动态荷载下约束再生混凝土本构关系试验研究及其应用

Experimental study on constitutive relation of confined recycled aggregate concrete and its application under dynamic loading conditions

通过箍筋约束再生混凝土短柱动态力学试验,获得了应力-应变试验曲线,研究应变率效应、箍筋约束效应和再生粗骨料取代率对约束再生混凝土力学和变形性能的影响。基于试验结果,提出了考虑应变率效应、约束效应和再生粗骨料取代率影响的约束再生混凝土(CRAC)单轴受压应力-应变关系模型。将提出的CRAC材料模型应用于再生混凝土结构的动力非线性分析。结果表明:结构动力分析结果和已有试验结果吻合较好,考虑应变率效应后,其计算结果与试验结果更为接近,更能真实地反映结构在地震动下的力学行为。验证了计算程序的可行性,以及所建议的CRAC材料模型的合理性,为再生混凝土结构动力非线性分析和抗震优化设计提供参考。

The dynamic tests of recycled aggregate concrete (RAC) short columns confined by transverse hoops were carried out. Based on the obtained measured stress-strain curves, the influences of the strain rate effect, the confinement effect and the replacement percentage of recycled coarse aggregate (RCA) on the mechanical and deformation performance of confined recycled aggregate concrete (CRAC) were thoroughly investigated. Based on the dynamic test results of the CRAC specimens, the analytical model of the uniaxial compressive stress-strain relation for CRAC was proposed by applying the dynamic increase factor (DIF), confining increase factor (CIF), and replacement influence factor (RIF) to the characteristic parameters. The proposed CRAC material model was employed in the dynamic nonlinear analysis of RAC structures. It is found that the values obtained from the analytical results agree well with experimental results. However, the numerical simulation results in which the strain rate effect is taken into account are more close to the experimental results, and more reasonably to capture the mechanical behaviors of RAC structures subjected to earthquake ground motions. It is indicated that the employed calculation program is operable, and the proposed CRAC material model is reasonable. The results provide a significant research foundation for the dynamic nonlinear analysis and seismic optimum design of RAC structures. © 2016, Editorial Office of Journal of Building Structures. All right reserved.