Failure analysis of corroded PC beams under flexural load considering bond degradation

An analysis model is proposed in the present study to predict the failure of corroded prestressed concrete (PC) beams under flexural load. The corrosion induced strand section loss, material deterioration and bond degradation are considered in the proposed model. The bond degradation is treated as a function of corrosion loss. The slip region caused by bond deterioration is determined by comparing the effective bond force and tension force of strand. And then, a strain-incompatibility analysis method is developed to calculate the flexural strength of beams. The proposed model is verified by experimental tests on corroded post-tensioned concrete beams. Results show that the bond degradation induced incompatible strain is important and should be considered into the flexural strength prediction. The proposed model provides an effective way to measure the incompatible strain and a reasonable prediction for flexural strength of beams. The incompatible strain depends on the corrosion loss and applied load levels. Corrosion loss < 13% has few effect on the incompatible strain. The further corrosion can decrease the compatibility coefficient to a small value with increasing the loading levels.