Behavior of self-centering steel plate shear walls and design considerations

This paper presents insights on the combined contribution of posttensioning and beam-to-column joint rocking connection in self-centering steel plate shear walls (SC-SPSWs). Moment, shear, and axial force diagrams along the boundary beam are developed based on capacity design principles and are compared with nonlinear cyclic push-over analysis results. These closed-form solutions are integrated into a design procedure to select cross-sectional areas of the posttension reinforcement and beam sizes: (1) to prevent in-span plastic hinges; (2) to ensure that posttension reinforcement remains elastic to maintain self-centering capability of the system; (3) to impose sufficient initial posttensioning to overcome wind and gravity loads; (4) to provide adequate beam plastic strength considering reduced moment capacity due to the presence of axial and shear forces; and (5) to consider posttension losses due to axial beam shortening. Using this fundamental behavior knowledge, and adding response-based performance objectives to the design procedure, a companion paper investigates the seismic response of SC-SPSW using time-history nonlinear analyses.