重载公路预应力混凝土箱梁疲劳性能研究

发布时间：2018-05-24 01:45

本文选题：重载公路 + 预应力混凝土桥梁　；参考：《北京交通大学》2017年硕士论文

【摘要】：预应力混凝土梁桥是高速公路常见的桥型,随着我国经济和交通运输车辆的快速发展,公路桥梁上的车辆荷载类型也发生着巨大的变化,重载运输趋势明显。尤其内蒙古作为我国的煤炭资源大省,运煤车辆的载重普遍较大甚至有相当一部分车辆属于超载运行,当大量的重载车辆驶过桥梁时,对桥梁可能造成局部损伤;这些损伤的累积会使桥梁损伤逐渐加重、承载能力逐渐降低,缩短桥梁的使用寿命,甚至导致桥梁在某次重型车辆通过时发生垮塌,给国家和人民带来巨大的经济损失和生命安全。本文选取高速公路G6内蒙古路段中常见桥型跨径为20m的预应力混凝土箱梁桥作为研究对象,研究其在重载交通作用下承载能力的变化,主要做了以下工作:(1)根据相似理论设计了缩尺比例为1:3的预应力混凝土模型梁,在实验室进行了模型梁的极限承载力静载试验。同时利用大型通用有限元软件ABAQUS建立模型梁的有限元模型,通过数值模拟计算出模型梁的极限承载力。与试验结果进行对比分析,来校正有限元模型的正确性。(2)基于内蒙古路段车辆荷载调查的基础上,结合《公路桥涵设计通用规范》(JTG D60-2015)中三种疲劳计算荷载模型以及超载20%、500%和70%的超载模型;利用影响线找到梁体的最不利荷载位置,用ABAQUS计算出以上各种疲劳荷载模型作用下梁体的应力幅。(3)基于普通钢筋和预应力筋应力-寿命曲线方程,计算模型梁在各应力幅下的疲劳寿命。结算结果表明应力幅越大,模型梁的疲劳寿命越短。按规范设计的桥梁能够满足设计使用寿命,但重载交通严重降低桥梁的使用寿命。(4)预应力混凝土梁在疲劳变形过程中呈现出明显的三阶段规律,总结各个阶段梁体各组成材料的疲劳本构关系的变化,利用有限元软件ABAQUS对预应力混凝土模型梁进行疲劳全过程数值模拟;计算模型梁在各应力幅下经过10年、30年、50年、70年、90年及100年疲劳荷载循环后的剩余承载力变化。结果表明应力幅越大,模型梁的剩余承载力下降的越快,而且下降幅度也更大。
[Abstract]:Prestressed concrete girder bridge is a common type of highway bridge. With the rapid development of economy and transportation vehicles in China, the type of vehicle load on highway bridge is also changing greatly, and the trend of heavy load transportation is obvious. In particular, Inner Mongolia is a big province of coal resources in China, the load of coal transport vehicles is generally larger, even a considerable number of vehicles are overloaded, when a large number of heavy-haul vehicles pass the bridge, it may cause local damage to the bridge. The accumulation of these damages will gradually aggravate the damage of the bridge, reduce the bearing capacity gradually, shorten the service life of the bridge, and even cause the bridge to collapse during the passage of a heavy vehicle. To the country and the people bring huge economic loss and safety of life. In this paper, the prestressed concrete box girder bridge with 20m span in G6 section of Inner Mongolia expressway is chosen as the research object, and the change of its bearing capacity under the action of heavy traffic is studied. Based on the similarity theory, a prestressed concrete model beam with a scale of 1:3 is designed, and the ultimate bearing capacity of the model beam is tested in the laboratory. At the same time, the finite element model of the model beam is established by using the large-scale universal finite element software ABAQUS, and the ultimate bearing capacity of the model beam is calculated by numerical simulation. Comparing with the test results to correct the correctness of the finite element model. (2) based on the investigation of vehicle load in Inner Mongolia section, Combined with the three fatigue calculation load models and the overload models of 20% and 70% overload in JTG D60-2015, the most unfavorable load position of beam is found by the influence line. Based on the stress-life curve equation of common steel bar and prestressed bar, the fatigue life of model beam under various stress amplitude is calculated by ABAQUS. The results show that the fatigue life of the model beam is shorter with the increase of stress amplitude. The bridge designed according to the specifications can satisfy the design life, but heavy traffic reduces the service life of the bridge seriously. (4) the prestressed concrete beam shows obvious three-stage rule in the process of fatigue deformation. This paper summarizes the changes of fatigue constitutive relation of each component material of beam body in each stage, and carries on the numerical simulation of the whole fatigue process of prestressed concrete model beam by using finite element software ABAQUS. The residual bearing capacity of the model beam is calculated after 10 years, 30 years, 50 years, 70 years, 90 years and 100 years of fatigue load cycles under various stress ranges. The results show that the larger the stress amplitude, the faster the residual bearing capacity of the model beam decreases and the larger the decrease is.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U448.35

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