Seismic Performance Of Frame-shear Wall Structure With Novel Coupling Beams Using SMA Dampers

With the development of social economy and the speeding process of urbanization in our country, more and more high-rise buildings are built nowadays and they are becoming an important part of infrastructures in modern cities. In these buildings, frame-shear wall is usually adopted as load bearing system because it has excellent earthquake resistance ability. At the same time, frame-shear wall provides the buildings large space that can be arranged flexibly. In conventional seismic design methods for civil infrastructures, coupling beams in frame-shear wall are often used as fuse element. That is coupling beams must yield and dissipate earthquake energy before frame and shear wall. Structural period can be reduced with the yielding of coupling beams and then resonance of structures with earthquakes can be avoided. However, the yielding of coupling beams will induce damage in structures. Rehabilitation of coupling beams is difficult and the cost is large.Shape memory alloy (SMA) is a kind of smart material with versatile properties. It started to be used as passive energy dissipation divices for civil infrastructures since 1990s. Because of its pseudoelastic behaviour, the passive dampers developed by SMA do not have residual deformation after earthquake. Then it does not need to be repaired or replaced after earthquakes. At the same time, this type of dampers also has good energy dissipation capability. In this study, SMA dampers were proposed to be installed under coupling beams in frame-shear wall structures through diagonal braces. The characteristic parameters of SMA dampers, together with the installation method and position of these dampers were investigated.The main contents are included as follows:First, in order to simulate seismic responses of shear wall using the multiple vertical line element model (MVLEM), the constitutive model of shear spring in MVLEM was developed based on the platform of Open System for Earthquake Engineering Simulation (OpenSEES). The program of this constitutive model was compiled by authors. In order to verity the accuracy of this program, the simulatied force and deformation of a shear wall modeled by MVLEM were compared with corresponding experimental results.Second, a piecewise linear model was proposed to describe pseudoelastic behaviour of SMA. The program of this model was compiled and inserted into OpenSEES. In order to demonstrate accuracy of this program, the SMA dampers described by the piecewise linear model were installed in a benchmark frame structure developed by Tongji University. The simulated hysteretic behaviour of SMA dampers was observed to check if it is consistent with the target of the program.Last, SMA passive dampers are proposed to be installed into a 7-story frame-shear wall structure. The dampers were mounted under the coupling beams between shear wall limbs. The influence of characteristic parameters of the dampers on structural seismic responses was investigated. Also, the installation method and installation position of the SMA dampers were addressed.