Shunsuke Bamba

Influence of Patching Repair Method on Structural Performance of pre-tensioned Prestressed Concrete Beam

Takumi SHIMOMURA

Structural performance of prestressed concrete (PC) structures are affected by the prestress loss due to patching repair. In particular, in case of large sectional repair, there are problems of the diminution of prestress loss and stress increase in existing concrete sections. In this study, the structural performance of PC structure and the stress state of prestressing steel bars after the step-by patching repair were investigated by conducting bending tests with corroded and non-corroded PC beams. Moreover, we conducted Finite Element (FE) analysis to simulate experimental results.
At first, we conducted bending tests. Test results cleared that the reduction of bending crack load and member stiffness are caused by prestress loss due to patching repair. However, those are able to be prevented by increment of repair steps and considering the location of joint between repaired sections.
Next, the re-distribution of prestress behavior were experimentally investigated by step-by patching repair. As a result, in the case of step-by patching repair, the prestress loss due to patching repair is able to be prevented, due to re-distribution of prestress in the repaired sections. Furthermore, the stress increment in existing concrete sections decreases because part of prestress is transferred to the repair parts.
Finally, the bending test results and re-distribution of prestress behavior due to step-by patching repair were evaluated with FE analysis. As a result, the reduction of member stiffness due to patching repair, and influence of repair steps on the stiffness were estimated accurately in FE analysis.
For the evaluation of long term structural performance, it is required to examine the relationship between structural performance and time variation after patching repair, and the analysis method of corroded PC member

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