FRP加固震损钢筋混凝土框架受力机理与抗震性能研究

Reinforced concrete frames occupy an important proportion of the earthquake-damaged structures in the earthquake-stricken areas of China. The seismic capacities of the retrofitted earthquake-damaged frames during the subsequent service period are urgently needed research. This project aims to investigate the mechanism and seismic capacities of the FRP-retrofitted earthquake-damaged frames utilizing basalt fiber reinforced polymer (BFRP) as the retrofitting material, due to the significant advantages of BFRP in cost-effectiveness and environmental protection. First, experimental and theoretical researches of the seismic capacities of the BFRP-retrofitted earthquake-damaged columns and frames are conducted under the simulated state of actual earthquake-damaged structures during retrofitting. The effects of earthquake damage level, residual displacement and axial compression ratio on the mechanism and seismic capacities of the FRP-retrofitted columns and frames are revealed and a restoring force model of the FRP-retrofitted earthquake-damaged columns is proposed. Then, a numerical analysis model for the FRP-retrofitted earthquake-damaged frames is established. The seismic response characteristic and failure mechanism of the earthquake-damaged frames after retrofitting are studied. After that, the calculation method of the seismic demand during the subsequent service period is investigated based on seismic hazard theory and an analysis method of the seismic capacities of the earthquake-damaged frames after retrofitting is proposed. At last, a performance-based seismic retrofitting method with FRP is proposed for the earthquake-damaged frames. The research of this project is beneficial to improve the strengthening theory of concrete structures and to promote the practical utilization of BFRP in the seismic retrofit of earthquake-damaged structures.

钢筋混凝土框架在我国地震灾区的震损结构中占有重要比例，震损框架加固后在后续服役期的抗震性能研究成为亟待开展的课题。玄武岩纤维增强复合材料（BFRP）具有高性价比和环保的显著优点。以其为加固材料，本项目研究FRP加固震损框架的受力机理与抗震性能。首先，模拟实际震损结构加固时的状态开展BFRP加固震损柱和框架抗震性能的试验与理论研究，揭示震损程度、残余位移和轴压比对FRP加固震损柱及框架受力机理和抗震性能的影响规律，提出FRP加固震损柱的恢复力模型；其次，建立FRP加固震损框架的数值分析模型，研究震损框架加固后的地震反应特征与破坏机制；然后，基于地震危险性理论研究震损框架在后续服役期的地震需求参数计算方法，提出震损框架加固后抗震性能的分析方法；最后，提出震损框架基于性能的FRP抗震加固设计方法。本项目的研究对混凝土结构加固理论的完善和推动BFRP在实际震损结构抗震加固中的应用具有积极意义。

本项目针对地震灾区存在的震损钢筋混凝土框架的加固问题，以玄武岩纤维增强复合材料作为加固材料，系统研究了FRP约束损伤混凝土、FRP加固震损钢筋混凝土柱以及FRP加固震损钢筋混凝土框架的力学及抗震性能，取得了如下研究成果：(1) 基于标准圆柱体的轴压试验，研究了损伤程度、FRP层数对FRP约束损伤混凝土柱轴压性能的影响规律，提出了考虑初始损伤的FRP约束混凝土强度模型、应变模型和应力—应变模型；(2) 基于OpenSees分析平台开发了FRP约束损伤混凝土材料模型，该模型可以应用于FRP加固震损钢筋混凝土柱、FRP加固钢筋混凝土框架的抗震性能分析；(3) 基于FRP加固足尺震损钢筋混凝土柱抗震性能试验，揭示了轴压比、残余位移、震损程度对FRP加固震损钢筋混凝土柱抗震性能的影响机理，验证了中等、严重震损钢筋混凝土柱经FRP加固后，延性和耗能能力均能得到显著提高，基于OpenSees分析平台建立了FRP加固震损钢筋混凝土柱的高精度有限元模型；(4) 完成了FRP加固震损钢筋混凝土框架振动台试验，研究了加固前后抗震性能的变化规律，验证了FRP用于震损结构加固的有效性，并提出了基于失效模式概念的FRP抗震加固设计方法，该加固方法可以将有薄弱节点框架的失效模式改善为强柱弱梁的失效模式；(5) 以OpenSees为分析平台完成了完好框架、震损框架和FRP加固震损框架结构的抗震性能分析，揭示了震损结构的失效概率明显大于完好结构，采用FRP加固后，震损结构的失效概率可以得到有效改善，并且具有可观的延性储备，对结构的抗震性能有利。在本项目的支持下，培养毕业硕士1人，在读硕士2人。共发表论文13篇，其中SCI检索论文8篇。