Strengthening Railway Bridges by External Prestressing

摘要

In this paper, a simplified method based on rigid body model, which can be used directly for design, has been set-up to predict the ultimate behavior of fully or partially prestressed concrete beams with external post-tensioning tendons. The following variables were considered in theoretical analysis: strength of concrete, type of loading, percentage of reinforcement, configuration and initial stress of external tendons and second-order effects. Three groups of beams (10 total beams) were tested and two groups (21 total beams) of test results reported in ACI Structure Journal and PCI Journal were used for analyzing. Theoretical calculations were found to agree with the test results very well. On the basis of the results of test and analysis, two railway concrete bridges were strengthened by using externals prestressing.