Dynamic Performance Analysis Of Buckling Restrained Brace In Large Cantilever Structure

With the development of our society,the large cantilevered frame structure has a tendency to increase day by day.However,due to its easy damage occurs,and therefore improve the seismic performance of large cantilevered frame structures become the focus.Traditional structural design will make part of the structure deformations to be too large,and can not meet its safety requirements.The energy-consuming and shock-absorbing technology deploys energy-consuming equipment in relatively weak parts of the structure to use its deformation to absorb seismic wave energy,to ensure the safety of the main structure.Among them,the buckling restrained brace(BRB for short)has excellent performance in hysteretic energy dissipation.Therefore,this paper systematically study the dynamic performance of the BRB in large cantilevered frame structures under seism action,aiming to provide a reference for the seismic design of similar structures.In this paper,the research work is as follows:(1)Briefly introduce the working principle of the BRB.Using SAP2000 finite element software,a finite element model of the BRB structure with a pure cantilever frame structure and an arrangement of ordinary steel supports and four different arrangements is established.(2)Perform response spectrum and linear time history analysis of each model to know under frequent seism conditions,reasonably arranged BRBs are basically the same as ordinary steel supports.both can effectively improve the seismic response of the original structure.(3)Perform dynamic elastoplastic analysis of each model to know under rare earthquakes conditions,the BRBs have excellent hysteretic performance,which shares part of energy,effectively protects the main structure,and its shock absorption performance is significantly better than ordinary steel support.The development process of plastic hinges clearly shows that ordinary steel supports are prone to failure and damage under rare earthquakes,lose bearing capacity,and endanger structural safety.BRBs can effectively control the development of structural plastic hinges.(4)Analyzing the comparison results of various layout schemes,it shows that the BRB is arranged close to the root of the cantilever and its performance is better,and it is verified that the two kinds of unreasonable BRBs layout schemes,which do not arrange cantilever roots BRBs and which do not arrange first and second BRBs have adverse effects on the structure.(5)The elasticity and elastoplastic analysis results of each model in the sole action of vertical seism indicate that the influence of vertical seism on the large cantilever frame structure is important and cannot be ignored.The seismic response law of each model is similar to that under three-dimensional earthquake.(6)Establish a number of calculation models with different positions and numbers of BRBs,through comparative analysis,using the displacement angle between floors as the representative result.further explore the law of the influence of the BRB layout on large cantilevered structures.