基于挠度理论的自锚式悬索桥受力特性分析

Analysis on Mechanical Behavior of Self-anchored Suspension Bridge Based on Deflection Theory

摘要:

基于挠度理论，分析了矢跨比、边中跨比、加劲梁竖向抗弯刚度、加劲梁纵坡和整体升降温对两塔三跨自锚式悬索桥结构受力特性的影响。此外，还讨论了加劲梁在轴向压力作用下的稳定性及其极限跨径。分析结果表明：矢跨比越小，主缆拉力越大、加劲梁的轴向压力也越大，而结构的整体刚度越低；边中跨比越大，结构的整体刚度越低，加劲梁在轴向压力作用下的横向稳定性也越差；主缆抗拉刚度或者加劲梁的竖向抗弯刚度越大，结构的整体刚度越大；加劲梁纵坡和整体升降温对结构受力的影响通常较小，可以忽略不计；自锚式悬索桥的极限跨径由加劲梁的横向第一类失稳及其屈服强度共同控制。

Abstract:

Based on deflection theory, the influence of rise-to-span ratio, side to mid-span ratio, vertical flexural stiffness of stiffening girder, longitudinal slope of stiffening girder and integrated temperature rise or fall on the mechanical behavior of a two-pylon, three-span self-anchored suspension bridge is analyzed. In addition, the stability of the stiffening girder under the axial compressive force and its extreme span are discussed. The analysis results show that the smaller the rise-to-span ratio, the greater the main cable tension and larger the axial compressive force of stiffening girder, but the lower the overall stiffness of the structure. The larger the side-to-mid span ratio, the smaller the overall stiffness of the structure, and the worse the transverse stability of the stiffening girder under the axial compressive force. The greater the tensile stiffness of the main cable or the larger the vertical flexural stiffness of the stiffening girder is, the larger the overall stiffness of the structure is. The influence of both the longitudinal slope of the stiffening girder and the integrated temperature rise or fall is usually small on the structure stress, which can be ignored. The extreme span of the self-anchored suspension bridge is controlled jointly by the lateral type I instability and the yield strength of the stiffening girder.