Damage and Failure Modes of Structural Steel Components. Appendices A-G. Federal Building and Fire Safety Investigation of the World Trade Center Disaster.
Damage and Failure Modes of Structural Steel Components.
Appendices A-G. Federal Building and Fire Safety
Investigation of the World Trade Center Disaster.
Banovic, S. W.; Foecke, T.
NIST NCSTAR 1-3C; 258 p. September 2005.
World Trade Center; high rise buildings; building
collapse; disasters; fire safety; fire investigations;
terrorists; terrorism; steel structuresl; damage;
failure modes; failure analysis; steels; degradation
This report describes damage characteristics, failure
modes, and fire-related degradation of the recovered
structural components from the World Trade Center (WTC)
1 and WTC 2. Assessment of the structural components was
divided into pre- and post-collapse analysis.
Pre-collapse analysis concentrated on impact damage
sustained by the exterior panel sections, with
assessment based solely upon photographic and video
images. These images were also used to locate areas on
the recovered and identified (i.e., known as-built
location) panels with pre-collapse fire exposure. The
second portion of the analysis focused on direct visual
examination of the recovered steel elements. Of
particular importance were the samples located near the
airplane impacts (north face of WTC 1 and south face of
WTC 2) and those where fire was known to exist prior to
collapse of the buildings. Metallographic analysis of
components with specific or unique damage patterns was
also conducted. The findings of this report were used
for validation of the modeling efforts in the baseline
structural performance and aircraft impact damage
analysis, the reconstruction of the thermal environment,
and the structural fire response and collapse analysis.
WTC 7 steel was not evaluated in this study of the tower
damage and failure modes.