摘要
研究目的:在山区不对称峡谷设置桥梁时,可采用长联高墩大跨不对称连续刚构桥。这种桥型与刚构连续体系相比,具有稳定性好、施工相对简单、桥型美观、养护维修方便等特点。本文结合工程实例,对具有这种特征的桥梁从结构受力与变形特点、合龙顺序与合龙措施、大的边中跨比值对结构的影响、T构悬臂施工阶段安全性等方面作了分析研究,以期能供类似桥梁工程设计施工时参考。研究结论:长联高墩大跨不对称连续刚构桥梁部弯矩、桥墩的水平位移、桥墩截面弯矩等均不对称,合龙段顶推能使结构墩顶、墩底弯矩有明显的减小,其减小幅度与桥墩刚度以及桥墩离不动点的距离有关,合龙时是否施加顶推力对箱梁弯矩影响很小。对于这种桥型,需要合龙顶推时,中跨→次边跨→边跨的合龙顺序有利于减小合龙成本,加快施工进度。顶推时合龙段处普通钢筋、临时锁定杆件等不能焊死,必须保持水平向的活动。当边中跨比值偏大时,应采取有效措施防止腹板开裂。由于全桥合龙后受力需要,在边主墩的双肢之间不设永久横撑,但为了保证没有设置永久横撑的高桥墩在T构悬臂浇注阶段的稳定性,可考虑设置型钢临时横撑。
Research purposes： When wanting to build a bridge over dissymmetrical valleys,a long connecting,high pile,large-span and dissymmetry continuous rigid-frame bridge is a better choice.Compared with rigid-frame continuous beam bridge,this type of bridge has many advantages,such as good stability,relatively easy construction,beautiful shape and easy maintenance.This paper analyzes and researches the the characteristics of the load bearing capacity and deformation of the structure,closure sepuences and closure mersures,the influence of large ratio between side span and mid-span on the structure,and the safety in cantilever construction for providing the reference to the similar construction.Research conclusions：The beam bending moment,the longitudinal horizontal displacement of piers and the bending moment of pier cross-sections of long connecting,high pier,large-span and dissymmetry continuous rigid-frame bridge are all dissymmetry.The closure thrusting can obviously decrease the bending moment on the top and bottom of piers.The decreasing range is not only relative to the pier stiffness,but also to the distance between piers and the zero displacement point.Wether the closure thrusting force is loaded or not has little effect on the beam bending moment.For this type of bridge,if the closure thrusting is needed,the closure sepuences from the mid-span to secondary side span to side span should be followed,which can lower the closure cost and speed up the construction process.When thrusting,the reinforcing steel bars and the temporary members for fastening two ends of cantilevers in the closure area should not be welded each other and should be kept horizonally movable.If the ratio between the side span and the mid-span is large,the effective action must be kaken to prevent the crack of web of the beam.Because of needing the load on the structure after closing,the permanent cross girders on side piers should not be installed,but temporary cross girders are necessary for the stability of high piers in the stage of cantilever construction.
出处
《铁道工程学报》
EI
北大核心
2010年第12期31-36,46,共7页
Journal of Railway Engineering Society
关键词
长联高墩大跨
不对称连续刚构
受力、变形特点
合龙顶推
桥墩临时横撑
大边中跨比值
long connecting and high pier and large-span
dissymmetry continuous rigid-frame bridge
loading and deformation features
closure thrusting
temporary cross girder on pier
large ratio between side span and mid-span
