Direct displacement-based seismic performance design of steel frame structures

Direct displacement-based seismic design is a more rational approach to performance-based seismic design, which was used to design steel frame structures. In this method, the yield displacement depends on the initial structures and the ductility factors are calculated according to objective displacement. Then equivalent viscous damping or strength discount factors are ensured, then high damping elastic displacement response spectra or elastic-plastic response displacement spectra are established. Based on structural bilinear model, effective period corresponding to objective displacement are ascertained on displacement response spectra, the structural stiffness and base shear force are confirmed. Component sections are modified to make the structural displacement approach to original displacement, then the structural design are accomplished. Seismic performance objectives of steel frame structures are implemented by the method. Compared to elastic response spectra, the application of elastic-plastic response spectra makes the design results more accurate. Base on elastic-plastic response spectra, performance-based seismic design of steel frame can be implemented by direct displacement-based design method.