Abstract: To study the interaction relationship between the forces of each span of a multi-span continuous girder bridge strengthened by prestressed CFRP plates, based on the engineering background of the Xinshuhe river continuous box girder bridge, this paper established a continuous girder bridge prestressed CFRP plate reinforcement model, and studied the reinforcement of prestressed CFRP plates. The interaction law between spans of multi span continuous beam bridge strengthened with prestressed CFRP plate and the influence law of prestressed anchorage position on the reinforcement effect are studied. Finally, the tensioning prestress ratio of each span when the whole bridge reaches the same reinforcement effect is given. The results show that the prestressed CFRP plate reinforcement of multi span continuous beam bridge will increase the deflection of adjacent odd spans, produce reverse arch effect of adjacent even spans, and significantly reduce the influence on the back of adjacent second spans. Compared with the simply supported beam bridge, the adjacent span of the continuous beam bridge has a weakening and restraining effect on the reinforcement effect, which is related to the position of the strengthened span. When the ratio of tension prestress between the middle span and its adjacent span is 1∶0.3, it can effectively reduce the impact on the adjacent span, and has little impact on the reinforcement effect of the reinforced span, and has the least impact on the smoothness of the bridge deck.

Key words: continuous girder bridge, prestressed CFRP plate, strengthen, numerical simulation