下承式半结合钢桁结合梁桥第一系统受力性能  

Features of the first system mechanical behavior of through steel truss semi-composite bridge

作　　者：张敏[1,2] 叶梅新[1] 韩衍群[1] 

机构地区：[1]中南大学土木建筑学院,湖南长沙410075 [2]中铁大桥勘测设计院有限公司,湖北武汉430034

出　　处：《中南大学学报（自然科学版）》2010年第3期1146-1151,共6页Journal of Central South University:Science and Technology

基　　金：铁道部科技发展计划项目(2003G003)

摘　　要：以下承式半结合钢桁结合梁桥为例,引入下弦节点水平刚性系数概念,根据下弦杆与桥面系变形协调条件,推导第一系统作用下桥面系纵向力分配系数的计算公式,形成"柔度矩阵";研究下弦节点水平刚性系数k对纵向力分配的影响,并给出k的经验表达式;最后,对64m下承式半结合钢桁结合梁桥进行计算。研究结果表明:在第一系统作用下,桥面系分摊的纵向力与下弦杆拉压刚度、桥面系拉压刚度、横梁水平抗弯刚度和k等因素有关,桥面系分摊纵向力的比例从桥端节间往跨中节间逐渐减小;在第一系统作用下,横梁水平弯曲应力不可忽略;本文计算结果与有限元计算结果和试验结果均较吻合;在计算下承式半结合钢桁结合梁桥第一系统受力时,本文公式方便、有效。As part of an investigation to comprehend features of first system effect （FSE）,a through steel truss semi-composite bridge was studied. Introducing rigidity coefficient k of truss joint at horizontal plane,the formula of floor system axial force distribution coefficient was obtained based on the deformation compatibility condition of bottom chord members and floor system,and ＂flexibility matrix＂ was formed. Additionally,the effect of k on the coefficient was discussed,and the calculating formula of k was suggested. Finally,a case of a 64 m through steel truss semi-composite bridge was calculated. The results show that in FSE,axial force distribution coefficient of floor system is mainly determined by tensile strength of bottom chord elements and floor system,horizontal bending rigidity of transversal beam and k. It diminishes gradually from the panel near the end of bridge to panels near the middle of bridge. In FSE,the horizontal bending stress of transversal beams cannot be ignored. The results are in good agreement with finite element analysis and experimental results. The formula is convenient and effective for calculating FSE of the through steel truss semi-composite bridge.

关 键 词：第一系统 纵向力 分配系数 钢桁结合梁 高速铁路 

分 类 号：U448.1[建筑科学—桥梁与隧道工程]