DS-SCB Braces And Its Seismic Reduction Application In Double-column Piers

Traditional brace will buckle instability under compression,which can not effectively dissipate the seismic energy.Buckling restrained brace(BRB)is an excellent damping element that does not buckle in state of tension or compression.However,BRB dissipates the seismic energy through plastic deformation of its steel,which leads to a large residual deformation after earthquake,Excessive residual deformation can lead to the collapse of structure or increase the difficulty after earthquake-repair.In order to solve the problem of excessive deformation of BRB,many scholars have proposed braces which have the characteristic of energy dissipation and self-centering,but most of existing self-centering braces adopted tensile material as self-centering element.In this paper,we combine combined disc spring that used as self-centering element with energy dissipation mechanism of soft steel,and propose a disc-spring self-centering buckling-restrained brace(DS-SCB),the following research were made:(1)The construction and working principle of DS-SCB were described in detail,the restoring force model of DS-SCB was established theoretically,the parameters which affect self-centering performance and energy dissipation were analyzed.(2)The performance of disc spring and the design of the combined disc spring were described.In order to verify mechanical properties of the combined disc spring and the BRB energy dissipation system and the SC system of DS-SCB,the BRB system and the SC system were designed separately to BRB and SCB brace,a combined disc spring device and three different conditions of brace were tested under low cycle loading.(3)Combining with the experimental results,the influence of stiffness and friction of combined disc spring were discussed.The failure characteristic of braces were discussed.The hysteresis curves and the skeleton curves of braces were studied.The bearing capacity,self-centering displacement and energy consumption were analyzed.The correctness of the restoring force model was verified by comparing tested curves and curves calculated by the restoring force model.(4)The structure model of three-span continuous bridges with double-column piers were established.The design of the brace in piers were described.The dynamic time history analysis were carried out with BRB-double-column piers,DS-SCBdouble-column piers and original-double-column piers.The effect of different brace on dynamic damping performance of original-double-column piers were studied.