既有钢筋砼铁路桥承载力及动力性能分析

发布时间：2018-04-19 19:54

本文选题：钢筋砼桥 + 承载力　；参考：《长安大学》2014年硕士论文

【摘要】：铁路被称为国民经济的大动脉，建国以来，我国铁路事业取得了长足的进步，铁路桥梁属于铁路线路的大型永久建筑物，它构造复杂、技术性强，建造工期久、价值比较高。为配合铁路事业的发展，我国20世纪六七十年代起兴建了一大批中小跨钢筋混凝土简支铁路桥，目前这些桥梁大多正在服役或已退出工作。对于正在服役的既有桥梁来说，由于长期受到列车动荷载和风吹雨淋、温度变化等大气环境的影响，其技术状态不断劣化，如不及时发现和预防，将会给桥梁的安全性带来巨大的隐患。因此对既有桥梁承载力和动力性能等进行研究、检测、评定，决定现有桥梁是继续使用还是需要维修加固或改造，具有重要意义。本文在总结前人的研究成果的基础上，结合宝鸡清姜河铁路桥检测项目，对现有钢筋混凝土简支梁桥进行静力荷载和动力荷载试验，，并根据桥梁特点，选择单片∏型梁建立适合实际情况的有限元模型。并针对清姜河铁路桥提出了相应的加固建议。具体内容如下： 1、既有钢筋混凝土桥梁性能评估方法介绍了桥梁评估方法研究的现状，说明了桥梁性能评估的流程与方法，指出对于既有钢筋混凝土桥梁的评估，主要包括桥面系外观检测、混凝土性能检测、钢筋性能检测等内容。 2、工程实例分析介绍了本次试验的工程背景，对桥梁外观检测的内容及应注意的问题做了说明，运用内燃机机车对桥梁进行了静载和动载试验，得出了反映桥梁静力性能和动力性能的应变、挠度、振幅、频率、速度、加速度响应实测数据，为有限元模型建立和制定相应合理有效的加固措施提供试验依据。 3、桥梁有限元模型建立与分析介绍了有限元软件MIDAS/Civil及求解的基本原理与过程，建立了单片∏梁的有限元模型，并对桥梁的受力情况进行模拟，利用跨中截面应力、挠度的模拟值与实测对比，验证桥梁模型的有效性；对桥梁进行了模态分析，得出纵横竖三个方向的自振频率和前8阶振型；分析跨中挠度在不同车速作用下的变化规律，为同类桥梁的承载力与动力性能分析提供参考。 4、钢筋混凝土桥梁加固结合宝桥的试验测试分析和有限元模拟分析结果，对混凝土表面及裂缝、桥面、桥墩、桥台、走道板、护坡提出了几点维修建议；为提高梁的抗剪能力并增强梁的整体性，同时为补足因锈蚀衰减的承载力，提出了主梁碳纤维布加固方案；为了增加主梁横向刚度，对增加主梁横隔板方案进行探讨。
[Abstract]:Railway is called the artery of national economy. Since the founding of our country, railway industry has made great progress. Railway bridge belongs to the large permanent building of railway line, which has complex structure, strong technology, long construction period and high value. In order to cooperate with the development of railway industry, a large number of small and medium span reinforced concrete simply supported railway bridges have been built in China since the 1960s and 1970s. At present, most of these bridges are in service or have retired from work. For the existing bridges in service, due to the influence of the atmospheric environment such as train dynamic load, wind and rain, temperature change for a long time, the technical status of the bridges is deteriorating continuously, such as not timely detection and prevention. It will bring great hidden danger to the safety of the bridge. Therefore, it is of great significance to study the bearing capacity and dynamic performance of existing bridges, to test, evaluate and decide whether the existing bridges should be maintained, strengthened or rebuilt. On the basis of summarizing the previous research results, combined with the inspection project of Qingjiang River railway bridge in Baoji, the static and dynamic load tests of the existing reinforced concrete simply supported beam bridge are carried out, and according to the characteristics of the bridge, A finite element model suitable for the actual situation is established by selecting a single piece of girder. Corresponding reinforcement suggestions are put forward for Qingjiang River railway bridge. The details are as follows: 1. Performance evaluation method of existing reinforced concrete bridges This paper introduces the research status of bridge evaluation methods, explains the flow and method of bridge performance evaluation, and points out that the evaluation of existing reinforced concrete bridges mainly includes the appearance detection of deck system and the testing of concrete performance. Steel bar performance testing and other content. 2. Engineering example analysis This paper introduces the engineering background of the test, explains the contents of the bridge appearance inspection and the problems needing attention. The static and dynamic load tests of the bridge are carried out by using the engine locomotive, and the strain reflecting the static and dynamic performance of the bridge is obtained. The measured data of deflection, amplitude, frequency, velocity and acceleration response provide experimental basis for the establishment of finite element model and the establishment of appropriate and effective reinforcement measures. 3. Establishment and analysis of bridge finite element model This paper introduces the basic principle and process of the finite element software MIDAS/Civil and its solution, establishes the finite element model of the single beam, and simulates the stress of the bridge. The stress and deflection of the mid-span section are compared with the measured values. The effectiveness of the bridge model is verified. The modal analysis of the bridge is carried out, and the natural vibration frequency and the first eight vibration modes in the three directions of vertical and vertical are obtained, and the variation law of the mid-span deflection under the action of different speed is analyzed. It provides a reference for the analysis of bearing capacity and dynamic performance of similar bridges. Reinforced concrete bridge reinforcement Combined with the results of test, test and finite element simulation of Baoqiao, some suggestions for maintenance of concrete surface and crack, bridge deck, pier, abutment, walkway board and slope protection are put forward in order to improve the shear resistance of the beam and enhance the integrity of the beam. At the same time, in order to supplement the bearing capacity of corrosion attenuation, the reinforcement scheme of main beam with carbon fiber sheet is put forward, and in order to increase the transverse stiffness of main beam, the scheme of increasing transverse partition board of main beam is discussed.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U448.13;U441

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