钢筋混凝土构件动态剪切行为及动态抗剪理论研究

Under strong earthquake and impact load, dynamic load components will induce the shear effect of reinforced concrete (RC) members. So, the RC member designed to the ductile failure should occur the brittle shear failure, which reduced seriously the ductility and energy dissipation capacity of RC members. The shear failure of RC members should cause the local brittle damage of RC structure and further lead to the progressive collapse of RC structure. In order to solve this kind of disaster problems, firstly, the dynamic shear tests of the concrete material and three kinds of typical RC member should be carried out to study the effect of the loading rate, reinforcement ratio, shear span ratio or axial compression ratio on the failure mode, shear bearing capacity, deformation properties and the energy dissipation of RC members. Secondly, the multi-scale computation model and computational method of RC members should be established to simulate the dynamic shear response of RC members and verify the dynamic shear test results. Finally, according to the results of the test and numerical analysis, the dynamic shear theory of RC members should be researched from two aspects: on the one hand, taken into account the effect of loading rate on the dynamic behaviors of concrete material and the failure mode of RC members, the dynamic shear design theory of RC members should be modified and improved. On the other hand, taken into account the effect of loading rate on the dynamic bearing capacity and deformation behaviors of RC members, the dynamic analysis model of RC member should be established.

强震和冲击荷载作用下，动态荷载分量会诱发钢筋混凝土构件的剪切效应，致使按延性设计的钢筋混凝土构件发生脆性剪切破坏，严重降低钢筋混凝土构件的延性和耗能能力，引起脆性局部破坏，并进一步导致结构发生连续倒塌破坏。本项研究针对这类灾害问题，首先对混凝土材料和三类典型钢筋混凝土构件进行动态剪切试验，研究加载速率、配筋率、剪跨比或轴压比对构件破坏模式、抗剪承载力、变形性能和耗能能力的影响；其次，建立钢筋混凝土构件多尺度计算模型，采用多尺度研究方法，对三类典型钢筋混凝土构件进行全面动态剪切数值分析，并验证动态剪切试验结果；最后，根据试验和数值分析结果，从两个方面研究钢筋混凝土构件的动态抗剪理论：考虑加载速率对材料动态性能以及对构件破坏模式的影响，修正和完善钢筋混凝土构件动态抗剪设计理论，建立抗剪设计方法；考虑加载速率对钢筋混凝土构件动态承载能力和变形性能的影响，建立钢筋混凝土构件动态计算分析模型。

强震和冲击荷载作用下，动态荷载分量会诱发钢筋混凝土构件的剪切效应，致使按延性设计的钢筋混凝土构件发生脆性剪切破坏，严重降低钢筋混凝土构件的延性和耗能能力，引起脆性局部破坏，并进一步导致结构发生连续倒塌破坏。本项研究针对这类灾害问题，首先对混凝土材料和三类典型钢筋混凝土构件进行动态剪切试验，研究加载速率、配筋率、剪跨比或轴压比对构件破坏模式、抗剪承载力、变形性能和耗能能力的影响；其次，建立钢筋混凝土构件多尺度计算模型，采用多尺度研究方法，对三类典型钢筋混凝土构件进行全面动态剪切数值分析，并验证动态剪切试验结果；最后，根据试验和数值分析结果，从两个方面研究钢筋混凝土构件的动态抗剪理论：考虑加载速率对材料动态性能以及对构件破坏模式的影响，修正和完善钢筋混凝土构件动态抗剪设计理论，建立抗剪设计方法；考虑加载速率对钢筋混凝土构件动态承载能力和变形性能的影响，建立钢筋混凝土构件动态计算分析模型。