铁路桥梁下部结构承载力评估与加固技术研究

发布时间：2018-01-13 06:35

本文关键词：铁路桥梁下部结构承载力评估与加固技术研究　出处：《兰州交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：近年来,随着客运专线及高速铁路建设的快速发展,对原有铁路旧桥的通行能力要求越来越高,尤其对下部结构承载能力要求增大。因此,需要对铁路桥梁下部结构承载能力进行分析,提出相应加固措施,以保证铁路桥梁在设计使用寿命内的正常使用。本文在总结目前关于桥梁承载能力评估和加固研究成果的基础上,以某特大桥为工程背景,对既有铁路桥梁的状态检测、下部结构承载能力评定、加固方法及加固后的承载能力进行了分析,主要研究内容如下:根据实例工程的结构及构造特点,河床冲刷较大,对河床断面进行测量;采用环境振动法测试梁体、桥墩的横向自振频率及阻尼比,了解桥梁结构的工作状态。在此基础上,建立并调整midas Civil有限元模型,依据相关规范规定,在不同荷载组合下,分析连续梁部分桥墩及基桩承载力,并依据有关规范及规程要求,综合判定桥梁的承载能力。归纳分析桥梁下部结构常用的加固方法,结合桥梁结构和构造特点,根据受力及构造要求,对承载力不满足要求的16#、17#桥墩及基桩进行加固。建立加固后结构评估模型,对加固后16#、17#桥墩及基桩承载力进行检算,从而评定其加固效果及加固后结构承载力。采用ANSYS有限元软件对加固前、后17#桥墩桩基承台进行有限元模拟,并考虑桩-土作用。分析有限元计算结果可知,承台内部主压应力沿桥墩与桩基沿线传递,其他区域无明显特征;主拉应力分布在承台底部,且主要有基桩顶部1倍桩径范围内的钢筋承台。桥墩与桩基沿线范围内的混凝土主要受压,相当于斜压杆;承台底部、基桩顶部1倍桩径范围内的钢筋相当于拉杆。承台内部应力传递符合空间桁架计算模型的特点,提出这一计算模型,为今后铁路桥梁桩基承台设计计算提供参考。
[Abstract]:In recent years, with the rapid development of passenger dedicated line and high-speed railway construction, the capacity of the old railway bridges is becoming more and more demanding, especially for the lower structure load capacity. It is necessary to analyze the bearing capacity of the lower structure of the railway bridge and put forward the corresponding reinforcement measures. In order to ensure the normal use of railway bridges in the design service life, this paper summarizes the current research results of bridge bearing capacity assessment and reinforcement, taking a large bridge as the engineering background. The state detection of existing railway bridges, the evaluation of the bearing capacity of the substructure, the reinforcement method and the bearing capacity after reinforcement are analyzed. The main research contents are as follows: according to the structure and structural characteristics of the engineering examples. The river bed scour is larger, the river bed section is measured; The transverse natural vibration frequency and damping ratio of beam and pier are measured by ambient vibration method, and the working state of bridge structure is understood. On this basis, the midas Civil finite element model is established and adjusted. According to the relevant codes and under different load combinations, the bearing capacity of some piers and piles of continuous beams is analyzed, and the requirements of relevant codes and regulations are also given. Comprehensive evaluation of the bearing capacity of the bridge. Summarized and analyzed the bridge substructure commonly used reinforcement methods, combined with the bridge structure and structural characteristics, according to the force and structural requirements, the bearing capacity does not meet the requirements of 16#. 17# bridge pier and foundation pile are strengthened. The evaluation model of strengthened structure is established, and the bearing capacity of the strengthened 16 #C17# bridge pier and foundation pile is checked and calculated. In order to evaluate the reinforcement effect and the bearing capacity of the strengthened structure, the finite element simulation of the pile cap of 17 # bridge pier before and after reinforcement is carried out by using ANSYS finite element software. Considering the pile-soil interaction, the finite element analysis results show that the main compressive stress in the cap is transmitted along the bridge pier and the pile foundation, and there are no obvious characteristics in other areas. The main tensile stress is distributed at the bottom of the pile cap, and there is mainly a reinforced pile cap in the range of one diameter of the pile top. The concrete along the bridge pier and the pile foundation is mainly compressed, which is equivalent to the oblique compression rod. The steel bar at the bottom of the cap and in the range of the pile diameter at the top of the pile is equivalent to the rod. The stress transfer in the cap accords with the characteristics of the spatial truss calculation model, and the calculation model is put forward. It provides a reference for the design and calculation of pile cap of railway bridge in the future.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446;U445.72

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