Seismic behavior analysis and energy-based design of SSTFs with multiple Vierendeel panels

This work presents an energy-based plastic design method for steel staggered truss framing (SSTF) structures with multiple Vierendeel panels. The effectiveness of the method was investigated and the improved seismic performance of plastically designed SSTF structures was verified. First, parameter analysis based on a refined finite element analysis model of steel trusses with multiple Vierendeel panels was conducted. The plastic bending resistance ratio of the chord member to the intermediate vertical member was recommended based on evaluating the failure modes. Then, the energy-based plastic design procedure for the SSTF structure with multiple Vierendeel panels were described step by step. Finally, three SSTF structures were comparatively analyzed by pushover analysis and nonlinear time-history analysis, including a force-based designed SSTF structure with single Vierendeel panels, a plastically designed SSTF structure with single Vierendeel panels, and a plastically designed SSTF structure with multiple Vierendeel panels. Compared with the forced-based designed structure, the plastically designed structures showed slightly lower load-carrying capacities, but much higher ductility. The force-based designed structure had obvious soft stories, while the two plastically designed structures showed more uniform story drift distributions and formed a controllable failure mode. Compared with the structures with single Vierendeel panels, the rotation demand on the chord members of SSTF structures with multiple Vierendeel panels was significantly reduced.