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基于22根具有不同配筋率和配箍率的钢筋混凝土梁试件的变幅加载试验,研究钢筋混凝土梁的变幅滞回性能、承载力和加载刚度的衰变规律及其损伤评估方法,提出变幅滞回荷载作用下钢筋混凝土梁的损伤量化指标,分析了峰值位移、累积滞回耗能和加载历程对RC梁损伤的影响。研究表明:对于变幅滞回荷载作用下钢筋混凝土梁,耗能能力衰减指数、承载力衰减指数和加载刚度衰减指数的发展不完全同步,但三者都与历史峰值位移、累积滞回耗能有关;耗能能力衰减指数与承载力衰减指数呈波动型非单调增长,而加载刚度衰减指数呈单调增长趋势,因此加载刚度衰减指数更适合用来作为变幅滞回钢筋混凝土梁的损伤评价指标;当RC梁的延性系数较小时(珔μk,max<3),其损伤与延性系数保持正相关关系,累积滞回耗能数量和峰值位移出现时点对这一关系影响甚微,而配箍率的增加能够明显降低RC梁的损伤。因此,控制延性系数并提高配箍率是控制RC梁地震损伤的一个稳定而有效的途径。
Based on the luffing loading tests of 22 reinforced concrete beam specimens with different reinforcement ratio and stirrup ratio, the decay laws and damage assessment methods of RC hysteretic properties, load bearing capacity and loading stiffness of reinforced concrete beam are studied. The damage quantification index of RC beams under variable hysteresis is analyzed. The influence of peak displacement, accumulated hysteretic energy dissipation and loading history on the damage of RC beams is analyzed. The results show that for the RC beams under variable amplitude hysteresis loading, the development of attenuation index, load capacity attenuation index and loading stiffness attenuation index are not completely synchronized with each other, but all of them are related to the historical peak displacement and cumulative hysteresis , And the decay index of energy-dissipating capacity and load-bearing decay index fluctuated non-monotonically, while the load stiffness decay index showed a monotone increasing trend. Therefore, the loading stiffness decay index is more suitable for the damage evaluation index ; When the ductility coefficient of RC beam is small (珔 μk, max <3), the damage and ductility coefficient keep a positive correlation, and the cumulative hysteresis energy dissipation and peak displacement appear to have little effect on the relationship The increase of the hoop rate can obviously reduce the damage of the RC beam. Therefore, controlling the ductility coefficient and increasing the stirrup ratio is a stable and effective way to control the seismic damage of RC beams.