.

AZZ Galvanizing Services www.azzgalvanizing.com

AZZ Galvanizing Service owns and operates 33 hot dip galvanizing plants strategically located across the US, with kettles ranging in size from 25 to 62 feet. They accommodate the largest projects with customized turnaround time at a competitive price. The company serves the after-fabrication steel market with corrosion protection.

Bekaert www.bekaert.com

Dramix® steel fibers, by Bekaert, are a practical alternative for traditional reinforcement. Its principle advantages are reduction in construction time, material and costs. Bekaert has received its ICC-ES certification for Dramix in concrete footings, slabs on ground, and elements. Dramix also meets the requirements of “steel fiber-reinforced concrete” per ACI318.

Bentley Systems Inc. www.bentley.com

Bentley’s flexible and scalable products, including RAM, STAAD and ProSteel, allow seamless workflow of analysis, design, detailing, documentation, and BIM for building, plant, and civil applications. Completely integrated solutions are available for steel, composite steel, cold-formed steel, cellular beams, as well as reinforced concrete, post-tensioned concrete, wood, aluminum, and masonry.

Boise Cascade Engineered Wood Products www.bcewp.com

Boise Cascade manufactures/markets engineered wood products such as VERSA-LAM® LVL (Beams Columns & Studs), BCI® and AJS® series I-Joists, Glulam Beams and Laminated Structural Decking. 60+ distributors across North America allow us to offer innovative value-added products and services to the construction industry.

Cast Connex Corporation www.castconnex.com

Cast ConneX® products and services simplify the design and enhance the performance of structures by enabling architects and engineers to implement cast steel components into their structural systems. Cast ConneX products and services include High-Strength Connectors™, Universal Pin Connectors™, Scorpion Yielding Connectors™, and Custom Components.

CMC Steel Products www.cmcsteelproducts.com

CMC Steel Products manufactures the cellular and castellated SMARTBEAM® – an innovative, economical and sustainable alternative for floor and roof framing systems. Manufactured from recycled materials, the beams are lightweight, have superior deflection properties, and can integrate MEP systems through the web openings. SMARTBEAM® – The Intelligent Alternative

COMSLAB http://bmp-group.com

The ComSlab System from Bailey is a two hour fire rated, structurally superior composite floor. ComSlab will accommodate all wall systems including lightweight steel framing, structural steel, masonry or poured concrete, insulated concrete forms or wood framing construction. It is a proven, reliable, and cost-effective composite steel deck.

15 Restroom

Registration

Construction Tie Products www.ctpanchors.com

CTP designs and produces masonry anchoring products used for the restoration and construction of masonry buildings. Product lines address retrofitting existing masonry and stone facades with non-obtrusive anchors that stabilize the existing veneer. Wall ties and anchors are also produced. CTP, Inc is an American corporation.

Corebrace www.corebrace.com

CoreBrace buckling-restrained braces are a sustainable and cost effective solution to improve the seismic performance of structures. This highly ductile system has been used in hundreds of projects for earthquake risk mitigation. CoreBrace’s expert staff works closely with engineers, and the entire design and construction team, to meet their requirements.

CSC Inc www.cscworld.com

CSC has developed innovative structural engineering software for over 35 years. Tedds automates daily structural designs by providing a comprehensive library of calculations with the flexibility to create and customize calculations within Microsoft Word. Fastrak is the definitive software for the design, documentation and BIM interoperability of structural steel buildings.

Design Data www.sds2.com

Design Data’s SDS/2 software solutions provide automatic detailing, connection design, engineering information, and other data for the steel industry’s fabrication, detailing and engineering sectors. As a BIM software, SDS/2 allows for the sharing of data between all partners, reducing the time required to design, detail, fabricate and erect steel.

Dwyer Companies www.dwyercompanies.com

Dwyer Companies is one of the largest Foundation Repair, Waterproofing, Soil Stabilization and Concrete Lifting companies in the United States.

Ecospan-Nucor Vulcraft Group www.ecospan-usa.com

The ECOSPAN Composite Floor System by Nucor-Vulcraft is a light weight, economical open web steel structural system for elevated concrete floor construction requiring no shoring or temporary forming. ECOSPAN® utilizes over 80% recycled steel materials produced at Nucor Steel mills that will assist in obtaining LEED accreditation for buildings. ®

Euclid Chemical Company www.euclidchemical.com

The Euclid Chemical Company manufactures high quality concrete and masonry materials for new construction, concrete repair, and decorative concrete. We strive to be “demonstratively better” for our customers through cutting edge research, technical support and service, product training and an education-driven specification effort.

STRUCTURE magazine

September 2012

Fabreeka International, Inc www.fabreeka.com

Fabreeka’s experience in vibration control includes the dynamic response of steel fabrications and support structures. Services include measuring building floor vibration, displacement response of floors/mezzanines and modeling of structures to predict performance. Fabreeka’s capabilities include NASTRAN and finite element analysis programs to analyze the static and dynamic conditions.

Fyfe Co. LLC www.fyfeco.com

A leader in the manufacturing of advanced composites used for civil and structural applications. The Tyfo® Fibrwrap® Fiber Reinforced Polymer (FRP) system is used on concrete structures including bridges, buildings, industrial facilities and pipelines, is the only FRP system available in the world with an ICC ES Report, ESR-2103, which meets 2009 IBC standards.

Hardy Frames, Inc www.hardyframe.com

Hardy Frames Inc. manufactures and markets the Hardy Frame shear wall system, and is the leader in the pre-fabricated shear wall industry. The Hardy Frame system allows Building Design Professionals to economically and safely minimize wall space and maximize wall openings while resisting high wind and earthquake loads.

Hayward Baker www.haywardbaker.com

Hayward Baker provides geotechnical construction techniques for structural support, ground improvement, and earth retention. We assist structural engineers to ensure a solid understanding of our techniques and how they can best be applied to solve geotechnical problems. Hayward Baker is the #1 Excavation/Foundation Contractor, ranked by Engineering News-Record.

Hercules Bolt Company www.herculesbolt.com

Hercules Bolt has the experience and superior service to get the job done right and on timewhen your job demands precision, exact tolerances and consistent, top-quality products. Since 1998, Hercules Bolt has been a leading manufacturer and distributor of heavy fasteners and customized products for fabricators and contractors.

Hilti North America www.us.hilti.com

Hilti is a world-leading manufacturer of quality, innovative tools and fastening and protection systems. With more than 190 highly trained engineers and technical team members, Hilti provides both onsite technical expertise and back office support. Hilti also offers PROFIS design software to assist design, specifying consultants and professional contractors.

Simpson Strong-Tie www.strongtie.com

ITW Red Head www.itwredhead.com

ITW Red Head is America’s largest manufacturer of fastening products used in concrete construction. Since the invention of the original “self-drill” anchor in 1910 and the first “powderactuated tool” in 1947, Red Head has led the industry with time saving, high performance products.

Kaplan Architecture & Engineering Education www.kaplanaecengineering.com

Kaplan Engineering Education provides focused learning tools to help you pass the FE/EIT, PE, or SE Exam. Comprehensive learning systems with up-to-date review guides, online diagnostic materials, and live-online review courses help you to coordinate a successful study program.

Lindapter International www.LindapterUSA.com

Lindapter saves time and money with innovative products for Structural Steel Clamping and Hollow Structural Section Connections The Girder Clamp and Hollo-Bolt (AISC recognized Blind Bolt) challenge the need to weld or drill, a safe, high strength connection can be quickly achieved by clamping two structural steel sections together.

LNA Solutions www.LNASolutions.com

LNA Solutions provides Structural Steel Connection Solutions without the need of field drilling or field welding. These methods are very cost effective, especially in cases where secondary steel is added to existing structures. LNA Solutions provides full service design of your connection without additional charge. Call 888-724-2323 for consultation today.

Nemetschek Scia www.Nemetschek-Engineering.com

Looking to migrate to, or improve your 3D design workflows? Don’t miss this opportunity! Stop by and see how a new breed for structural design software is helping firms plug analysis and design into today’s 3D workflows, and allowing engineers to work iteratively with others on the design team.

Nucor-Vulcraft Group www.vulcraft.com

Vulcraft is the largest steel joist, girder and deck producer in the United States. We have 7 joist plants and 9 deck plants that service the entire US as well as Mexico and Canada. A division of Nucor, we share the same #1 goal of Taking Care of Our Customers!

Powers Fasteners www.powers.com

Powers Fasteners is a privately held company specializing in global marketing of quality anchoring and fastening products for concrete, masonry and steel. Powers has been providing innovative fastening solutions for more than 85 years. Powers can provide answers to all of your construction fastening needs.

RISA Technologies www.risa.com

RISA has been developing leading edge structural design and optimization software for over 20 years. Our products are used around the world for buildings, stadiums, bridges and everything in between. The seamless integration of RISAFloor and RISA-3D creates a powerful structural design environment, ready to tackle your next design challenge.

SECB www.secertboard.org

The Structural Engineering Certification Board was formed to identify those professional engineers with the additional education, experience, and skills that are particular to the practice of Structural Engineering.

St. Louis Screw & Bolt www.stlouisscrewbolt.com

St. Louis Screw & Bolt is one of the longest operating bolt manufacturers in the world, and one of the the only manufacturers who sells direct to Fabricators and Erectors. St. Louis specializes in manufacturing A325 & A490 bolts type I, type III, Hot Dip and Mechanical Galvanized finishes.

Star Seismic www.StarSeismic.net

Star Seismic designs and manufactures buckling restrained braces, the most rapidly growing seismic system. Not only do you get a superior seismic performance, but you save construction time and money as well. Let Star Seismic reduce your risk by assisting you through the design of your next project.

STRAND7 PTY LTD www.strand7.com

Strand7 is a sensibly priced FEA system. It comprises preprocessing (with CAD import, automeshing), solvers (linear, non linear, dynamic and thermal) and post processing. Release 2.4 has many new features include staged construction, new solvers including quasi-static for shrinkage and creep/relaxation problems.

TurnaSure LLC is the manufacturer of Direct Tension Indicators strictly adhering to the ASTM F959 Standard. TurnAnut™ DTI fastener is an ingenious new tensioning device linking a TurnaSure® DTI to an ASTM A563 DH nut. Now the nut, hardened washer and Direct Tension Indicator become one piece.

Unbonded Brace www.UnbondedBrace.com

Unbonded BraceTM is the original, and most widelyused buckling-restrained brace (BRB) in the world, with more than 20 years research and development and 1,000 projects worldwide. Now offering a trio of welded, pinned and bolted connections, Unbonded Brace (UBB), continues to set the standard for product quality and high-end applications.

Vector Corrosion Technologies www.vector-corrosion.com

Innovative solutions for concrete corrosion repair and protection include electrochemical chloride extraction, cathodic protection, and an array of galvanic protection systems like embedded galvanic anodes, galvanic jackets and activated arc spray zinc metalizing. Vector also provides corrosion evaluation, repair/mitigation services for posttension corrosion and temperature resistant composite strengthening systems.

Conference Hotel Hilton St. Louis Frontenac 1335 South Lindbergh Blvd. Saint Louis, Missouri 63131 Reserve a room online, linking from the NCSEA website (www.ncsea.com), or call 314-993-1100 and use group code NSES to secure a room at the group rate of just $102/night, good until Tuesday, September 11.

Airline Discount American Airlines: 5% discount for flights booked directly through their website aa.com. Use group code 2492BP. United Airlines: Tiered discount (2-10%). Use code ZNDX665898.

Airport/Hotel Shuttle Available at no cost: In the St. Louis Airport baggage claim area, use the courtesy phones to dial the St. Louis Frontenac Hilton (#20). Let the operator know that you are ready to be picked up. Reservations not required.

Free Time Options The hotel will be providing free transportation to the following:

SE Solutions, LLC www.LearnWithSEU.com www.FindYourEngineer.com

SE Solutions works to help companies involved in structural engineering in two key ways. First, we have a unique continuing education resource for structural engineers called SE University. Second, we have a business unit that helps companies find and hire highly talented structural engineers.

SidePlate Systems, Inc. www.sideplate.com

For more than 50 years, Simpson Strong-Tie® has led the industry in product solutions that increase the structural integrity of homes and buildings, making them stronger and safer. Products include Wood and Steel Strong-Wall® shearwalls, Strong Frame® ordinary moment frames, products for Cold-Formed Steel, and Simpson Strong-Tie Anchor Systems®.

TurnaSure, LLC www.TurnaSure.com

Steel frame solutions for structures in all design environments without CJP welds. With the advent of SidePlate FRAME™ connection technology, superior performance now comes with the least cost, saving time and money on virtually any project when compared to alternative structural systems, regardless of whether wind, seismic or blast/progressive collapse governs.

The Anheuser-Busch Brewery, offering a complimentary tour to introduce you to how Budweiser is crafted by following through the steps of the brewing process. The St. Louis Zoo, located on 90 acres in beautiful Forest Park and home to 655 species of animals, many of them rare and endangered (free admission). Shopping: Galleria Mall and West County Mall (10% off Macy’s coupon card available at registration). Metrolink train for reaching other St. Louis destinations, including the Gateway Arch.

STRUCTURE magazine

September 2012

Jumbo HSS Meets ASTM A500, CSA G40 Standards When a structure has greater demands, Jumbo HSS is the solution. New Jumbo HSS from Atlas Tube can be an economical alternative for concentric bracing, heavy column loads or long spans. For the largest offering of HSS in North America, look to Atlas Tube.

Design questions? Call 800.733.5683 to schedule a Lunch & Learn, or to speak with an Atlas structural engineer today! atlastube.com/jumbo-HSS

ConstruCtion issues

This article investigates the use of large ground assembly of stay-in-place (SIP) formwork, re-usable formwork support framing and reinforcing steel in 5-foot to 15-foot thick reinforced concrete power plant structures, in part to compress a project’s critical path via parallel construction at grade.

he heavy industrial formwork and shoring required for constructing up to 6-foot thick reinforced concrete, aircraft-protection-shield (APS) roof slabs and up to 15-foot thick turbine generator (TG) decks in large (up to 1600 Megawatt (MW)) power plants are some examples of complex construction found in the industry. Both examples are labor-intensive and schedule consuming. In addition, shoring of the thick APS roof slabs and domes to multiple slabs or the containment structure below, and shoring the thick TG decks to a base mat up to 100 feet below, results in a delay of mechanical and electrical construction until the shoring is removed. In addition to the labor-intensive shoring and formwork installation/removal, these structures are heavily reinforced, with multiple layers of large diameter reinforcing steel in each direction at both the top and bottom of the slabs and decks. Multiple layers of side bars are also required at the vertical faces of TG decks along with closely spaced reinforcing steel ties between the top, bottom and side layers. For TG decks, other associated tasks include the installation of work platforms, embedded plates and anchor bolts. From a financial perspective, power plant projects with the aforementioned structural components have enormous indirect costs and capital costs on the order of $100 million per month in the latter stages of the construction schedule. Thus, substantial commercial benefit may be achieved by focusing on schedule compression. One method of achieving this schedule compression is through the use of standardized, modular stay-in-place (SIP) formwork and re-usable formwork support systems in lieu of conventional formwork and shoring. Such approaches increase craft productivity with work at grade, and amortize the formwork support system over multiple repetitive uses on a site or at multiple sites. Notably, the ever increasing crane capacities (now on the order of 1000 tons at over a 300-foot reach) facilitate such construction methods. In this article, schematic designs are discussed for three specific applications: • TG decks in standardized nuclear, fossil, or combined cycle plants • Flat airplane-crash-resistant roofs for nuclear power plants and defense facilities

discussion of construction issues and techniques Figure 1: Conventional cast-in-place turbine generator deck (1,600 MW).

• Airplane-crash-resistant domes above containment structures The schematic designs involve groundassembled super-modules (up to 100 x 100 feet and 800 tons) comprising SIP formwork (or partial SIP formwork for TG decks), reinforcing steel, embedded plates, anchor bolts, work platforms, and a re-usable formwork support structure. Such ground assembly is performed in parallel with conventionally constructed adjacent areas, resulting in months of schedule savings. In the case of nuclear power plant APS structures, the schedule savings is typically for critical path construction activities. For TG decks, the modular approach may either facilitate critical path construction or, in the case of nuclear power plants, allow available craft to be shifted to the critical path Nuclear Island (i.e., containment and adjacent structures) construction. The designs are merely incremental improvements, using standard structural steel trusses, shapes, plates, and formwork in specific configurations. In addition, the designs extrapolate from Bechtel Power Corporation’s power plant floor modularization schemes used for pulverized coal projects for over 10 years. Specifically, shop-fabricated SIP formwork modules (up to 12 feet wide by up to 60 feet long) are used as permanent formwork components for the ground assembled “super-modules”.

Modular Stay-In-Place Formwork

Turbine Generator Deck Modules Figure 1 illustrates a 1,600 MW reinforced concrete turbine generator (TG) deck constructed with conventional cast-in-place techniques and discrete deck support columns. In addition to requiring an enormous amount of formwork and shoring, the conventional approach delays the erection of the adjacent turbine building bay. Although not visible, such TG decks are typically spring-supported, requiring 10-foot by 10-foot embedded plates on the deck underside at each deck support leg. continued on next page

STRUCTURE magazine

By James L. Ryan, P.E., Neha Gidwani, P.E. and Luis M. Moreschi, Ph.D., P.E.

James L. Ryan, P.E. is a Senior Engineering Specialist (Steel Structures and Modularization) at Bechtel Power Corporation. James can be reached at jryan@bechtel.com. Neha Gidwani, P.E. is a Senior Engineer at Bechtel Power Corporation. Luis M. Moreschi, Ph.D., P.E. is a Civil/Structural Supervisor at Bechtel Power Corporation.

Figure 2: TG deck with SIP formwork & re-usable formwork support system.

In lieu of conventional TG deck construction, a modular approach of large scale ground assemblies 60-foot by 60-foot, and 15 feet deep is used. These assemblies include SIP formwork, a re-usable formwork support system, access/work platforms, and the majority of reinforcing steel. With work at grade instead of 100 feet in the air, the modules are safer to construct, yet at a significantly higher craft productivity (i.e., on the order of 40 percent per a reference subcontractor). Figure 2 provides an isometric view of the TG Deck with SIP formwork and re-usable formwork support system. The shop-fabricated SIP formwork assemblies are up to 12 feet wide by 20 feet long. Shop welded WT-shapes stiffen ASTM A572, Grade 50 plate, ½-inch thick. The WT stiffeners are oriented parallel to the direction of the heavy reinforcing steel, such that any local void would have no impact on the gross section. These stiffened plate assemblies also function as embedded plates for commodity supports and deck support springs, mitigating direct field hours associated with discrete embeds. The stiffened plate assemblies, in turn, are supported by beams at truss work-points.

The maximum truss depth of the re-usable formwork support system is nominally 10 feet (dimensioned to the top and bottom chord centerlines) to facilitate shipment to the initial site and from site-to-site. This size typically precludes the need for a police escort. Stringent deflection criteria of L/1000 are used for all trusses. Templates above the trusses and top of deck are used for embeds to achieve/satisfy the TG deck supplier specified tolerance. The truss weights are reasonable, with a maximum member size of W14 x 68 for the deck shown in Figures 2 and 3. Access for jacking, spring adjustment/setting, and shimming is only required parallel to or perpendicular to the TG axis. Therefore, there is no interference with the outboard truss support brackets. Inboard truss brackets are removable to avoid any interference with mechanical equipment (i.e., condenser) installation. For clarity, Figure 3 provides an isometric view of the underside of the formwork support system. Due to the size of the modules, which encompass many TG deck beams, a large amount of reinforcing steel (including a large number of splices) may be installed at grade before lifting. Up to three layers

Figure 3: Isometric view of TG deck formwork support underside.

STRUCTURE magazine

September 2012

Figure 4: Isometric view of box truss-supported module (100-foot x 100-foot).

of reinforcing is typical for top and bottom layers of the TG deck beams, with up to two layers on each side. Closely spaced ties are required both horizontally and vertically. Thus, significant savings in field job-hours is achieved when mitigating work at 100 feet above grade. Using standard historical rates, modularizing large TG decks up to 1,600 MW is estimated to save on the order of $1M for a single application relative to conventional TG deck construction. Cost savings are nominally $5M when such a design approach is replicated at three sites, primarily due to the amortization of the formwork support structure. In addition to cost benefits, construction safety is increased with work mostly being performed at grade. For nuclear power plants, increased overall project schedule certainty may be realized by shifting available craft labor to the Nuclear Island construction from the Turbine Island.

Ground Assembly of Flat APS Roofs Flat APS roof slabs in standardized nuclear power plants and defense facilities require multiple layers of closely spaced reinforcing steel at the top and bottom, along with closely spaced ties. Construction also involves both installation and removal of formwork and shoring. Shoring may be of significant height with horizontal bridging (such as above spent fuel pools) or to multiple floors in other safety related structures. In addition, the shoring to multiple floors below interferes with the “open top” construction method, whereby large equipment and commodities are dropped from above prior to construction of the concrete slab immediately above. To mitigate costs and the schedule duration, an alternate design/build methodology

involves constructing large scale, ground pre-assembled roof super-modules up to 100 feet by 100 feet. As shown in Figure 4, these include modular SIP formwork panels (12 feet wide by 40 feet long), re-usable formwork support box trusses and reinforcing steel. The trusses are sized for truck delivery in two sections. The assemblies do not require removable formwork or shoring. The SIP shop-fabricated formwork panels consist of 3/8-inch thick plate (conforming to ASTM A572, Grade 50), WT stiffeners, and two parallel beams at their longitudinal edges. Shop fabricated SIP formwork panels on the two sides of the 100-foot by 100-foot module can be installed after the large module is set in place. Figure 5 provides a cross-section, illustrating how the SIP formwork panels are rod-supported from the trusses. Embedded couplers at the top of the concrete serve to permanently anchor the rods in the depth of the slab. In turn, these rods anchor the SIP formwork panels, including during a postulated aircraft impact. As such, the SIP formwork actually provides additional aircraft impact protection against scabbing of the roof slab. To confirm the cost effectiveness, the evaluation included finite element analyses and preliminary design. The top and bottom chords of box trusses for the nominal 100-foot span are W14x233, with W14x145 diagonals and verticals. For a single application of a formwork support system on a given 1600 MW plant, a nominal $1M premium is forecast. However, the approach is typically applied a minimum of two locations at any site, i.e., above the spent fuel pool and at least one other safety related building. When applied twice, the approach is cost-neutral. The approach has significant cost savings when applied to a second site. More

Figure 5: Cross-Section of box truss and rod hangers.

importantly, as construction is typically on the critical path, the schedule compression of up to two months may yield enormous savings associated with the cost of capital and indirect costs. The cited critical path construction schedule compression results both from expedited APS construction and the ability to perform “open top” construction.

Ground Assembly of Reactor Building APS Domes Construction of Reactor Building APS domes requires reinforcing steel placement and installation/removal of complex formwork/shoring systems in a confined space. To mitigate this issue, SIP formwork and a re-usable formwork support structure is evaluated. Design goals included: • Maximizing the module size, yet assuring the lift is within available crane capacities, • Mitigating the quantity of temporary shoring posts via detailed finite element analyses of the containment dome, and • Mitigating the quantity of shop fabricated SIP formwork panels. Figure 6 reflects the optimum framing selected from several configurations. The outside

diameter of a ground-assembled module comprising reinforcing steel, SIP formwork, and support steel that could be lifted as one unit was defined by a 100-foot outside diameter of reinforcing steel, as well as support steel and SIP formwork extending to a maximum dimension of 60 feet from the dome apex. The temporary support posts consist of a single post at the apex, 8 posts at 30 feet from the apex, and 16 posts at nominally 60 feet from the apex. The outer ring is constructed using SIP formwork and conventional rebar construction for fit-up with the vertical rebar of the cylinder. The support steel consists of a mix of nominally 6 foot deep plate girders and W44 shapes. Shop-fabricated SIP formwork panels use materials similar to the flat APS roof slabs. Static finite element analyses were performed using ANSYS software. Membrane and membrane plus bending stresses, as well as radial shear stresses in the concrete, were shown to be within code allowable limits. Ground assembly of APS domes appears to be warranted if the construction is determined to be on the critical path or if improving schedule certainty is desired. A commercial comparison was not performed, as it involves non-standard fabrication costs and specialty formwork supplier pricing. Instead, the evaluation is intended to define one optimized approach for future consideration.

Conclusions Significant cost, schedule and safety benefits may be achieved in standardized large power plants and defense facilities with the use of SIP formwork and re-usable formwork support structures. While not typically used in the past, industry developments since the previous generation of such large power plant units have made such approaches both viable and cost effective. These developments include increases in: crane capacities, material yield stresses, shop weld automation, and awareness of indirect costs and costs of capital in the early design stages of large projects.▪

Figure 6: Isometric view of proposed SIP formwork system with RSB APS.

STRUCTURE magazine

September 2012

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notable structural engineers

Great achievements

William LeMessurier Builder of Elegant Cutting-edge Structures By Richard G. Weingardt, D.Sc. (h.c.), P.E., Dist.M.ASCE, F. ACEC

t his zenith, William (“Bill”) James LeMessurier, Jr. (Figure 1) was known around the world as one of America’s most daring tall building designers. Based in Cambridge, Massachusetts, his firm’s list of outstanding projects included elite high-rises in all of the northeastern states and in many others scattered around the country. Internationally, several of his company’s more noteworthy projects were found in Egypt and in Middle Eastern countries like the United Arab Emirates, Saudi Arabia, Bahrain and Iraq. Although best known for skyscrapers, LeMessurier’s life-time body of work also included numerous civic and educational buildings, and a wide array of commercial and industrial facilities. According to William Thoen, a long-time personal friend and professional partner, LeMessurier was a Renaissance man who collaborated with architects in such a way that “his structural organization and economy showed through in the finished work. In many cases, Bill worked closely with the architect from the concept stages to final design so that the project, while still the architect’s design, had the subtle structural harmony of form that the problem called for. He had an exceptional talent for interfacing with architects to make even their most difficult designs feasible.” Additionally, said Thoen, “Bill loved teaching as much as engineering, and was always at his best with an audience. He was extremely intelligent, insightful and highly articulate, and if you got into a verbal argument with him you would surely lose, usually in the first round. He thought very carefully about whatever he said and was precise in his use of language. I think

that is what made him such a good leader, lecturer and teacher.” Bill was born on June 12, 1926 in Pontiac, Michigan, the youngest of four children of Bertha (Sherman) and William James LeMessurier, Sr., who owned a dry-cleaning business. After finishing high school, Bill left Michigan to major in mathematics at Harvard University, earning a Bachelor of Arts degree in 1947. He then studied architecture at Harvard’s Graduate School of Design, and received a master’s degree from Massachusetts Institute of Technology (MIT) in building engineering and construction in 1953. While at MIT, LeMessurier worked part-time for Albert Goldberg, an established Boston structural engineer with a good reputation. Shortly after receiving his master’s, LeMessurier joined Goldberg full-time. By the mid-1950s, he had become a partner and the firm was renamed Goldberg-LeMessurier Associates. In April 1961, the two separated, dividing up staff and clients, and Bill launched LeMessurier Associates. It began with a dozen engineers and draftsmen. In addition to 35-year-old LeMessurier, the new company’s partners were William Thoen, Emil Hervol and James Collins. Prominent among the firm’s early projects were elementary schools. From the very beginning, LeMessurier always gave his architectural clients innovative structural solutions whether projects were large-scale or minor in size. For example, on a small school gymnasium project, the architect wanted to match the gableroof shape and style of the other buildings on campus. Because the space was intended for basketball and other games, a deep ridgeline girder or tie rods at the knees of the frame were out of the question. Rigid frames were also

Figure 2: Exeter, New Hampshire, Athletic Center. Courtesy of Bill Thoen.

STRUCTURE magazine

September 2012

ruled out because of cost and the architect’s objection to sub-floor tie rods. The LeMessurier Figure 1: William J. solution? A funicu- LeMessurier. Courtesy of lar truss within both Bill Thoen. planes of the roof that spanned from end to end of the building, effectively taking advantage of the full depth of the slanted roof. Utilized in the system were laminated wood rafters, two continuous (draped and diagonally placed) flat steel bars secured to the rafters (one bar on each side of the roof) and a layer of plywood sheathing on top of the rafters (and steel bars) acting as a diaphragm. For the Exeter, New Hampshire Athletic Center and Ice Skating Rink (Figure 2), the goal was to give visitors a clear view into the activity spaces from a galleria along a central spine, without having to look though a ceiling cluttered with structural framework. LeMessurier put the structural frame on the outside of the building, and hung the roof from it. This achieved maximum structural economy because deep structural frames could be utilized. One of LeMessurier’s first and longest-lasting architectural clients was Hugh Stubbins, a promising architect just appearing on the national scene in the mid-1950s. Said Thoen, “There were not a lot of structural engineers in the area then, and Stubbins came to GoldbergLeMessurier one day for us to do an elementary school. As soon as Hugh and Bill met, there was a chemistry between them. Both were looking for excellence in their work. From then on LeMessurier became Hugh’s only structural engineer. Stubbins was sort of a destiny’s tot, and as his reputation grew, so did ours.” Representative of Stubbins-designed, highprofile skyscrapers engineered by LeMessurier were the 770-foot-tall Singapore Treasury Building (Figure 3, page 36) and the 920-foottall Citicorp Tower in New York City (Figures 4 and 5, page 36). The Treasury Building (aka Temasek Tower) has a round concrete spine or core that supports the entire weight of the building, from which the floors cantilever out 40 feet. One major element, its concrete tube, essentially provides all the required framing strength and rigidity needed for the entire building. The unique base column configuration of the Citicorp Tower came about because of an

Figure 4: Citicorp Tower, New York City. Courtesy of Wikimedia Commons.

Figure 5: Base of Citicorp Center tower. Courtesy of Wikimedia Commons.

unusual site constraint: St. Peter’s Church, which had sold its air rights but would not allow columns from any building above it to penetrate into its floor area. Instead, the new skyscraper’s four major corner columns were relocated to the center of the building’s four sides. From these side columns, the building edges were supported using large-scale chevron trusses. The building required a light steel structure and lightweight glass and aluminum curtain walls,

all of which had a very low mass. Although the building had sufficient strength, additional damping was needed to enhance structural performance and provide for better occupant comfort. A tuned-mass damper – the first use of such a damper in a major tall building – was the low-cost solution. In June 1978, shortly after Citicorp Tower was completed and occupied, a potential weakness was uncovered. If hurricane-force winds – 70

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Figure 3: Singapore Treasury Building (aka Temasek Tower). Courtesy of Wikimedia Commons/Sengkang.

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STRUCTURE magazine

September 2012

miles an hour or more – hit it at a 45-degree angle, the building might be unsafe or unstable. First alerted to the problem by a Princeton University senior-class engineering student, Diane Hartley, LeMessurier revisited his structural design. In doing so, he discovered another aggravating issue: The building’s vital chevron trusses, originally designed to be welded, had been joined with weaker bolted joints, a cheaper method substituted during construction to save the owner money. To eliminate the structure being vulnerable to a lethal problem from a severe hurricane and to provide for a higher factor of safety, LeMessurier oversaw a furious schedule of repairs in August 1978, in which drywall workers, carpenters and welders worked around the clock to strengthen and repair the flawed joints. Because of his quick actions in resolving the issue, stepping forward and taking responsibility whatever the consequences to himself or his reputation, most structural engineers today celebrate LeMessurier as an industry hero and a role model for ethics. David Fowler, the legendary University of Texas professor, reflects the general sentiment: “What LeMessurier did was absolutely the right thing.” In addition to Exeter, Singapore and Citicorp, representative of LeMesurier’s many other notable buildings are the National Air and Space Museum, Washington, DC; Dallas-Fort Worth Regional Airport, Texas; King Khalid Military City, Al Batin, Saudi Arabia; City Hall, Boston, Massachusetts; First Republic Bank Plaza, Dallas, Texas; Metro-Dade Administration Building, Miami, Florida; and Federal Reserve Bank, Boston, Massachusetts. Robert McNamara, co-founder of McNamara-Salvia, who joined LeMessueier

Richard G. Weingardt, D.Sc. (h.c.), P.E., Dist.M.ASCE, F. ACEC (rweingardt@weingarddt.com) is the Chairman of Richard Weingardt Consultants, Inc. in Denver, CO. He is the author of ten books, including Circles in the Sky: The Life and Times of George Ferris and Engineering Legends. His latest book, Empire Man, is about Homer Balcom, structural engineer for the Empire State Building.

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after receiving his master’s degree from the University of California at Berkeley, recalled LeMessurier’s skill in dealing with new engineers, especially with those like him having in-depth training in the use of the latest and greatest computer methods. “Bill took me under his wing and we applied this new technology to most of the new projects in the office. My experience working with Bill was certainly a highlight of my early career. He openly shared his experience and creativity, and I learned quickly the importance of looking at the total system from the start.” As time went on, LeMessurier developed a close association with the Harvard Graduate School of Design, and served in his later years as an adjunct professor who lectured Harvard graduate students on building design, emphasizing the need for a close relationship between architects and structural engineers. An avid reader, LeMessurier also enjoyed playing the piano, which he did expertly. Although not a sailor, he owned a speedboat, which he used to get from the mainland to his retreat island on Lake Sebago in Maine – and which he often liked to operate at high speeds. Originally called “Doctor’s Island,” LeMessurier’s private island was a quiet, remote, and out-of-themainstream place where he went to rest, relax and reflect. Inducted into the National Academy of Engineering (NAE) in 1978, LeMessurier was made an honorary member of the American Institute of Architects (AIA) in 1988 and an honorary member of the American Society of Civil Engineers (ASCE) in 1989. He was also the recipient of an honorary degree in engineering from Rensselaer Polytechnic Institute. Among his many other prized awards were the 1999 Kimbrough Award from the American Institute of Steel Construction (AISC), 1996 President’s Medal from ASCE and 1968 Allied Professions Medal from AIA. LeMessurier died on June 14, 2007, in Casco, Maine, at age 81. He was survived by his wife of 54 years, the former Dorothy Judd; by two daughters, Claire and Irene; by a son, Peter, a mechanical engineer; and by seven grandchildren.▪

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nOteWOrthY

ames J. Rongoe, Jr, P.E. passed away on Thursday, August 9, 2012 at Stamford Hospital. Jim received his B.S. from the University of Virginia and an M.S. from Columbia University. He completed graduate studies at Cornell University and Hofstra University and established his structural engineering firm, Rongoe Engineers, LLC, in 1980, which is where he 12dB102DbmStructuresBwAd.indd worked until the time of his death. Jim was the author of numerous technical papers and journal articles, and Ad holdssize: a U.S.4.75" patent x for5" a composite wide girder system. He chaired the Connecticut Code Advisory Committee, served on January technical committees of ASCE and AISC, and was 2012 a member of the Board of Directors of the James Merriam Delahay Foundation. Jim, James Delahay, and John Hooper were the first practicing structural engineers on the International Code Council Structural Committee; and Jim’s work on building codes on behalf of NCSEA earned him the first James Delahay Award. He was also honored with a Lifetime Achievement Award from the Structural Engineers Coalition of the American Council of Engineering Companies of Connecticut, marking his induction into the Connecticut Structural Engineers Hall of Fame. Jim is survived by his wife, Toni-Ann, two daughters, Christine Osborn and Catherine Rongoe, his son, Nicholas Rongoe, and two granddaughters. Jim served his profession as few do and made countless friends in the process. He was a gentleman, a scholar, an inventor, and a good engineer. He will be sorely missed by his family, his friends and the structural engineering profession to which he gave so much. Donations in Jim’s memory may be made to the Carl and Dorothy Bennett Cancer Center, c/o Stamford Health Foundation, 1351 Washington Blvd., Suite 202, Stamford, CT 06902, or the Whittingham Cancer Center, 24 Stevens Street, Norwalk, CT 06850.

STRUCTURE magazine

September 2012

CASE BuSinESS PrACtiCES

business issues

Too Many Codes Spoil the Design? Conflicts and Hidden Requirements Can Hurt You! By Kirk A. Haverland, P.E., SECB

tructural engineering is a profession that can give an individual engineer or an entire firm a wide variety of design experience. If you and your firm work in a practice that is fairly diverse in the types of clients and industries you serve, after several years you may be very competent in designing many structures from lightweight commercial or residential buildings to heavy industrial structures and several types in between. When you have this type of experience, you realize that in large part, a structure is a structure. Whether the floor system is designed for 500 psf or 50 psf, the mechanics are the same. And you learn the differences between types of structures and the relative importance of the various parameters that affect design. You know that the multi-story hospital in a high seismic zone is going to have a significantly different design and design complexity than the single level strip mall across the street from it, but you understand these differences and you can produce well-designed structures that serve their intended purpose. If presented with an opportunity to design a structure that is a little different, hopefully you spend some time researching the idiosyncrasies of industry practices, design requirements, different codes and standards etc. You may feel after this research that you are comfortable in taking on a project. Usually, if you have done your homework, you can be successful in producing a competent design even though you may not have experience in that specific type of structure. But not always. As structural engineers, we have codes that we use to guide us through the process. The codes have commentaries that usually clarify various code sections. Then there are different industry standards and practices that may or may not be codified or even written. This is the ground that can get us in trouble. If you do a lot of work with reinforced concrete structures you know that there are many more ACI codes and standards in addition to ACI 318. Not all of these codes and standards are updated on a regular basis, and in some there are significant conflicts between

current seismic code requirements and practices versus those that were in force when the specific code or standard was written. Logic would lead us to believe that using the most recently adapted building code would govern the design. Unfortunately, this is not always true. Let’s look at a real life example where a design was deemed inadequate due to conflicts in the owner-specified codes and standards to be used for design. These conflicts created a significant financial penalty for the design firm and the contractor that hired the design firm; so this is an example of why you need to be careful. The project was a design-build contract for a reinforced concrete chimney at a power plant. The design-build contractor had experience in both designing and constructing this type of structure. However, the contractor’s in-house staff was unable to perform the design because of their current workload, so they hired a sub-consultant they had used successfully on several other projects. The sub-consultant had staff with heavy industrial experience, including tall stack structures; the firm itself had not designed any tall concrete chimneys. The design of the structure was not overly complex; however, the project location dictated a seismic site class of F and yielded a seismic design category of E. The design parameters appeared to be fairly straightforward. The project specifications referenced the state adaptation of the 2000 IBC, ACI 307-98 Code Requirements for Reinforced Concrete Chimneys, and provided technical supplements for site meteorological data, seismic data and seismic design procedures. This is not intended as a criticism of ACI, it is simply the result of many different codes and standards, all written by different committees, where it is not always possible to obtain complete agreement on changes or updates. It is my understanding that ACI does recognize that conflicts exist and is working on updating those codes and standards that may be outdated.

STRUCTURE magazine

–Kirk A. Haverland

September 2012

The owner-specified design requirements stated that the seismic design was to be per the 2000 IBC as referenced in the state adaptation of the same, and the seismic forces were to be determined from the basic parameters in the site specific seismic data. Design forces and distribution were to be determined using a dynamic analysis and procedures listed in the “specified building code”. Load combinations were to be in accordance with the “specified building code”. The owner-specified design requirements went on to say that non-building structures were to be analyzed using either the equivalent lateral force method or dynamic modal analysis, but then stated that seismic design of reinforced chimneys shall use the dynamic response spectrum analysis method of ACI 307-98. At this point, it can be seen that there is a conflict. The state building code (2000 IBC) references ACI 318-99 and ASCE 7-98 which used NEHRP-97 for seismic criteria. ACI 307-98 references ASCE 7-95 which used NEHRP-94 for seismic criteria. The question then is which seismic criteria to use? The 2000 IBC states that the site specific response spectrum maximum considered earthquake is based upon a 2% probability of exceedance within a 50 year period. In Section 1616.6, the IBC requires a modal analysis procedure per Section 1618 using site specific response spectrum. A chimney is a non-building structure, so Section 1622.2.5 refers to Table 1622.2.5(1) which lists a response modification factor R=3 for chimneys. This section also states that the vertical distribution of forces is to be in accordance with Section 1618.5 – Modal Forces, Deflections and Drifts. One could therefore reasonably conclude that by following the state adapted version of the IBC requirements using a modal analysis and a response factor R=3, that you would be correct. Except there is the contract document reference to ACI 307-98 Code Requirements for Reinforced Concrete Chimneys. ACI 307, Section 4.3 Earthquake Loads, states that chimneys are to be designed by means of dynamic response spectrum analysis, and that the vertical component may be ignored.

It also refers to the outdated effective peak velocity acceleration maps of ASCE 7-95. Section 4.3.2, Dynamic Response Spectrum Analysis Method, requires a site specific response spectrum based upon a different return period (which in this case was corrected by specification), and does not indicate a value for the response modification factor (R), does not indicate a value for the seismic importance factor IE, and fails to give specific information on methods such as determination of base shear or distribution of vertical forces. The commentary on this section provides no additional information for the missing criteria either. In following the ACI 307-98 code, where does one look for the missing parameters? One would think that it would lead back to the owner specified design requirements and the governing building code, in this case the state adapted version of the 2000 IBC. Logically then, you can be fairly comfortable with complying with the 2000 IBC in order to satisfy the specified requirements. In this case, the site specific response spectrum was used, a modal analysis was used, and the seismic forces per IBC Section 1622.2.5 were used. The design

also complied with IBC Section 1622.2.4 regarding the seismic requirements for the material, which includes ACI 318-99. So, where is the problem? Apparently, for those “in the know” in the tall chimney design industry, a response modification factor of R=1.33 is typically used. This information is not codified in any way, and would obviously have a significant effect on the seismic forces used in the design. A construction inspector noticed a small issue in the field, which led to someone else questioning the design, which ultimately lead to the claim that the structure was not designed properly. This, even though the design and construction complied with the governing building code. The sub-contractor and engineer were forced to pay for the cost of strengthening the chimney to meet the forces from the lower unpublished R value. The main take away from this should be that you may need to dig deeper in doing your homework for some specialized designs that are in unique industries or, regardless of your abilities and experience, you still may get into trouble. If there are conflicts in the requirements for the project, get them resolved before starting to design; don’t pick ADVERTISEMENT - For Advertiser Information, visit www.STRUCTUREmag.org

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September 2012

the one you think is correct and merrily go on your way. The CASE National Practice Guidelines for Specialty Structural Engineers emphasizes the necessity to be on the same page as the Engineer of Record. While, in this particular situation, it may have been a little more difficult to do so, at least the issue would have been raised earlier in the process and then hopefully been resolved prior to construction. The goal of The Council of American Structural Engineers (CASE) is to promote excellence in structural engineering business practices and risk management. The tool presented in this article, National Practice Guidelines for Specialty Structural Engineers, was developed by CASE members who volunteer their time and expertise to advance the structural engineering profession.▪ Kirk Haverland, P.E., SECB is a Principal and Regional manager for Larson Engineering, Inc. Mr. Haverland resides in Oshkosh, WI and manages Larson Engineering’s Wisconsin operations. He can be reached at khaverland@larsonengr.com.

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September 2012

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SEAOI SE Exam Review Course October 25, 2012–March 28, 2013

the most comprehensive review courses available: 40 sessions, organized by subject area: Earthquake Resistant Design, Geotechnical Design, Structural Steel Design, Structural Concrete, Masonry, Bridge Design, Timber Design

Outstanding value in terms of cost per hour of class Web-accessible Continuing education credit available for most sessions Highly-qualified instructors with experience in practice and academia

The SEAOI Course is fully updated for the 16-hour structural exam. All courses are taught on Monday and Thursday evenings from 6:00–7:45 p.m. in downtown Chicago. The class is fully accessible via the Web. Participants can take the entire course or focus on specific areas.

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from past participants:

“I just wanted to take a quick minute to say THANK YOU for having an absolutely amazing SE Review course. I have taken the SE Exam a few times (the SE-2 exam was easy, but I could never pass the SE-1) and have taken review courses in the past … This course was absolutely wonderful.” “Both days I was able to walk out of the test and know that I passed the test. So now I will be able to get my Illinois SE license, and my company is very pleased.” “Thanks for all of the help in getting together my CEU’s. I really got a lot out of the course, and I will be recommending it to other engineers in my office.” “I have to say your review class was immensely helpful in passing the exam. During previous attempts to pass it I am sure I studied many things that were irrelevant. By concentrating on what was covered in the class I believe I made much better use of my study time.” “(I) just wanted to let you know that I received exam results over the weekend … I was successful, and I believe the review class was very helpful for me. Thanks to you & SEAOI for offering it via the Web.”

Visit www.seaoi.org to access the registration form or call the SEAOI office at 312.726.4165 x200 for more information.

award winners and outstanding projects

Spotlight

The Case of the Sagging Floors – What Engineers Should Know Best Presentation at the Structures 2012 Congress By Craig A. Copelan, P.E., M. ASCE and Joyce E. Copelan, P.E., M. ASCE, SEI Sacramento Section Chair At the SEI Structures 2012 Congress in Chicago, conference attendees selected the presentation they found to be the “Best of the Best” among those offered during the three days of technical sessions. This year’s winner for best presentation was “The Case of the Sagging Floors,” a panel presentation moderated by John Tawresey of KPFF Consulting Engineers, an engineering firm headquartered in Seattle. It is a multi-office, multi discipline firm with projects across the United States and around the globe. Mr. Tawresey is a licensed professional engineer in the state of Washington and a past president of the Structural Engineering Institute.

of the Masonry Society and chair of SEAW’s Professional Practice Committee. Mr. Tawresey’s background and interests, as well as the credibility he has gained through his years of service to the industry and profession, made him an excellent moderator for this panel discussion of a project that was the subject of a major construction claim. Because of the sensitive status of the claim, which has only recently been resolved, the presenters are not identified as a part of this article. They included the structural engineer, the structural engineer’s expert and the defense attorney who assisted with the resolution of the claim. The presentation covered the design and construction of an upscale high-rise condominium. The structure was framed in concrete with two-way concrete slab floor construction. Pressure from the developer to minimize cost demanded longer spans and thin slabs. The engineer used advanced analysis methods to meet deflection calculation requirements, using tools such as SAFE and the RAM Concept. Moreover, construction schedules were tightened, forms were pulled sooner, and reshoring sequences shortened. The project experienced short-term deflections that were inconsistent with the developer’s expectations and budgets. The floors required fill and grinding and, as a result, higher than expected costs resulted in a claim against the structural engineer. In this claim, forensic experts were willing to testify that the design engineer should have been using calculation methods other than what is prescribed by the applicable code or what is consistent with the modern standard of care used by practicing engineers when calculating deflections of two-way slabs. This is a situation many in practice today

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September 2012

could relate to; the presentation provided an insight into the resolution of a claim in an area of practice that was familiar to those in the audience. Because of his years of technical experience, enhanced by service within his community, Mr. Tawresey has developed skills in communicating complex subjects in a straightforward and clear manner. These skills allowed him to lead this session in a manner that the members of the audience were able to easily grasp and find relevant to their own work experience. This excellent panel presentation and the leadership provided by Mr. Tawresey in its development, is acknowledged by the professions in attendance by selecting it as the SEI Structures 2012 Congress Best Presentation.▪ Mr. Tawresey is looking for a professional practice liability story to be told at the next Structures Congress to be held in Pittsburgh, May 2-4, 2013. If you have a story that would be appropriate, he can be reached at johntaw@aol.com or 206-622-5822.

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riginally founded in 1960, KPFF Consulting Engineers has grown from an office with 20 staff to more than 900 since Mr. Tawresey joined the firm. His educational background includes a bachelor’s degree in civil engineering from Cornell University, where he graduated with distinction, and a master’s degree from Cornell University in Theoretical and Applied Mechanics. Mr. Tawresey’s first assignment after completing his education was with the Boeing Commercial Airplane group where he gained five years of valuable experience. He joined KPFF Consulting Engineers in 1973, and he became Chief Financial Officer and Vice President in 1976. During his tenure, the firm has experienced steady growth. Mr. Tawresey’s assignments in the Seattle area have included the curtain wall structural design of the Seattle Art Museum, the Starbucks Building, Washington Mutual Tower, and the First Interstate Center. Utilizing his experience in the development of reinforced brick panels and light-framed stone curtain wall panels, he taught structural masonry (CEE 455) at the University of Washington for more than 26 years. Mr. Tawresey has given back a great deal to his profession and the community during the course of his career, serving in various leadership capacities with ASCE’s Structural Engineering Institute, including a term as president of the Institute from 2001 to 2003. He was recognized by his peers in the Washington Society of Professional Engineers as their Engineer of the Year in 2011. Mr. Tawresey is keenly interested in the professional practice aspects of structural engineering, serving as president of the Structural Engineers Risk Management Council [SERMC], president

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NCSEA News

News form the National Council of Structural Engineers Associations

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President’s Report: Volunteer and Make a Difference! Thomas A. DiBlasi, P.E., SECB

It’s hard to believe that nearly a year has passed since the honor of being NCSEA President was bestowed upon me. In that short period of time, I have been amazed at the amount of work that has been accomplished by the many committees that form the backbone of NCSEA: • The Code Advisory Committee (CAC) under Ron Hamburger’s leadership has been extremely active as the development process for the 2015 International Code Council (ICC) has been getting underway. Between the various CAC subcommittees, 46 Code Change Proposals were developed and submitted to ICC for consideration. In addition, the subcommittees reviewed 445 structuralrelated Code Change Proposals that were submitted by other organizations and individuals. During the two weeks of Code Change Hearings that were held in Dallas in May, three of the subcommittee chairs (Ed Huston, David Bonowitz and Kirk Harman) provided testimony on the NCSEA proposals, as well as many of those other 445 proposals. • The Licensing Committee, chaired by Susie Jorgensen, continues to promote separate structural licensure throughout the country. While no new states adopted structural engineering practice acts this year, legislation was introduced in several states for the first time and other organizations are joining the movement. In June, NCSEA along with SEI, SECB and CASE, announced the formation of the Structural Engineering Licensure Coalition, to provide a unified voice in support of structural engineering licensure. • The Structural Engineers Emergency Response (SEER) Committee, led by Scott Nacheman, completed the second edition of the Structural Engineers Emergency Response Plan (available for download from the NCSEA website). In addition, through an agreement with the California Emergency Management Agency, NCSEA delivered the Safety Assessment Program (CalEMA SAP), a six-hour post-disaster assessment webinar that is one of only two post-disaster assessment programs that will be compliant with the requirements of the forthcoming Federal Resource Typing Standards for engineer emergency responders. This training will be offered by NCSEA on a semi-annual basis. • This year the Continuing Education Committee, under the leadership of Mike Tylk and Carrie Johnson, succeeded in scheduling 19 continuing education webinars delivered by industry-recognized experts. In addition, the committee continues to make refinements to the SE Exam Review Course, developed in a partnership with Kaplan Education Services. Notably, the committee has established a new group pricing structure that will allow MOs to offer the review course to groups at a significant discount when compared to individual registration fees. Finally, the committee has been retooling the Winter Institute, transforming it from its historic technical roots to a more practice-oriented, leadership-development conference. • The Publications Committee, led by Tim Mays, has released its latest publication, “Inspection, Testing, and Monitoring of Buildings and Bridges” (available through ICC). By the Annual Conference, the committee expects STRUCTURE magazine

to complete and present the work of two additional new publications: “Guide to the Design of Serviceability of Building Systems: In Accordance with the 2012 IBC and ASCE 7-10” and “Design Guide on IBC Chapter 18 (Foundations)”. The STRUCTURE Editorial Board, under the stewardship of Jon Schmidt, continues to deliver outstanding issue after issue of STRUCTURE, securing its position as the definitive publication for the practicing structural engineer. • After a long tenure, Bob Durfee has handed over the reins of the Advocacy Committee to Rick Boggs and Brian Dekker. The Students and Educators Subcommittee has been developing a prototype PowerPoint presentation entitled “What is Structural Engineering?” that is intended for presentations to high school audiences. This presentation is expected to be released at the Annual Conference, will be available for download by the MOs, and will be customizable by the presenter. A new poster is under development, and some promotional videos have also been produced. The Clients and Prospects Subcommittee has developed a brochure describing structural engineering services to a lay-person. Although scheduled for release at the Annual Conference, this is already available and downloadable from the NCSEA website. MOs can use the PDF of the brochure, with NCSEA’s logo on it, or download the editable format and add their own logos. The Code Officials and Government Agencies Subcommittee has produced a couple of white papers to provide general guidance to code enforcement agencies, which it is planning to make available at the Annual Conference; and the General Public and Media Subcommittee is near completion of a “Working with the Media” PowerPoint presentation, to provide pointers for engineers who find themselves in the media spotlight. • The Basic Education Committee, under the leadership of Craig Barnes and new Co-Chair, Brent Perkins, has completed another structural engineering curriculum survey, encompassing data from over 200 colleges and universities throughout the country. The survey results are being compiled and are scheduled to be released in 2013. While the ultimate goal would be to encourage colleges and universities to increase their course offerings to include the basic minimum structural engineering courses recommended by the committee, this is clearly a long-term goal. Dependent on the survey findings, however, NCSEA is contemplating the development of a webinar series that will deliver the basic structural engineering coursework that is found to be most consistently lacking in the university offerings. All of NCSEA’s committees are composed of, and led by, dedicated volunteers. These volunteers are the heart and soul of NCSEA, and their commitment cannot be overstated. For those of you who volunteer on one or more of our committees….a heartfelt THANK YOU! For those of you who do not currently serve, I encourage you to get involved….give back to the profession…and make a difference for yourself and others! Help mold the future of NCSEA and the structural engineering profession! September 2012

We have a great program planned (see the Conference insert, page 26), sandwiched between an amazing number of interesting activities on Wednesday, October 3, and a fabulous Awards Banquet on Friday night, October 5. The business meeting, including breakfast and lunch on Saturday, is a requirement for Delegates, but it is also open to anyone else interested in hearing and talking about what’s happening with NCSEA. Please see this month’s NCSEA Annual Conference insert and visit www.ncsea.com to hear and see NCSEA Board members talking about why you shouldn’t miss this Conference.

2012 NCSEA Awards Banquet

News from the National Council of Structural Engineers Associations

OCTOBER 5, 2012 – The National Council of Structural Engineers Associations (NCSEA) will be announcing the 2012 Excellence in Structural Engineering Awards on Friday evening, October 5, during the 20th NCSEA Annual Conference in St. Louis, Missouri. Three awards will be given in eight categories, with one project in each category being named the Outstanding Project. Categories for 2012 were as follows: • New Buildings under $10 Million • New Buildings $10 Million to $30 Million • New Buildings $30 Million to $100 Million • New Buildings over $100 Million • New Bridge and Transportation Structures • International Structures • Forensic/Renovation/Retrofit/Rehabilitation Structures • Other Structures This will be a formal banquet, black tie requested, and is included for all Conference registrants.

NCSEA News

2012 NCSEA Annual Conference

NCSEA Past Presidents at the 2011 NCSEA Awards Banquet.

September 13 Webinar Design of Environmental Concrete Structures with ACI-350

September 2012

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The cost for this webinar is: $225 –NCSEA member, $250 – SEI/CASE member, $275 – nonmember, FlexPlan option available. Several people may attend for one connection fee. This course will award 1.5 hours of continuing education. The times will be 10:00 am Pacific, 11:00 am Mountain, 12:00 pm Central, and 1:00 pm Eastern. Approved in All 50 States

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from nearly 32 years of federal government service in various structural engineering positions that included over 23.5 years with the Fort Worth District Corps of Engineers (the last 11 of those years as Chief, Structural Design Section) and 8 years with the Natural Resources Conservation Service – National Design, Construction, and Soil Mechanics Center (Structural Engineer) located in Fort Worth, Texas. He received both his B.S.C.E. and M.S.C.E. from the University of Texas at Arlington (UTA), where he currently serves as an adjunct professor of structural engineering. Mr. Wallace, a registered P.E. (structural) in the state of Texas, was a member of the federal inter-agency task group on the Structural Analysis of Concrete Dams that developed analysis procedures for use by dam owners and regulators.

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This presentation by William Wallace, P.E., SECB, serves as an introduction to the ACI 350 Code and environmental engineering concrete structures. It will be an overview of the evolution of reinforced concrete design criteria for environmental concrete structures over the past 50 years, up to the current ACI 350-06 code. Comparisons between ACI 318 and ACI 350 will be made in a side-by-side format, to point out some of the major differences between the two ACI documents. William Wallace, P.E., SECB, is the structural discipline lead for the Fort Worth, Texas Office of Huitt-Zollars, Inc. Mr. Wallace joined Huitt-Zollars in September 2010 after retiring

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Structural Columns

The Newsletter of the Structural Engineering Institute of ASCE

Structural Engineering Institute Local Activities You are invited to join the events and activities of your local SEI Chapter or Structural Technical Group. Local groups offer a variety of opportunities for professional development, student and community outreach, mentoring, scholarships, networking, technical tours, etc. To connect with your local SEI Chapter or STG, visit the SEI Local Activities Division webpage at http://content.seinstitute.org/committees/local.html. If your ASCE Section or Branch doesn’t have an SEI Chapter or structural group, and would like to start one contact Suzanne Fisher at sfisher@asce.org. Some of the benefits of becoming an SEI Chapter include: • Use of SEI logo and branding • Funding for local Chair or their representative to attend SEI Local Leadership Conference. The 2012 SEI Local Leadership Conference will be held October 12-13, 2012 in Salt Lake City and includes main session meetings, a technical tour, a presentation on Accelerated Bridge Construction in Utah, and on Saturday, October 13 a Post Disaster Safety Evaluations Workshop sponsored by SEI and the ASCE Committee on Critical Infrastructure, in cooperation with the California Emergency Management Agency (CalEMA) and the Applied Technology Council (ATC).

ATC & SEI Advances in Hurricane Engineering Conference

• Discounted ASCE Continuing Education item sponsored by the SEI Endowment Fund • Chapter announcements published on SEI website and in SEI Update

Errata SEI posts up-to-date errata information for our publications at www.asce.org/SEI. Click on “Publications” on our menu, and select “Errata.” If you have any errata that you would like to submit, please email it to Paul Sgambati at psgambati@asce.org.

SEI/ASCE Student Structural Design Competition

Learning from Our Past Miami, Florida October 24-26, 2012

Professionals who design, engineer, regulate and build projects in hurricane affected regions will be welcomed to Miami, October 24-26, 2012 for the ATC-SEI Advances in Hurricane Engineering Conference. The cutting-edge technical program will focus exclusively on wind and flood design topics and bring together professionals from a number of different perspectives. Specific hurricane engineering topics include wind design using ASCE 7-10, building code changes in Florida and in the 2012 International Building Code, storm surge inundation modeling, discussion of wind pressure modeling using new wind tunnels, and more. Conference organizers recently confirmed Dr. Rick Knapp, new Director of the National Hurricane Center, as the keynote speaker in the closing plenary. Educational sessions will be given by industry luminaries such as Larry Griffis, P.E.; Chris Jones, P.E.; David Prevatt, Ph.D., P.E.; Ron Cook, Ph.D., P.E.; Scott Douglass, Ph.D., P.E.; Peter Irwin, Ph.D., PEng, and many more. Post-conference workshops and tours will also be available. Visit the conference website for more information at www.atc-sei.org/.

STRUCTURE magazine

2011 SEI Local Leadership Conference – Tour of USACE West Closure Complex, New Orleans

The Structural Engineering Institute of ASCE is proud to announce the winners of the 2012 Student Structural Design Competition. These three projects were presented at a special session of the Structures 2012 Congress in Chicago, Illinois. Each year SEI sponsors this competition to recognize excellence in structural engineering education and to encourage innovation. First Place Award Winner The Villanova University Team created a design for the US Rte. 67 Corridor Project–Jerseyville Bypass Bridge. Student team members: Matthew Bandelt, Stephen Kane, Scott Albarella, John Garland, Michael Mignella, and Louis Ross, with Faculty Advisor Zeyn Uzman. Second Place Winner The University of Colorado at Denver Team project was to design the Idaho Springs Maintenance Facility. Student team members: John Pettit, Jose Cordoba, Jeff Gee, Ramon Martinez, and Jeff Felling, with Faculty Advisor Peter Marxhausen. Third Place Winner The Milwaukee School of Engineering Team project was their design of the Sweet Water Organics Vertical Farm. Student team members: Austin Meier, Mark Peterson, and Stephanie Pichotta, with Faculty Advisor Christopher Raebel. For more information about the Student Structural Design Competition and the winning projects, visit the SEI website: www.asce.org/SEI. September 2012

2012 Electrical Transmission and Substation Structures Conference

The O. H. Ammann Research Fellowship in Structural Engineering is awarded annually to a member of ASCE or SEI for the purpose of encouraging the creation of new knowledge in the field of structural design and construction. All members or applicants for membership are eligible. Applicants will submit a description of their research, an essay about why they chose to become a structural engineer, and their academic transcripts. This fellowship award is at least $5,000 and can be up to $10,000. The deadline for 2013 Ammann applications is November 1, 2012. For more information and to download an application visit the SEI website at http://content.seinstitute.org/inside/ammann.html.

The Electrical Transmission and Substation Structures Conference is widely recognized as a one-of-a-kind conference that focuses specifically on transmission and substation structure issues to help utility engineers meet the daily challenges of today’s high-stakes energy environment. This must-attend event offers an ideal setting for learning and networking for utilities and suppliers. Visit the conference website for more information: http://content.asce.org/conferences/ets2012/index.html.

Columbus, Ohio November 4-8, 2012

Call for 2013 SEI/ASCE Award Nominations Nominations are being sought for the 2013 SEI and ASCE Structural Awards. The objective of the Awards program is to advance the engineering profession by emphasizing exceptionally meritorious achievement, so this is an opportunity to recognize exemplary colleagues. Nomination deadlines begin October 1, 2012 with most deadlines falling on November 1, 2012. Visit the SEI Awards and Honors page on the web at http://content.seinstitute.org/inside/honorawards.html for more information and nomination procedures.

Jack E. Cermak Award This award was created by the Engineering Mechanics Division/ Structural Engineering Institute to recognize achievements in the field of wind engineering and industrial aerodynamics. Norman Medal and J. James R. Croes Medal The Norman and Croes Medals recognize papers that make a definitive contribution to engineering science. Shortridge Hardesty Award The Shortridge Hardesty Award may be given annually to individuals who have contributed substantially in applying fundamental results of research to the solution of practical engineering problems in the field of structural stability. Ernest E. Howard Award This award may be presented annually to a member of ASCE who has made a definite contribution to the advancement of structural engineering, either in research, planning, design, construction, or methods and materials. Walter L. Huber Civil Engineering Research Prizes Up to five Walter L. Huber prizes may be awarded each year to help stimulate research in civil engineering.The prize recognizes notable achievements in research related to civil engineering and are often seen as helping to establish careers of the top researchers in civil engineering. Moisseiff Award The Moisseiff Award recognizes a paper contributing to structural design, including applied mechanics, as well as the theoretical analysis or construction improvement of engineering structures, such as bridges and frames, of any structural material. Raymond C. Reese Research Prize The Raymond C. Reese Research Prize may be awarded to the author(s) of a paper published by ASCE that describes a notable STRUCTURE magazine

achievement in research related to structural engineering and recommends how the results of that research (experimental and/ or analytical) can be applied to design.

Structural Engineering Institute Awards

(Contact SEI directly for more information on these awards. Visit the SEI website at www.asce.org/SEI.) Dennis L. Tewksbury Award The Tewksbury Award recognizes an individual member of the Structural Engineering Institute who has advanced the interests of SEI through innovative or visionary leadership; who has promoted the growth and visibility of SEI; who has established working relationships between SEI and other structural engineering organizations; or who has otherwise rendered valuable service to the structural engineering profession. Walter P. Moore, Jr. Award This award honors Walter P. Moore, Jr. for his dedication to technical expertise in the development of structural codes and standards. The award is made annually to a structural engineer who has demonstrated technical expertise in, and dedication to, the development of structural codes and standards. The contribution may have been in the form of papers, presentations, extensive practical experience, research, committee participation, or through other activities. Gene Wilhoite Award The Wilhoite Award recognizes an individual who has made significant contributions to the advancement of the art and science of transmission line engineering. The SEI Technical Activities Division Awards Committee makes recommendations regarding who should receive the Gene Wilhoite award. However, they seek the opinions of the members as to which papers are meritorious. If a reader encounters a paper that s/ he believes is outstanding for any reason, please convey this information along with a statement as to why s/he considers the paper exceptional to Susan Reid at sreid@asce.org.

September 2012

The Newsletter of the Structural Engineering Institute of ASCE

American Society of Civil Engineering Structural Awards

Structural Columns

2013 Ammann Fellowship Call for Nominations

CASE in Point

The Newsletter of the Council of American Structural Engineers

CASE is on LinkedIn LinkedIn is a great virtual resource for networking, education, and now, connecting with CASE. Join the CASE LinkedIn Group today! www.linkedin.com.

You can follow ACEC Coalitions on Twitter – @ACECCoalitions.

Earthquake Damage Assessment of the Washington Monument Headlines CASE Convocation at ACEC Fall Conference On August 23rd, 2011, one of the largest earthquakes to impact the east coast occurred along a fault line approximately 84 miles southwest of Washington, DC. Two iconic structures were seriously impacted by that event: the Washington Monument and Washington National Cathedral. Members of the project team for Wiss, Janney, Elstner Associates, who performed the damage assessment on both structures, will be at the CASE Convocation (held in conjunction with the ACEC Fall Conference) to provide an overview of their findings and the various treatment and restoration strategies that will guide the repairs. The CASE Convocation offers a full day of sessions on Monday, October 15 dedicated to best-practice structural engineering: 10:30 am Risk Management Essentials for Structural Engineers Randy Lewis, XL Group 2:15 pm Project Risk Management Plans Stephen Cox, GHD 4:00 pm Seismic Assessment and Repair Design: Washington Monument and National Cathedral Daniel J. LeMieux & Eric Sohn, Wiss, Janney, Elstner Associates, Inc. 5:30 pm Coalition Meet and Greet Other Fall Conference Highlights include: • Rich Karlgaard, Forbes Columnist & Publisher on Challenge of Private vs. Public Growth – Central Issue of Our Time • CEO Market Outlook on Energy, Water and Transportation STRUCTURE magazine

• Ron Insana, CNBC Senior Financial Commentator, on America’s Coming Economic Boom • Stu Rothenberg, Rothenberg Political Report Editor and Publisher, on Handicapping the November Elections • CEO Roundtables • 2013 Industry Economic Update • 30 Industry Education Sessions offering 21.5 PDHs

NEW AT FALL CONFERENCE The Young Professionals Forum

NEW! The Young Professionals Forum will feature a kickoff as well as a closing session, facilitated by industry consultants. In addition, those who qualify for and are registered for the Young Professionals Forum will have access to all of the other Fall Conference sessions and events. The tentative program of Young Professionals Forum sessions includes: • Monday, October 15, 10:30 am-11:45 am Strategies for Developing Leadership and Management Skills – Panel of ACEC Senior Executive Institute graduates, facilitated by SEI faculty • Wednesday, October 17, 8:30 am-9:45 am Next Steps for the Young Professionals Forum – Workshop and small group discussion on what was valuable learning at the Conference and how future Forum meetings should be structured, facilitated by SEI faculty Register now at www.acec.org/conferences/fall-12/ September 2012

National Practice Guidelines for the Structural Engineer of Record may be applicable to other project delivery methods like design/ build, integrated project delivery and fast tracked projects. It is CASE’s position that this document should not attempt to cover all of the nuances and differences associated with these alternative project delivery systems; rather, the basis of these Guidelines should be made clear to the reader. These guidelines are also based on the SER’s client being the prime design professional, typically the project architect. Sometimes, the SER may be contracted with the owner, the contractor, or even another consultant to the prime design professional. The SER’s client also typically has a client and the contract between those parties may directly impact the role and responsibilities of the SER. While these Guidelines are based on the SER’s client being the prime design professional, many of the described principles are applicable to the various different types of contractual relationships. It is CASE’s position that this document should not attempt to cover all of the nuances and differences associated with these different contractual relationships. CASE 962 (2012) is available for download online at www.booksforengineers.com.

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

Pay if Paid Some firms are lamenting the return of this provision into contracts and attribute its rise to the decline in the economy. Courts have both upheld and declared invalid these provisions. In some jurisdictions, they are illegal by statute. Some think this risk-shifting mechanism is bad for business and makes it easy to justify non-payment. Like any contract provision, it is negotiable. If you are in the subcontractor’s role, explore the possibility of contracting directly with the owner instead of the prime. You can also require in your contract with the prime that it will submit your invoices to the client in a timely manner or within a prescribed time.

Accommodating Employees Religious Beliefs Employers must reasonably accommodate employee’s religious beliefs unless it creates an “undue burden” according to the Equal Employment Opportunity Commission Compliance Manual www.eeoc.gov/policy/docs/religion.html#_Toc203359518. They must also comply with OSHA which requires a workplace STRUCTURE magazine

free of recognized hazards. Such accommodation may include altering workplace policies, dressing and grooming codes. Employers must show that there is a real safety risk if there is a conflict between religious beliefs and safety requirements. A prior workplace accident may dictate a decision. The employer must balance a worker’s religious beliefs against a safe workplace.

Engineering Expert’s Testimony Excluded An engineer was hired as an expert and gave testimony as to what was required to meet the standard of care for bridge construction. He mentioned several items that were not noted in the code or anywhere else. The court concluded that, although he was qualified to testify as an engineering expert, he was not qualified to give opinions about bridge construction traffic control. It was determined he drifted too far from his area of expertise. The Contracts Central website (www.contractscentral.net) provides a list of engineering expert witnesses including their specific areas of expertise. www.contractscentral.net/expertwitness/expert_witness_ listing.pdf.

September 2012

CASE is a part of the American Council of Engineering Companies

The purpose of these Guidelines is to give firms and their employees a guide for establishing consulting structural engineering services, and to provide a basis for dealing with clients generally and negotiating contracts in particular. Since the Structural Engineer of Record (SER) is normally a member of a multi-discipline design team, these Guidelines describe the relationships that customarily exist between the SER and the other team members, especially the prime design professional. Furthermore, these Guidelines seek to promote an enhanced quality of professional services while also providing a basis for negotiating fair and reasonable compensation. The Guidelines also provide clients with a better opportunity to understand and appreciate the scope of services that the structural engineer should be retained to provide. With the publication of the 2012 edition of these Guidelines, it is important to recognize that the Guidelines were developed originally on the basis of the traditional design/bid/build system of project delivery. This project delivery system continues to be the basis for the current edition. While these Guidelines are specific to design/bid/build, some of the described principles

CASE in Point

CASE Guideline 962 Updated For 2012

Structural Forum

opinions on topics of current importance to structural engineers

Developing the Next Generation of Structural Engineers Part 1: A Crisis of Opportunity

Note: This is the first article of a four-part series on the opportunities and challenges we face in developing the next generation of structural engineers. It is based on the author’s keynote address at the SEI Structures Congress in March 2012.

By Glenn R. Bell, P.E., S.E., SECB A Crisis of Opportunity A year ago, I was invited to join the SEI Young Professionals Committee, which is addressing issues of interest to future generations of structural engineers. The members of this committee have concerns that I share… Our business is becoming commoditized as computers and software are doing more of our work. We face the threats of global outsourcing and competition. Increasingly, we are having trouble attracting and retaining the best and brightest to our profession. At the same time, these young professionals yearn to tackle the future challenges of the world in a much more profound way than they are empowered to do today. While some may see this as a crisis, I prefer to see it positively, as a crisis of opportunity – a chance to change the practice of structural engineering in a profound way. This starts with developing a new breed of structural engineers, more broadly capable than ever before – more creative, collaborative, and communicative – to become global leaders in society’s grand challenges. The World of Future Engineering Generations

opportunities in this changed world. The massive population in developing countries will need affordable, sustainable housing and infrastructure on an enormous scale. There is a lot of building to be done! No. 2: Globalization In the future, our workplace will be worldwide. The global engineering workforce will be leveled. We already face offshore competition, much of it high in quality and lower in cost. But we also have more opportunities to work elsewhere in the world, especially in developing countries. For American engineers to compete internationally, we must become more mobile – more willing to travel to far-flung places. A globally flattened market means that engineers of the future will need breadth, both in technical and soft skills, to operate in many diverse locations and cultures. Perhaps most importantly, we need to be adept at collaborating on teams with members scattered around the globe. No. 3: Sustainability

To understand what this new breed of structural engineer will look like, I invite you to consider with me what the world of future generations will look like. I suggest that we glimpse about forty years ahead. This may seem like a long time from now, but it is actually within the likely career span of today’s engineering students. New World Reality No. 1: Developing Population By 2050, there will likely be about 9 billion people on our planet; 8 billion of them will live in developing countries. Pundits predict that, by 2050, the most prevalent language will not be English; it will be Chinese, followed by Hindi and Arabic, with English and Spanish vying for fourth place. Many domestic industries will not exist in their present forms. Ones that do exist may no longer be headquartered in the United States. The structural engineer of the future will need imagination to seek different business

We in the United States are consuming the earth’s irreplaceable resources at an unsustainable rate. If developing economies adopt our rate of consumption, we will bankrupt our planet of these resources in short order. While energy concerns are at the forefront of our public dialogue, the challenges are much broader. For example, a recent report by the United Nations projects that, within the next 20 years, virtually every nation in the world will face some type of water supply problem. Moving forward, the building and operation of all of our constructed works will require a drastically more responsible approach. Balancing quality of life with natural resources will be critical. No. 4: Climate Change Recent awareness of the impact of climate changes on natural hazards are causing us to question the efficacy of our criteria and approach for design against natural hazards, particularly wind, flooding, and sea level. This will drive us toward more flexible, performance-based

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, C3Ink, or the STRUCTURE magazine Editorial Board.

STRUCTURE magazine

September 2012

approaches. It also requires that engineers take leadership roles in major policy questions in hazards management, or even in some cases advising societies on where not to build. No. 5: Complexity Our large-scale civil/structural systems are becoming increasingly complex, and lessons from recent natural disasters like Katrina and Fukashima Daiichi have pointed out the vulnerability of such complex systems. To manage complexity, we need to understand systems engineering, and we need to be able to work better together on collaborative, interdisciplinary teams. No. 6: Knowledge Exchange and Global Competition Access to knowledge is enabling developing countries to educate high-quality engineers at an enormous rate. Many of them are able and willing to work very hard for a fraction of the wage rates within the United States. This means that, for the future, American engineers must offer added value through superior knowledge and skill. Our differentiators will be leadership, innovation, and entrepreneurship. No. 7: Technology This last point has perhaps the most significant impact on our practice. Advancements in computer techniques and simulation mean that we simply do not need the manual numbercrunching resources that we have supplied in the past. Sure, our engineers will need to be skilled in modeling and knowing how to extract correct and reliable results from simulations; but much of what we have been doing in the recent past will be done by machines in the future. This leaves us wondering what our roles will be. In the next article, we will consider the opportunities that these New World Realities present to future generations of structural engineers, and the attributes required to meet those opportunities.▪ Glenn R. Bell, P.E., S.E., SECB (GRBell@sgh.com), is the Chief Executive Officer at Simpson Gumpertz & Heger in Waltham, Massachusetts.

STRUCTURE magazine | September 2012

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