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经济型贝雷桁架双导梁架桥机拼装设计及应用研究
【作者】 林胜利；
【作者基本信息】 中南大学 ， 建筑与土木工程， 2011， 硕士
【摘要】 贝雷桁架拼装式架桥机结构形式变化很多,随着架梁的数量,梁的跨径、重量和现有的贝雷桁架器材的数量等条件而定。本文是基于汝郴高速水口高架桥预制梁的架设工作,对经济型贝雷桁架架桥机拼装设计及应用展开研究。汝郴高速水口高架桥工程特点是：20m空心板梁比40mT梁重量小很多,而20m空心板梁数量较多,40mT梁数量不到总梁数的十分之一。工地现有架设20mT梁贝雷桁架架桥机,如果另外购置拼装40mT梁架桥机,费用较高,周期较长。如何利用现有20mT梁架桥机,经合理改造后,能安全、经济地实现40mT梁的架设任务,是本文研究的重点。主要取得以下研究成果：(1)改装后的贝雷桁架架桥机,单边主导梁采用3排加强贝雷桁架,40m跨中设临时支墩,架梁过程中T梁沿架桥机中心线运行。通过初步计算得到,抗弯能力及刚度完全满足要求；但抗剪能力相当不足,究其原因是中支腿上方竖杆应力相对加大,发现贝雷桁架拼装的连续结构很难像简支结构那样充分的发挥贝雷桁架片的性能,为此必须采取补强措施。本文提出了在中支腿处用4排贝雷桁架片加强、增设加强竖杆等加强措施。然后利用有限元软件建立贝雷桁架架桥机主导梁模型,经计算分析得出,通过上述加强方案,静力计算满足要求。特别是在中支腿前后增设加强竖杆,贝雷桁架架桥机的整体抗剪能力明显提高,能完全满足架设40mT梁的抗剪要求,并且所需材料较少,能充分发挥贝雷桁架架桥机的整体作用。(2)改装后的贝雷桁架架桥机能够满足稳定性要求。分析比较了风荷载对贝雷桁架架桥机稳定性的影响,得出风荷载对贝雷桁架架桥机稳定性影响较小。(3)本文通过模型对比计算,发现支撑架角钢类型对贝雷桁架架桥机的影响较大。增设加强竖杆后,对运梁天车位于支腿附近的架梁工况稳定性有较大的提高,对其他架梁荷载工况也有一定的提高,所以应该增设加强竖杆。释放贝雷桁架架桥机临时支墩上部的横向约束,架桥机整体稳定性会降低,应控制临时支墩墩顶的位移。
【Abstract】 The structure of Bailey truss bridging machine changes a lot depending on the conditions of the number of the beams, beam span, weight, and the existing quantity of Bailey truss.This article is based on the erection of precast beams of the Ru Chen high-speed outlet viaduct and the assembly design and application of the the economical Bailey truss bridge machine.The project Features of Ru Chen high-speed outlet viaduct is: 20m hollow beams weight less than 40m T-beams, and 20m hollow beams have a large number,40m T-beam accounts one-tenth of the total beams.The site has already got 20m T-beam truss girder bridge machine,if the site purchase the 40m T-beam truss girder bridge machine,it will cost a lot in money and time.The focus of this paper is how to achieve 40m T-beam task with the existing 20m T-beam bridge machine safely and economically.The following results have been achieved.(1)The modified Bailey truss bridge machine, with 3 rows of strengthening Bailey truss in the side beam, setting temporary buttress in 40m span,the bridge machine runs along the T-beam center line.The Initial calculate shows the flexural capacity and stiffness fully meet the requirements; but short of shear strength, the reason is that the leg above the vertical bar has a relative increase stress and found that Bailey truss structure is difficult to work fully as simple structure, this must be taken to reinforce measures.In this paper,4 rows Bailey truss strengthen in the leg, additional strengthening measures such as strengthening the vertical bar. Then use the finite element software to establish the leading beam model of the Bailey Truss bridge machine, the calculation shows that it meets the demand through the strengthening program, Especially strengthening the vertical bar before and after the legs,the shear strength of Bailey truss bridge machine Increase obviously to fully meet the shear requirements of 40m T-beam, and the small amount of material required, to give full play to Bailey truss bridge machine.(2)The modified Bailey truss bridge machine meets the stability requirements. The paper analysis and compare the stability effects of the wind load on the Bailey truss bridge machine, draw the conclusion that the wind load on the Bailey truss bridge machine stability is less affected.(3) By comparing the calculation model it was found that the type of angle steel support frame affect a lot in Bailey truss bridge machine. After the addition of strengthening the vertical bar, the stability of the girder crane in the leg near the girder condition has greatly improved,and the stability of other girder loading conditions have improved to some extent, the strengthening vertical bar should be established.The release of the upper part of the lateral buttress constraints will reduce the overall stability of bridge machine,so we should control the displacement of top of the temporary support Buttress.