摆式惯容-零二次刚度自复位阻尼器并联加固双柱墩抗震性能研究

Seismic performance of a double-column bridge retrofitted with a self-centering damper with a zero secondary stiffness and a pendulum-based inerter in parallel

提出一种由摆式惯容(PI)和零二次刚度自复位阻尼器(ZSCD)并联组成的新型阻尼系统(IZSCD),用以加固钢筋混凝土双柱墩,以减轻自复位支撑加固对双柱墩桥基底剪力及加速度的不利影响。通过对IZSCD加固结构单自由度线性化系统的卷积积分和数值时程分析,提出并验证了含惯容系统位移反应谱。基于该反应谱,用直接基于位移设计(DDBD)方法对IZSCD加固双柱墩进行抗震设计,并用弹塑性时程分析验证了设计结果。进而研究了惯质比和杠杆放大比等对加固结构抗震性能的影响。结果表明,所提出IZSCD能有效减小自复位加固双柱墩桥的加速度和基底剪力。该研究提出了一种兼顾位移、加速度和基底剪力的双柱墩自复位加固技术,并为该类加固结构的抗震设计提供指导。

A novel damping system(IZSCD),consisting of apendulum-based inerter(PI)and a self-centering damper with zero secondary stiffness(ZSCD)in parallel,was proposed to retrofit the double-column bridge bent,aiming to reduce the increment of base shear and acceleration of the bridge induced by the self-centering dampers(SCDs).Through the convolution integral and numerical calculation of the equivalent linearized single-degree-of-freedom system of the retrofitted structure,the displacement response spectrum of the system with inerter was developed and verified.Based on this spectrum,the seismic design of the bridge bents with IZSCD was carried out by the direct displacement-based design method,which was verified by elastic-plastic time history analysis.The effects of inertance-mass ratio and amplification factor of the lever on the seismic performance of the retrofitted bridge bents were investigated.Results show that IZSCD can effectively mitigate the acceleration and the base shear of the bridge bent with self-centering dampers(SCD).The research provides a method and a guideline for retrofitting the double-column bridge bent to consider the displacement,base shear and acceleration simultaneously.