配有高强箍筋的ECC框架异形柱损伤灾变规律及设计理论研究

This research project is mainly to conduct static and dynamic test of the framed special shaped column with the high-strength and high toughness cement-based composites(ECC) confined by high-strength stirrup, to carry out dynamic test for the loading process of the specimens by using the acoustic emission system, analysis and measurement systems of strain displacement that contingency-based image processing, to reveal the law of full field deformation、crack propagation、internal damage evolution of framed special shaped column with ECC under the vertical load, to develop the static random damage constitutive model of ECC in framed special shaped column; to study the deformation characteristics and strength of cement-based composites in the special shaped column that influenced micro steel fibers and high toughness fiber amount、the strength of cement-based composites, characteristic value of stirrup, to develop the stress-strain model of the ECC in framed special shaped column; based on the fiber reinforced theory and experimental research, to develop vertical bearing capacity theory for the framed special shaped column with the ECC; to study 3D full field strain、shear failure、bending deformation、crack propagation and stiffness degradation of specimens with the ECC, to reveal the damage disaster law of structural members, to obtain hysteretic and skeleton curve、ductility and energy dissipation capacity of specimens subjected to high axial-load ratio; to propose the analysis method of shear strength of framed special shaped column with the ECC confined by high-strength stirrup.

本课题开展配有高强箍筋的高强高韧性水泥基复合材料（ECC）框架异形柱静动力试验，基于数字图像处理应变测试分析与声发射系统联合方法，对构件加载过程进行动态测试，揭示竖向荷载作用下ECC复合材料异形柱全场变形、裂缝扩张、内部损伤灾变演化规律；建立异形柱ECC复合材料静力随机损伤本构模型；研究超高韧性纤维掺量、水泥基复合材料强度、高强箍筋配箍特征值对异形柱内ECC复合材料的强度特性和变形特性影响规律；建立高强箍筋约束ECC复合材料的应力－应变本构模型；提出配有高强箍筋的ECC框架异形柱竖向承载力计算理论。通过低周反复水平加载试验和理论分析，研究ECC构件的三维全场应变、裂缝扩展、剪切破坏、弯曲变形、内部损伤累积与刚度退化，揭示结构构件损伤累积灾变演化规律。获得高轴压比条件下，构件的滞回和骨架曲线、延性和耗能能力；提出配有高强箍筋的ECC框架异形柱抗剪承载力计算方法。

本课题开展配有高强箍筋的高强高韧性水泥基复合材料（ECC）异形柱的静动力受力性能试验研究和理论分析。首先，对超高性能水泥基复合材料的配合比进行了研究，研制出配置超细钢纤维和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，并建立了纤维含量对ECC强度特性和本构关系的影响规律。在此基础上，对配有高强箍筋的ECC水泥基复合材料异形柱进行了轴心受压试验，并对构件受力全过程进行测量，揭示了ECC复合材料异形柱的变形、裂缝扩张过程和破坏过程。研究了超高韧性纤维掺量、水泥基复合材料强度、高强箍筋配箍特征值对异形柱强度和变形特性影响规律；从而建立了配有高强箍筋的ECC柱承载力设计计算理论。最后，通过低周反复试验和理论分析，获取了构件滞回曲线和骨架曲线，深入研究了ECC构件在反复荷载下的变形、裂缝扩展、刚度退化、损伤积累过程、延性等特性。最终提出配有高强箍筋的ECC混凝土柱设计方法。