Sensitivity Analysis of Structural Parameters of Longspan Threetower Cable Supported Bridges

Abstract:

Finite element analysis models were established to analyze the variable characteristics of key structural parameters of threetower suspension bridge, threetower cablestayed bridge and threetower cablestayed suspension bridge. By using ANSYS parametric design language (APDL), a calculation program was prepared to analyze the maximum deflection of boxgirders, the maximum displacement of tower and the antislide coefficient of main cable and their sensitivity to the stiffness of boxgirders and tower, the appropriate stiffness of longitudinal constrain between boxgirders and tower, risespan ratio and central buckle of main cable in consideration of the effect of geometric nonlinearity. Finally, the reasonable range of the stiffness of boxgirders and tower was determined. It is shown that the stiffness of boxgirders has little effect on suspension bridge. The stiffness of tower is the key factor that affects the structural characteristics of the bridges and the appropriate stiffness of longitudinal constrain is beneficial to the structural characteristics of the bridges. The reduction of risespan ratio or the setting of central buckle of main cable can improve the structural stiffness, but reduce the antislide capability of main cable of cable supported bridge.