Research On The Dynamie And Statie Load Test Of Lijiasha Cable-stayed Bridge

In recent years, lots of security accidents come to pass due to the reasons ofstructure quality defects, overloading of vehicles, flooding rain and disrepair. It isgreat important to ensure the safety of the bridge structures through regular tests andevaluations of bridge structure. According to the test results dynamic and static loadtests should be carried out to find out the structural safety hazards. The dynamic andstatic load test of bridge scientific experimental works which directly apply actualloads to the bridge structure, and is the most effective method in the evaluation ofbridges. At the same time, this method is very suitable for exterminating the carryingcapacity of suspension bridges and other high-order statically indeterminate bridges.According to the structural characteristics of cable-stayed bridges, the finiteelement model of Lijiasha Bridge was built up. And the dynamic and static load testprogram was designed. The carrying capacity of the bridge was evaluated accordingto the dynamic and static load test results. This study includes:(1) Summary the basic theories of static and dynamic load test for long-spanbridges.(2) Elaborate the structure characteristics and calculation methods of cable-stayedbridge. And establish the finite element models of the Lijiasha Bridge based onMIDAS/Civil software, including single girder model and double girder model. Thestatic and dynamic analysis was carried out to obtain the stress of control sections andstats of the whole bridge. The difference between the two models was comparedaccording to the calculation results.(3) Based on static load test, the strain and displacement of the control sectionsunder various conditions were measured. The test results were compared to thetheoretical calculating results, to evaluate whether the bridge structure meets thedesign requirements under static loading.(4) Based on pulse test, non-obstacle and obstacle driving tests, the naturalfrequencies, damping ratio, mode shape and power coefficient characteristic parameters were obtained to evaluate the stiffness and the withstanding capability ofdynamic loads.(5) The performance of the bridge structure is evaluated according to all the testdata, which provide a scientific basis for the completion, acceptance and futuremaintenance work.