Seismic retrofit schemes for staggered truss structures

In this study the seismic performances of staggered truss system (STS) structures with and without vierendeel panels were evaluated. The force-displacement relationship and seismic fragility of basic type STS were compared with those of the structures retrofitted with additional members such as interior columns, vertical cables, end braces, and buckling-restrained braces (BRB). The analysis results showed that the seismic performance of the STS with vierendeel panels could be greatly enhanced by installing interior columns. The use of end bracing and vertical cable also turned out to be somewhat effective in enhancing strength and ductility and decreasing inter-story drifts and residual displacements. Similar results were obtained in the STS structure without vierendeel panels retrofitted with end bracing or designed with some of the diagonal members replaced with BRB.