Resarch On The Dynamic Performance Of Concrete Simple Supported Skew Beam Bridge

In the construction of high-grade highway,more and more skew girder bridges have been designed and constructed in order to fit the routes.With the widespread application of fabricated simply supported concrete skew girder bridges,many problems arise correspondingly.Because of the existence of oblique angle,there is a big difference between the skew beam bridges and the straight beam bridge on the vibration characteristics,which names the so-called bending-torsion coupling effect,and it is not considered in the current standard calculation formula of bridge fundamental frequency.In addition,the dynamic characteristics of the skew beam bridge must change with the service time increases,which will inevitably lead to the change of the dynamic performance of the vehicle.However,in the Chinese current bridge design specification,there are no relevant regulations about the impact coefficient of the skew beam bridge under the effect of the mobile vehicle.Therefore,the coupling vibration analysis of the skew girder bridge is carried out to clarify the dynamic characteristics of skew girder bridge and the influence parameters of the dynamic impact of the vehicle.Meanwhile,the revised formula or suggestion for the skew beam bridge is put forward to the current formula of the basic frequency and the impact coefficient,which is of great importance to the engineering.Taking skew beam bridge as subject,the coupling dynamic behavior of the bridge is systematically and comprehensively analyzed in this paper.The main research results are as follows:From static and dynamic perspectives,the stress characteristics of the skew girder bridge are theoretically analyzed.Based on engineering practice,the basic principles and specific modeling methods of dynamic characteristics of skew girder bridges are pointed out through comparison of various finite element methods.On this basis,considering the influence of oblique angle,span,bridge width and lateral torsional stiffness on the dynamic characteristics of skew beam bridge,the analysis results is sorted out by statistical method,and the basic frequency correction formula of the assembled concrete simply supported oblique beam bridge is put forward,which lays the foundation for the later coupling vibration analysis of the girder bridge.Based on the existing theoretical research results of vehicle dynamic performance and vehicle-bridge coupled vibration,a MATLAB program for vehicle bridge coupled vibration analysis is developed for skew girder bridges.Combined with the actual bridge cases,the analytical methods and procedures adopted in the study are verified.On this basis,the coupling vibration analysis of the skew girder bridge under the influence of many factors is carried out.Based on the analysis results,a simplified correction formula for the impact coefficient of skew beam bridge is proposed.Based on the actual project,the influence of external prestressed reinforcement on the dynamic performance of skew girder bridge is analyzed based on the vehicle bridge coupling analysis method and the program compiled.On this basis,different reinforcement methods are compared to provide suggestions and basis for reasonable selection of reinforcement schemes from the perspective of vehicle power performance.