Structural Assessment of Bomb Damage for World Trade Center

On Friday, February 26, 1993, a van loaded with explosives entered the underground parking garage of the World Trade Center. The van was parked on the B2 underground level, next to the south wall of Tower A. At 12:18 p.m., the van exploded, instantly destroying a large portion of the garage under the Vista Hotel, blasting out a 38‐mm (1.5‐in.) thick steel double‐tee tower cross brace, and sending $44\times {10}^3\mathrm{kN}$ (5,000 tons) of debris crashing onto the heating and refrigeration plant for the World Trade Center complex. Evacuation of the complex commenced, with some office workers making their way down the smoke‐filled stairs while others were trapped in elevators until rescued. Structural damage assessment, emergency repairs, and construction of temporary supports began soon after the explosion.