This forensic architecture case involves a construction project on a 10-story apartment building. The building was supposed to have 2 parking levels and 8 apartment levels. The building had 2 offset rectangular towers that were separated by a construction joint at a central elevator lobby. The structural frame of the building was made of steel columns and concrete flat plate floors, and the finished product was meant to have stucco walls. The two towers were being constructed by the lift-slab method where they were cast in a stack at grade level and then jacked up along steel columns into their final position. Steel columns supported the floor slabs which were lifted in stages by hydraulic jacks, threaded rods, and welded steel shearhead collars placed in the concrete floor slab at each column. When the building was halfway completed, workers were tack-welding wedges under the 9th to 11th floor packages to temporarily hold them in position when they heard a loud “bang” followed by rumbling sounds. The entire building structure collapsed and 7 construction workers were killed. Expert witnesses specialize in forensic engineering and hydraulic engineering were retained for this case.