高延性纤维混凝土构件抗剪机理与设计研究

From the perspective of improving the material properties, it proposes that it replaces concrete with ECC in shear components such as couple beam, short column and squat shear wall by use of the tensile strain hardening property and hign damage resistance capacity of ECC, which can reduce the amount of shear stirrups, can prevent member brittle shear failure, can improve the performance of members of the shear deformation capability and resistance to damage performance, and can reduce the extent of earthquake damage to structures. .The project will start from studying the shear property and shear failure criterion and constitutive relation of high ductile fiber reinforced concrete (ECC), to research the shear performance, failure modes and failure mechanism of high ductile fiber reinforced concrete members, to present the shear nonlinear analytical model of ECC components based on material ductility by considering the constitutive relation of ECC, to propose the shear deformation capacity design method and to establish the shear capacity design method of members based on material ductility and modified compression field theory. .On the basis, it is proposed that the performance-based design method of ECC members which is free repair after earthquakes and based on the ductility of material, which can guarantee the brittle shear failure does not occur in the key components under moderate and strong earthquakes, and provide a scientific basis for application of ECC in key components and free repair design after earthquakes.

从提高材料性能的角度出发，利用高延性纤维混凝土（ECC）的受拉应变硬化特性和高耐损伤能力，提出在连梁、短柱、低矮剪力墙等受剪构件中采用高延性纤维混凝土代替普通混凝土，以减少抗剪箍筋数量，防止构件发生脆性剪切破坏，提高构件的抗剪性能、变形能力和耐损伤性能，减轻结构的地震损伤程度。本项目研究高延性纤维混凝土（ECC）材料受剪性能和破坏准则和本构关系；研究高延性纤维混凝土构件的受剪性能、破坏形态和破坏机理；考虑ECC材料的本构模型，研究基于材料延性的高延性纤维混凝土构件受剪非线性分析模型；提出基于材料延性和修正压力场理论的构件剪切变形能力设计方法；建立基于材料延性和修正压力场理论的ECC构件受剪承载力计算方法。在此基础上，提出基于材料延性的ECC构件震后免修复抗震性能设计方法，保证中震和大震下关键构件不发生脆性剪切破坏，为高延性纤维混凝土在关键构件的应用和震后免修复设计提供科学依据。

基于高延性纤维混凝土（HDC）的受拉应变硬化特性和高耐损伤能力，提出在梁、连梁、短柱、低矮剪力墙等受剪构件中采用高延性纤维混凝土代替普通混凝土，以减少抗剪箍筋数量，防止构件发生脆性剪切破坏，提高构件的抗剪性能、变形能力和耐损伤性能，减轻结构的地震损伤程度。本项目建立了HDC材料受剪破坏准则和本构关系；揭示了高延性纤维混凝土构件的受剪性能、破坏形态和破坏机理；考虑HDC材料的本构模型，建立了基于材料延性的高延性纤维混凝土构件受剪非线性分析模型；建立了基于材料延性和修正压力场理论的构件剪切变形能力分析方法；建立了基于材料延性和修正拉-压杆模型理论的HDC构件受剪承载力计算方法。在此基础上，提出基于材料延性的HDC构件震后免修复抗震性能设计方法，保证中震和大震下关键构件不发生脆性剪切破坏，为高延性纤维混凝土在关键构件的应用和震后免修复设计提供科学依据。