Experimental Study On Seismic Behavior Of Frame-shear Wall Structures Equipped With SMA Dampers In Coupling Beams

Nowdays frame-shear wall structures are usually adopted in high-risebuildings. The coupling beams are offen designed to be chief component,which yield before wall limbs. While the span-depth ratio of coupling beamsis usually small (less than5), the failure mode is offen brittle shear failureand the energy dissipation capability is limited. Many scholars at home andabroad try to improve the ductility and energy dissipation of coupling beams.But there are some limitations, such as problems related to constructiondifficulty and post earthquake recovery, problems related to dampermaterial’s durability, residual deformation and damper replace after strongevents.Shape memory alloys (SMA) become a research focus on seismicenergy dissipation materials in Civil Engineering, because of the uniqueshape memory effect and characteristics of superelasticity effect, highcorrosion resistance and damping. In order to improve the damage andenergy dissipation mode of coupling beams in reinforced concrete (RC)frame-shear wall structures, SMA dampers are installed in the couplingbeams in this study. By appropriate design, the deformation and energydissipation of coupling beams are fucosed in the dampers. Then the damageof concrete coupling beams and wall limbs are alleviated. Due to thepseudoelasticity of SMA, the deformation of the SMA damper will restoreautomatically after earthquakes and there is no need to replace the damper.The main contents in this thesis are as follows:(1) A SMA damper in RC coupling beams and its characteristicparameters are proposed, together with design parameters of RC couplingbeams equipped with SMA dampers.(2) The performance tests for the dampers are conducted. The testsprove that the design of SMA damper is reliable. The SMA damper has goodenergy dissipation ability and self-centering ability. The pseudoelasticperformance of SMA wires is utilized very well.(3) Pseudo-static tests for two coupling beams are conducted. One beamis traditional RC coupling beam, and the other is self-centering beamequipped with SMA damper. The test results show that the beam equippedwith SMA damper can improve the damage mode compared with traditionalRC beam. Deformation of the beam is concentrated in the damper. Damageof concrete beam is reduced and the beam has self-centering ability.(4) Pseudo-dynamic tests for two18-story frame-shear wall structuresare conducted. One structure is traditional RC frame-shear wall, and theother is self-centering frame-shear wall that every coupling beam isequipped with SMA damper. The tests show that the damage of coupling beams and wall limbs in the self-centering frame-shear wall is remarkablyreduced compared with traditional RC structure. The structure with SMAdampers in coupling beams has stable energy dissipation capability. Afterearthquake, the deformation of the SMA damper can restore automaticallyand the building function can recover immediately.