Abstract: The steel-concrete composite girder bridge truss has the advantages of good economic performance, high bearing capacity, large bending stiffness and so on, so it is widely used in our country. However, because the rods that make up the truss are long and thin, the overall heating and cooling of the structure will affect the closing of the truss and the positioning of the truss joints.In this paper, combining with engineering examples, MIDAS software is used to analyze the transverse displacements of trusses produced by different temperatures at the erection stage and the influence of vertical displacements of trusses on other joints after erection.Through the research results, it is concluded that the lateral displacement of the truss is linear under temperature load, and the vertical displacement of the nodes increases or decreases in the same way with other nodes.Therefore, in truss assembly, it is necessary to control the closing temperature within a reasonable range, and in elevation control, multiple nodes can be adjusted simultaneously, and the position and forced displacement of nodes can be determined by superposition principle.

Key words: steel-concrete composite truss bridge, temperature load, node control, finite element analysis

摘要： 钢混组合梁桥桁架具有经济性能好、承载能力高、抗弯刚度大等优点,因此在我国应用广泛,但由于组成桁架的杆长细比较大,结构整体升温降温会影响桁架的合龙与桁架节点的定位。文中结合工程实例,利用MIDAS软件分析不同温度对桁架拼装阶段产生的横向位移以及桁架拼装完后节点竖向位移对其他节点的影响。研究结果表明,温度荷载对桁架的横向位移是线性的,节点的竖向位移对其他节点的影响同样是同倍增加或减少的,因此在桁架拼装时,需要将合龙时的温度控制在合理范围内,在标高调控时,可同时调节多个节点,并利用叠加原理,确定节点位置和强制位移。

关键词: 钢混组合桁架桥, 温度荷载, 节点调控, 有限元分析