Key Problems Study Of Long-span Steel Trussed Arch Bridges

This paper is supported by a grant from the Research Fund for the Doctoral Program of Higher Education and involves following contents:(1) Based on large quantity of reference, paper looks back the development of steel trussed arch bridges systematically and summarizes the structural style and mechanical characteristic of this type bridge.(2) Paper discusses following seven aspects of steel trussed arch bridge overall design: layout of arch rib truss, arch axial cord, ratio of rise to span, definition of arch crown and spring, different boundary condition, section form and section area. Moreover, paper studies the selection of truss joint and secondary stress of joint rigidity. Some useful suggestions on joint constitution are advised finally.(3) Paper introduces several suitable construction methods of steel trussed arch bridges and compares the different features between crane on the arch and cable crane. Combining with the construction procedure of Chaotian Gate bridge, author investigates the features and calculation methods of construction and proposes some useful advice.(4) Paper considers the influence of initial geometry defect using plate and shell finite elements, studies the ultimate carrying capacity of thick plate-welded or stiffened box-section compression bars and suggests reasonable buckling safety factor.(5) With the ultimate carrying capacity analysis of Chaotian Gate bridge and Daning River bridge, paper determines the failure route and mechanism of steel trussed arch bridges.(6) Several parametric analysis are carried out in the paper, such as boundary condition, initial defect, load layout and design parameter etc. Then critical factors which affect the ultimate carrying capacity of steel trussed arch bridges are determined at last.