Based On Modal Test Methods Arch Seismic Assessment

To the inservice multiple-arch bridge, the conditions of elastic foundation have a great influence on its dynamic performance. While the conditions of foundation is unknown generally and hard to obtain through normal method. This paper undertakes three parts of work accordingly:1. Through comprehensive analysis of seismic design and seismic performance evaluation for existing bridge, the seismic performance modal updating method of multiple-arch bridge is put forward, which is suitable for unknown elastic foundation parameters, and simplified finite element model containing unknown foundation parameters is built. Through obtaining structural modal parameters with modal test and rectifying simplified model with modal test results, the seismic force can be calculated using the rectified model, which can be used to evaluate the structural antiknock performance.2. The model test is designed and analyzed to verify the reliability of modal test. The simplified model is put forward to calculate the test model, of which results are used to contrast with test results in order to verify the reliability of the rectified model.3. Through analyzing the feature of multiple-arch bridge, the procedure of antiknock performance evaluation is given.Through model's modal test, the method of modal test for continuous arched bridge is proved reliable and can obtain satisfied results. At the same time, through contrasting with test results, the simplified element used in the paper can simulate the foundation's effect and the simplified model can reflect the dynamic performance of structure satisfactory.