Self-centering Steel Plate Shear Wall Research Articles

Investigation of the performance of the self-centering steel plate shear wall considering stress relaxation in pre-stressed cables

Self-centring systems are one of the novel earthquake-resistant systems that can eliminate permanent earthquake-induced damage in buildings. In these systems, damage can be limited to those members that can be easily replaced after earthquakes. Self-centring steel plate shear walls (SC-SPSW) with pre-stressed cables combine the lateral load-resisting capacity of conventional SPSWs with the self-centring capabilities of PT beam-to-column connections and provide sufficient ductility and stiffness for the system. The stress relaxation phenomenon in pre-stressed cables can lead to stress reduction in cables with the passage of time. This phenomenon should not be neglected. In this study, the self-centering steel plate shear wall is simulated using finite element (FE) modeling and verified based on available experimental results; then, the effect of stress relaxation on stiffness and energy dissipation capability of the system is evaluated at different initial pre-stressing forces and time intervals. According to the results, after five years and for cables with a pre-stressing ratio of 0.7, the stiffness and dissipated energy have reduced by 26 and 5 percent, respectively, in comparison to the time just after pre-stressing. These values was 40 % and 2 % for stiffness reduction and energy dissipation capacity reduction, respectively when the cables were pre-stressed with the pre-stressing ratio of 0.9. Furthermore, A method is also suggested to improve the seismic performance of the self-centering connections which includes employing low yield point steel in energy dissipater devices. Results showed that the energy dissipation capacity of the system doubles by using low-point steel for the web plates. The cumulative dissipated energy was about 1.044 MJ with A1008 steel and it was increased to 2.058 MJ with LYP100 material. This increase was mostly observed after the 10th cycle of the hysteresis curve.

Steady-state dynamic response analysis of single-degree-of-freedom dual frame-wall resilient system

A mixed dual frame-wall resilient system, composed of a high-strength moment-resisting steel frame (HS-MRF) and self-centering steel plate shear walls (SC-SPSWs), was proposed to address the issue of frame expansion. To study the steady-state dynamic responses of the structural system, an analytical solution of a single-degree-of-freedom nonlinear oscillator under harmonic excitation was solved using the method of averaging. The steady-state responses of HS-MRF, self-centering frame and steel plate shear wall that are represented by the bilinear, self-centering and pinching hysteresis, respectively, were studied individually, followed by a full system study. A stability analysis was also carried out to evaluate the behaviour of the singular points. The results show that the hysteretic damping in the bilinear system can significantly reduce the resonance, and the responses are always stable. Jump phenomenon occurs in the self-centering system, and increasing the post-yield stiffness can reduce the nonlinearity, thus decreasing the resonance and unstable region. Unbounded resonance responses appear in the pinching system under large excitation but can change to jump behaviour under small excitation. A left-unbounded unstable region was also found when the unloading force is small. In the combined-hysteresis system, increasing the portion of bilinear hysteresis has negligible effects on the resonance but can reduce the nonlinearity under lower excitation intensities. However, under higher intensities, increasing bilinear hysteresis can significantly decrease peak responses and reduce both the jump and unbounded phenomena. The unstable regions also strongly depend on the ratio of hysteretic models. These findings shed light on the inherent dynamic properties of the dual frame-wall system and suggest that a well-design can achieve a favourable seismic performance.

Seismic behavior of a novel RSSC-SPSW: An experimental and numerical study

Self-centering steel plate shear walls (SC-SPSWs) offer superior seismic properties if properly designed. This paper deals with experimental and numerical studies of Ring-shaped Self-Centering Steel Plate Shear Walls (RSSC-SPSWs). For this purpose, a SC-SPSW specimen previously tested up to a drift of 2.5% by Clayton et al. (2012) was selected, verified in the Abaqus environment, and simulated in the same software package to obtain 23 numerical models by cyclically changing the thickness, topology, and steel type of the web plate. One model, exhibiting a better seismic performance than the control was chosen for constructing a 2/3-scale experimental specimen that was subjected to a lateral cyclic loading regime. Results revealed that the RSSC-SPSW specimen proved energy dissipation and peak strength by 2.6 and 3.0 times, respectively, higher than those recorded for the control. It was also observed that, despite its increased web plate thickness, the specimen retained its self-centering behavior, which was attributed to the fact that neither did the web plate fail nor did its strength decline throughout the experiment. Finally, the numerical model of the experimental specimen was simulated cyclically up to a drift of 5% in the Abaqus software to study the failure model, buckling, and necking, which verified an acceptable agreement between the predicted and experimental results.

Investigation of the performance of self-centering steel plate shear walls under fire loading

Investigation of the performance of self-centering steel plate shear walls under fire loading

Study on seismic behaviors of self-centering steel plate shear walls with slits

The self-centering steel plate shear walls with slits(SC-SPSWS) is a new seismic load-resisting system that combines the good ductility, energy dissipation capacity of the steel plate shear walls with slits(SPSWS) and the recentering capabilities of the self-centering steel frames(SCSF). This paper presents the finite element analysis of SCSF under cyclic loading, the results correlate well with those from the experiments, which validates the modeling method and provides a reliable basis for modeling the whole system. A 2-story SC-SPSWS is established and analyzed to investigate the effect of individual changes in geometric parameters on lateral stiffness, ultimate bearing capacity, ductility, reset performance and energy dissipation capacity of the system. Results show that the structure with more flexural link layers and thicker steel plates owns higher ultimate bearing capacity and better energy dissipation capacity, but at the same time the recentering capability is weakened. It is also concluded that as the span-height decreases, the ductility of the structure decreases sharply. Differently, an increase in the number of steel strands can enhance the ductility of the structure

State-of-the-art of Research Progress of Self-centering Structure System

Traditional building structures dissipate seismic energy through the plastic deformation of members in the earthquake, which may lead to a large residual deformation after the earthquake. Those structures are very difficult to repair. Traditional building structure can become a new structure with self-centering ability by using a special energy dissipation component, adding prestressed tendons or supplementing dampers. Compared to the traditional building structure, this new self-centering structure can more effectively reduce the residual deformation caused by the earthquake, and it has a desirable capability to dissipate seismic energy so as to enable itself to be of more security. In this study, the domestic and foreign self-centering structures are classified and summarized. This study deals with research progress of self-centering structures including self-centering concrete shear wall structure, self-centering concrete frame structure, self-centering steel moment frame structure, self-centering braced steel frame structure, self-centering steel plate shear wall structure and self-centering offshore platform structure. Besides, this study introduces the related research progress of other research fellows.

Seismic demand assessment of self-centering steel plate shear walls

In previous studies, a post-tensioned rocking system has been introduced to steel plate shear wall (SPSW) system as a means for reducing its residual drifts. The success of this method and the performance of self-centering SPSWs (SC-SPSWs) is evaluated, in this study, by nonlinear dynamic analysis of previously-designed structures. For this purpose, a numerical model is developed and validated against experimental results. This model is, then, used for representing five 3- and 9-story SC-SPSWs that reflect various design assumptions. The median and dispersion of various response parameters are then extracted using a set of 20 ground motion records scaled to three different intensity levels. A comparative assessment is next performed between response of the studied structures in presence and absence of the rocking system. This assessment reveals that the rocking system is not effective in reducing the residual deformations of SPSW system. Nevertheless, the rocking behavior is shown to effectively mitigate the ductility demand at the beams' end portion and provide a more uniform distribution of plasticity along beams and within web plates of different stories.

Quasi-static cyclic testing and analytical investigation of steel plate shear walls with different post-tensioned beam-to-column rocking connections

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.

Kinematics of Self-Centering Steel Plate Shear Walls with NewZ-BREAKSS Post-Tensioned Rocking Connection

This paper presents information on the combined contribution of post-tensioning and beam-to-column joint rocking connections in self-centering steel plate shear walls (SC-SPSWs) with the NewZ-BREAKSS connection (i.e., NZ-SC-SPSW). Detailed free-body diagrams developed and presented in this paper provide insights on the basic, fundamental kinematic behavior of this lateral force-resisting system. The fundamental equations presented provide information on the behavior of SC-SPSWs and are suitable to facilitate design. These are needed for the implementation and understanding of these types of self-centering steel frame systems.

Self-centering steel plate shear walls for improving seismic resilience

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.

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 Pseudodynamic Testing of Self-Centering Steel Plate Shear Walls

AbstractThis paper presents the first full-scale experimental investigation of the self-centering steel plate shear wall (SC-SPSW) system. The SC-SPSW system is a lateral force-resisting system developed to provide system recentering and limit structural damage to easily replaceable energy dissipating fuses (i.e., thin steel web plates). Recentering is provided by posttensioned (PT) beam-to-column connections. This test program is composed of two two-story SC-SPSW specimens, each with a different PT beam-to-column connection. For one specimen, connections rock about both beam flanges; for the other, connections rock about the top beam flange only. Both specimens incorporated a posttensioned column base detail to further promote recentering and damage mitigation. The specimens were tested pseudodynamically using excitations representing three different seismic hazard levels. Results show that the SC-SPSW system is capable of meeting and exceeding the specified performance objectives.

Comparison of web plate numerical models for self‐centering steel plate shear walls

SummaryPrevious research has shown that self‐centering steel plate shear walls (SC‐SPSWs) are capable of achieving enhanced seismic performance at multiple hazard levels, including recentering following design‐level earthquakes. When modeling SC‐SPSWs numerically, these studies considered an idealized tension‐only steel plate shear wall (SPSW) web plate behavior. Research has shown that web plate behavior is more complex than predicted by the idealized model, and web plates can provide more strength, stiffness, and energy dissipation than predicted by the idealized model. The idealized model of web plate behavior is used widely in SPSW numerical models where the moment‐resisting boundary frame provides supplemental hysteretic damping and stiffness; however, in SC‐SPSWs, where the post‐tensioned boundary frame is designed to remain elastic during an earthquake, accounting for the more complex web plate behavior can have a significant impact on seismic performance estimates from numerical simulation. This paper presents different methods for modeling SC‐SPSWs. Responses from these models are compared with experimental results. A simple modification of the tension‐only model, referred to as the tension‐compression strip model, is shown to provide a reasonable approximation of SC‐SPSW behavior. Results from nonlinear response history analyses of SC‐SPSWs with the tension‐only and tension‐compression web plate models are compared to assess how the approximation of web plate behavior affects SC‐SPSW seismic performance. Copyright © 2015 John Wiley & Sons, Ltd.

Seismic performance of self-centering steel plate shear walls with beam-only-connected web plates

In the self-centering steel plate shear wall (SC-SPSW) system, thin steel web plates provide the primary lateral strength and energy dissipation, while post-tensioned connections in the boundary frame provide recentering and mitigate frame damage. In most steel plate shear walls (SPSWs), web plates are connected to the beams and columns; however, connecting the web plates to the beams only has been proposed as a means of reducing boundary frame demands and mitigating web plate damage. This paper investigates the impact of using beam-only-connected web plates on SC-SPSW design and seismic performance. Expressions for determining beam demands for purposes of design are developed. Three- and nine-story prototype SC-SPSWs are designed using beam-only-connected web plates and are compared with equivalent SC-SPSWs designs with fully-connected web plates. To evaluate the potential for material savings, the weight of steel required for each system is compared. The seismic performance of the SC-SPSWs with beam-only-connected and fully-connected web plates is compared using results of nonlinear response history analyses in which relatively simple, yet conservative, modeling techniques are employed.

Subassembly testing and modeling of self-centering steel plate shear walls

Experimental and numerical studies have shown self-centering steel plate shear walls (SC-SPSWs) to exhibit enhanced performance including recentering during extreme loading, making them a viable lateral load resisting system for high seismic regions capable of reducing structural repair costs and loss of building functionality after an earthquake. SC-SPSWs utilize thin steel web plates to provide lateral load resistance and energy dissipation, while rocking post-tensioned (PT) beam-to-column connections recenter the building and, if properly designed, eliminate costly damage to the boundary frame. A series of quasi-static cyclic tests have been conducted on SC-SPSW subassemblages. The purpose of these tests is to better understand SC-SPSW and component behavior and the impact of certain web plate and PT connection parameters on performance. This paper presents the results from the test program and also compares the experimental results to those of simple numerical models.

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 axia...

Experimental Investigation of Self-Centering Steel Plate Shear Walls

AbstractA series of subassembly tests were conducted to investigate the behavior of the self-centering steel plate shear wall (SC-SPSW) system under cyclic loading. The SC-SPSW system utilizes thin steel web plates to provide energy dissipation and the primary strength and stiffness of the system, whereas posttensioned (PT) beam-to-column connections provide recentering capabilities. In this new system, the web plate is intended to yield under cyclic loading, whereas the boundary elements and PT connection elements remain undamaged. The web plate can then be replaced relatively easily following significant inelastic cycles. This experimental program studies the effects of various design parameters on the system and connection response and compares the response with approximate analytical formulas. The experimental results show that the SC-SPSW system has high ductility, high initial stiffness, recentering capabilities, an overall system response as anticipated, and more energy dissipation than expected.

Seismic Design and Performance of Self-Centering Steel Plate Shear Walls

The self-centering steel plate shear wall (SC-SPSW) is a new seismic load-resisting system that combines the strength and stiffness properties of the SPSW with the recentering capabilities of posttensioned (PT) beam-to-column connections. This paper outlines a proposed seismic design procedure aimed at achieving specified structural performance targets and analytical methods for modeling such a system. A series of 3-and 9-story prototype buildings located in a high seismic zone in California was designed using the procedure, and nonlinear, dynamic analyses were performed for these prototype buildings using ground motions representing three seismic hazard levels. The analysis results show that the systems achieved the desired performance objectives, including recentering of the lateral system.