Analysis And Reinforcement For Cracks Of Prestressed Concrete Continuous Rigid Frame Bridge

With its reasonable Mechanical behavior and good driving performance, prestressed concrete continuous rigid frame bridge occupy a dominant position in quantity on many types of bridge in our country. It plays an extremely important role in the road transport. Large span prestressed concrete continuous rigid frame bridge has a larger crossing capacity and strong adaptability. It is widely used in china mountain plateau. However, due to changes in the material itself, environmental factors, and loading conditions, Continuous rigid frame bridge has varying degree of damage during its operational phases. According to the survey and analysis of Diseases for existing prestressed concrete continuous rigid frame bridge, its major damage is the vertical deflection of the mid-span and cracks in the different locations of box beam. Cracks located in the part of the beam with specific distribution form weaken the rigidity of beam section and promote the lager deflection. So it is closely related to the beam crack and deflection of mid-span.In this paper, a prestressed concrete continuous rigid frame bridge located on a freeway in Yunnan is selected as the basis. Firstly, Finite element analysis software Midas Civil is used to analyze main factors that caused the beam cracks on the operational phase and simulate the stress state of the bridge in the actual operations approximately based on the analysis of the outcome. Secondly, According to the theoretical analysis and combining the results of the crack detection,a part of this bridge beam that the cracks distribute intensively is chosen and built analysis detailed model using the finite element analysis software ABAQUS. Thirdly, one of the most unfavorable cracks is chosen to calculate fracture mechanics parameters, analysis mechanical characteristics quantitatively and judge the manifestations of cracks qualitatively under external loads combining the fracture mechanics of concrete. The analysis results can assess the impact of the cracks on the bridge structure. Finally, Based on the bridge, the initiative reinforcement method is analyzed combined with external prestressed tendons as an example, the bearing capacity and the crack control of structure is different with different locations of external prestressed tendons, And then reinforcement effects is evaluated.By calculating the crack fracture parameters and crack extended state, real damaged situation of the bridge under the using load can be reflected. An appropriate reinforce method based on the analysis results can be selected, a suggestions for strengthening program can be made on this bridge so as to provide economic and security basis for the bridge structure repairmen and reinforcement.