Shaking table test of a frame structure retrofitted by externally-hung rocking wall with SMA and disc spring self-centering devices

Abstract

An innovative externally-hung rocking wall (ERW) with shape memory alloy (SMA) and disc spring self-centering devices for retrofitting existing structures was proposed in this paper. By arranging steel corbels on the columns of an existing structure, the rocking walls were connected to the corbel using H-shaped connectors. Two types of self-centering devices, using disc spring and SMA separately, were installed between rocking wall and foundation to prevent collision damage, and can provide self-centering capability for the structure. The seismic performance characteristic of the ERW structure was studied via a shaking table test. For comparison, an unretrofit control (UC) structure was also tested. The UC structure was severely damaged and nearly collapsed after PGA = 1.2 g test cases: some steel bars at the bottom of the beam were fractured, and concrete at the beam end and column foot were crushed. For the ERW structure, the damage was significantly reduced after PGA = 1.5 g test cases: there were some cracks appeared in the structure, and concrete at the column foot were slightly crushed. However, no obvious damage was observed in the self-centering devices. The maximum story drift and residual deformation of the ERW structure are reduced 86.7% and 91.2%, respectively, relative to the UC structure.