大跨度PC梁桥的静动载试验研究

发布时间：2018-10-13 11:07

【摘要】：大跨度PC连续梁桥是我国常用的桥型之一,大跨度PC连续梁桥的主要特点是变形和缓、伸缩率小、行车平稳,使得桥面伸缩缝设置少,这样有利于高速行车。根据我国交通部颁布的《公路养护技术规范》要求,大跨度桥梁必须进行承载能力的鉴定。由于现阶段的理论计算与桥梁实际情况往往存在一定的差距,所以进行承载能力的鉴定就离不开荷载试验。目前,无论是现有桥梁还是新建桥梁都存在车辆-桥梁耦合振动问题,一方面,车辆在桥面上行驶会对桥梁结构产生动力冲击作用,使得桥梁结构发生振动影响桥梁的正常运营状况,另一方面,桥梁结构的振动反过来又作用于车辆,使得车辆行驶的平稳性和舒适性受到影响,则对桥梁进行荷载试验是必要的。桥梁荷载试验是评价桥梁质量的最直接和有效的手段。进行桥梁荷载试验不仅能够验证理论计算的合理性,同时还能够促进理论计算和试验理论的发展。本文针对大跨度PC连续梁桥的静、动载试验进行研究,以东风大桥为研究对象。研究该桥在静、动载试验下,影响应变、挠度的变化规律。利用大型通用有限元软件MIDAS/Civil对东风大桥进行建模,输入截面数据、边界条件和各种荷载值。对桥梁静载试验的研究过程,分别计算东风大桥在设计荷载及试验荷载作用下的控制截面的内力值,使得到荷载效率系数;计算各种工况下,各测点的应变及挠度理论值与现场实测值进行对比分析。对桥梁动载试验的研究过程,对东风大桥模型进行模态分析,采用子空间迭代法计算特征值,得出桥梁的前几阶振型,从而得到固有频率,根据相应规范计算得出冲击系数值,模态分析得到的值与现场通过试验仪器对跑车、跳车等试验数据得出的桥梁振型、固有频率和冲击系数进行对比分析,并与相应的桥梁设计规范标准、荷载试验的规范标准的容许值做对比;桥梁结构在静、动载作用下的变形特性和动力特性正常,则说明桥梁的整体刚度良好,承载能力满足设计要求,进一步验证设计的合理性,对同类桥梁的承载能力进行分析提供了参考,也为将来的桥梁养护、维修和运营健康监测系统提供宝贵的资料。
[Abstract]:The long-span PC continuous beam bridge is one of the commonly used bridges in China. The main characteristics of the long-span PC continuous beam bridge are gentle deformation, small expansion rate, steady driving, so that the bridge deck expansion joints are less, which is beneficial to high-speed driving. According to the requirements of the Technical Code for Highway maintenance issued by the Ministry of Communications of China, the bearing capacity of long-span bridges must be evaluated. Because there is a certain gap between the theoretical calculation and the actual situation of the bridge at the present stage, the identification of the bearing capacity can not be separated from the load test. At present, there exists the problem of vehicle-bridge coupling vibration in both existing and newly built bridges. On the one hand, the vehicle driving on the deck of the bridge will have a dynamic impact on the bridge structure. On the other hand, the vibration of the bridge structure acts on the vehicle in turn, which affects the ride stability and comfort of the vehicle, so that the vibration of the bridge structure affects the normal operation of the bridge, on the other hand, the vibration of the bridge structure acts on the vehicle in turn. It is necessary to carry out load test on the bridge. Bridge load test is the most direct and effective method to evaluate bridge quality. The bridge load test can not only verify the rationality of theoretical calculation, but also promote the development of theoretical calculation and test theory. In this paper, the static and dynamic load tests of long span PC continuous girder bridge are studied, and Dongfeng Bridge is taken as the research object. The variation law of strain and deflection of the bridge under static and dynamic load test is studied. The model of Dongfeng Bridge is modeled by MIDAS/Civil, and the cross section data, boundary conditions and load values are inputted. In the research process of bridge static load test, the internal forces of the control section of Dongfeng Bridge under design load and test load are calculated respectively, so that the load efficiency coefficient is obtained, and the load efficiency coefficient is calculated under various working conditions. The theoretical values of strain and deflection of each measuring point are compared with the field measured values. For the research process of bridge dynamic load test, the modal analysis of Dongfeng Bridge model is carried out, the eigenvalue is calculated by subspace iteration method, and the first several vibration modes of the bridge are obtained, and the natural frequency is obtained, and the impact coefficient value is calculated according to the corresponding specifications. The value obtained by modal analysis is compared with the bridge mode shape, natural frequency and impact coefficient obtained from the test data of sports car, jump and so on, and it is compared with the corresponding standard of bridge design code. The allowable values of the standard of load test are compared, and the deformation and dynamic characteristics of bridge structure under static and dynamic loads are normal, which indicates that the overall stiffness of the bridge is good, and the bearing capacity meets the design requirements. Furthermore, the rationality of the design is verified, the bearing capacity of the similar bridges is analyzed, and valuable data are provided for the bridge maintenance, maintenance and operation health monitoring system in the future.
【学位授予单位】：广州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U446.1

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