This report summarizes the National Institute of Standards and Technology (NIST) study of the collapse of the Dallas Cowboys indoor practice facility that occurred on the afternoon of May 2, 2009, during a severe thunderstorm. The indoor practice facility was a fabric-covered tubular steel frame structure, designed and constructed in 2003. The structure was upgraded in 2008 with additional purlins and reinforcements for some members and a new fabric roof covering. The report reviews the wind environment during the storm and outlines the wind conditions, including wind speed and direction at the time and location of collapse. The report also details the NIST field reconnaissance, including the survey of the collapsed structure and of wind damage to the surrounding areas, eyewitness interviews, and information collected from the Dallas Cowboys organization and from the City of Irving, Texas. The survey identified collapse patterns and structural failure modes. The report summarizes the analyses conducted to review the structural design of the practice facility under dead and wind loads, and to identify factors that might have contributed to the collapse. A two-dimensional structural model of a typical frame of the practice facility was developed and analyzed under various loading conditions. Specifically, the analyses included: (1) a Baseline Case that calculated the design demand-capacity ratios using wind loads specified in the ASCE 7-05 Standard and member capacities based on the AISC specifications to assess the ability of the structure to support design wind loads, (2) evaluation of the assumptions and calculations in the 2003 original design and 2008 upgrade to ascertain how those two designs differed from the Baseline Case, and (3) response of the structure to the wind conditions observed during the wind storm of May 2, 2009, to identify frame members that were overstressed and explain the observed failure modes.
Citation: NIST Interagency/Internal Report (NISTIR) - 7636Report Number:
NIST Pub Series: NIST Interagency/Internal Report (NISTIR)
Pub Type: NIST Pubs
Failure analysis, fabric-covered frame structures, microburst, steel structure, structural collapse, wind loads