Based On The Overall Safety Of The Bridge Load Test Study

Load test is one of important testing methods for evaluating civil structures. A series of valid test data from the test are of basic for administrators to evaluate bearing capacity of bridge, and for relative researchers and designers to innovate structural theory or to apply new structures to bridge engineering as well. Thus, integrated safety evaluation of bridge performance based on load test is one of significant investigation projects in China now.On the basis of absorption in relative technical literatures, the author paid much more attention on integrated safety evaluation of a chosen bridge in Changsha City. The combined method of theoretical analysis, numerical modeling and in-site test is used to investigate into the response of the bridge under the static and dynamic load. Main conclusions of the work are as follows:1. Through theoretical analysis and numerical modeling (FEM, ANSYS), the in-site static loading test frame of the bridge, consisting of the determination of four loading-unloading conditions, loading-unloading procedures and load level of each condition, and the location of the main control sections and sensors instrumented in the sections, was established.2. Through the static test, the bridge's stress, deflection and displacement at the sensor's locations were tested. Further, comparison analysis of tested stress, deflection and displacement, with related those obtained from numerical modeling, was done, in order to determine whether the bridge performance under load meets its design expectant standards or not.3. Based on the fact that there is no acceptance regulation of bridge evaluation under the dynamic load at present, in-site experimental investigation, including pulse test, car test, bump test and brake test, on the response change of bridge, was carried out. As a result, the related the bridge's mode parameters, forced and natural vibration characteristics, and impact coefficient, were obtained. Application of these dynamic response parameters further enriches the integral performance bridge and related evaluation system. 4. To some extent, main conclusions of the work is able to guide acceptance check of the bridge and its maintenance decision in future.