预应力高强混凝土管桩抗震性能研究

发布时间：2018-08-22 13:25

【摘要】：预应力混凝土管桩（Prestressed High Strength concrete Pile，PHC管桩）具有单桩承载力高、质量可控制、价格便宜施工速度快等优点，在工程建设中得到广泛的应用。由于PHC管桩在地震作用下的水平承载力较差，，限制了其在地震区的使用范围。因此，为扩大PHC管桩在工程中的使用范围，深入的研究PHC管桩的抗震性能具有重要的意义。本文通过试验、有限元数值计算对往复荷载作用下PHC管桩以及PHC管桩与承台连接节点进行了研究，研究成果可为PHC管桩在我国地震区的推广应用提供科学依据。对PHC管桩进行了低周往复荷载试验和单调加载试验。试验结果表明：预应力钢筋被拉断导致PHC管桩发生脆性的受弯破坏；PHC管桩耗能性能较差，AB型桩的延性系数大于A型桩，耗能性能优于A型桩。对PHC管桩非线性受力过程的有限元分析表明：PHC管抗弯承载力随着有效预压应力的增加而增加，而配箍率对其影响较小。 PHC管桩在往复荷载作用下受力性能的有限元分析得出，在7度设防地区应将其使用时的最大曲率控制在0.01/m以内，轴压比宜控制在0.35以内。通过PHC管桩与承台连接节点桩端低周往复荷载试验表明：节点桩端发生受弯破坏，破坏形式主要有：1）桩端预应力筋被拉断，导致桩端破坏严重，构件发生脆性破坏；2）锚固钢筋发生屈服，桩与承台交接处出现塑性铰，桩端与承台破坏严重，构件发生延性破坏。通过PHC管桩与承台连接未截桩和截桩两种典型连接方式的有限元参数分析结果表明，轴力对两种节点桩端承载力和延性影响较大；桩端嵌入承台的长度、锚固钢筋的直径以及数量对未截桩节点桩端的承载力和延性影响不大，但是对截桩节点桩端却有着显著的影响。对改进的管桩与承台连接节点桩端进行了低周往复荷载试验和有限元分析，结果表明：由于节点区域的承台混凝土被压碎，节点形成铰，失去承载力，但桩端并未发生破坏。因此，在进行节点设计时，应该在节点有一定转动能力的基础上，保证承台不会由于桩端转动时产生的挤压力或撬力作用过早的发生破坏，使得桩端承载力能得以充分发挥。
[Abstract]:Prestressed concrete pipe pile (Prestressed High Strength concrete PilePHC-PHC-pipe pile) has been widely used in engineering construction because of its high bearing capacity, controllable quality and fast construction speed. Because of the poor horizontal bearing capacity of PHC pipe pile under earthquake action, its application scope in earthquake area is limited. Therefore, in order to expand the application range of PHC pipe pile, it is of great significance to study the seismic behavior of PHC pipe pile. In this paper, the PHC pipe pile under reciprocating load and the connection joint between PHC pipe pile and cap are studied by means of experiment and finite element numerical calculation. The research results can provide scientific basis for the popularization and application of PHC pipe pile in earthquake area of our country. The low cycle reciprocating load test and monotone loading test were carried out for PHC pipe pile. The test results show that the ductility coefficient of PHC pile is higher than that of A-type pile, and the energy dissipation performance of AB pile is better than that of A-type pile. The finite element analysis of nonlinear stress process of PHC pipe pile shows that the flexural capacity of PHC pipe increases with the increase of effective preloading stress. The finite element analysis of the mechanical behavior of PHC pipe pile under reciprocating load shows that the maximum curvature should be controlled within 0.01 / m and the axial compression ratio should be controlled within 0. 35 in the 7 degree fortification area. Through the low cycle reciprocating load test of PHC pipe pile and cap connection joint, it is shown that the bending failure occurs at the end of the joint pile, the main failure form is: 1) the prestressed tendons at the end of the pile are broken, which leads to the serious damage of the pile end and the brittle failure of the members. 2) yielding of Anchorage steel bar, plastic hinge at the interface between pile and cap, serious damage between pile end and cap, and ductility failure of component. The results of finite element parameter analysis of two typical connection modes of PHC pipe pile and pile cap show that the axial force has great influence on the bearing capacity and ductility of the pile end of the two joints, the length of the pile end embedded in the pile cap, the length of the pile end embedded in the pile cap, and the bearing capacity and ductility of the pile end are greatly affected by the axial force. The diameter and quantity of Anchorage bar have little effect on the bearing capacity and ductility of the untruncated pile joint, but have a significant effect on the pile end of the truncated pile joint. The low cycle reciprocating load test and finite element analysis on the pile end of the improved tubular pile and cap connection joint are carried out. The results show that because of the crushed concrete of the cap in the joint area, the joint forms hinges and loses the bearing capacity, but the pile end is not destroyed. Therefore, in the design of the joint, it is necessary to ensure that the pile cap will not be destroyed prematurely because of the extruding force or the prying force when the pile tip rotates, on the basis of the certain rotation ability of the joint, so that the bearing capacity of the pile end can be brought into full play.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU473.1;TU352.11

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