Error Analysis Of Finite Element Model Of Suspension Bridge For Health Diagnosis

It is indispensable to establish finite element models for long-span bridges. And high-accuracy, real dimensional model, and separate description of components are basic properties to finite element models for health diagnosis. Analyzing and controlling the error of finite element model to obtain high-accuracy finite element model, it is very important to achieve the identification and diagnosis of structural damage successfully.A span of 1000m and 3-span continuous beam suspension bridge is invented. Then a span of 10m scale test model of suspension bridge has been designed for health diagnosis. Meanwhile, based on design papers of the test model, corresponding finite element model has been established. To compare the results of static and dynamic test with initial finite element model calculations, error analysis of finite element modeling has been developed. With the adjustment of initial model parameters, the static and dynamic analysis of the model, and the comparison of initial model calculations, the sensitivity of static and dynamic responses is examined, and some valuable suggestions are put forward to finite element modeling for health diagnosis.In the sensitivity analysis, examined parameters involve the treatment of nodal stiffness areas, the cross-sectional area of stiffening girder, the main cable curve, the initial inner force of main cable, the boundary conditions and the elastic modulus of girders and cables. By analyzing the error of these parameters, the following conclusions are obtained:1. When the major monitoring objects are main cables and hangers of middle span, the stiffening girder of finite element model can be simplified, and it affects the results little because the girder is controlled by the big sag of span.2. The cable curves at cable finish stage, which utilizes equal rise of the quadric curve or the catenary curve, bring little difference to static and dynamic behaviors of suspension bridges.3. The joint conditions of saddle on tower and cable affect structure much. With improper treatment, it will make the structure great variance and lead to the big error of dynamic properties.4. The affection of all vibration modes is in accordance by adjusting girder elasticmodulus. But the adjustment of cable elastic modulus only influences the specific modes. The cable elastic modulus is sensitive to the girder deflection.