Effect of Design Optimality and Overstrength on the Seismic Performance of Steel Plate Shear Walls

This study proposes and implements an automated design optimization program for steel plate shear wall (SPSW) systems and evaluates the effect of design conservatism level on the seismic collapse performance of SPSW archetypes. Initially, a MATLAB program is prepared that develops elastic and inelastic SPSW models with variable geometric and loading conditions and automates the manual seismic design process of these structures. The program is connected to a set of OpenSees scripts for computing the required response parameters. SPSW archetypes with 4, 8, 12 and 16 stories are then designed twice, using the genetic optimization algorithm and manual iterations. The seismic collapse performances of the two design sets are finally investigated with respect to the FEMA P695. The results indicate that design optimization leads to a weight reduction of up to 27%, and can still lead to acceptable collapse margin ratios (CMRs) according to FEMA P695. In addition to the buildings weight and CMR, the distribution of ductility and inter-story drift demands are assessed along heights when the manual design is replaced with an optimization procedure. In general, design optimization has shown more pronounced effects on the studied low-rise structures in terms of economy and seismic performance.