R/ECC联肢剪力墙结构基于最优屈服机制的抗震性能设计理论与方法

This project focus on R/ECC coupled wall systems which replace common concrete with high performance composites ECC in the critical regions. Based on the idea of yield mechanism control and performance design, through experimental research, numerical simulation and theoretical analysis, the following research questions are studied. First, the impact of span-depth ratio, reinforcement arrangement and ECC strength on seismic behavior of coupling beams are studied, and then the bearing capacity model and sectional deformation capacity design method meeting the needs of ductility of coupling beams are proposed. Second, the impact of coupling ratio on R/ECC coupled wall systems is studied, and then the reasonable coupling ratio which meets the optimal yield mechanism of the systems is proposed. Furthermore, qualitative description and quantization methods of the limit state of various performance standards，failure discriminant parameter and criterion， allowable value of seismic deformation, and seismic performance objectives applicable to the different functional requirements for the systems are studied，and then the control methods of damage degree of various performance standards for the systems are proposed. Based on the above, the seismic performance design theory and methods of R/ECC coupled wall systems which meet the optimum yield mechanisms and the needs of ductility are established. The research results have an important theoretical significance and practical value to fundamentally improve seismic performance as well as disaster prevention and reduction of concrete structures.

本项目以联肢剪力墙预期损伤部位采用高性能ECC材料代替普通混凝土的R/ECC联肢剪力墙结构为研究对象，基于联肢剪力墙屈服机制控制和性能设计理念，通过试验研究、数值模拟和理论分析，研究跨高比、配筋方式、ECC强度等对R/ECC连梁抗震性能的影响，提出该连梁承载力计算模型及满足延性需求的截面变形能力设计方法；研究耦联率对R/ECC联肢剪力墙抗震性能的影响，提出满足R/ECC联肢剪力墙最优屈服机制和延性需求的耦联率确定方法；研究R/ECC联肢剪力墙各种性能水准极限状态的定性描述和量化方法、失效的判别参数及准则、抗震变形容许值和适用于不同功能要求的抗震性能目标，提出R/ECC联肢剪力墙各性能水准的结构损伤程度控制方法。在此基础上，建立满足最优屈服机制和延性需求的R/ECC联肢剪力墙抗震性能设计理论与方法。研究成果对于从根本上提高钢筋混凝土结构的抗震性能和减灾防灾，具有重要的理论意义和实用价值。

基于提高混凝土结构抗震性能的理念，以联肢剪力墙预期损伤部位采用高性能ECC材料代替普通混凝土的R/ECC联肢剪力墙结构为研究对象，对其进行试验研究、理论分析和数值计算，主要成果如下：1）为减少河砂用量，同时降低ECC成本，用沙漠砂替代部分精细河砂对ECC材料配合比进行优化设计，对其力学性能和抗碳化性能进行试验研究，结果表明沙漠砂替代率对ECC各项力学性能影响较小，高沙漠砂替代率有利于ECC抗碳化性能。2）考虑跨高比、箍筋间距和ECC强度等因素的影响，设计了7个小跨高比ECC连梁试件和1个普通混凝土连梁对比试件。拟静力试验研究表明：R/ECC连梁的受剪承载力和位移延性系数比普通混凝土连梁分别提高了9.71%和24.31%，达到极限荷载时的累积耗能是普通混凝土连梁的1.5倍。3）对3个对角斜筋加设拉筋对角斜筋小跨高比ECC连梁的进行了拟静力试验研究，结果表明：在小跨高比连梁对角斜筋上增设拉筋之后，连梁的破坏形态由剪切破坏变为弯曲剪切破坏，延性、抗损伤能力和耗能能力提高。4）基于试验研究和受剪机理分析，提出了R/ECC连梁的受剪承载力计算公式，建立了三折线恢复力模型；基于R/ECC连梁屈服时连梁梁端埋入墙肢部分形成的力与约束弯矩平衡条件，提出了预制连梁梁端埋入墙肢长度计算方法；借助复形法求最优解的思路，将R/ECC连梁的工程造价和抗剪承载力作为优化目标建立目标函数，建立了R/ECC连梁多目标优化设计方法。5）利用经试验验证的R/ECC 联肢剪力墙有限元模型，通过对比不同耦联率R/ECC联肢剪力墙的抗震性能，揭示了耦联率对联肢剪力墙抗震性能的影响程度和范围，建立了满足最优屈服机制和延性需求的耦联率确定方法。6）基于屈服机制控制和性能设计理念，建立了R/ECC联肢剪力墙结构满足最优屈服机制和延性需求的抗震性能设计方法。本项目的研究成果，对于提高RC结构的抗震性能、减小震后修复费用等，具有重要的理论意义和实用价值。