Research Of Bearing Capacity Assessment Of Existing Prestressed Concrete Continuous Girder Bridge

With the development of China's traffic cause,bridges play a crucial role in transportation,and the number of bridges also increase rapidly.Due to environment,construction,load changes and other factors,the bearing capacity of some bridges cannot meet the requirements,especially some bridges that have been used for a long time,due to material aging,loss of prestress,reinforcement corrosion,increase of traffic load,increase of traffic volume and other factors,more and more old bridges are experiencing insufficient bearing capacity.Therefore,it is very important to test these bridges and evaluate the bearing capacity.The assessment results can also provide a basis for maintenance,repair and reinforcement.This paper proposes to reduce stiffness of the cracked section of the beam,calculate and analyze the stress state of the beam with cracks.Taking variable section prestressed concrete continuous beam bridge and equal section prestressed concrete continuous beam bridge as examples,modeled with Midas Civil,applied the method of reducing the stiffness of the cracked section of the beam,analyzed the moment redistribution and deflection change after prestressed concrete continuous beam bridge cracking.The method for assessing the bearing capacity of bridges based on the detection results was studied.This method is based on detection results to determine the checking coefficient of old bridge,section reduction coefficient,live load correction factor,and deterioration coefficient,live load correction coefficient,and deterioration coefficient,the coefficients was reflected in the structural resistance expression to evaluate the bearing capacity of the bridge.When evaluating the bearing capacity of a highway bridge based on the detection result,considered the effect of continuous beam cracks on moment and deflection,Bridge Model is built in Midas Civil,the model is modified according to the detection result,and reduced the stiffness of cracking unit.analyzed and calculated the revised model to evaluate the bearing capacity of the bridge.The study found that the cracks of prestressed concrete continuous beam have influence on the deformation and internal force of continuous beam.,The influence of cracks should be considered when assessing the bearing capacity of old bridges.The study provides some reference for the evaluation of bearing capacity of prestressed concrete continuous beam bridges with cracks.