Figure 1.9 WTC 7 steel frame building geometry prior to its collapse (FEMA, 2002

Figure 1.9 WTC 7 steel frame building geometry prior to its collapse (FEMA, 2002).

The UAF research team reviewed the steel erection drawings of WTC 7 in order to develop our simulation of the building prior to its collapse. These drawings included plan views showing the framing for 47 stories as well as numerous details related to the construction methods used for each floor. We then carefully prepared the geometry of the virtual structure two floors at a time using AutoCAD. The digital drawings were checked against the steel erection drawings by all members of the research team to ensure quality control. The quality control-checked digital AutoCAD geometry was then imported into the latest versions of both SAP2000 and ABAQUS, which are finite element programs. The two finite element programs were used to simulate and study the building’s structural response to various load conditions. Each program was used by a different researcher and the results were compared. Figure 1.10 shows the framing plan view for Floors 12 and 13. The drawings are difficult to read because of the number of framing members shown on the drawing. Figure 1.11 shows a