Study on the influence of flat plates for stiffening on the force transmission of frame cross bracing

Abstract The main girders of the I-section steel-concrete composite twin girder bridge is usually connected together by frame cross bracing. When the cross girder is connected with the main girders by welding, the flat plates for stiffening can be used to strengthen the connection to ensure the effective transfer of connection forces between the two. In this paper, the finite element simulation method is used to study the influence of flat plates. The results show that, compared with the twin girder structure without flat plates for stiffening, when the same load acts on the cross girder: the stress peak value of the cross girder of the twin girder structure with flat plates is obviously reduced, and the stress peak value of the main girders is increased; the bending stress of the web of T-shaped connection stiffeners diffuses faster from the welding part to the end; the peak value of the axial stress on the web of T-shaped connection stiffeners decreases obviously, and the position of the peak value changes from the side near the cross girder to the side near the web of main girder. The above results show that it is necessary to set the flat plates for stiffening in the twin girder bridge to ensure the transfer of forces between the main girders and cross girder.