锈蚀钢筋混凝土柱的地震破坏模式与易损性研究

Damage of reinforced concrete (RC) column is one of the most important causes for collapse or difficult rehabilitation of RC structures after strong earthquake. Steel corrosion induced by the carbonation or chloride ingress may greatly decrease the seismic performance of the RC column during its service life. Most of the study is focused on the influences of corroded longitudinal bar on the seismic performance of RC column. However, corrosion of stirrup usually is often more serious than that of longitudinal bar, resulting in reduction of shear capacity of RC column and transforming seismic failure model from ductile flexural failure into the brittle flexural-shear failure even shear failure. Therefore, investigation of the influences of the corroded stirrup on seismic failure models and fragility of corroded RC column is desirable for a more realistic disaster prevention and mitigation of RC structures. This proposed research program is focused on the investigation of the influences of the corroded stirrup on seismic failure models and fragility of corroded RC column. The influences of both the corroded stirrup and longitudinal bar on the failure models of existing RC column will be discussed, while the restoring force model for the corroded RC column will be developed. The obtained results are to be used as the basis to construct the probabilistic seismic demand spectra and multi-objective seismic fragility curves for corroded RC column. Use of the results for seismic design, seismic risk evaluation and maintenance decision-making of the RC structures will also be considered.

钢筋混凝土柱发生破坏是引起混凝土结构倒塌和震后难以修复的重要原因。随着服役年限的增加，在役钢筋混凝土柱的锈蚀问题日益突出，目前主要关注纵筋锈蚀对钢筋混凝土柱抗震性能的影响。然而，箍筋锈蚀程度往往比纵筋更严重，箍筋锈蚀降低柱的抗剪承载力和对核心混凝土的约束力，导致柱的破坏模式极有可能从延性的弯曲破坏向脆性的弯剪破坏甚至剪切破坏转变，加剧损伤程度。因此，锈蚀钢筋混凝土柱的地震破坏模式演变规律和地震易损性研究，成为当前工程结构防灾减灾领域极为关注的科学问题。 本项目重点围绕锈蚀钢筋混凝土柱的地震破坏模式演变规律和地震易损性开展研究：揭示箍筋和纵筋锈蚀对钢筋混凝土柱地震破坏模式演变的影响规律，建立锈蚀钢筋混凝土柱的恢复力模型，构建不同强度地震动作用下锈蚀钢筋混凝土柱的概率地震需求谱，进而建立锈蚀钢筋混凝土柱的多级性能目标地震易损性曲线，为在役钢筋混凝土结构的地震风险评估和维护加固决策提供科学依据。

本项目重点围绕锈蚀钢筋混凝土柱的地震破坏形态演变规律、恢复力模型、概率地震需求和地震易损性等方面开展研究，所取得的代表性研究成果包括：（1）提出了能够综合考虑强度退化、刚度退化、捏拢效应、非对称滞回特性等典型滞回特性的锈蚀钢筋混凝土柱的非弹性恢复力模型及其参数识别方法；（2）提出了锈蚀箍筋约束混凝土的单轴受压本构关系模型，建立了能够有效考虑钢筋锈蚀和轴压力影响的钢筋混凝土柱的临界斜裂缝倾角模型和概率抗剪承载力模型；（3）分别建立了锈蚀钢筋混凝土柱的等强度延性需求的均值谱和标准差谱的预测方程，建立了考虑钢筋锈蚀引起的刚度和强度退化效应的非弹性体系震后残余位移的预测模型，建立了结构的地震易损面；（4）建立了矿物掺合料混凝土碳化深度分析的多场耦合数值模型和实用预测模型，提出了混凝土中钢筋锈蚀率分析模型和钢筋腐蚀等级概率评估方法；（5）定量分析了钢筋混凝土结构材料尺度的变异性对构件和结构尺度非线性静动力响应变异性的影响规律。相关研究成果在Engineering Structures、Journal of Structural Engineering-ASCE、Construction and Building Material、Ocean Engineering、Journal of Earthquake Engineering等期刊上发表学术论文33篇（SCI收录10篇、EI收录12篇），出版学术专著1部，获授权国家发明专利3项、计算机软件著作权1项，培养硕士生16名。