Research On Seismic Damping Mechanism Of BRB-based Double-column Bridge Piers

Double-column bridge piers are the most common substructure forms of highway bridges.However,in recent years,the occurrence of bridge damage in all over the world has demonstrated the vulnerability of double-column bridge piers under strong earthquakes,especially the pier with low early fortification level and small volume reinforcement ratio.How to improve the seismic performance of these double-column bridge piers is particularly important.In view of this,a Buckling-restrained Braces(BRB)was installed in the double-column bridge piers to improve the seismic performance of the bridge piers in the transverse direction in this paper,and the damping mechanism of BRB in double-column pier was analyzed based on that.Based on extensive reading of related literatures both at home and abroad,this article had conducted the following researches:1.Taking the single pier model as the research object,the working mechanism of BRB changing the inertia force transmission path in the substructure system was revealed through static analysis.2.The static analysis bridge piers are brought into the original bridge to verify the correctness of the static analysis of the single pier model.The dual working mechanism of BRB in the double column pier seismic system was proposed to change the force path of the substructure and the hysteretic energy consumption.The influence of BRB layout and core section area on the damping mechanism in bridge pier system was discussed based on this.3.Taking two kinds of continuous beam bridges with different piers as the research object,the effects of the BRB layout and the yield strength of the core material on the seismic response of the bridge ware analyzed.The optimal placement of BRB in two structural forms and the reasonable value of yield strength of core segments ware proposed.4.Based on the pseudo-static experiment of a double-column bridge pier,the numerical analysis model of the bridge pier was established by OpenSees,and the accuracy of the numerical analysis model was verified.BRB was installed laterally in a double-column bridge pier based on this model.By applying the pseudo-static low cycle reciprocating load on the pier model,the effect of hysteretic curve,skeleton curve and energy dissipation capacity of double column pier with BRB in different reinforcement ratio,pier column spacing and pier height is analyzed.On this basis,it is put forward in the reinforcement of the old bridge.The suggestion for using BRB as energy dissipation element in old bridge reinforcement was put forward based on this.