钢筋混凝土柱变形性能指标限值及其试验验证

基于收集的469个钢筋混凝土(RC)柱低周往复荷载试验结果,对RC柱破坏形态的影响因素进行研究,提出以剪跨比和弯剪比为参数划分RC柱破坏形态的方法.根据我国现行规范将RC柱的抗震性能状态划分为7个等级,基于构件的力-位移角骨架曲线的3个关键性能点(屈服点、承载力退化20%点及丧失承载能力点)提出RC柱各性能状态变形指标限值的确定方法.结合469个RC柱试验结果的回归分析,确定不同破坏形态RC柱的变形性能指标限值,并对该变形性能指标限值体系进行易损性评估.进行11个RC柱的拟静力试验,利用试验结果进一步验证本文提出的RC柱变形性能指标限值.结果表明:本文提出的RC柱变形性能指标限值的准确性、离散性及超越概率均在合理范围内.

Deformation Limits of Reinforced Concrete Columns and Their Experimental Verification

Parameters affecting the failure modes of reinforced concrete (RC) columns were investigated using low frequency cyclic loading experimental data from 469 reinforced concrete (RC) columns. A method using shear span ratio and moment shear ratio as parameters was proposed to classify the failure modes of RC columns. With reference to the current codes for seismic design, the performance states of RC columns were divided into seven levels. And the method for determining the deformation limits of these levels were put forward. The proposed method was based on three key performance points (point of yielding, point of losing 20% load capacity, point of losing bearing capacity) of the force displacement backbone curves. Regression analyses of deformation limits of RC column, considering multiple combination of parameters, were performed using the collected test data of 469 RC columns, and deformation limits of RC columns of different failure modes were put forward using the most statistically significant regression formula. The proposed deformation limits were then evaluated using fragility analysis method. Finally, quasi static tests on 11 RC columns were conducted and used to verify the proposed deformation limits. The results show that the accuracy, the discreteness and the failure probability of the deformation limits are all within reasonable range.