Influence of Cracks Parameters on Bearing Capacity for Prestressed Concrete Box Girder

For long-span pre-stressed concrete continuous box girder bridges, cracks and other damage problem are often found because of influence of loads, climate, operations management and other factors during operation. The problem of cracking is serious increasingly, which has a direct impact on usability, durability and security. In order to analyze the bearing capacity of the bridge with cracks under different parameters, such as cracks width, cracks height and cracks spacing and provide the basis for the safety assessment and reinforcement, the paper puts forward the cracking reduction coefficient that evaluates the bearing capacity of the damaged bridge based on the tensile stress control. A three-span continuous rigid frame bridge is analyzed and the result shows that the bearing capacity of the bridge is in inverse proportion to cracks width and cracks height. The bearing capacity of the bridge is in direct proportion to cracks spacing.