基于抗侧刚度比的防屈曲支撑组合框架优化研究

Optimization Research of Buckling Restrained Brace Composite Frame based on Lateral Stiffness Ratio

针对某26层设置了防屈曲支撑的钢管混凝土组合框架的benchmark模型,以振型分解反应谱法作为基础算法,编制了基于遗传算法的优化程序,通过改变结构各层的抗侧刚度比,对设置防屈曲支撑的钢管混凝土组合框架结构进行了防屈曲支撑截面面积的优化设计,对以变化抗侧刚度比设计的结构和以固定抗侧刚度比设计的结构进行了弹性阶段和弹塑性阶段的地震响应对比分析。结果表明：以变化抗侧刚度比设计的结构能在不减弱抗震性能的同时,减少48%的防屈曲支撑用量。在罕遇地震作用下,以变化抗侧刚度比设计的防屈曲支撑的耗能比例达54.98%,充分发挥防屈曲支撑的塑性变形能力消耗地震能量,起到保护框架梁、柱的作用。

According to a 26-storey benchmark model of concrete-filled steel tubular（CFST）composite frame with buckling restrained brace（BRB）,an optimization program was designed based on mode response spectrum method and genetic algorithm.The optimal design of cross-sectional area of BRB for CFST composite frame was presented by calculating the lateral stiffness ratio of each storey.Moreover,the seismic response during elastic and elastic-plastic stages was analyzed for of the structure designed with varying or fixed lateral stiffness ratios.The results show that the structure designed with varying lateral stiffness ratios can reduce the consumption of 48% of BRB while maintaining earthquake-resistant properties.Under the influence of rarely occurred strong earthquakes,the energy dissipation ratio of the BRB designed with varying lateral stiffness ratio is 54.98%,and the plastic deformation capacity of the BRB can effectively consume earthquake energies,which protects the beams and columns from damage.