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MT. VERNON, IOWA (Jan. 26, 2012) – The Tilt-Up Concrete Association (TCA) – a non-profit international organization that serves to expand and improve the use of site-cast Tilt-Up as the preferred construction method – has published an initial report from the Natural Disaster Task Force.

Formed last summer to investigate the performance of site-cast Tilt-Up construction in high winds events such as tornados, the Task Force consists of a nationwide group of practicing structural engineers with a diverse range of experience in Tilt-Up construction and “big box” buildings.

According to Jeffrey Needham, P.E. and chairman of the Task Force, the group identified five general recommendations that focus on increasing building safety in catastrophic storms through enhanced building performance and/or the use of shelters. The recommendations also stress the inherent strength and durability of Tilt-Up construction and recommends the TCA develop responses that take advantage of this performance.

Needham noted that building codes are continually changing to minimize the damage and injuries that occur during these high wind and catastrophic storms. While all natural disasters can bring destruction to an area, windstorms typically produce the most damage. Wind, however, is a force that the Tilt-Up industry has been facing with considerable success over decades of development, he said.

“As early as the 1970s, Tilt-Up began to play a significant role in new construction throughout the state of Florida and much of the southeastern U.S. With this area being a primary target for hurricanes each year, Tilt-Up quickly became influential in withstanding these storms due to the monolithic concrete panels that span greater lengths and widths,” said Needham. “Tilt-Up also offered more flexibility in structural systems and aesthetic treatments. Through hurricanes and tornados from the southeast to the heartland of America, including the state of Texas where significant numbers of both tropical storms or hurricanes and tornados impact the built environment every year, Tilt-Up grew as a primary construction method to deliver a wide range of building types.”

According to Jim Baty, Technical Director of the TCA, there are numerous examples of Tilt-Up structures resisting high wind events, whether hurricanes or tornadoes. Tilt-Up history provides considerable evidence for structures impacted by many wind force levels, he said.  In recent years, the TCA has been made aware of many Tilt-Up structures that were design rated to meet category 5 hurricanes and EF-3 tornadoes or greater.

“In light of recent high wind events, there have been many questions related to the construction of today’s structures,” said Baty. “There are numerous cases every year of buildings constructed using Tilt-Up walls panels that have resisted significant storm forces, whether on a coast from hurricanes or inland from tornados.”

David Tomasula, P.E., a structural engineer and Principal of LJB Inc of Dayton, Ohio, noted that LJB and its design-build construction partners have designed and constructed more than 1,400 buildings using Tilt-Up construction in the past 40 years. According to Tomasula, many of these buildings were designed to resist extreme forces – such as hurricane force winds, seismic activity, even blast and bomb loading – and he is confident about the ability of Tilt-Up to perform as intended. Furthermore, he said, a number of LJB’s construction partners have even built their own offices and shops with Tilt-Up construction.

“We, along with our construction partners, have no doubts about the structural integrity nor safety of Tilt-Up construction in the buildings that we occupy,” said Tomasula.

In addition, the Task Force noted that TCA should work with the Steel Deck Institute, Steel Joist Institute, National Council of Structural Engineers Associations (NCSEA), and code bodies to develop specific design and construction guidelines and recommendations for high winds. This must include more accurate information regarding the performance of deck attachment in simultaneous high uplift and shear.

Members of the task force include:

• Jeffrey Needham, P.E., S.E. of Needham/DBS in Lenexa, Kan., Chairman Task Force
• Karen Hand, P.E. of Needham/DBS in Lenexa, Kan., Secretary Task Force
• David Tomasula, P.E. of LJB, Inc., in St. Louis, Mo., Chairman Technical Committee
• Jeffrey Griffin, P.E. of LJB, Inc. in Dayton, Ohio
• Jerry Coombs, P.E. of Coombs Engineering P.C. in Wylie, Texas
• Brent Gibson, P.E. of TLC Engineering Inc. in Cocoa, Fla.
• Mark Johnson, P.E., SECB of Johnson Structural Group, Inc. in Boca Raton, Fla.
• Ken Luttrell, P.E. S.E. of CYS Structural Engineers Inc. in Sacramento, Calif.
• Wes Britson, P.E., S.E. of PEC in Wichita, Kan., Non TCA at-large member

Tilt-Up construction is a method of constructing a concrete wall system safely and efficiently on the job site. Often referred to as site-cast precast, Tilt-Up involves casting a concrete element in a location other than its final destination. Once the panels are stood vertically with a crane, they are temporarily braced until the final structural elements of the building’s force-resisting system are in place and approved by the engineer-of-record. The performance of the wall panels in the final structure is dependent upon decisions of the structural engineer.

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About TCA

TCA was founded in 1986 to improve the quality and acceptance of site-cast Tilt-Up construction, a method in which concrete wall panels are cast on-site and tilted into place. Tilt-Up construction is one of the fastest growing industries in the United States, combining the advantages of reasonable cost with low maintenance, durability, speed of construction and minimal capital investment. At least 10,000 buildings, enclosing more than 650 million square feet, are constructed each year using this construction method. For more information, visit www.tilt-up.org or contact TCA at 319-895-6911.