Characterization of Submerged-Arc Welds From the World Trade Center Towers: As-Deposited Welds and Failures Associated With Impact Damage of the Exterior Columns
Stephen W. Banovic, Thomas A. Siewert
Intact and aircraft impact-damaged welds from the exterior columns of the World Trade Center towers were evaluated. The fillet welds joining the various steel plates composing the built-up columns were primarily deposited using submerged-arc welding. Characterization of the undamaged welds suggested that the joining materials used were adequate for design specifications and that the welding procedures employed were appropriate relative to contemporaneous standards. Upon aircraft impact, the weld metal displayed a fair amount of strength and ductility given the high-strain rate conditions. Impact damaged associated with these joints consisted of fracture primarily initiating at and traveling through the heat affected zone (HAZ) of the steel plates that had their rolling plane normal parallel to the travel of the aircraft. This HAZ region had a lower cross-sectional area than the weld throat and diminished mechanical properties as a results of microstructural changes (with respect to the base plate further from the weld). Based upon the either brittle or very log energy ductile fractures of the plates observed, it was determined that the failure of the joints had little effect in relation to steel plate deformation, on the amount of energy absorbed upon impact and subsequent damage to the interior structure by the high-density aircraft components.
characterization, impact damage, submerged-arc welding, World Trade Center Towers
and Siewert, T.
Characterization of Submerged-Arc Welds From the World Trade Center Towers: As-Deposited Welds and Failures Associated With Impact Damage of the Exterior Columns, Welding Journal
(Accessed November 29, 2023)