Study On Seismic Performance Of Buckling-Restrained Brace With Corrugated-Steel Core

Because of its light weight,simple manufacture and design,easy to replace after earthquake and good energy dissipation performance,the all-steel buckling-restrained braces with single plate is widely used in the seismic design of different structures.However,during the transition from first-order to higher-order deformation of the core unit,fatigue damage is easily generated at the wave initiation,which reduces the energy dissipation performance.To solve the these problems,a new type of Buckling-restrained brace with corrugated-steel core(CSC-BRB)is proposed.The core element member adopts the construction mode of "corrugated steel plate" along the thickness direction of the energy-dissipating core element.The purpose is to reduce the large fatigue damage at the beginning of the wave when the core is transiting from first-order deformation to high-order deformation.Meanwhile,the length of the energy-dissipating section is relatively increased through the pre-designing the corrugation,and the energy-dissipating performance of the BRB is increased.In this paper,the energy dissipation performance,stress distribution and the formation mechanism of high-order deformation of CSC-BRB were studied through experiments and finite element analysis,and the influence of different wave number and wave height on the performance of CSC-BRB was investigated.The main research contents and conclusions of this paper are as follows:(1)Study the structural rationality and feasibility of corrugated steel plate buckling restrained brace;The main mechanical properties calculation method of corrugated steel plate buckling restrained brace and the stability performance verification method are presented.(2)A pseudo-static test was carried out on seven new corrugated steel plates with different wave heights and different wave numbers to study the mechanical properties and stability of CSC-BRBs.The results show that the design of reasonable ripples has little effect on the main mechanical properties of BRBS,but when the wave heights are large,The compression side of hysteresis curve has obvious jitter phenomenon.When the wave number is the same,the stiffness and yield force of BRB decrease with the increase of wave height.When wave height is the same,the stiffness and yield force of BRB decrease with the increase of wave number.When the wave number is large(> 12)and the wave height is large(> 8mm),the stiffness and yield force of BRB decrease obviously.BRB-0-1 without wave has the best energy dissipation performance,but BRB-4-4 has the highest cumulative plastic ductility coefficient CPD and total energy dissipation,indicating that reasonable corrugation design can increase the cumulative energy dissipation capacity of BRB.(3)The finite element analysis of CSC-BRB with different design parameters was carried out to investigate the effects of different wave numbers and wave heights on the mechanical properties,stress distribution,cumulative plastic strain and the formation process of higher-order deformation of CSC-BRB.The results of the study showed that the core unit of CSC-BRB produced multi-wave deformation directly when it was compressed,which achieved the expected design purpose;The stress increase during the transition from first-order to higher-order deformation of the CSC-BRB core unit is small,and the deformation is mainly concentrated at wave initiation,reducing the fatigue damage at the wave initiation during the transition from first-order to higher-order deformation of the core;the higher the wave height,the more obvious the jump in the hysteresis curve of the CSC-BRB;the more the number of waves,the greater the influence on the mechanical properties of the CSC-BRB;the fatigue properties of the members with a wave number of 4are all better than those of the members with no waves or the rest of the wave numbers.(4)(4)Propose a design method for dual CSC-BRB energy dissipation and seismic reduction structures,and provide the design process.Taking a practical project using CSC-BRB as an example,the entire process of designing and analyzing BRB energy dissipation and seismic reduction structures is demonstrated.The analysis results indicate that after the installation of CSC-BRB in the structure,the interlayer displacement angle can meet the requirements of the specifications,reach the design level of "no damage during small earthquakes,no collapse during large earthquakes",and achieve the preset energy dissipation and seismic reduction goals.The proposed CSC-BRB energy dissipation and seismic reduction structure design method is reasonable and feasible,and can be used for practical engineering analysis and design.