The Analysis Method Of The External Prestress Reinforcement On The PC Continuous Beam Bridge

External prestress reinforcement is widely used as a powerful active reinforcement technology in engineering.However,the research of scholars at home and abroad is mainly focused on simply-supported beams.There is less research on PC continuous beams as statically indeterminate structure.So the calculation method for external prestress reinforcement on PC continuous beam bridge is not perfect.Moreover,the theory of judging the effective prestress in the old bridge is not yet mature,and it is difficult to identify the degree of damage to the bridge that needs to be reinforced,leading to a lack of quantitative design basis for the external prestress reinforcement on PC continuous beam bridge.Based on the research results of experts and scholars,this paper proposes to establish the relationship between the actual diseasedamage model and the reinforced feasible region,and proposes an analytical method for the design of PC continuous beam bridges with external prestress reinforcement.Firstly,according to the stress characteristics of the reinforcement system,it is divided into two stages of external tensioning prestressing and external loading.The force analysis method is used to analyze the force of each stage,and a theoretical analytical calculation method for the statically indeterminate system reinforcement is established,and verified with finite element analysis.Then,through an example of a three-span PC continuous box girder bridge,based on the distribution of the effective prestress along the box girder,the effective stiffness of each section of the box girder is calculated,and the structural damage parameters are substituted into the structural finite element model to establish a real structural finite element damage model.The stress degree method is used to reinforce the design of the external prestressing,and the feasible region of the external prestress reinforcement is obtained.Finally,through an engineering example of a seven-span PC continuous box girder bridge,the reinforcement design analysis method proposed in this paper is adopted to identify the structural damage parameters based on the load test and appearance detection,and to calculate the external prestress reinforcement design.Through the analysis of the reinforcement of the engineering example,it is shown that the analysis method of the external prestress reinforcement design proposed on the PC continuous beam bridge in this paper is effective,and provides a theoretical basis for the design of similar bridges with external prestress reinforcement.