考虑加载循环次数影响的弯剪破坏RC柱荷载-变形关系计算模型及其抗震性能评估

Load-deformation relationship calculation model and seismic performance evaluation of RC columns subjected to flexural-shear failure considering influences of cycle number

为研究不同循环次数地震作用下弯剪破坏型钢筋混凝土(RC)柱的抗震性能,对2组(8根)不同剪跨比的RC圆柱进行了不同循环次数的拟静力试验。研究了不同加载循环次数作用下弯剪破坏RC圆柱的变形性能和滞回特性,基于试验结果提出了不同加载循环次数下弯剪破坏RC圆柱的荷载-变形关系计算模型和等效阻尼比模型,并给出了考虑地震作用循环次数影响的弯剪破坏单柱墩结构的抗震性能分析方法。结果表明:加载循环次数越多,RC柱剪切效应越显著,水平承载能力和变形能力降低越明显,这一循环退化效应引起的RC柱抗震性能下降现象应在分析中予以考虑;提出的不同加载循环次数下弯剪破坏RC圆柱的荷载-变形关系模型和等效阻尼比模型计算值与试验值吻合较好,可用于考虑不同循环次数影响的地震作用下弯剪破坏RC圆柱荷载-变形关系建立和抗震性能评估。

In order to study the seismic behavior of reinforced concrete(RC)columns failed in flexural-shear under seismic excitation with different cycles,two groups(eight specimens)of circular RC columns with different shear span ratios were tested under quasi-static loading with different cycles.The deformation properties and hysteretic characteristics of RC columns failed in flexural-shear under different cycles were studied.Based on the experimental results,the load-deformation relationship and equivalent damping ratio calculation model for RC columns failed in flexural-shear under different cycles were proposed,and the seismic behavior analysis method of the single pier structure failed in flexural-shear considering the influence of the number of cycles was given.The results show that the shear effect increases obviously with the increase of loading cycles,thus reducing the lateral bearing capacity and deformation capacity,which should be considered in seismic behavior analysis.In addition,the proposed load-deformation relationship and equivalent damping ratio calculation model for RC columns failed in flexural-shear under different cycles can be used to establish the load-deformation relationship and evaluate energy dissipation capacity of RC columns failed in flexural-shear under different cycles of seismic action,and the predicted results are in good agreement with the experimental results.