Abstract:The related parameter study for twinI girder bridges composite with concrete deck is few in current research. In the paper, FE analyses were developed to study the bending, local buckling and the maximum load capacity of twin-I girder bridges. The design parameters were studied including flange widththickness ratio, web depththickness ratio, stiffener arrangement, and girder depth. Design recommendations were proposed in the paper. A recommendation for girder depth value was given from material saving perspective.