Bending and shear strengths of partially encased composite I-girders

Abstract

This paper has proposed the use of partially encased composite I-girders as bridge girders. Reinforcing bars were welded to the upper and lower flanges and concrete was poured into the area surrounded by the flanges and web. Bending and shear tests were performed, showing that the bending strength of the partially encased girder model is 2.08 times higher and the shear strength is 2.98 times higher than the conventional steel I-girder model. In the model where the reinforcing bars were not welded to the flanges, the bending strength slightly decreases but it is still 1.75 times higher than the steel I-girder model. When the buckled steel I-girder model is encased with concrete, its bending strength is greatly improved and rose to 1.89 times of that of the non-buckled steel I-girder model. Analytical methods were proposed to calculate the bending and shear strength of the encased composite girders and are validated by the experimental data.