预应力型钢砼梁-角钢砼柱互贯式节点抗震性能研究

In the prestressed steel reinforced concrete frame with build-in solid web steel, there are several problems are faced with, such as the prestressing tendons running through the steel flange in the columns, the decreasing capacity of the panal zone and the complex connecting of the build-in steel in beam and column in constrction. In order to solve the former problems, a new type of composite structure composed of prestressed steel reinforced concrete beams and angle steel concrete columns is proposed in this project. In this new type of frame structure, the angle-steel, H-shaped steel, longitudinal steel bars and prestressing tendons could interpenetrate each other in the joint with simple construction without obstruction, and the angle-steel and plate stirrup could enhance the shear capacity and ductility of the panel zone. At present, this new type of structural system has not been used in practice, and the seismic behavior, mechanical mechanism, and capacity design method are the problems needed to solve urgently in engineering practice. For this purpose, this project intend to conduct experimental research on the joint of the new type of structure with interpenetrating mode under low cyclic loading to observe the seismic behavior and failure mode. Otherwise, this project will reveal the mechanical mechanism and investigate the influence of parameters such as prestressing level, axial compression ratio, steel reinforcement ratio and beam column flexural capacity ratio on the load-displacement relation based on the tests and refined finite element analysis, and will put forward the shear capacity design formulas and shear-shear deformation model. This proposed project will provide the technique support for the application of the new type of structure in the seismic region.

针对内置实腹型钢的预应力型钢混凝土框架存在的预应力筋在节点内贯穿柱内型钢翼缘、削弱节点承载力及梁柱内置型钢在连接时施工工艺复杂等问题，本项目提出了一种由预应力型钢混凝土梁和角钢混凝土柱构成的新型组合框架结构。该组合框架节点内型钢、钢筋和预应力筋能相互贯通、构造简单，同时节点内角钢和钢板箍可提高节点的抗剪承载力和延性。目前，该结构体系尚未有相关应用，其节点的抗震性能、受力机理及承载力设计方法等都是工程实践中迫切需要解决的问题。为此，本项目拟对此类新型框架结构的互贯式节点开展低周往复荷载试验，研究节点的抗震性能和破坏形态，通过试验及精细化有限元分析揭示组合框架节点核心区的受力机理，考察预应力度、轴压比、配钢率及梁柱抗弯承载力比等参数对框架节点荷载-变形关系的影响规律，提出组合框架节点核心区抗剪承载力计算公式及剪力-剪切变形恢复力模型，为此类新型组合框架在地震区的推广应用提供技术支撑。

本项目提出了一种由预应力型钢混凝土梁和角钢混凝土柱构成的新型组合框架节点，解决了普通预应力型钢混凝土框架在节点部位存在的预应力筋贯穿柱内型钢翼缘削弱节点承载力及梁柱内置型钢在连接时施工工艺复杂等问题。该组合框架节点构造简单，节点内角钢和钢板箍可提高节点的抗剪承载力和延性。为此，本项目开展了此类新型框架节点的低周往复荷载试验，研究了节点的抗震性能和破坏形态，建立了组合节点的有限元模型，分析了组合框架节点核心区的受力机理，考察了预应力度、轴压比、型钢腹板厚度、核心区配箍率和柱角钢配钢率等参数对框架节点受力性能的影响规律。结果表明，此类组合框架节点具有良好的抗震性能。通过参数分析可知，节点核心区抗剪承载力随着轴压比的提高略有增加，延性降低；随着核心区配箍率的提高，节点抗剪承载力略微提高；梁型钢腹板的厚度对节点抗剪性能的影响较大；随着角钢配钢率的增大，节点抗剪承载力有一定提高。在此基础上，通过参数分析和数据拟合，提出了组合框架节点核心区抗剪承载力计算方法，其计算结果能较好的与试验结果吻合，可为此类新型组合框架节点的设计提供一定的参考。