同级位移多次循环作用下型钢混凝土柱地震损伤分析

Seismic damage analysis of steel reinforced concrete columns under repeated equal displacement cycles

传统拟静力加载试验不能考虑长周期地震动作用特性的影响,无法准确评估长周期地震动作用下SRC柱的损伤程度。采用屈服后每级水平位移循环10次的长周期加载制度模拟长周期地震动作用,比较研究了SRC柱的损伤发展过程。结果表明:峰值荷载后,位移多次循环作用使SRC柱的损伤开始快速增长乃至急剧发展,随着同级位移循环次数的增加,长周期加载试件的裂缝宽度增大、损伤程度加重,达到相同破坏特征时对应的位移角减小。考虑混凝土开裂、有效滞回耗能对SRC柱损伤的影响,建立了基于最大位移和有效累积滞回耗能组合的SRC柱双参数地震损伤模型,评估了含钢率、配箍率和轴压比对SRC柱地震损伤的影响,分析表明该模型能够很好地描述SRC柱的损伤发展历程。结合试验现象和损伤指数计算结果,给出了SRC柱不同损伤程度对应的损伤指数范围。

The conventional quasi-static loading test can not consider the influence of long-period ground motion,and can not accurately evaluate the damage degree of SRC column under long-period ground motion.The long-period loading system with 10 horizontal displacement cycles after specimen yield was used to simulate the long-period ground motion,and the damage development process of SRC columns were studied comparatively.The results show that after the peak load,the damage of SRC column begins to increase rapidly and even develop rapidly due to repeated equal displacement cycles.With the increase of the number of repeated equal displacement,the crack width and damage degree of long-period loaded specimens increase,and the corresponding displacement angle decreases when reaching the same failure characteristics.Considering the effects of concrete cracking and effective hysteretic energy dissipation on the damage of SRC columns,two-parameter seismic damage model of SRC column based on the combination of the maximum displacement and effective cumulative hysteretic energy dissipation was established,and the effects of steel ratio,stirrup ratio and axial compression ratio on seismic damage of SRC columns were evaluated.The analysis shows that the model can well describe the damage development process of SRC columns.Combined with the experimental phenomena and damage index calculation results,the damage index ranges corresponding to different damage degree of SRC columns were given.