Steel Joist Institute Standards Open for Review
The 2015 draft of the Steel Joist Institute’s “Single Joist Standard Specification for K-, LH-, and DLH-Series and Joist Girders” will be available for public review until May 31, 2014. The consolidation effort of these three separate American National Standards (ANS) into one ANS will eliminate contradictions between the series and provide a simplified approach for the specifying professional.
These specifications will be available for download on the SJI website at http://steeljoist.org/ANSI along with the review forms. Please submit comments online, or by sending comments to Ken Charles, SJI’s managing director, at firstname.lastname@example.org by May 31, 2014, for consideration. Printed copies of the specification document also are available for $24 by calling (843) 407-4091.
Besides setting standards for the steel joist industry, the Steel Joist Institute works closely with major building code bodies throughout the country helping to develop code regulations regarding steel joists and Joist Girders. The Institute also offers a complete library of publications and other training and research aids. For more information, visit www.steeljoist.org or join the Steel Joist LinkedIn group.
CTBUH 2014 International Research Seed Funding
Submission Deadline: May 12, 2014
The Council on Tall Buildings and Urban Habitat is pleased to announce the Call for Proposals for its 2014 International Research Seed Funding – culminating with an award of US$20,000 to be recognized at the 2014 International Conference, to be held in Shanghai, China from September 16-19, 2014. This seed funding has been made possible with the kind support of ECADI, through the Shanghai Conference Gold + Research Seed Funding Sponsorship Package.
The goal of the CTBUH research seed funding is to assist researchers in developing projects/ideas to a level to secure additional, more significant, funding – in conjunction with the CTBUH.
Research proposals should directly relate to the tall building typology and/or urban habitat, but can come from any topic/discipline – including but not limited to: architecture, construction, energy issues, energy harvesting, environmental engineering, facades, financial & cost issues, fire & life safety, geo-technics, humanities, infrastructure, interiors, maintenance & cleaning, materials, MEP engineering, policy making, resource management, seismic, social aspects, structural engineering, systems development, urban planning, vertical transportation, wind engineering etc. There are no institutional or geographic restrictions.
A non-exhaustive list of possible research topics is provided in the “Roadmap on the Future Research Needs of Tall Buildings”, produced by the CTBUH in conjunction with UNESCO and CIB, and available free at www.ctbuh.org/roadmap.
See the 2013 research seed-funded project winner announcement here.
See the 2012 research seed-funded project winner announcement here.
See the 2012 research seed-funded project final paper here.
Proposals should use the proposal template form (download here) and are due by May 12, 2014. Submissions or questions should be submitted to email@example.com.
Visit the CTBUH Website to Learn More
2013: Second-Busiest Skyscraper Year in History
The tallest 20 buildings completed in 2013
The Council on Tall Buildings and Urban Habitat (CTBUH) has released its annual report, the 2013 Tall Building Data Research Report, part of the Tall Buildings in Numbers data analysis series.
By all indications, the small increase in the total number of tall-building completions from 2012 into 2013 is indicative of a return to the prevalent trend of increasing completions each year over the past decade.
Tall buildings 200 meters or taller completed each year from 1970 to 2014.
Insert: Total Number of 200m+ Buildings in Existence
Key findings of the report include:
- 2013 was the second-most successful year on record for completion of buildings 200 meters or greater in height. In 2013, 73 such buildings were completed, second only to the 81 completions of 2011. In 2012, the number had dropped slightly to 69.
- For the fourth year running, nine “supertall” buildings of 300 meters or greater were again completed in 2013. These 36 supertalls, built over the last four years, comprise nearly half the total number of supertalls that now exist (77).
- Of the 73 buildings completed in 2013, 12 buildings – or 16 percent – entered the list of 100 Tallest Buildings in the World.
- For the sixth year running, China had the most 200-meter-plus completions of any nation, at 37 – located across 22 cities.
- The tallest building to complete in 2013 was the 355-meter JW Marriott Marquis Hotel Dubai Tower 2 in Dubai, UAE.
- Three of the five tallest buildings completed are in the United Arab Emirates, for the second year in a row.
- Europe has two of the 10 tallest buildings completed in any given year for the first time since 1953.
- Of the 73 buildings over 200 meters completed in 2013, only one, 1717 Broadway in New York, was in the United States.
The tallest buildings completed each year, 2000-2013
The Tall Buildings in Numbers data analysis series takes a statistical and graphical look at various topics related to tall buildings, such as height, function, geographical location, energy requirements, structure and others.
In addition, at the close of each year, the CTBUH produces a study which provides a written and graphical synopsis of tall buildings completed during the subject year, with a focus on buildings over 200 meters in height.
This synopsis is published annually in the first issue of the CTBUH Journal.
For more Tall Building information and statistics, please visit The Skyscraper Center.
View the Full Report Online
Download the Full Report
AISI Publishes Report That Examines Performance Of Individual Cold-formed Steel Components In A Building During A Seismic Event
Research provides new data focusing on CFS members, connections and systems
The American Iron and Steel Institute (AISI) has completed the first phase of a three-phase research program that will help fill a knowledge gap in understanding how cold-formed steel (CFS) members, connections and systems in a building perform during an earthquake. The research is being conducted by a team from the Structural Engineering and Materials Program at Virginia Tech, and the results of the first phase are published in a report titled: “RP13-2: Energy Dissipation of Thin-Walled Cold-Formed Steel Members.” A free download is available here (86 pages).
Traditional analysis and design procedures for cold-formed steel light frame buildings subject to earthquakes tend to focus on utilizing the strength of individual shear walls or diagonal flat strapped braced walls, which is adequate for providing protection against collapse during design-level seismic events. However, in order to make buildings more resilient and cost-effective, researchers need to better understand how the individual components making up these walls contribute to the performance of the whole structure.
Measuring how these individual components perform during seismic testing allows researchers to develop more accurate and computationally efficient design models. This first phase of the research examined the cyclic behavior and energy dissipation of cold-formed steel C-section structural axial and flexural framing members. Twenty-four axial tests and 24 flexural tests were performed to evaluate the energy dissipation characteristics of axial and flexural members experiencing global, distortional and local buckling deformations.
“The resulting data from this research was used to calibrate a hysteretic model that represents the full response of cold-formed steel C-section structural framing members,” said Bonnie Manley, P.E., Regional Director, Construction Codes and Standards and leader of AISI’s Seismic Code Team. “From the model, we are developing a toolbox of nonlinear elements that are capable of accurately simulating the seismic behavior of CFS members and their infinite number of possible configurations in cold-formed steel structures. The remaining two phases of the program will focus on connections and systems. When those are completed, the toolbox will be fully stocked with a suite of models that will greatly improve the accuracy of seismic analysis and performance-based earthquake engineering of CFS structures. The end result will be safer buildings and more design flexibility for design professionals.”
“RP13-2: Energy Dissipation of Thin-Walled Cold-Formed Steel Members” includes:
- A review of available literature that explores the cyclic behavior of axial and flexural members experiencing buckling,
- A description of the testing program,
- A summary of the experimental results of cyclic and monotonic tests of CFS axial and flexural members exhibiting local, distortional and global buckling, and
- The calibration of a hysteretic model that represents the cyclic response of CFS members.
AISI’s codes and standards work is conducted under the Construction Market Council of the Steel Market Development Institute (SMDI), a business unit of AISI, which oversees the industry’s investment in advancing the competitive use of steel by meeting the demands of the marketplace. For more information on SMDI’s Construction Market program, visit www.smdisteel.org.
ICC Rolls Out Cloud-Based Code Development Process
International Code Council Members and others with an interest in public safety in the built environment have begun to use the first version of cdpACCESS—the new, cloud-based tool built exclusively for ICC's code development process (cdp). Once referred to as remote voting, cdpACCESS is much more than that. With cdpACCESS, you can create code change proposals and submit them online. Code change proposals for ICC Group C for the International Green Construction Code are due by January 10. Go to cdpACCESS.com to experience cdpACCESS.
“The ultimate goal is to provide a superior way to develop codes and increase participation in code development,” said ICC CEO Dominic Sims, CBO. “We are confident that code development participants and public safety will benefit from cdpACCESS.”
In the coming weeks additional features will be rolled out in stages based on the steps in the code development process. These features will include:
- Online collaboration with one or many colleagues;
- View, download and print the Code Change Agenda;
- Online submittal of floor modifications at the Committee Action Hearing;
- Online vote on assembly floor motions following the Committee Action Hearing;
- View, download and print the Report of the Committee Action Hearing;
- Online creation and submittal of public comments to the Committee Action Hearing results;
- View, download and print the Public Comment Agenda; and
- Online voting on proposed code changes/public comments following the Public Comment Hearing.
All ICC Members are eligible to vote online on assembly floor motions. Only Governmental Member Voting Representatives and Honorary Members can vote on proposed code changes/public comments. cdpACCESS allows you to participate in code development from a computer or tablet, when you cannot attend in person.
ICC has extensively tested cdpACCESS on a wide variety of Windows and Apple computers and the iPad. cdpACCESS is designed for use on Internet Explorer, Firefox, Safari and Chrome. Internet Explorer version 7 and earlier versions are not supported. Analysis of ICC website traffic has shown this will affect a very small percentage of users.
cdpACCESS is now the way to submit code changes to the International Green Construction Code (IgCC) for the 2014 Group C Committee Action Hearings, April 27–May 4, in Memphis, Tenn. To provide participants additional time to become familiar with cdpACCESS, and due to the year-end holidays, ICC extended the Group C online code change submittal deadline to Jan. 10 from Jan. 6. Online voting on assembly motions made at the Committee Action Hearings will take place after hearings.
Support for cdpACCESS includes help by phone and email to answer questions, receive comments and suggestions, and report any system errors. The toll-free cdpACCESS hotline is 855-ICC-CDP-1 (422-2371); email can be sent to cdpACCESS@iccsafe.org. A schedule of free cdpACCESS webinars can be viewed at iccsafe.org/cdpACCESS. To see answers to questions about cdpACCESS, go to www.iccsafe.org/cdpACCESSQA.
CTBUH Affirms One World Trade Center Height
The Council on Tall Buildings and Urban Habitat convened its Height Committee on November 8th in Chicago to evaluate its criteria for determining the official height of buildings, and to rule on the official height of One World Trade Center in New York.
The Height Committee has reached a consensus that One World Trade Center’s height to its architectural top is 1,776 feet (541.3 meters).
Note, because One World Trade Center is still unfinished and has not received its certificate of occupancy, it cannot yet enter CTBUH rankings as a “completed building,” but its height is no longer in dispute.
This determination was made through examination of design and construction drawings, and continued through dialogue among the Height Committee’s 25 members.
“We were very satisfied with the detailed information presented by the team, in particular, that which affirmed that the structure on top of the building is meant as a permanent architectural feature, not a piece of functional-technical equipment,” said Timothy Johnson, Chairman of CTBUH and Design Partner at NBBJ.
“The design of One World Trade Center, as explained to us, reinforces its role as a symbol of resurgence on this important site,” said CTBUH Executive Director Antony Wood. “In particular, the spire which holds the beacon light, shining out at the symbolic height of 1,776 feet, is especially poignant – echoing the similarly symbolic beacon atop the Statue of Liberty across the water.”
New Edition Of The North American Specification For The Design Of Cold-formed Steel Structural Members Is Published
This edition supersedes all previous issues of the “Harmonized North American Standard”
WASHINGTON, D.C., November 12, 2013 – The American Iron and Steel Institute (AISI), in cooperation with CSA Group, today announced publication of the new edition of the North American Specification for the Design of Cold-Formed Steel Structural Members. This latest edition provides updated information from recent advances in research on cold-formed steel design. It supersedes all previous editions.
The North American Specification harmonizes cold-formed steel design technology across the United States, Canada and Mexico, allowing for faster introduction of new technologies as well as opening up the market for a variety of derivative products such as design aids and educational materials. The Specification includes a main document—Chapters A through G and Appendices 1 and 2—that is intended for use by all three countries. There are two country-specific appendices: Appendix A is for use in the United States and Mexico, and Appendix B is for use in Canada. The Specification provides an integrated treatment of Allowable Strength Design (ASD), Load and Resistance Factor Design (LRFD), and Limit States Design (LSD).
Reflecting ongoing research to develop new and improved information on the structural behavior of cold-formed steel members, the new edition includes the following additions and revisions:
- Addition of material standard ASTM A1063.
- Reorganization of all referenced ASTM material standards in accordance with the ranges of the minimum specified elongation.
- Addition of Section B1.3, Corner Radius-to-Thickness Ratios.
- Addition of Section B2.5, Uniformly Compressed Elements Restrained by Intermittent Connections.
- Unification of country-specific provisions on tension member design, which have been moved to the main body of the Specification.
- Revision of the reduction factor for combined bending and torsional loading.
- New provisions on combined shear and tension on arc spot welds and top arc seam sidelap welds.
- Provisions for determining the web shear strength using the Direct Strength Method, which is an alternative approach for determining the strength and stiffness of cold-formed steel beams and members.
- New design provisions for power-actuated fasteners, which are widely used in building construction.
The North American Specification is the result of a cooperative effort by AISI’s Committee on Specifications for the Design of Cold-Formed Steel Structural Members and the CSA Group Technical Committee on Cold Formed Steel Structural Members.
The new edition is designated as AISI S100-12 in the United States and is available for purchase on AISI’s website at www.steel.org. In Canada, this edition is designated as CSA S136-12 and is available for purchase on the CSA Group’s online store at www.shop.csa.ca. It has been approved in the U.S. by the American National Standards Institute (ANSI) as the American National Standard, developed in Canada by CSA Group, and endorsed in Mexico by Camara Nacional de la Industria del Hierro y del Acero (CANACERO).
ICC, NCSEA Guide Details Design for Serviceability Required by Code
Guide to the Design of Building Systems for Serviceability: In Accordance with the 2012 IBC® and ASCE/SEI 7-10 provides valuable guidance on areas of serviceability required by the code but not always specified. Co-published by the International Code Council and National Council of Structural Engineers Associations (NCSEA), this comprehensive guide includes a wide range of resources in a single document.
"The new guide is a must-have resource for all practicing engineers,” said Timothy W. Mays, Ph.D., P.E., Associate Professor at The Citadel and Chair of the NCSEA Publications Committee. “Common code provisions on serviceability are fully explained and practical applications for most building types are illustrated with completely worked out example problems."
In addition to being an essential resource for practicing professionals, educators can use the publication to teach upper-level structural engineering classes. It is also an excellent reference for the architectural or engineering design office, legal firms or other construction-related industry professionals who must be familiar with code requirements related to the serviceability performance of buildings.
“Serviceability design is a subject with few resources offering specific guidance to engineers on proper application of code requirements and how to approach the complex problems in the design of common building systems,” said John R. Henry, Principal Staff Engineer at International Code Council. “This guide fulfills this need by explaining the provisions with practical applications and actual building design examples. It is an essential resource for practitioners involved in structural engineering and building design.”
Author Kurt D. Swensson, Ph.D, P.E., LEED AP is an expert in his field with 26 years of structural engineering and project design experience with buildings varying in type, size and material. Dr. Swensson graduated Summa Cum Laude, with honors in Civil Engineering from Vanderbilt University and earned his M.S., Civil Engineering degree and his Ph.D. from the University of Texas at Austin. He has served on several technical committees involved with innovative steel structures, composite structures, and seismic design and has authored more than 40 publications and presentations on a local, national and international level.
Guide to the Design of Building Systems for Serviceability: In Accordance with the 2012 IBC® and ASCE/SEI 7-10 is available for purchase in hardcopy for $62 ($50 for ICC Members, Product Item #7071S12) or PDF download for $58 ($46 for ICC Members, Product Item #8950P293) directly from the ICC Store.
The International Code Council is a member-focused association. It is dedicated to developing model codes and standards used in the design, build and compliance process to construct safe, sustainable, affordable and resilient structures. Most U.S. communities and many global markets choose the International Codes.
Tall Buildings in Numbers: Vanity Height – The Use-less Space in Today’s Tallest Buildings
CTBUH has investigated the increasing trend towards extreme spires and other extensions of supertall (300-meter-plus) buildings that do not enclose usable space, and created a new term to describe this – Vanity Height, the distance between a skyscraper’s highest occupiable floor and its architectural top, as determined by CTBUH Height Criteria. Here are some key findings of the study:
- At 244 meters, the vanity height of the Burj Khalifa, Dubai, UAE, could be a skyscraper on its own – in fact, it would be Europe’s 11th-tallest building.
- The Burj Al-Arab, Dubai, UAE, has the greatest vanity ratio of any supertall building – 124 (39 percent) of its 321 meters is devoted to non-occupiable space above the highest occupiable floor.
- Without their vanity height, 44 (61 percent) of the world’s 72 supertalls would measure less than 300 meters – thus losing their supertall status.
- United Arab Emirates clocks in as the nation with the most “vain” supertall buildings, with an average vanity height of 19 percent.
- New York City, USA has two of the tallest 10 vanity heights, and is set to gain a third with the completion of One World Trade Center in 2014.
- According to CTBUH Height Criteria regarding telecommunications towers, a 50 percent vanity height would deem any structure a “non-building.”
- The “vainest” building overall in the CTBUH database, although not a supertall, is the Ukraina Hotel in Moscow, Russia – 42 percent of its 206-meter height is non-occupiable.
PCI Announces Winners of the Daniel P. Jenny Fellowships
Five $20,000 Fellowships Awarded for the 2013–2014 School Year
The Precast/Prestressed Concrete Institute has announced the recipients of the 2013-2014 Daniel P. Jenny Fellowships. The annual fellowships program accepts proposals applicable to precast/prestressed concrete that potentially contribute to the state of the art of precast concrete and impact the industry market.
Five proposals were selected for this year’s honor and awarded $20,000:
- University of Wisconsin
- "Fiber Reinforced Concrete to Provide Shear Capacity in Lightweight Hollow-Core Panels"
- Student: Lyle Milliman
- Faculty Advisor: Gustavo Parra-Montesinos
- Producer Support: Spancrete, Waukesha, Wis.
- Clemson University
- "Debris Impact Resistance of Precast Concrete Solid and Insulated Panels"
- Student: Behnam Naji
- Faculty Advisor: Scott D. Schiff
- Producer Support: Metromont, Greenville, S.C.; and Prestressed Casting Co., Springfield, Mo.
- Michigan State University
- "Use of Graphite Nanoplatelets Toward Enhancement of the Efficiency, Service Life, and Economy of Precast/Prestressed Concrete Products"
- Student: Amirpasha Peyvandi
- Faculty Advisor: Parviz Soroushian
- Producer Support: Kerkstra Precast, Grandville, Mich.
- Iowa State University
- "Understanding Dynamic Decay of Rocking Precast Concrete Members"
- Student: Dimitrios Kalliontzis
- Faculty Advisor: Sri Sritharan
- Producer Support: Oldcastle Precast, Fontana, Calif.
- University of North Carolina at Charlotte
- "Characterization and Case Study of Geopolymer Cement Concrete in Precast Structural Applications"
- Student: Maria Trejo
- Faculty Advisor: Brett Tempest
- Producer Support: Metromont, Greenville, S.C.
“PCI is proud to support student research in the precast concrete structures industry through the Jenny fellowships program,” said PCI President James Toscas, P.E. “This research enhances the development and refinement of the Body of Knowledge for our industry.”
The Daniel P. Jenny Fellowship program is designed to introduce graduate students to the precast/prestressed concrete industry through participation in meaningful research. Support from a PCI Producer Member (or members) is an essential part of the program and offers a unique opportunity for the graduate student to interact with the industry. Fellowships generally conclude with a master’s degree thesis and a summary paper published in the PCI Journal.
For more information about the fellowship awards, contact Roger Becker at (312) 360-3213 or firstname.lastname@example.org.
CTLGroup saddened by the loss of W. Gene Corley, Preeminent Structural Engineer
CHICAGO, IL (March 4, 2013) – CTLGroup is saddened by the news that W. Gene Corley, Ph.D., S.E., P.E., Senior Vice President, died on March 1, 2013 after a brief battle with cancer. With a legendary career that spanned over 50 years, Dr. Corley developed his structural engineering expertise at CTLGroup and its predecessor, the Portland Cement Association. His diverse work included applied research, structural evaluations and repairs, and structural forensic investigations.
Dr. Corley, dubbed the “preeminent expert on building collapse investigations and building codes” by the American Society of Engineers (ASCE), built his reputation as one of the world’s experts on structures damaged by natural and manmade disasters as he investigated some of the most notable building failures in recent U.S. history. As Team Leader, he directed the FEMA investigation into the September 11, 2001 collapse of the World Trade Center’s twin towers.
A recognized industry leader, Dr. Corley was at the forefront of the structural engineering profession and the development of building codes and standards. He served in key leadership roles of numerous technical and professional organizations. Gene was a Fellow of the American Society of Civil Engineers where he helped establish the Structural Engineering Institute and served as Chair of the Technical Council on Forensic Engineering. He was also a Fellow of the American Concrete Institute where he serviced as Chair of the Institute’s Committee 318, Structural Concrete Building Code. Gene was elected to the National Academy of Engineering in 2000, one of the highest distinctions accorded to an engineer, for his leadership in raising the standards of the engineering profession for building and bridge construction.
“The management and staff of CTLGroup want to acknowledge Gene’s contributions to the firm and his exemplary technical and professional accomplishments,” said Jeffrey L. Garrett, Ph.D., S.E., CTLGroup President & CEO. “Gene’s legacy in the structural engineering profession is unparalleled. He was an innovative thought leader who consistently contributed generous amounts of his time and knowledge to the profession.”
Dr. Corley’s leadership in the development of CTLGroup’s forensic engineering capabilities laid the foundation for CTLGroup to become the expert consulting engineering and materials science firm that it is today. Thanks to Gene’s example, CTLGroup’s thought leaders continue to apply their diverse expertise to solve our clients’ most challenging problems as CTLGroup grows, expands, and diversifies. Over the years, CTLGroup has broadened its capabilities, expert services and geographical coverage to serve significant markets within the engineering and materials science industries. The firm’s senior management and staff include many industry leaders, providing consulting and materials science expertise in such diverse markets as the Transportation Industry, Buildings & Facilities, Energy & Resources, Litigation & Insurance, Materials & Products, and Advanced Technologies.
APA Assumes Responsibility of ANSI Glulam Standards
The American Institute of Timber Construction (AITC) has transferred three American National Standards from AITC to APA with an effective date of January 1, 2013. The standards include:
- ANSI A190.1 – 2012 (previously ANSI/AITC A190.1) American National Standard for Wood Products, Structural Glued Laminated Timber, renamed to ANSI A190.1 under APA’s management,
- ANSI 405 – 2008 (previously AITC 405) American National Standard, Standard for Adhesives for use in Structural Glued Laminated Timber, renamed to ANSI 405 – 2008, and
- ANSI 117 – 2010 (previously AITC 117) American National Standard, Standard Specification for Structural Glued Laminated Timber of Softwood Species, renamed to ANSI 117 – 2012.
“APA has had a good working relationship with AITC for many years. We’re pleased to take the responsibility for these standards, which are vital to the glulam industry,” said APA President Dennis Hardman. “We’re taking steps to ensure a smooth transition of the standards committee and to provide uninterrupted support to the industry with up-todate product standards and design specifications.”
APA is a national standards developer accredited by the American National Standards Institute (ANSI) and has a long and extensive history in building codes and standards development activities. It serves, for example, as the sponsor for the standing committees of U.S. Voluntary Product Standard PS 1 for Structural Plywood, the consensus softwood plywood standard, and Voluntary Product Standard PS 2, the U.S. harmonized performance standard developed under the U.S.-Canada Free Trade Agreement. It has developed performance standards over the years for numerous products, including ANSI/APA PRP 210-2008 for engineered wood siding, ANSI/PRR 410-2011 for engineered wood rim boards, ANSI/PRG 320-2012 for cross-laminated timber, and APA PRI-400 for prefabricated wood I-joists.
APA also serves as a third-party quality auditing and testing agency. It is recognized as a certification body, inspection agency, and/or testing organization by the International Accreditation Service (IAS), Standards Council of Canada (SCC), U.S. Department of Housing and Urban Development (HUD), State of Florida, Miami-Dade County (Florida), New York City, City of Los Angeles, Japan and Dancert (for certification of APA member products in the European Union).
Tilt-Up Concrete Association Releases New Temporary Wind Bracing Guideline
MT. VERNON, IOWA – The Tilt-Up Concrete Association (TCA) – an international nonprofit organization that serves to expand and improve the use of Tilt-Up as the preferred building system – has announced the release of a revised guideline on Temporary Wind Bracing of Tilt-Up Concrete Panels During Construction.
According to Jim Baty, Technical Director of the TCA, the guideline is intended to provide a standardized method for the design and erection of a temporary bracing system for use during construction of a Tilt-Up structure. The current OSHA requirement requires that Tilt-Up concrete panels be temporarily braced to prevent panels from overturning or collapsing during the construction of a Tilt-Up structure. Since OSHA does not specify how to prevent Tilt-Up wall panels from overturning or collapsing, the TCA developed a temporary bracing guideline for use by the construction industry.
“The 2012 edition of the TCA Wind-Bracing Guidelines is a combination of technological progress in this industry and reassurance for the performance of these systems,” said Baty.
Baty noted that the industry was challenged when ASCE 37 identified it would change to adopt ASCE 7 pressures as it established the concern that bracing schemes may be under-designed for the resulting wind conditions. However, he noted, TCA’s engineering experts have been able to confirm that Tilt-Up bracing systems are sufficiently designed with today’s standards.
“This confirmation permitted us to move forward with recommendations for response design recommendations on slab thickness and integrating helical ground anchor systems to this more robust version,” he said.
The original TCA Bracing Guidelines, published in September 1994, suggested a temporary bracing design based on a minimum uniform lateral wind pressure of 10 psf., applied over the entire panel area. This was based on a 40-year history of bracing panels that were for the most part, shorter than 30-feet tall. TCA revised the document in 1998 to incorporate the analytical procedures contained in ASCE Standard 7-95, Minimum Design Loads For Buildings And Other Structures. This ASCE standard forms the basis for calculation of wind forces used in the design of wind force resisting systems in completed structures. The wind load provisions of section 6.0, ASCE 7-95 were followed in the design of temporary bracing for Tilt-Up panels during construction.
The application of ASCE 7-95 resulted in an applied lateral wind pressure that varies over and increases with the height of the panels. The 1998 guideline used a construction period wind speed of 70 mph as a minimum in the design of temporary bracing. This was based on a basic wind speed of 90 mph, with a fifty year mean recurrence interval and multiplying it by 0.78 to convert it to a construction period wind speed of 70 mph with a five year mean recurrence interval. This method also incorporated the 3-second gust speeds reported by the national weather service and other weather information services.
In 2005, TCA revised its 1998 wind-bracing guide to incorporate the provisions of SEI/ASCE 37-02, Design Loads On Structures During Construction. The SEI/ASCE 37-02 standard incorporates the design wind load requirements of the ASCE 7-95 standard, using a basic wind speed of 90 mph. For construction periods up to one year, the SEI/ASCE 37-02 standard specifies the use of an adjustment factor of 0.8 to be applied to the basic 90 mph wind speed. This adjustment results in a 72 mph construction period design wind speed, which is the wind speed recommended for design of the temporary bracing system.
The 2012 edition continues to base its design loadings on SEI/ASCE 37-02, however, the wind loadings are now based on ASCE 7-10 provisions. ASCE 37-02 will adopt the ASCE 7-10 wind provisions in the next revision to the publication. In addition, it is very likely that many, if not all local building codes, will endorse ASCE 7-10 in the near future. As such, the TCA decided to endorse ASCE 7-10 as the standard for temporary bracing of Tilt panels during construction.
The major changes to wind load provision of ASCE 7-10 include:
- Introduction of new wind speed maps to be used with a 1.0 load factor for LRFD design
- A 0.6 load reduction factor for ASD design
- Re-introduction of Exposure D in hurricane prone Regions
To purchase your copy of the new Guideline, visit www.tilt-up.org/resources. Considering the environmental impact and declining use of printed material, this publication is available solely in its digital form.
Public Comments Requested for Several MSJC Standards
The Masonry Standards Joint Committee (MSJC) has proposed revisions to the 2011 Edition of its Building Code Requirements for Masonry Structures (TMS 402-11/ACI 530-11/ASCE-5-11), Specification for Masonry Structures (TMS 602-11/ACI 530.1-11/ASCE6-11) and their companion commentaries for a planned 2013 edition of the Standards. The MSJC is sponsored by the The Masonry Society (TMS), American Concrete Institute (ACI), and the Structural Engineering Institute of the American Society of Civil Engineers (SEI/ASCE). In accordance with the rules of The Masonry Society, and consistent with the rules of the other sponsoring organizations, proposed changes to standardized documents must be open for public comment for a period of not less than 45 days. That Public Comment Period opens tomorrow and closes at 11;59 pm Eastern Time on January 14, 2013. Details on the public comment period, including a summary of major proposed changes to these documents and a complete Working Draft of the proposed revisions to MSJC Code, Specification, and Commentaries can be accessed at the link below. If you wish to submit a comment on the provisions, please use the table provided here before 11:59 pm Eastern Time on January 14, 2013.
If you have questions about the Public Comment Period or the MSJC, contact TMS at 303-939-9700.
New Reinforced Masonry Engineering Handbook Now Available
The most up to date reference for masonry design, the Reinforced Masonry Engineering Handbook, 7th edition, is now available. This book is based on the 2012 International Building Code and reference documents, Minimum Design Loads for Buildings and Other Structures, (ASCE 7-10) and Building Code Requirements for Masonry Structures (TMS 402-11/ASCE 5-11/ACI 530-11). Originally authored by the legendary James Amrhein, the handbook maintains practical and easy-to-understand design examples and expanded design aids of Tables and Diagrams.
Topics include masonry materials, assembly properties, loads, distribution of forces and design by Strength Design and Allowable Stress Design. There are also typical building details and special topics relating to structural reinforced masonry. To order, visit the ICC Bookstore www.iccsafe.org/store or the Technical Publications section of the Masonry Institute of America Bookstore www.masonryinstitute.org.
WINNERS NAMED IN 2nd ANNUAL COLD-FORMED STEEL DESIGN STUDENT COMPETITION
Virginia Tech Wins Big With “More Challenges, Greater Rewards”
WASHINGTON, D.C. – The winners of the second annual Student Competition on Cold-Formed Steel Design, hosted at the University of North Texas (UNT), have been announced. The competition is held to promote higher education in cold-formed steel structural design and to encourage students to use creative thinking skills to solve engineering problems. Co-sponsors of the competition include the American Iron and Steel Institute (AISI), the Cold-Formed Steel Engineers Institute (CFSEI), the University of North Texas and the National Science Foundation (NSF).
This year’s theme was “More Challenges, Greater Awards” as students sought to design an open section shape for a 48-inch-long cold-formed steel truss member which yields the highest possible nominal compression strength, where distortional buckling is ignored. UNT received 56 entries from four different institutions in the United States and China. The winners were:
- First Place – Matthew Wilde - Virginia Tech, Blacksburg, VA
- Second Place – Armen Adekristi, Virginia Tech, Blacksburg, VA
- Third Place – Duping Zhang, Chongqing University, China
“There were many excellent projects submitted, and the judges were faced with their own challenges in ranking them according to the design’s efficiency and constructability as well as the quality of the essay,” Jay Larson, P.E., F.ASCE, managing director of AISI’s Construction Technical Program, said.
Noting that special kudos is in order for Virginia Tech, whose students claimed eight of the top 10 entries, Larson said: “Each entry was reviewed carefully. We congratulate the finalists, and appreciate the time and effort taken by each of the contestants to submit their cold-formed steel solutions.”
WINNERS NAMED IN 2012 COLD-FORMED STEEL DESIGN STUDENT COMPETITION
Cheng Yu, Ph.D., associate professor at the University of North Texas, said: “We welcome ideas and suggestions for future competitions and look forward to hosting this event again in 2013.”
The top three winners will receive monetary awards and award plaques, with recognition provided by Dr. Cheng Yu at the 21st International Specialty Conference on Cold-Formed Steel Structures being held October 24-25, 2012. The top 10 students in the 2012 competition will receive one-year student memberships in the Cold-Formed Steel Engineers Institute (CFSEI). The winning designs are posted here.
The competition was launched in March 2012, with entries due on June 30, 2012. Entries were judged by a panel of individuals who are nationally recognized in the area of cold-formed steel design:
- Rick Haws, P.E., engineer, NUCOR Building Systems
- Roger A. LaBoube, Ph.D., P.E., Distinguished Teaching Professor, Missouri University of Science and Technology and director of the Wei-Wen Yu Center for Cold-Formed Steel Structures
- Cristopher Moen, Ph.D., P.E, assistant professor, Virginia Tech
- Sutton Stephens, Ph.D., P.E., S.E., Kansas State University
- Cheng Yu, Ph.D., associate professor, University of North Texas
AISI’s codes and standards work is conducted under the Construction Market Council of the Steel Market Development Institute (SMDI), a business unit of AISI, which oversees the industry’s investment in advancing the competitive use of steel by meeting the demands of the marketplace. For more information on SMDI’s Construction Market program, visit www.smdisteel.org.
AISI serves as the voice of the North American steel industry in the public policy arena and advances the case for steel in the marketplace as the preferred material of choice. AISI also plays a lead role in the development and application of new steels and steelmaking technology. AISI is comprised of 25 member companies, including integrated and electric furnace steelmakers, and 124 associate members who are suppliers to or customers of the steel industry. AISI's member companies represent over three-quarters of both U.S. and North American steel capacity. For more news about steel and its applications, view AISI’s website at www.steel.org.
New Report from IBHS Evaluates Building Codes in 18 Coastal States
The Insurance Institute for Business & Home Safety (IBHS) released a new report which provides an analysis of residential building codes in the 18 hurricane-prone coastal states along the Gulf of Mexico and the Atlantic Coast. Building codes are intended to increase the safety and integrity of structures, thereby reducing deaths, injuries and property damage from hurricanes and a wide range of other hazards.
Rating the States: An Assessment of Residential Building Codes and Enforcement Systems for Life Safety and Property Protection in Hurricane Prone Regions is the first of its kind, state-by-state assessment of individual state performance in developing and promulgating a residential building code system, which uses modern building codes, coupled with strong enforcement related activities to enhance the protection of homes and families.
“The report goes beyond just evaluating each state’s code system,” said Julie Rochman, IBHS president and CEO. “The report offers each state the detailed information and tools it needs to improve its building code process to better protect its citizens. It also gives interested citizens useful information so that they can understand the need for, and demand, better building codes.”
The report combines IBHS’ engineering expertise and regulatory research to examine the three main elements of a state’s building code system:
1. Code adoption and enforcement – Statewide mandatory code adoption and enforcement are the primary elements to require that the minimum standards of codes are utilized.
2. Code official training and certification - Code official training and certification are part of the regulatory scheme to ensure that code officials are properly educated, trained and tested in order to correctly enforce building codes.
3. Licensing requirements for construction trades - Licensing requirements for construction trades ensure that contractors and subcontractors are familiar with the sections of code that impact them, that
Full report and state-specific information is available on the IBHS Building Code Ratings web page.