Effect of Strand Debonding on Prestressed Concrete Girder Shear Performance

摘要

The effect of excessive debonding of prestressed strands can present a marked impact on the shear performance of prestressed concrete girders. This effect is taken into account by the AASHTO LRFD Specifications and the maximum percent of strand debonding is limited to 25% of the total number of strands. This paper presents field and experimental results demonstrating the effect of strand anchorage on the shear behavior of prestressed concrete girder. Two case studies presented and discussed in this paper show the effect of excessive strand debonding and proper strand anchorage on the shear performance of prestressed concrete girders. The shear behavior of the bridge girders under different load cases was predicted up to failure using nonlinear finite element analysis. The analysis accounts for the influence of strand debonding at the ends of the girders on the shear capacity. The applicability of the AASHTO bridge design specifications for the calculation of the nominal shear sectional capacity of prestressed girders with shielded strands is demonstrated. The interaction between shear and bond, and the favorable effects of strand anchorage on the shear capacity of the girders is highlighted.