高强不锈钢绞线网/ECC加固混凝土受压构件破坏机理及计算理论研究

In order to greatly improve the overall performance of RC compression members, and fundamentally solve the problem of brittle failure and steel corrosion. The new composite material "high strength stainless steel wire mesh /ECC" developed by our research group is used for the reinforcement of concrete compression members, and the research on the mechanism of compression failure and computation theory is carried out in this project. Firstly, the experimental research and numerical simulation analysis of high strength stainless steel wire mesh /ECC reinforced concrete and RC columns are carried out to reveal the damage mechanism and failure mode. By using the theory of mechanics, concrete structure, reliability, and the theory of correlation analysis, the constitutive model of high strength stainless steel stranded wire mesh /ECC reinforced concrete is established, and the theory of normal section calculation of RC compression member with high strength stainless steel wire mesh /ECC also is proposed. Then, the simulate earthquake action test for seismic performance of RC column with high strength stainless steel wire mesh /ECC is carried out. Based on the test results, and by using the theory of damage mechanics and mathematical statistics, the relationship between axial compression ratio and seismic fortification intensity is investigated, the axial compression ratio of RC column with high strength stainless steel wire mesh /ECC is proposed, and the seismic restoring force model of the reinforcement RC column is constructed. The research results have enriched the theory and method of concrete structure reinforcement and provided a new way for improving the overall performance of concrete structure.

为了大幅提升RC受压构件整体性能，并从根本上解决其脆性破坏和钢筋易锈蚀问题。本项目将课题组研发的新型复合材料“高强不锈钢绞线网/ECC” 用于混凝土受压构件加固，围绕其受压破坏机理和计算理论开展研究。首先，对高强不锈钢绞线网/ECC加固素混凝土和RC柱受压性能进行试验研究和数值模拟分析，揭示其损伤机理和破坏形态；运用力学、混凝土结构及可靠度等理论和相关分析原理，构建高强不锈钢绞线网/ECC加固素混凝土受压本构模型；提出高强不锈钢绞线网/ECC加固RC受压构件正截面计算理论。然后，对高强不锈钢绞线网/ECC加固RC柱抗震性能进行模拟地震作用试验，基于试验结果运用损伤力学理论和数理统计原理，探究其轴压比和抗震设防烈度的相关关系，提出高强不锈钢绞线网/ECC加固RC柱轴压比限值；构建加固RC柱抗震恢复力模型。研究成果丰富了混凝土结构加固理论和方法，并为提高混凝土结构整体性能提供了新的途径。

本项目基于课题组研发的新型高性能复合材料“高强不锈钢绞线网/ECC”，研究将该新型复合材料用于加固混凝土受压构件，以达到使其整体受压性能和抗震性能大幅度提升的目标。项目分别考虑钢绞线用量、ECC配合比、配筋率、混凝土强度、加固形式以及轴压比等工程实际参数，进行了高强不锈钢绞线网/ECC加固混凝土柱轴心受压、偏心受压、以及模拟地震作用下的试验研究、理论分析和数值模拟，揭示了高强不锈钢绞线网/ECC加固混凝土受压构件在不同工况（轴心受压、大小偏心受压以及模拟地震作用）下的受力性能及损伤破坏机理，探明了各参数对于不同工况下混凝土受压构件整体性能的影响规律；结果表明，高强不锈钢绞线网/ECC用于加固RC柱混凝土受压时，可大幅提升其承载力、控裂性能、延性、韧性、刚度、耗能能力等整体受压和抗震性能，并在试验和数值模拟基础上，提出了高强不锈钢绞线网/ECC加固RC柱的受压承载力计算理论和抗震设计方法。首先，运用材料力学、弹性力学、混凝土结构等理论，提出了高强不锈钢绞线网/ECC约束混凝土受压本构设计模型和分析模型，分别用于后续加固RC柱设计计算理论研究和数值模拟分析；然后，基于平截面假定和上述约束素混凝土受压本构设计模型，考虑不同加固形式，分别建立了高强不锈钢绞线网/ECC加固RC柱轴心受压承载力计算理论和偏心受压（包括大小偏心受压）正截面承载力计算理论（包括基本假定、承载力计算公式和相应适用条件）；最后，基于模拟地震作用（拟静力）下加固柱发生的受弯破坏模式和剪切破坏模式的试验结果，分别构建了高强不锈钢绞线网/ECC加固RC受压构件的抗震恢复力力学模型和剪切强度模型，建立了高强不锈钢绞线网/ECC加固RC受压构件损伤评估方法。并针对不同工况分别确定了合理、有效的加固及界面处理方式和措施。项目研究成果丰富了《混凝土结构加固规范》中新型高性能复合材料加固的内容，具有重要的科学意义和实用价值。