Mechanical Characteristics of Three-Truss Plate-Truss Composite Bridges on High-Speed Railways

This paper presents a study on mechanical behaviors of three-truss plate-truss composite bridges. Both a model test and numerical finite element analysis (FEA) have been conducted. The results indicate that the deck load is allocated to each truss in twice. The first allocation is among the panel points of bottom chord elements (tie beams), and the other through lateral bracings. When the stiffness of each truss (arch) is approximate, the load allocated to middle truss is about two times more than that in edge truss in the first allocation, and the second allocation makes the load tend to approximate among 3 trusses. But the vertical bending moment of bottom chord elements and the axial force of spandrel hangers in middle truss are about twice as that in the edge truss, which should be paid attention to. The results will be useful as references for design of three-truss plate-truss composite bridges.