【摘要】 混凝土是一种率敏感性材料,正确把握应变率效应对钢筋混凝土构件在强震等动力荷载下力学性能的影响,对结构抗震和抗风设计至关重要。采用CEB规范建议的考虑混凝土应变率效应的动力本构关系,运用纤维模型对钢筋混凝土柱在不同加载速率下的动力性能进行了数值模拟。对4个钢筋混凝土柱构件的快速加载试验的试验结果与模拟结果进行比较,结果表明所建立的纤维单元模型能够较好预测混凝土柱恢复力特性,验证了基于动力本构的纤维单元模型的有效性。基于此模型,研究了不同纵向配筋率和体积配箍率对钢筋混凝土柱动力性能的影响,结果表明纵向配筋率和体积配箍率对动力性能的影响呈现出不同的特征。更多还原

【Abstract】 The mechnical characteristics of concrete is sensitive to the strain rate and it is crucial to consider the effect of load rates on the behavior of reinforced concrete(RC) structures subjected to dynamic loads such as severe earthquakes.In this study,numerical simulations on the dynamic behavior of typical RC column specimens under dynamic loadings with different load rates were performed.Concrete constitutive model considering the strain rate effects proposed by the CEB code was employed with a fiber model to characterize the nonlinear strain rate dependent behavior of RC columns.The developed dynamic fiber element model was validated by comparing the simulated results of four RC column specimens with the fast loading test results.Results show that the developed fiber element model can predict the behavior of RC columns with acceptable accuracy.After valiating the proposed fiber elemen model considering the strain rate effect,the load carrying capacity of different RC columns with various longitudinal reinforcement ratios and volumetric stirrup ratios were simulated.Results show that the trends of the influences of longitudinal reinforcement ratios and volumetric stirrup ratios on the load carrying capacity of the RC columns under dynamic loadings are different.更多还原