Study On Mechanical Properties And Application Of SMA Composite Isolation Rubber Bearing

The occurrence of the earthquake has caused great damage to the bridge as a lifeline.There are many bridges built and under construction in China.In view of the good development of the bridge,how to improve and evaluate the seismic capacity of bridges is of great significance.In order to optimize the seismic performance of the bridge,the shape memory effect and superelastic effect of the shape memory alloy are combined with the LRB to form a composite isolation rubber bearing,and the new type of bearing is used in isolated continuous girder bridges.The research in this paper mainly includes the following contents:(1)Experimental study on mechanical properties of SMA-isolated rubber bearings:firstly,the mechanical properties of SMA wire are studied,including the influence of strain amplitude,loading rate and SMA wire diameter material.,the constitutive model and related parameters were obtained;SMA-LNR and SMA-LRB were tested on the mechanical properties of different arrangements and the quantity of SMA wires and their hysteretic behavior curves were obtained,the mechanics of the two bearings and the unconfigured SMA wire were tested at the same time,the comparative analysis of the performance parameters shows that the two-line cross arrangement can make a greater contribution than the single-line cross arrangement,and the composite isolated rubber bearings have better performance than the isolated rubber bearings.(2)Finite element simulation of SMA-isolated rubber bearings:firstly,the finite element software ANSYS was used to simulate SMA,LNR and LRB,and the correctness of the simulation method was verified;then the model of the composite bearing is obtained by superimposing the isolated rubber bearing and the SMA simulation constitutive model,the model is compared with the experimental results to verify the correctness of the constitutive model;finally,the simulations of the composite bearings with 10,20,40,60,80 and 100 SMA wires are compared and analyzed,the result shows that the more the SMA wire is configured,the greater the horizontal stiffness and energy consumption of the composite bearings.(3)Application of SMA-isolated rubber bearings in continuous girder bridges: firstly,the finite element software OpenSees is used to compare the seismic response of isolated continuous girder bridges using LRB and SMA-LRB,the analysis results show that SMA-LRB can better reduce the residual displacement of main components of bridge such as main beams and bearings compared with LRB;then the seismic demand analysis of the bridges using these two bearings is carried out to obtain their seismic demand model;finally,the fragility curve of the bridges is obtained,the analysis of the curves show that the use of SMA increases the seismic response of the pier,but SMA-LRB has better self-reset and energy dissipation than LRB.