Daniel M. Dowden

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. DOI: 10.1061/(ASCE)ST.1943-541X.0000424.

Dynamic Shake-Table Testing and Analytical Investigation of Self-Centering Steel Plate Shear Walls

AbstractRecent 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...

Full-scale testing of self-centering steel plate shear walls

This paper presents the results of a self-centering steel plate shear wall (SC-SPSW) experimental program conducted at the National Center for Research on Earthquake Engineering (NCREE) as part of a collaborative research endeavor. Two full-scale two-story SC-SPSW specimens were tested under pseudo-dynamic loading. The specimens investigated two different post-tensioned (PT) beam-to-column connection configurations—one using a PT connection detail where a gap forms in a connection as the beam rocks about its flanges, and one using a PT connection (called the NewZBREAKSS connection) where the beam in a connection always rocks about its top flanges, thus eliminating the problem of frame expansion. The test specimens also incorporated a post-tensioned column base connection that allowed the column to rock about its flanges, relying on vertical post-tensioned rods anchored along the column height. The PT column base provides additional recentering capabilities, as well as eliminates the damage and residual plastic deformations that occur in the moment resisting base connections of SC-SPSWs. The results from this project will be used to validate numerical models and inform construction and design recommendations.

Seismic design and analysis of self-centering steel plate shear walls

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.

Advances in self-centering steel plate shear wall testing and design

The self-centering steel plate shear wall (SC-SPSW) was developed as part of a NEESR-SG research project aimed at leveraging the benefits of self-centering post-tensioned steel frames with the strength and ductility of steel plate shear walls. Initial proof-of-concept numerical simulations showed that the SC-SPSW was capable of providing enhanced seismic performance, including recentering under design-level earthquakes. This paper will present recent advances in experimental testing of the new lateral force-resisting system, as well as, design recommendations that followed from these experiments and supporting finite element analyses. The extensive test program consisted of three major components: (i) large-scale quasi-static testing of SC-SPSW subassemblies, (ii) quasi-static and shake table testing of third-scale, threestory SC-SPSWs, and (iii) pseudo-dynamic testing of two full-scale, two-story SC-SPSW at multiple seismic hazard levels. Major outcomes of these experimental and numerical studies include: validation of seismic performance of various SC-SPSW configurations, development of a new post-tensioned (PT) beam-to-column connection to eliminate frame expansion that is typical of self-centering systems, incorporation of PT column base connections into the SCSPSW performance-based seismic design procedure, and recommendations for SC-SPSW design, detailing, and modeling. The results of this research program can be used to inform designers and bring SC-SPSWs closer to implementation. 1 Assistant Professor, Dept. of Civil, Architectural & Environmental Engineering, University of Texas at Austin, Austin, TX 78712 2 Graduate Student Researcher, Dept. of Civil, Structural & Environmental Engineering, University at Buffalo, Buffalo, NY 14260 3 Assistant Research Fellow, National Center for Research on Earthquake Engineering, Taipei, Taiwan 4 Associate Professor, Dept. of Civil & Environmental Engineering, University of Washington, Seattle, WA 98195 5 Professor, Dept. of Civil, Structural & Environmental Engineering, University at Buffalo, Buffalo, NY 14260 6 Professor, Dept. of Civil Engineering, National Taiwan University, Taipei, Taiwan Clayton PM, Dowden DM, Li C-H, Berman JW, Bruneau M, Tsai K-C, Lowes LN. Advances in Self-Centering Steel Plate Shear Wall Testing and Design. Proceedings of the 10 National Conference in Earthquake Engineering, Earthquake Engineering Research Institute, Anchorage, AK, 2014. DOI: 10.4231/D3GM81P60 Advances in Self-Centering Steel Plate Shear Wall Testing and Design P. M. Clayton, D. M. Dowden, C.-H. Li, J. W. Berman, M. Bruneau, K.-C. Tsai, L. N. Lowes