【作者】 康省桢；

【导师】 王复明；

【作者基本信息】 郑州大学 ， 水利工程， 2010， 博士

【摘要】 近年来,随着我国经济建设的飞速发展,公路交通流量不断增加,运输车辆日益大型化、重载化,交通运输需求与在役桥梁通行能力之间的矛盾日趋突出。由于频繁承受超限、超载车辆的作用,加上结构自然老化、环境侵蚀等因素的影响,我国病险桥梁数量不断增多,大量桥梁亟待加固。因此深入开展既有桥梁的承载能力评定工作,研究其损伤程度、承载潜力和安全储备是在役桥梁合理利用的关键,对于确保交通运输安全、促进我国公路交通建设的可持续发展具有重要的理论和现实意义。本文开展了既有预应力混凝土空心板梁桥破坏—加固—再破坏的现场综合试验,并结合三维实体非线性有限元仿真分析,系统研究了预应力混凝土空心板梁桥的安全储备、承载潜力及其在极限荷载作用下的结构响应和破坏机制,深入分析了体外预应力加固对空心板梁桥受力全过程的力学行为和承载性能的影响,主要内容可概括如下：(1)开展了预应力空心板梁桥实桥破坏性试验研究。以京珠高速安新段东孟姜女桥为对象,采用堆载加载方式,实施了预应力混凝土空心板梁桥现场破坏试验,获得了该桥受力全过程挠度、裂缝和应变的发展规律,探讨了该桥的破坏机制、破坏形态及其真实承载性能。(2)对破坏后的空心板梁桥,采用体外预应力筋方法,开展了桥梁横向和纵向体外预应力加固技术的试验研究,初步总结了体外预应力加固技术、工艺,分析了体外预应力加固后桥梁的承载力及力学状态的变化。(3)基于两次破坏性试验结果,利用大型有限元分析程序ANSYS,对实桥破坏性试验过程实施了三维实体非线性有限元仿真；深入分析了受力全过程空心板桥的力学响应和破坏机理,研究了体外预应力加固对结构力学行为和破坏机制的影响。更多还原

【Abstract】 With the rapid development of Chinese social economy in recent years, the contradiction between transportation needs and load capacity of existing bridges becomes more and more prominent due to the quickly increasing traffic flow and vehicle axle load. Affected by some harmful factors such as frequent overloaded vehicles, design defect, construction quality problem, environmental erosion, et al, the number of damaged or dangerous bridges gradually increased and quite a few of them need to be strengthened. The key problem of utilizing those old bridges properly is to deeply carry out the scientific research on load-carrying capacity assessment of in-service bridges and evaluate their damage degree, bearing potential, and safety reserve, et al, and therefore carrying out relevant research is of great significance for transportation safety and sustainable development of highway transportation construction in China.So, in this paper a comprehensive field experiment is performed using an existing prestressed concrete hollow slab bridge. The experiment includes three steps: first destructive test before reinforcement, strengthening test, and second destructive test after reinforcement respectively. Combined with test results and three dimensional nonlinear FEM simulation, the safety reserve, bearing potential, failure mechanism, as well as structural response of the prestressed concrete hollow slab bridge under ultimate loads are studied systematically. In addition, the influences of reinforcement on mechanical behavior and bearing capacity of the bridge are deeply analyzed. The main content can be summarized as follows:(1) Using a prestressed concrete hollow slab bridge, East Meng Jiang Nu bridge, which belongs to An-Xin expressway, a destructive test is performed. The variation laws of deflections, cracks, and strains of the bridge during test are obtained. Moreover, its failure mechanism, failure mode, and actual load capacity are studied.(2) For the damaged prestressed concrete hollow slab bridge which experienced first destructive experiment, a strengthening test research is carried out by applying longitudinal and transverse external prestressing to it. The reinforcement technology and progress of external prestressing to the bridge are preliminarily summarized. The changes of bearing capacity and mechanical state of the bridge after reinforcement are also investigated.(3) Based on the test results and using the FEM software, ANSYS, a three-dimensional (3-D) finite element (FE) simulation study on the twice destructive test of East Meng Jiang Nu bridge is carried out considering material nonlinearity. The bridge’s mechanical responses and failure mechanism during the test are deeply discussed. In addition, the influences of external prestressing reinforcement on the mechanical behaviors and damage mechanism of the bridge are explored.更多还原