一种适用于下承式钢桁结合桥计算的板梁组合单元

下承式钢桁结合桥具有建筑高度较低、行车时燥声、震动较小、刚度较大等优点,是高速铁路桥梁中比较理想的结构形式之一。为了能较合理和方便地分析下承式钢桁结合桥的力学行为,本文提出了一种考虑板梁共同作用和相对滑移的板梁组合单元。该单元以矩形板的4个结点的结点位移和板梁结合面3个点的相对滑移作为单元的基本自由度,板的位移模式通过对常规4结点矩形平板壳单元的形函数修正得到,梁的位移模式则根据板和梁之间的变形协调条件来确定。文末的算例表明,本文的解与试验结果和通用工程软件解较为吻合,说明了本文理论和方法的正确性。

A plate-beam composite element suited to calculate through steel-truss composite bridges

With the advantages of low architecture height,light noise and vibration in the train moving,great stifferness,through steel-truss composite bridge is one of the ideal structures in the bridges on high-speed railways.For analyzing the mechanics properties of this structure expediently,this paper sets up a plate-beam composite element in which the joint actions and relative slips between plates and beams were considered.The basic displacement degree of freedom of the element were the displacement of 4 nodes on rectangular plates and the relative slips of 3 nodes at combing surface between plates and beams.The displacement pattern of plates was obtained by modifying the shape functions of the common rectangular plate-shell element with 4 nodes.The displacement pattern of beams was determined by the deformation conforming conditions between plates and beams.The example shows that the results are in accordance with those of the test and the engineering software,which explains the correctness of this method.