The American Society of Civil Engineers (ASCE) has released the latest version of Standard 37. To those in the tilt-up industry, this is the guiding provision that defines the parameters for the temporary bracing condition integral to every project. With the 2014 edition, the task of designing for the proposed force levels and exposure categories has become so conservative that the Tilt-Up Concrete Association’s “Guideline for Temporary Wind Bracing of Tilt-Up Concrete Panels During Construction” must be revised to present new direction to the industry.

One of the significant directions that 37-14 deviates from, when compared to previous versions, is defining the risk category of the structure under construction as category 2, or as an occupied structure. However, “It’s not just the risk category that is forcing us to reevaluate how we interpret 37-14,” states Scott Collins, Chief Engineer for Meadow Burke. “The other issues are how it addresses hurricanes in the Gulf Region, and how 7-10 eliminates segmental wind pressures. One of these changes we could handle, but not all three concurrently.”

During their October meeting, the Tilt-Up Concrete Association (TCA) Board of Directors authorized staff to produce an RFP for authorship of a complete revision to the bracing guideline document. The goal is the creation of a new technical position that establishes rationale for alternatives to the stated requirements of ASCE 37 and the application of forces from ASCE 7. This new document is proposed to:

• Establish safety protocols for contractors to implement on site including wind-speed based warning systems for site evacuation.
• Rate sites for exposure criteria for implementation of warning systems or increased bracing requirements.
• Deliver new graphs, charts and figures for prescriptive implementation of bracing conditions as well as demonstrating the evaluation process.
• Provide the minimum requirements to achieve the performance-based solutions for increasing wind speeds, exposure categories (with respect to available safety controls) and any alteration of the base conditions, such as slab thickness or integrity.

The current schedule for the production of this document anticipates market availability by TCA Convention 2016 – Denver, CO (10/10/16). For more information on this project, please contact James Baty, FACI, TCA’s Manager of Regulatory and Technical Affairs at (319) 895-6911 or jbaty@tilt-up.org.