Mechanical Behaviors Of Bolted Coreless Self-centering Braces

Earthquake is a serious threat to human life.Traditional seismic design method sacrifices structural integrity,which will inevitably introduce residual deformation after medium to large earthquakes,and seriously increase the cost of structural repair.Therefore,how to control the residual deformation of the structure after earthquake is very important.In this paper,a Bolted Coreless Self-Centering Brace(BCLSCB)is proposed to reduce the residual deformation of structure after earthquake,and it can be used together with different dampers to reduce the maximum deformation of a structure.The BCLSCB has the advantage of being easy to install and replace compared to the team’s previous research.In this paper,the mechanical properties of its stiffness,elastic bearing capacity and stability capacity are studied.The main contents are as follows:(1)The configuration of BCLSCB was described,and the restoring force curve of BCLSCB was obtained through ABAQUS simulation.According to the configuration of BCLSCB,the simplified spring model was given,and theoretical formulae for calculating the stiffness of each stage of the bilinear elastic restoring force model were obtained.Parameter analysis of BCLSCB was carried out,and the fitting formulae of initial stiffness were proposed based on the parameter analysis results and theoretical formulas.Based on the principle of interpolation and extrapolation,four groups of new size models were created to verify the applicability of the formulae.(2)To ensure the BCLSCB to work in an elastic range during expected earthquakes,it is necessary to understand the elastic bearing capacity and elastic deformation capacity of the BCLSCB.The influence of different structural parameters on the elastic bearing capacity and elastic deformation capacity is studied considering four failure conditions controlled respectively by angle steel,reduction reinforcement,rectangular plate and outer casing,and left T-plate and inner casing.The fitting formulae of the elastic bearing capacity under different control zones are given.(3)The eigenvalue instability includes local instability and global instability.In the case of integral instability,the first-three-order instability modes and the first-order instability bearing capacity of the BCLSCBs,and that of the inner and outer casings are studied.The nonlinear instability mode and bearing capacity of BCLSCBs were studied considering material nonlinearity and geometric imperfections.The constraint from the end plates on the inner and outer casings during compression is studied.