宽幅多室混凝土箱梁横梁受力研究.pdf

2023No.381上海么路SHANGHAI HIGHWAYS宽幅多室混凝土箱梁横梁受力研究管如意，姜凯？，徐常泽，赵洪蛟（1.山东省交通规划设计院集团有限公司，山东济南2 50 0 3 1；2.山东高速菏泽发展有限公司，山东菏泽2 7 4 2 0 0）摘要：宽幅混凝土箱梁的横梁受力较为复杂。常规设计中，横梁简化计算时的顶底板与腹板传力比例可能与实际受力存在较大偏差。为得到真实的横梁受力模式，结合工程实例，采用三维实体有限元分析，准确计算出顶底板和腹板的传力比例，并通过桥梁博士4.4 进行杆系模型计算，得到横梁较为合理的预应力布置。关键词：桥梁工程；有限元；横梁计算；宽幅；传力比例；预应力0引言在预应力混凝土和钢筋混凝土梁桥结构中，横梁起着很大作用，可增强结构整体性，加强横向联系。尤其在桥梁宽度不断增大时，横梁已成为桥梁结构设计中比较重要的一部分。箱梁作为梁式桥中常见的一种截面，一般在梁端以及中支点处设置横梁。其中，宽箱梁由于梁宽较大，横梁受力比较复杂。故大多数设计师会根据某些假定，按照简化模型来进行计算。其中，恒载在顶底板和腹板的分配比例以及各个腹板间的分配比例选择不同，结果会有较大差异。若选择不当，会与横梁实际受力偏差较大 1-2 本文通过仿真计算，对宽箱梁桥的横梁受力进行分析对比，确定了合理的恒载分配比例，可供桥梁设计者设计时参考。并结合工程实例，通过midas fea进行仿真分析，研究顶底板和腹板恒载传力比例、腹板之间恒载传力比例。通过简化模型计算，进行了实用的横梁设计及预应力布置。1横梁简化计算对于张拉预应力的横梁，预应力效应对横梁本身应力有较为明显的影响。但对于远离横梁范围的箱梁，影响则迅速减弱 3 。这一点，很多仿真模型可以验证。故横梁简化计算模型可截取横梁一定范围内的脱离体，见下图1。中横梁简化单梁计算截面可按下式（1）取。S=b+2b,+12hr(1)收稿日期：2 0 2 3-0 5-3 0其中，S一中横梁计算截面全宽，b一中横梁计算截面全宽,b一承托长度,h一箱梁顶底板厚度。6h66h6h图1中横梁计算截面2恒载和活载加载方式在恒载的作用下，简化横梁模型中的剪力通过顶底板和腹板传递。由顶底板传递的恒载以均布荷载的形式加载到横梁；由腹板传递的恒载以集中力的形式于腹板中心加载到横梁。在计算中，有的设计人员为简化加载方式，认为恒载全部由顶底板传递到横梁，以均布荷载的方式加载；也有设计人员认为，恒载全部由腹板传递到横梁，把恒载以集中力的形式，均分到各个腹板，或根据腹板面积，按比例分配恒载 4 。横梁简化计算模型范围内的汽车荷载，直接为车辆重轴作用在横梁上产生的。对于远离横梁的汽车荷载，则同恒载一样，通过顶底板和腹板传递至横梁。汽车荷载对横梁通过影响线进行加载，求出沿横梁的内力、位移以及支反力等。这是一个偏保守的处理方法，通过平面杆系有限元程序，可自动实现 52023No.382上海么路桥隧工程SHANGHAI HIGHWAY3实例分析3.1 工程概况如图2 所示，某钢混混合梁斜拉桥，跨径布置为（4 8+7 2+18 0）=3 0 0 m，桥面宽53.1m。混凝土主梁采用单箱五室箱梁型式，整幅桥箱梁采用单箱五室断面，箱梁等高。中心线处梁高3.5m，底板底面水平，顶板顶面设置横坡。上部箱梁顶板全宽53.1m，两侧悬臂长3m；箱内顶板厚3 0 6 0 cm，悬臂板端部厚2 0 cm、根部厚6 0 cm；箱梁底板直线段宽度3 4 m、斜底板水平宽度6.55m，坡度为0.2 5:1，底板厚3 0 50 cm；箱梁腹板厚5090cm，见下图3。主梁采用C55混凝土。3.2实实体计算分析该桥辅助墩处的中横梁宽度2.5m。由于箱梁宽度较大，箱式较多，所以恒载作用下的传力比较复杂。为研究其传力，通过midasfea，进行混凝土节段仿真分析，如图4 所示。以中横梁为中心，分别取10 m（模型一）、3 0 m（模型二）、6 0 m（模型三）三种不同节段的长度来进行分析。索力以集中荷载的形式添加，节段两端面分别提取恒载作用下的相应单元荷载，并通过节点耦合，施加到整个面上，根据中横梁处的支座布置添加约束。如图5所示，本模型主要考虑恒载作用下，研究剪力在顶底板以及各个腹板上的分布情况。然后作用于横梁，即可得到横梁的受力。截取2.5m横梁节段，通过查看局部方向合力，可查询恒载剪力的分布。主要关注剪力在顶底板及各个腹板上的分布情况。三种模型的计算结果如表1、图6 所示。800+7200+18000妆塔钢箱果解拉桥4.800120018.00图2 斜拉桥总体布置图（单位：cm）531030023552355300F3F1F6支座！支座2655500120012005006554710图3 箱梁横断面（单位：cm）83No.32023上语么缘SHANGHA桥隧工程图4箱梁仿真模型图5横梁节段表1计算结果项目F1F2F3F4F5F6顶底板腹板汇总总计模型一剪力/kN1754.777438.54 180.044.116.267311.31796.8217073.6626.597.6943671.35(10 m)占比/%0.0400.1700.0960.0940.1670.0410.3910.6091.000模型二剪力/kN2.495.0310640.65698.415235.739 833.72 632.620549.836536.0757085.87(30 m)占比/%0.0440.1860.1000.0920.1720.0460.3600.6401.000模型三剪力/kN3125.4213 3566748.56 775.312.042.63 416.8426 105.4445 464.6671 570.1(60 m)占比/%0.0440.1870.0940.0950.1680.0480.3650.6351.000顶底板腹板0.70.60.50.40.30.2一0.10.010m30m60m图6 腹板与顶底板传力比例（%）由以上计算结果可得，对于该算例中横梁，腹板传递剪力的比例为6 0%7 0%，顶底板传递剪力的比例为3 0%4 0%。腹板1 3 传递剪力的比例约为1：4：2.5,结构横向对称，对称位置的腹板传递剪力大小基本一致。3.3林横梁杆系模型计算根据以上计算结果，采用桥梁博士4.4，建立横梁平面杆系模型，见图7、图8。活载按一列车在中横梁处的支反力为加载系数，按横向影响线加载。恒载根据上述比例，按6 5%通过腹板以集中力的形式传递、35%通过顶底板以均布荷载的形式传递，来加载作为工况一；恒载10 0%通过顶底板以均布荷载的形式图7 桥博模型2023No.384上么路桥隧工程SHANGHAI HIGHWAY豆37支座中心线支座中心钱30063848050014005004806385310图8 钢束布置图（单位：cm）传递，来加载作为工况二；恒载10 0%通过腹板以集中力的形式传递、且腹板之间均分恒载，来加载作为工况三。通过配置预应力钢束，按预应力混凝土A类构件控制，保证结构的承载能力和抗裂验算均能满足规范要求。其中，M1钢束布置5束，N2钢束布置2 束,N3钢束布置3 束。各工况计算结果见下表2。表2 各工况计算结果汇总项目工况一工况二工况三支点负弯矩/(kNm）-70.441.7-9110197 607.3跨中正弯矩/(kNm）36 071.912.902.821 151.815.2mm预应力钢束151615171519不同的恒载分配方式对计算结果的影响很大，也会影响到设计人员的结构设计尺寸和材料类型，以及对数量的选用。4结语本文介绍了一项中横梁计算实际算例，并通过仿真模型分析，确定荷载分配比例。横梁通过杆系模型简化计算的关键有两点，一是模型截面的选取，二是荷载的加载方式。顶底板和腹板以及腹板之间的恒载分配比例对于不同的结构往往不同，且不同比例的加载对于计算结果影响很大，有必要通过仿真模型来计算确定。文中所述的计算方法是将横梁受力近似为腹板集中力加载和顶底板均布力加载的方式，具体各腹板和顶底板间剪力分配比值需通过实体计算来确定。本研究对相似结构的设计和计算具有一定的参考意义。参考文献1宫亚峰,毕海鹏,李祥辉.箱梁横隔梁计算方法研究 J.中外公路,2 0 10,3 0(0 4):14 0-14 4.2林峰,包启航.预应力混凝土常规箱梁横梁计算模式探讨J.现代交通技术,2 0 18,15(0 4):56-58.3单晓方.箱梁横隔梁的简化计算方法及在工程中的应用 J.广东公路交通,2 0 0 6(0 3):4 2-4 4.【4 】包启航.现浇单箱多室宽箱梁横梁受力特性研究 J.中外公路,2 0 18,3 8(0 6):10 9-112.5许鹏.中小跨径连续箱梁横梁简化计算方法的探讨 J.北方交通,2 0 0 7(0 3):7 2-7 3.Analysis of the Force and Influencing Factors of Large-span PC Beam FloorAbstract:The large-span PC beam with box section is the most widely used and most common scheme of medium and large span girderbridge.In the long-term operation process,typical representative diseases such as beam cracking and mid-span deflection have also beenfound.Bottom plate cracking is a more common type of disease.In this paper,the influence of constant load and live load on the force of thebase plate is revealed through the quantitative calculation of different influencing factors,and a structural optimization design scheme is pro-posed on this basis.Key words:large span PC beam;box-type section;bottom plate cracking;transverse frame calculation;bottom plate bundle collapse forceDiscussion on the Influence of Gradient Temperature and other Effect on the Anti Overturning Calculation ofSteel BoxGirdersAbstract:Municipal bridges mostly use single-column vase piers,which have a beautiful shape and save road space.However,due to thesmall spacing between its supports,overloading and other factors,multiple beam overturning accidents have also occurred in recent years.This article provides a detailed discussion on the anti overturning calculation of bridges based on current specifications and practical engineer-ing,aiming to provide reference and reference for future bridge design.Key words:steel box girder;anti overturning;specificationDesign Practice and Summary of Low Clearance River-crossing Bridge Slow Passage through ReconstructionAbstract:Taking waterfront space as the starting point,creating a charming quality urban area with temperature,vitality and characteristics,realizing the connection of waterfront and returning the shore to the people will become an important means of urban renewal in the future.Among them,the small bridges of municipal roads across non-navigable rivers often become the breakpoints of riverside slow-moving walk-ways because of the low clearance under the beams.Combined with the practice of similar projects in recent years,this paper sums up the re-construction methods for the slow passage under the low clearance river-crossing bridge,and points out the progressive reconstruction strategywith three types and seven grades,so as to provide some reference for similar projects in the future.Key words:low clearance;under the bridge across the river;slow move channel;through recongstructionComfort Analysis and Vibration Reduction Control of Pedestrian Bridge with Three Span Steel Box Continuous Beam underHuman Induced VibrationAbstract:With the increase of footbridge span and the wide application of lightweight and high-strength materials,the fundamental frequen-cy of the structure is constantly decreasing,which brings a significant problem of comfort of human-induced vibration on bridges.Based on hu-man-induced vibration theory,this paper analyzes the action characteristics of pedestrian load and the similarities and differences between do-mestic and foreign standard evaluation methods for pedestrian comfort.Finite element simulation calculation is used to analyze the human-in-duced vibration response under high-density crowd,and three different beam height schemes are compared,together with their human-in-duced vibration effects and the effects of applying vibration reduction measures.The results show that the vibration control measures based onmultiple TMD have good cost control feasibility under the premise of ensuring the human-induced vibration performance of steel box girderfootbridge structure.Key words:pedestrian bridge;human-induced vibration;damping control;TMDApplication of Jacking and Sliding Technology of Steel Structure Bridge in Chunshentang Bridge Project onJinghong RoadAbstract:With the rapid development of infrastructure construction in China,steel structure bridges have been widely used.Steel structurebridge installation usually uses installation techniques such as large lifting machinery and bridge erecting machines.However,due to limita-tions in the construction site and environmental factors,some projects cannot adopt conventional methods for the installation of steel structurebridges.In recent years,the push sliding technology has gradually been widely applied in the installation of steel structure bridges.Taking thenew construction project of Chunshentang Bridge on Jinghong Road(Jindu Road-Huajing Port)as an example,this article aims to provide ref-erence for similar projects.Key words:steel structure bridge;top push;slippageResearch on the Force of the Transverse Beam of Wide Multicell Concrete Box GirderAbstract:The force of the transverse beam for wide concrete box girder is relatively complex,and the force transmission ratio between the topand bottom plate and the web plate in the simplified calculation of the beam in the conventional design may have a large deviation from the ac-tual force.In order to get the real force mode of the beam,the three-dimensional solid finite element analysis is used to accurately calculatethe force transfer ratio of the top and bottom plates and the web plates.The reasonable prestress layout of the beam is obtained through the cal-culation of Dr.Bridge 4.4.Key words:bridge engineer finite element;beam calculation;wide;force transmission ratio;prestressing forceKey Techniques for Walking Type Jacking Construction of Large-span Steel Box Girders for Bridges AcrossExisting HighwaysAbstract:For the construction of steel box girders crossing existing highways,due to high traffic volume,high safety requirements are re-ZHANGYan(52).CHENNan(56)HUANG Chenghua(60)HEWei,LU Haixiao,ZHU Jianfeng(68)XURen(74).GUAN Ruyi,JIANG Kai,XU Changze,ZHAO Hongjiao（8 1)ZHANG Xiaoxin(85)