Long-term Performance And Configuration Mode Of Transverse Pre-stress Of Large Cantilever Box Girder Bridge

In recent years, with the development of urban traffics, ordinary box girder bridges can hardly meet the traffic demand, thus pre-stressed concrete continuous beam bridges of box sections with large cantilever gain popularity. In large cantilever bridge structures, transverse pre-stressed steel bars are usually set up in the roof to prevent the cracks of bridge roof. In the process at the bridge operation stage, factors like the effects of continuous load and concrete weaken may lead to transverse pre-stressed steel bars' loss of pre-stress, which poses a threat to the safety of the bridge structure.Based on the engineering background of a certain pre-stressed concrete continuous box girder with large cantilever, combining the stress test and pre-stressing loss test, using the software ANSYS to establish finite element models and studying the long-term performance and configuration mode of transverse pre-stress for continuous box girder with big cantilevers are carried out in the paper. And the study has certain theoretical value and engineering practical significance. The main work and results of the paper are following:1. By using ANSYS to establish solid finite element models, combining the stress test analysis and contrasting the model data with test model, and verifying the mechanical characteristics of the big cantilever box girder bridge are conducted.2. Conducting transverse pre-stressing loss experiments on the big cantilever box girder, combining theoretical results and evaluating pre-stressing losses of box girder are carried out. The result shows that the test data of pre-stressing loss are larger than design values and the quality of the hole created by pipes needs to be improved.3. Combining test data of pre-stressing loss, analyzing the effect of the bridge structure caused by the transverse pre-stressing loss is also carried out. The result shows that if the transverse pre-stressing loss of the bridge is too large, pull stress might appears at deck at operation stage, and it might influence the crack resistance and integrity of the structure.4. Analyzing the influence of the stress of box girder caused by different configurations of transverse pre-stress and proposing a reasonable configuration of transverse pre-stress are conducted.