半开式桁架桥结构稳定性分析  

STABILITY ANALYSIS OF HALF-THROUGH TRUSS BRIDGE

作　　者：岳子翔 温庆杰 卓涛 YUE Zi-xiang;WEN Qing-jie;ZHUO Tao(School of Mechanics and Civil Engineering,State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining ＆ Technology,Xuzhou,Jiangsu 221116,China)

机构地区：[1]中国矿业大学力学与土木工程学院深部岩土力学与地下工程国家重点实验室,江苏徐州221116

出　　处：《工程力学》2018年第A01期270-277,共8页Engineering Mechanics

基　　金：中国工程建设标准化协会标准<铝合金人行天桥技术规程>编制项目(2013);中国矿业大学青年科研基金项目(2012QNB28);国家自然科学基金项目(51108452)

摘　　要：半开式桁架桥无上部联系,其上弦杆易发生平面外屈曲。在上弦杆屈曲后的整桥体失稳模态中,存在明显的横向弯曲与扭转变形,上弦杆屈曲临界力和屈曲模态与理论结果有一定差异。该文使用有限元软件对一定数量的半开式桁架桥进行分析,通过有限元结果对影响桁架桥稳定性的因素进行了探讨,发现影响半开式桁架桥稳定性的尺寸参数是宽跨比,对这一桥型而言,稳定性与其宽跨比有正比关系;宽跨比对稳定性的影响来自其对整桥横向刚度和扭转刚度的影响,两种刚度共同决定整桥稳定性,但横向刚度是决定性因素;横向刚度会影响整桥失稳模态,若失稳模态产生突变,稳定性能随之产生巨大变化;对单座桥梁而言,若要通过增大宽跨比来提高稳定性,必须使两榀主桁建立有效联系,否则会起反作用;加装风撑能有效联系主桁,加强整桥横向刚度,进而提升整桥稳定性,但风撑无法加强抗扭刚度。Half-through truss bridges without upper lateral members are vulnerable to out-of-plane buckling of the upper chords. The instability modes caused by upper chords buckling involve obvious lateral bending and torsional deformation. The observed critical buckling load and buckling modes of upper chords are different with theoretical results. Based on FEA analysis, we analyzed some half-through truss bridges, and found that the stability is proportional to the width-span ratio. For those bridges, stability is directly proportional to its width-span ratio. The influence of the width span ratio on the stability was investigated by considering its influence on lateral stiffness and torsional stiffness. The influence of lateral stiffness is more significant, which affects the instability mode of the whole bridge. If the instability mode suddenly changes, the stability performance will change greatly. It is necessary to set effective link between the two main trusses of a bridge. Installing wind braces can effectively link the two main trusses, increase the lateral stiffness, and thus improve the stability, but the wind brace can not increase the torsional stiffness.

关 键 词：桥梁工程 半开式桁架桥 稳定性 横向刚度 扭转刚度 宽跨比 风撑 

分 类 号：TU311.2[建筑科学—结构工程]