Structural Form and Conceptual Design of Novel Truss-Arch Bridge with 1000 m Scale

Abstract

Abstract The main span of conventional arch bridges is difficult to reach 1000 m due to the sharp decline of mechanical properties (e.g., structural stiffness, natural frequency and stability). In order to overcome this limitation, the structural form and conceptual design of a novel truss-arch bridge with 1000 m scale was proposed. Firstly, a novel truss-arch bridge was presented based on the structural form of conventional deck arch bridges by introducing auxiliary arch and substituting columns for triangular network consisting of web members. The mechanical rationalities of this structural form were clarified. Then, a conceptual design of new truss-arch bridge with a span of 960 m are performed and the main components (e.g., main/auxiliary arch, triangular truss network and main beam) are designed. Finally, the structural responses of new truss-arch bridge were numerically investigated based on finite element analysis (FEA) by comparing with conventional deck arch bridges. The numerical analysis demonstrates shows that the proposed bridge combines the complementary strength of both arch and truss structures. As compared to conventional deck arch bridge, the stress, stiffness and stability of the proposed bridge have greatly improved and meet the requirements of the design codes. Quantifications show that the stress and displacement are reduced by 10% and 15%, while the stability and natural frequency are increased by 35% and 24%. The conceptual design of the proposed bridge can provide an alternative solution for the construction of super-long span bridges.