Study On Impact Coefficients Of Continuous Concrete Beams For Highways With Different Section Types

With the rapid development of China’s economy and the increasing volume and load of highway transportation traffic,it is found that the bridge damage problems caused by the coupled vibration impact effects of vehicles and bridges are increasing.The impact coefficient of bridges is influenced by many factors,and the bridge section type may have some influence on the impact coefficient,however,there are few related studies.Therefore,this paper takes three three-span highway concrete continuous girder bridges with the same span and different cross-section types as the research object,and conducts joint simulation of vehicle-bridge coupling vibration by combining the finite element software ANSYS and the dynamic software UM.The method is used to solve the problem numerically and analyze the influence of vehicle moving loads on the impact effect of concrete continuous beam bridges on highways.The main research contents and conclusions of this paper are as follows:(1)The influence of the vehicle-bridge coupling vibration response when the vehicle is running at a constant speed is studied.When the vehicle passes the bridge deck at a constant speed,as the vehicle speed increases,the mid-span deflection of the single-box double-chamber girder bridge is the smallest,and the impact coefficient does not monotonically increase or decrease with the increase of vehicle speed,and the impact of vehicle speed on the impact coefficient is not very significant;The mid-span deflection of continuous girder bridges of different cross-section types increases with the increase of vehicle weight,and the impact coefficient decreases with the increase of vehicle weight;under the same vehicle action,the mid-span deflection of continuous T-girder bridge is the largest,and the single-box double-chamber girder The mid-span deflection is the smallest;as the unevenness of the bridge deck becomes worse,the impact coefficients of the continuous girder bridges of the three cross-section types all increase.(2)The effect of vehicle braking on the coupled vibration response of the vehicle and bridge is studied.When vehicle braking is applied to continuous girder bridges with the same span and different cross-section types,the size relationship of the impact coefficient,the sensitivity of the impact coefficient braking,and the variation trend of the impact coefficient with the vehicle braking position may not be consistent,but they are all in the The impact coefficient of the front half-span braking of the continuous girder bridge is greater than that of the rear half-span;in the process of vehicle braking,the impact coefficients of the three continuous girder bridges all increase with the increase of the absolute value of the deceleration.(3)The influence of the vehicle-bridge coupling vibration response when the vehicle jumps is studied.The mid-span deflection and impact coefficient of continuous girder bridges with three cross-section types increase with the increase of jump height.At the same vehicle jump height,the mid-span deflection of the side span of the T-beam bridge is the largest.When the vehicle jump height is larger,the impact coefficient of the side-span mid-span of the T-beam bridge also increases;the mid-span deflection and impact coefficient of the three continuous girder bridges With the increase of vehicle jumping speed,it shows a trend of first increasing and then decreasing;the closer the vehicle jumping position is to the mid-span,the greater the dynamic response and impact coefficient of the bridge mid-span,the impact coefficient of the side span of the composite box girder bridge is the largest,and the mid-span of the T-girder bridge has the largest impact coefficient.The cross-impact coefficient is the largest.(4)The influence of continuous vehicles on the vehicle-bridge coupling vibration response is studied.The dynamic impact coefficient increases with the increase of the number of lanes.When there are two lanes,the impact coefficient of the single-box double-chamber girder bridge is the largest;the mid-span deflection of the three-section continuous girder bridge decreases with the The reduction of the side span of the bridge is the smallest,and the overall impact coefficient is the largest,and the impact coefficient shows a trend of fluctuation with the increase of the distance between vehicles;with the increase of the number of vehicles,when the distance between vehicles is small,the impact coefficient under the action of continuous vehicles is greater than that of single vehicles,when the distance between vehicles is large,the peak value of mid-span deflection also increases with the number of vehicles.