Assessment of Structure Steel From the World Trade Center Towers. Part V: Forensic Photographic Evidence of Tower Collapse Initiation and Progression

Published

October 16, 2008

Author(s)

Timothy J. Foecke, Stephen W. Banovic, Frank W. Gayle

Abstract

Photographic forensic evidence for the global collapse of the building structures was also developed as part of this investigation. The image library accumulated during the NIST BPAT collapse investigation was searched for images that showed gross building distortions preceding or during the collapse events. Images showing draw-in of the east face of WTC 2 and the south face of WTC 1 were analyzed to map the distortion field, which was traced over time. The inward distortions were seen to increase in magnitude as the building burned, reaching a maximum at the time of collapse. Evidence of dropped floors within the towers before global collapse was developed, as was evidence of the kinking and rotation of the top portion of WTC 2 just before and during collapse.

Citation

Journal of Failure Analysis and Prevention

Pub Type

Journals

Keywords

collapse inward bowing, World Trade Center Towers

Citation

Foecke, T. , Banovic, S. and Gayle, F. (2008), Assessment of Structure Steel From the World Trade Center Towers. Part V: Forensic Photographic Evidence of Tower Collapse Initiation and Progression, Journal of Failure Analysis and Prevention (Accessed October 7, 2025)