On the afternoon of September 11, 2001, ASCEýýýs Structural Engineering Institute established a building performance study team to examine the structural damage inflicted on the Pentagon by the crash. The members of the team reviewed available information on the structure, crash loading, and eyewitness accounts and drew on focused assessments by others. After performing impact, static and thermal analyses, the BPS team made recommendations for future design and construction and suggestions on areas where research and development is needed. Their findings are disclosed in the Pentagon Building Performance Report. With over 150 full color illustrative photos, diagrams and tables, The Pentagon Building Performance Report provides a thorough assessment of the structural system that prevented extensive collapse of the building. From the redundant and alternative load paths of the unique beam and girder framing system, to the ability of the structure to absorb excess energy, the Pentagon withstood both structural and thermal trauma better than would have been expected. Complete with a chronological description of the events leading to impact, the crash and its subsequent effect on the structural system, this report reveals exactly how and why the Pentagon structure performed so well on the morning of the September 11, 2001 attacks.