Research About Vehicle Impact Action Effect On Prestressed Concrete Continuous Bridge With Multi-span And Wide Box-girder

With the improvement of China’s bridge engineering technology, the bridge structure is developing toward the high pier, large cross, shaped and soft direction, and the increase of traffic density and vehicle load, which lead to the live load proportion that the bridge structure withstands increase significantly. Questions from this and come, First of all, vehicles exacerbated the impact on the bridge structure, which endanger the structure of the bridge operator status and fatigue life. Followed, the vibration of the bridge will pass to the vehicles, which seriously impact driving safety and passenger ride quality. Researches are more on bridges of railway at home and abroad, but less on bridges of highway and city road relatively. The study of the bridge structure is mostly concentrated in the multi-beam girder bridges of T-shaped cross-section or the box-section. However the study was relatively less on the form of multi-span and wide box-girder bridge. Bridge structure form restricts and affects vehicle shock and vibration effects, the form of multi-span and wide box-girder bridge occupies an important position in continuous system of prestressed concrete bridge. In this paper, base upon vehicle-bridge coupling vibration theory and finite element method, The author study effect of vehicle impact on multi-span and wide box prestressed concrete continuous beam bridge, thinking of a variety of influencing factors. The main study is as follows:1. Review the current situation of the domestic and international bridge Coupled Vibration, Illustrates the results achieved in the course of the study and surviving issues.2. Using finite element analysis software ANSYS to establish the grillage Law model and the solid model of the studied bridge. Analysis and calculated the structure’s natural vibration characteristics. Based on GB/T7031-86Pavement power spectral density function, which is from the standard vehicle vibration input pavement roughness method. Use MATLAB software to simulate the different levels of pavement irregularity domain sample curve. Establish4degrees of freedom of the biaxial plane vehicle model and7degrees of freedom biaxial space vehicle model. Apply D’alembert’s principle to deduce Vibration equation of the two models, and give a corresponding matrix form.3. Give the iterative calculation of numerical analysis method of the vehicle bridge coupling system, the calculation steps and procedures flowchart. Write the command stream program of the Car inducing bridge coupling vibration response for study.4. Based on the engineering examples YingZe Bridge, analyze the dynamic response of the bridge structure, when the factors about traffic speed, traffic load, road grade and vehicle partial load are alterant.5. In the study of the strength factor on the multi-factor of vehicle bridge coupled vibration effect, author select vehicle layout, traffic speed, traffic load, axle frequency ratio and the road surface flatness to conduct conspicuousness orthogonal experiment analysis. For the result data, we also carry out range analysis and trend analysis. Based on the orthogonal test, select and use the related factor level combinations on car causing the bridge structure dynamic response to research horizontal and longitudinal direction of the bridge.Conclusions of this study in the paper provide a theoretical basis and technical reference for the further research on vehicle bridge coupled vibration problem about the multi-span and wide box prestressed concrete continuous beam bridge of highways and city roads, and are much valuable for promoting the application and improvement of the calculation method about multi-parameter bridge impact coefficient.