Research On Dynamic Characteristics And Damage Detection Of Semi-Supported ArchBridges

Along with the development of society and the civil engineer technology, more and more long-span bridges are built. Although the reasonable design is the basic guarantee to the structural security, the limited recognition about the large-size and complicated structure, many uncertain, unknown and unpredicted factors (over-time work, corrosion, tired, sudden earthquake, bumps/collision of vehicles or vessels etc dangerous events) existing, people couldn't control and predict effectively. In order to ensure the security and long-lasting of the design, to reach the expected standards, especial the important structure of the long-span bridges, it is very important to constantly master its healthy condition.The damage detection and the condition estimation of the long-span bridges concern many fields such as structure, computer, communication ^ experience and measure. At present, all the research merely offer all kinds of methods and discuss each other. No more research can really recognize the damage detection, and most of them just in the simple structure. The bridges technology's improvement and the deep recognition of the bridges' working environment and the dynamic characteristic in operating condition are supposed to realize the damage detection and the condition estimated All these are the latest and wannest research in the international research fields at present.The paper analyses the dynamic characteristic and does a deep and systematic research on the bridges damage detection of the latest technology and uses, being directed to the present bridges designs, especial the most competitive bridge-model-semi-supported arch bridges. According to the calm-loading and move-loading tests, the modal analysis and the damage detection, the paper estimates the structural wholly-level and achieves the function and the ability of the structural design service, reaching the purpose of estimating the loading ability of the present bridges reasonable.The paper studies the modal analysis and the dynamic characteristics analysis about the long-span semi-supported arch bridges adopting the finite element method, at the same time modifies the calculation results. All these offer useful data for the bridges design, healthy inspection and condition estimated; According to the calm-loading and move-loading tests, to inspect whether the actual loading ability of the bridges, the structural changing and the dynamic characteristic agree with the design request, to seed the regularization of changing, to understand the actual loading condition and working condition, to offer scientific bases for using, mending and managing in the future. To accumulate the actual material for improving the design of the similar kind bridges, strengthening the structure, and improving the artwork according to setting up the concerned technology files.The paper mainly studies vibration-based method about the damage detection of the engineer structure. The main idea of vibration-based method is that the changes of the mass and the stiffness may be lead to the change of the dynamic characteristic. Abstracting the information about the different places from the actual data, compare the similar information in the no-damaged instruction to realize the damage detection and the condition estimated. The paper does a resemble analysis to a simple structure-the cantilever beam model, researching the relation the dynamic characteristic and the following information to the damage places and degrees. The paper gets a conclusion about the changingregularization of the simple structure-the cantilever beam model's damage behaviors. According tothe dynamic characteristic changing and curvature modal, realize the damage detection to the cantilever beam model. At the same time, the paper does the resemble analysis of the long-span semi-supported arch bridges' damage detectioa Because the main loading consists are the rib arch and the suspension rod, the paper analyses L/2 across, L/4 across of the rib arch and bumped 8# suspension rod different damage degree's dynam...