考虑循环荷载作用历史的弯剪破坏RC柱抗震性能及地震损伤机理研究

Reinforced concrete (RC) columns (including frame columns, piers and piles, etc.) are vulnerable to flexural-shear or shear failure with low ductility during earthquakes due to inappropriate seismic design, poor shear details and random seismic loading, thereby causing a total or partial structural collapse of the buildings. In order to prevent the shear failure of RC members and reasonably assess the seismic performance and damage status of flexural-shear critical RC members under random seismic loading, a research project on the seismic performance and seismic damage mechanism of flexural-shear critical RC columns including the influences of cyclic loading history is carried out based on the experimental study and theoretical analysis. In this research, the seismic damage status, failure modes as well as their identification methods of RC columns subjected to different cyclic loading history (including the effects of loading sequence, number of cycles and displacement amplitude) are studied. Low cycle fatigue properties and damage mechanism of flexural-shear critical RC columns are studied based on the quasi-static tests with different loading displacement amplitudes, and seismic damage models of flexural-shear critical RC columns considering the effects of cyclic loading history are presented. In additon, the analytical methods of lateral load-deformation relationship and seismic performance for the flexural-shear critical RC columns including the effects of cyclic deterioration are also developed based on the experimental results. In conclusion, research results in this research project will contribute to deepen the understanding of shear failure mechanism and seismic damage properties of RC members under seismic loading, and also provide a theoretical basis for improving the current seismic performance analysis and design methods of RC structures or members.

钢筋混凝土（RC）框架柱、桥墩及桩等由于设计不合理、抗剪措施不当及遭受复杂地震作用会发生低延性的弯剪或剪切破坏，从而引发结构整体或局部倒塌。为防止随机地震作用下RC构件发生剪切破坏以及合理评估弯剪破坏RC柱的抗震性能和损伤状态，本项目通过试验结合理论分析开展考虑循环荷载作用历史的弯剪破坏RC柱抗震性能及地震损伤机理研究。主要研究内容包括：循环加载模式（考虑加载顺序、循环次数及位移幅值影响）对RC柱破坏模式和损伤状态的影响，建立考虑循环荷载作用路径影响的RC柱地震破坏模式判别方法；弯剪破坏RC柱在不同加载位移幅值下的低周疲劳特性和损伤破坏机理，建立考虑循环荷载作用历史的弯剪破坏RC柱地震损伤模型；提出考虑循环退化效应影响的弯剪破坏RC柱荷载-变形关系及抗震性能分析方法。研究成果有助于深化地震作用下RC构件剪切破坏机理以及损伤特性的认识，为完善现有结构或构件抗震性能分析和设计方法提供理论依据。

为防止随机地震作用下钢筋混凝土（RC）柱发生剪切类破坏以及合理评估弯剪破坏RC柱的抗震性能和损伤状态，本项目通过试验研究和理论分析开展了考虑循环荷载作用历史的弯剪破坏RC柱抗震性能及地震损伤机理研究。开展了不同加载模式下RC柱地震破坏模式及抗震性能研究，分析了加载循环次数对弯剪破坏柱变形性能及受剪承载力的影响，并基于试验结果提出了考虑循环加载次数影响的RC柱受剪承载力计算模型和荷载-变形关系计算模型；提出了考虑塑性变形和累积滞回耗能影响的弯剪破坏RC柱地震损伤模型，以评估地震作用下弯剪破坏RC柱的损伤状态；同时开展了纤维网增强混凝土（TRC）复合材料加固弯剪破坏柱抗震性能研究，提出了TRC加固柱荷载-变形曲线分析模型和抗震性能分析方法。本项目研究成果对于明确地震作用下RC柱的损伤破坏机理、改进RC结构的抗震设计方法、提高弯剪破坏RC柱的抗震性能等具有重要意义，为进一步完善现行RC结构抗震设计理论和保证大震作用下结构的抗倒塌能力提供理论基础。在该项目研究中，目前发表（含录用）论文12篇，其中SCI收录2篇、EI收录（一级学报论文）2篇；申请专利8项，目前授权3项；共培养硕士研究生8名，目前已毕业3名，5名在读。后续论文成果整理和研究生培养的工作目前也在持续开展。