加劲梁外伸跨对悬索桥静动力特性的影响

Effect of Extended Span of Stiffening Girder on Static and Dynamic Characteristics of Suspension Bridge

为研究加劲梁外伸跨对悬索桥静力、动力特性的影响,以一中等跨度悬索桥为例,利用桥梁非线性分析系统BNLAS,分别建立加劲梁单跨简支、三跨连续以及五跨连续的单跨悬吊体系有限元模型,对结构进行静力、动力特性分析。结果表明:外伸跨加劲梁能够有效降低梁端最大纵向位移及转角,降低了活载作用下加劲梁的挠度,而且有效提高了结构整体面外刚度;外伸跨加劲梁有效减弱了行车下梁端位移的响应,降低了梁端支座的往复式位移总量;在动力特性方面,外伸跨加劲梁同样具有较多的优点。为提高伸缩缝及支座的耐久性,单跨悬吊悬索桥推荐采用带外伸跨的连续加劲梁体系。

In order to study the influence of stiffening girder outreach span on the static and dynamic characteristics of suspension bridges, a medium-span suspension bridge is taken as an example, and the finite element models of single-span simple-supported, three-span continuous and five-span continuous single-span suspension systems are established by using the bridge nonlinear analysis system BNLAS, respectively. The static and dynamic characteristics of the structure are analyzed. The results show that the extended span stiffening beam can effectively reduce the maximum longitudinal displacement and rotation angle at the end of the beam, reduce the deflection of the stiffening beam under live load, and effectively improve the overall out-of-plane stiffness of the structure.Extended span stiffening beam can effectively reduce the response of the lower beam end displacement and the total reciprocating displacement of the beam end support.In terms of dynamic characteristics, stiffened beams with extended spans also have many advantages.In order to improve the durability of expansion joints and supports, the continuous stiffening girder system with extension span is recommended for single-span suspension bridges.