Performance-Based Capacity Design of Steel Plate Shear Walls. I: Development Principles

This is Part I of two companion papers on performance-based capacity design of steel plate shear walls. Most previous research has been conducted with the primary aim of maximizing ductility and robustness under severe cyclic loading, without any explicit consideration of the costs of achieving this behavior. This has resulted in onerous capacity design rules in current codes and standards for achieving highly ductile systems, and has effectively discouraged their use in low and moderate seismic regions. These companion papers aim to provide a holistic and sound basis for capacity design to any of three explicit performance levels. In this paper, Part I, two target yield mechanisms associated with the two extreme performance levels (ductile and limited-ductility) are identified and justified, and the capacity design principles applicable to these performance levels are discussed. The limited-ductility mechanism departs from conventional treatment and is established based on finite element simulations and experimental observations. Two complementary new concepts for designing moderately ductile walls are also proposed and verified. Because design is an iterative process, modeling efficiencies for use with the performance-based approach are suggested and validated. Inconsistencies between current capacity design methods for evaluating the demands imposed by the infill plates on the boundary elements and the true infill plate behavior are identified and discussed.