下承式密布横梁体系钢-混组合桥受力状态研究  

Force of through steel-concrete composite bridge in multi-crossbeam floor system

作　　者：陈佳[1] 叶梅新[1] 周德[1] 

机构地区：[1]中南大学土木建筑学院,湖南长沙410075

出　　处：《中南大学学报（自然科学版）》2010年第2期775-783,共9页Journal of Central South University:Science and Technology

基　　金：铁道部科技研究开发计划项目(2006K002-D)

摘　　要：对客运专线上1座96m跨度的下承式密布横梁体系钢桁-混凝土组合桥进行空间、平面有限元计算分析，并设计制作了比例尺为1：6的全桥模型，分3个阶段进行模型试验，以考察桥梁的位移和应力状态，分析混凝土板不同结合方式对结构受力的影响。研究结果表明：空间有限元分析结果与试验结果较吻合；下弦杆受到轴向拉力和较大的面内弯矩作用，各节间最大应力出现在节间中点附近；节点横梁最大应力发生在横梁2的下翼缘，节问横梁最大应力发生在位于端节间中部的小横梁上；混凝土板顺桥向整体受拉，并在竖向集中荷载作用下产生弯曲变形；全结合模型大部分节间内的桥面板参与主桁共同作用的程度为55％左右，半结合模型桥面板的参与程度为42％-43％；桥面板与下弦杆结合能够增加桥面板的参与程度，减轻下弦杆荷载，减少节点横梁尤其是靠近桥头横梁的面外弯曲；对桥梁进行初步设计时，主桁杆件的位移与内力可按照1个等效的平面刚架计算，下弦杆的等效刚度由原下弦杆截面和混凝土桥面板截面组合而成，桥面荷载可转化为均布荷载施加。A full-bridge model test of a 96 m-span through steel-concrete composite bridge in multi-crossbeam floor system in passenger dedicated line was conducted. The test was divided into three steps in order to observe the statement of stress and displacement, and to investigate the difference between different composition forms of concrete slab. The results show that space finite analysis results are close to test ones, bottom chords suffer axial force and large in-plane bending, and the max stress is nearby each middle internode. The max stress of node crossbeams occurs in No.2 bottom flange, and that of internode crossbeams happens in ones lying in the middle of every internode. The concrete slab is in tension at the longitudinal direction, and also suffers bent at vertical loads. The degree of completely-composite model taking part in the combined actions is about 55%, while that of semi-composite model is 42%-43%. The combination of concrete slab and bottom chord increases the degree of floor system taking part in the combined actions, lightens the burden of bottom chord, and reduces out-of-plane bending of node crossbeams especially the ones near bridgehead. Stress and displacement of main truss can be evaluated by a equivalent plane rigid frame in preliminary design, and effective stiffness of bottom chords are composed of original ones and concrete slab, and the concentrated load from deck can be translated into uniform load.

关 键 词：密布横梁体系 下承式钢-混组合桥 应力 位移 模型试验 

分 类 号：U448.38[建筑科学—桥梁与隧道工程]