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Self-Centering Steel Plate Shear Walls (SC-SPSW) have been recently proposed to help achieve possible immediate occupancy following an earthquake for buildings located in regions of high seismicity. For this purpose, like other recently developed low-damage systems, SC-SPSWs seek to: (1) eliminate damage to the surrounding gravity frame of the seismic force resisting system; (2) provide frame recentering, in order to return the building back to its pre-earthquake near vertical alignment, and; (3) concentrate hysteretic energy to replaceable elements, providing rapid and practical reparability. A testing program was conducted investigating the quasi-static cyclic behavior of SC-SPSW systems detailed with three different beam-to-column connections and two SPSW infill configurations. Specimens consisted of one-third scaled single-bay three-story frames. Results are presented for SC-SPSWs detailed with three different post-tensioned (PT) beam-to-column rocking connections that: either (1) rock about the top and bottom beam flanges; (2) rock about the top beam flanges only referred to as the NewZ-BREAKSS connection, or; (3) rock about the beam centerline. The latter two connections were investigated to mitigate floor system damage due to PT boundary frame expansion (i.e., beam-growth) that occurs with the first mentioned rocking connection detail. Experimental and numerical results are presented for both a solid infill web plate and infill web strip configuration. Results presented show that solid infill web plates provide some additional strength and energy dissipation due to their strength in compression and affects frame recentering for quasi-static loading conditions of progressive increasing displacement cycles. In contrast, infill web strips are essentially tension-only and have the benefit that they are not susceptible to tearing from the boundary frame and does not affect frame recentering. Numerical results show that the compression strength of the solid infill web plate in these experiments was approximately 10 percent that of the yield strength of the infill web plates in tension. Furthermore, lessons learned from this testing program are presented that show that for a multiple actuator configuration along the height of a multi-story SPSW specimen, a top level displacement control with force control of the lower actuators is necessary to avoid undesired actuator interaction along the frame heights.

This paper presents the results of an exploratory study performed to examine the potential of using bolted connections between perforated infill panels and the boundary elements of steel plate shear walls. Perforated infill panels have the advantage over solid infills in that these panels can be detailed to minimize the forces imposed to the panel connections and surrounding boundary members. Furthermore, addition of perforations will accommodate the use of thicker perforated infill panels where solid infill thinner panels may not be practical. For such applications, bolted connections can be used to improve the replaceability of the web panels after a strong earthquake to facilitate rapid repairability. Hence, the combination of bolted connections with perforated infill panels could lead to an overall effective design solution for steel plate shear walls. This paper presents the results of a shake table test program on one-third scale three-story specimens as a proof of concept on the use of bolted perforated infill panels. The experimental results are compared to those obtained with conventional solid infill panels welded to the boundary elements. The results demonstrated that perforated SPSWs with slip-resistant bolted infill panels of thin cold-formed steel can provide a hysteretic behavior and seismic performance comparable to SPSWs having with conventional solid infill panels with welded connections.

As part of a Network for Earthquake Engineering Simulation research project led by researchers at the University of Washington with collaborators at University at Buffalo, and Taiwan National Center for Research on Earthquake Engineering, a self-centering steel plate shear wall (SC-SPSW) system has been developed to achieve enhanced seismic performance objectives, including recentering. The SC-SPSW consists of thin steel infill panels, referred to as web plates that serve as the primary lateral load-resisting and energy dissipating element of the system. Posttensioned (PT) beam-to-column connections provide system recentering capabilities. A performance-based design procedure has been developed for the SC-SPSW, and a series of nonlinear response history analyses have been conducted to verify intended seismic performance at multiple hazard levels. Quasi-static subassembly tests, quasi-static and shake table tests of scaled three-story specimens, and pseudo-dynamic tests of two full-scale two-story SC-SPSWs have been conducted. As a culmination of this multi-year, multi-institutional project, this paper will present an overview of the SCSPSW numerical and experimental research programs. This paper will also discuss innovative PT connection and web plate designs that were investigated to improve constructability, resilience, and seismic performance and that can be applied to other self-centering and steel plate shear wall systems.

Recent research has shown that self-centering steel plate shear walls (SC-SPSWs) offer an enhanced seismic performance over conventional steel plate shear walls by providing an additional self-centering capability using steel frames detailed with posttensioned (PT) beam-to-column rocking connections. As with other previously proposed self-centering frames detailed with similar beam-to-column connections, this detailing facilitates the incorporation of replaceable energy dissipation components, as part of the lateral force resisting system (LFRS). In doing so, by design, the gravity frame components of the LFRS are also protected from damage during an earthquake. To investigate the dynamic seismic response of this proposed structural system, one-third scaled SC-SPSW specimens were subjected to ground motions during a series of dynamic shake-table tests. The experimental investigation results presented in this paper are the first shake-table tests conducted on SC-SPSWs. This test program was compose...

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 axia...

An innovative Self-Centering Steel Plate Shear Wall (SC-SPSW) system is proposed. It relies on post-tensioned (PT) beam-to-column connections that allow beams to rock about their flanges and provide system re-centering capabilities. A design procedure for the SC-SPSW system, developed based on a performance based design (PBD) approach, is presented, followed by analytical results for a prototype SC-SPSW building designed using this PBD approach, and subjected to a suite of ground motions simulating three different seismic hazard levels. The results of the nonlinear response history analyses show the proposed SC-SPSW design procedure to adequately achieve the desired enhanced performance objectives. Concepts of capacity design principle are integrated in the above approach, to prevent in-span plastic hinges of the beam considering reduced moment capacity due to the presence of axial and shear forces and to ensure that PT reinforcement remain elastic, among other things. To facilitate understanding of the behavior and design of an SC-SPSW system, the moment, shear and axial force distribution along the length of a boundary beam are established based on first principles. Closed form formulations describing the moment, shear and axial force beam diagrams are developed based on component capacity design approach and are used in the performance-based system design approach.