Xu, Xiao and Li 2021
In this study, a new type of self-centering shear wall with disc spring devices (SCSW-DSD) was introduced and was evaluated for its seismic performance. The proposed shear wall consists of a reinforced concrete (RC) wall and two disc spring devices (DSDs) where each disc spring device has a self-centering component and a friction energy dissipator. The two specimens of the proposed shear wall were tested under cyclic loading with different additional friction forces. Supported by the results, the system exhibits sufficient self-centering and energy dissipation capabilities, and satisfies the seismic-resilient demands, although minor damage occurred at the base of the RC walls.
System Concept
In the proposed system, two disc spring devices(DSDs) are connected to the foundation of the RC walls with high-strength bolts allowing easy replacement of the damaged parts after earthquakes. The self-centering device in the DSDs consists of disc springs connected in parallel and a free-floating spring plate. The friction energy dissipator includes several friction pads to dissipate seismic energy and internal plates to fix the initial position of the disk springs. When the system is subjected to lateral load on top of the RC wall, DSD on one end compresses while the other experiences tension. This causes a restoring force in the compressed DSDs and returns the SCSW-DSD to its initial position once the load is removed
Experimental Study, Results and Discussion
Four low reversed cyclic loading tests on a 2000-kN damping system were conducted on the two SCSW-DSD specimens that have similar design parameters. Different additional friction force was designed for each specimen and the behavior under additional friction force was investigated. A constant vertical load of 477.5kN was applied to the top of the specimens by a jack and a cyclic loading was applied by a hydraulic actuator.
A flag-like shaped hysteretic response was generated by the SCSW-DSD specimens except with small residual deformations. Furthermore, it was noted that the bearing capacity of the specimens increases with the increase in additional friction force and displacement of the RC wall. When the system was subjected to large deformations, most of the energy was dissipated by DSDs, due to its high bearing capacity and good self-centering capability. After repeated
loading, damage began to form at the foot of the RC wall which contributed to the inclined cracks after tests. However, the proposed specimens were still able to achieve desirable seismic performance with adequate energy dissipation and self-centering capability which verified the proposed model as a seismic-resilient device.
Reference
Xu, Longhe, et al. “Experimental Investigation on the Seismic Behavior of a New Self-Centering Shear Wall with Additional Friction.” Journal of Structural Engineering, vol. 147, no. 5, May 2021, p. 04021056.