大跨径三塔缆索承重桥梁力学参数敏感度分析

建立了主跨为1 400m的三塔悬索桥、三塔斜拉桥和三塔斜拉-悬吊协作体系3种桥型的有限元分析模型.考虑几何非线性效应,利用ANSYS参数化设计语言(APDL)编制了计算程序,分析了主梁的最大挠度、索塔塔顶最大位移及主缆抗滑移系数对主梁刚度、索塔刚度、塔梁约束刚度、矢跨比、中央扣等参数的敏感程度,并进一步确定了主梁刚度和索塔刚度合理取值范围.结果表明:主梁刚度对悬索桥影响较小;主塔刚度是3种桥型的核心参数;塔梁约束可改善3种桥型的力学性能;减小矢跨比或设置中央扣可提高结构刚度,但会降低主缆抗滑性能.

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

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.