刚柔混杂纤维ECC约束混凝土结构损伤破坏机理及静动力特性研究

This topic to conduct soft hybrid fiber ECC constraint mechanism of concrete structure damage and the static and dynamic characteristics research. Is based on the principle of greening, localization, practical, the superfine fiber and PVA fiber hybrid ECC mechanical properties and their mutual relations, optimizing the mixture ratio, material tensile and compression constitutive model is established. Hybrid fiber ECC in soft structure of confined concrete column vertical compression failure pattern, synergy, constraint mechanism, the internal and external strength match, stress and strain law study, establish ECC confined concrete constitutive model and the bearing capacity of the structure calculation theory. Hybrid fiber ECC pseudo dynamic constraint concrete structure in soft low reversed cyclic loading test, based on hysteresis curves, skeleton curves, displacement of bearing capacity and deformation, the component characteristics of ductility and energy dissipation capacity, evaluation of the seismic performance of structures, the proposed method to calculate the shearing resistance of the components. Strain test system based on digital image processing, combined with acoustic emission system method, the vertical and horizontal components to test the dynamic loading process, and the research component of the whole deformation and acoustic emission parameters, to reveal the structure of the crack extension, internal damage evolvement and stiffness degradation. Establish a hybrid fiber ECC confined concrete under the action of the static and dynamic nonlinear finite element model of structure, structural numerical simulation and the simulation analysis.

本课题开展刚柔混杂纤维ECC约束混凝土结构损伤破坏机理及静动力特性研究。基于绿色化原则，研究超细钢纤维和PVA纤维混杂ECC的力学性能及其相互关系，优化配合比，建立材料的拉伸和压缩本构模型。开展刚柔混杂纤维ECC约束混凝土结构柱竖向压缩破坏形态、协同作用、约束机理、内外强度匹配、应力-应变规律研究，建立ECC约束混凝土的本构模型和结构的承载力计算理论。开展刚柔混杂纤维ECC约束混凝土结构拟动力低周反复加载试验，基于滞回曲线、骨架曲线、承载力和位移变形，研究构件的延性特征和耗能能力，评价结构构件的抗震性能，提出构件抗剪承载力计算方法。基于数字图像处理应变测试系统与声发射系统联合方法，对构件竖向和水平加载过程进行动态测试，研究构件的全场变形和声发射参数，揭示结构的裂缝扩展、内部损伤和刚度退化演化规律。建立混杂纤维ECC约束混凝土静动力作用下结构的非线性有限元模型，进行结构数值仿真模拟。

为了提高框架结构的承载和变形能力，本研究提出一种利用刚柔混杂纤维水泥基复合材料约束混凝土的新型组合柱．采用超细钢纤维（直径0.2mm，长度12mm）和PVA纤维（13mm）进行混杂，对高性能水泥基复合材料的配合比进行了研究，优化配制出超细钢纤维和PVA纤维的混杂纤维ECC水泥基复合材料，对ECC复合材料的立方体抗压强度、圆柱体抗压强度、弹性模量、劈裂抗拉强度、应力应变曲线、弯曲韧性等进行了系统研究。利用混杂纤维ECC水泥基复合材料作为组合柱的约束层，开展截面为外圆内圆、外方内圆、外方内方形、及内置钢管混凝土的刚柔混杂纤维ECC约束混凝土柱的静动力受力试验和理论分析。获得了组合柱的荷载、应力-应变曲线及裂缝扩展变形，分别研究了组合柱的破坏特征、荷载-应变关系、荷载计算和峰值应变计算方法，建立了组合柱结构峰值应力和峰值应变的计算公式，分析了约束层厚度、强度等级以及内芯混凝土强度对组合柱裂缝、承载力、变形、延性等的影响，建立了截面分别为外圆内圆、外方内圆、外方内方形组合柱的应力-应变本构模型，基于平衡原理、局部受压约束和统计原理建立组合柱的轴心受压承载力计算公式，通过组合柱的低周反复试验，可获得组合柱动力荷载下的变形、裂缝扩展、刚度退化、损伤积累过程、延性等抗震性能，最终为刚柔混杂纤维ECC约束混凝土组合柱的设计奠定理论基础。