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Steel Inventory and Identification. Federal Building and Fire Safety Investigation of the World Trade Center Disaster (NIST NCSTAR 1-3B) ***DRAFT for Public Comments***



Stephen W. Banovic


As a result of the recovery efforts of the Structural Engineers Association of New York. Federal Emergency Management Agency/American Society of Civil Engineers, and the National Institute of Standards and Technology (NIST), NIST possesses 236 structural steel elements from the World Trade Center (WTC) buildings. These samples include full exterior column panels, core columns, portions of the floor truss members, channels used to attach the floor trusses to the interior columns, and other smaller structural components (e.g., bolts, diagonal bracing straps, aluminum facade). Many significant pieces were recovered from the impact and fire-affected floors. Additionally, the recovered structural elements have yielded sufficient representative samples, with respect to the determination of the quality and mechanical properties of the steel, for all 12 grades of the exterior panel material, 2 grades of the core column material (representing 99 percent by total number, of the columns), and both grades for the floor truss material. The lack of WT 7 steel precludes tests on actual material from the structure; however, WTC 7 was constructed of three grades of conventional steel (36 ksi. 42 ksi, and 50 ksi). and literature values may be used to estimate properties.
National Construction Safety Team Act Reports (NIST NCSTAR) - 1-3
Report Number


World Trade Center, high rise buildings, building collapse, disasters, fire safety, fire investigations, terrorists, terrorism, steels, identification, inventory, structural elements, recovery, structural steels, recovered
Created September 1, 2005, Updated February 19, 2017