Research On Vehicle-bridge Coupled Vibration Response And Impact Coefficient For Ganjiang Bridge Of Fushan

Composite box girder bridge with corrugated steel webs has been widely used because it can significantly reduce the deadweight of box girder,improve the prestressed bar efficiency,simplify the construction process,and reduce the cracking problem of web plate.The dynamic action of vehicle-bridge has always been the main cause of local fatigue failure of highway bridges during their service life and the reduction of the bearing capacity of bridges.However,the research on box girder bridge with corrugated steel webs is mainly focused on static performance.For the long-span box girder bridge with corrugated steel webs,there are few studies on vehicle bridge vibration response.Therefore,it is of great significance to study the dynamic response of long-span box girder bridge with corrugated steel webs.On basis of the vibration theory,the vehicle and bridge equations are derived in this paper.Besides,the vehicle-bridge coupling equations are established by the boundary condition of the contact position between the wheels and the bridge deck.What's more,the road irregularity is numerically simulated by the trigonometric series superposition method,and the dynamic response of the vehicle-bridge coupling model is solved by the time-domain integral Newmark-? method.According to the proposed method,based on the Ganjiang bridge of Fushan,ANSYS and ETABS are used to model the bridge.Furthermore,the solution program written by MATLAB for vehicle-bridge coupled vibration equation is applied to solve the dynamic response and dynamic impact coefficient of long-span box girder bridge with corrugated steel webs under the influence of speed and pavement grade which corresponding to the operating condition with single vehicle and the working condition with multiple vehicles in vertical,respectively.And the calculated results are compared with those values that is calculated by the current code.The results show that: For the operating condition with single vehicle,it's shown that the effect of speed on the impact coefficient of the Ganjiang bridge of Fushan is complex,the impact coefficient does not increase linearly with the increase of speed.Driving speed and road roughness play different role in long-span box girder bridge with corrugated steel webs.The worse the pavement condition,the greater the impact coefficient of the bridge.Meanwhile,for the working condition with two vehicles in vertical,the dynamic impact coefficient of the bridge is smaller than that of the bridge under the single vehicle excitation,the curve of bridge dynamic impact coefficient changing with speed fluctuated with that under the the excitation of single vehicle.The variation law of dynamic response and impact coefficient caused by speed,road roughness and span are similar to that under the operatingcondition with single vehicle.In this paper,the study of vehicle-bridge coupling vibration of long-span corrugated steel web continuous box girder bridge can provide theoretical basis for the design and optimization of bridge structure.