大跨度上承式钢桁拱桥主梁顶推施工技术研究

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Abstract

Incremental launching is an important methodology for bridge construction which can date back to 1959.Incremental launching can go with light and simple construction equipments, it has nearly no impact on traffic, it provides good environment for workers.Moreover, incremental launching is easy for construction management. It is very suitable to use incremental launching in rivers, in the deep valley and cross-line projects, more than one thousand bridges have been built at home and abroad with this method. However, during incremental launching process, the boundaries of the steel box girder are constantly changing, each of the cross section must undergo alternating changes of positive and negative bending moments, which makes the stress of the girder become complicated. For the girders of long span deck steel-trussed arch bridges, comparison of construction technology, optimization of design parameters of steel nose, linear shape of girders during launching, and impact of incremental launching on the stability of arch columns have yet to be further studied.

Through consulting a lot of references, this paper traced the origin of the incremental launching methodology and summarized its development overview, classification method, temporary facilities, and technical limitations.

Taking the nujiang Bridge of Darui Railway as the engineering background, the model was innovatively constructed by the grid method to more accurately simulate the counterforce and deformation and simplify the calculation. The influences of three parameters, including the length, unit weight, and stiffness of the steel nose on the performance of the beam were analyzed by analytical methods. The rationality of parameter selection was verified by the finite element calculation results.

The Incremental launching process of the whole girder was divided into 79 stages for simulation analysis, the maximum stress and deflection of each cross section of the main girder during the incremental launching process and the maximum supporting force of the columns on each arch were traced. The elastic buckling analysis of the bridge was performed on the maximum supporting force conditions of the column and the results showed that the stability of the bridge during the incremental launching process meets the requirements.

The local analysis of the steel box girder under the maximum supporting force conditions was performed to obtain the stress distribution of each plate of the steel box girder,and the safety of the beam during the launching process was evaluated and suggestions for improvement were proposed.

Key Words: Steel truss arch bridge; Incremental launching; steel box girder; grid method;

steel nose optimization

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目录

摘要·························································································I

Abstract ··························································································II

第1章绪论 (1)

1.1 引言 (1)

1.2 顶推施工技术发展概况 (1)

1.2.1 国外顶推施工技术发展概况 (1)

1.2.2 国内顶推施工技术发展概况 (4)

1.3 顶推施工技术研究概况 (6)

1.4 论文目的和主要研究工作 (7)

第2章顶推施工工艺介绍 (9)

2.1 顶推施工方法分类 (9)

2.1.1 按照施加水平力的方法分类 (9)

2.1.2 按动力装置的多少分类 (10)

2.1.3 按照动力装置的类别分类 (13)

2.1.4 按照支撑系统分类 (13)

2.1.5 按照顶推方向分类 (13)

2.1.6 按照梁体节段的成型方式分类 (14)

2.2 顶推施工中的临时设施 (14)

2.2.1 梁制台座 (14)

2.2.2 临时墩 (14)

2.2.3 导梁 (15)

2.2.4 滑动装置 (15)

2.2.5 导向和纠偏装置 (16)

2.3 顶推注意事项 (16)

2.3.1 防开裂 (16)

2.3.2 箱梁“爬行” (16)

2.3.3 滑板损坏 (16)

2.3.4 钢梁底板屈曲的问题 (17)

2.5 顶推施工的优缺点 (17)

2.5.1 顶推施工法的优点 (17)

2.5.2 顶推施工法的缺点 (17)

2.6 本章小结 (17)

第3章导梁的优化设计 (19)

3.1 工程背景介绍 (19)

3.2 顶推施工梁格法模型建立 (20)

3.2.1 主桥梁格法模型 (21)

3.2.2 引桥梁格法模型 (26)

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3.3 导梁优化设计 (30)

3.3.1 导梁长度与单位长度重量优化 (31)

3.3.2 导梁刚度优化 (35)

3.3.3 导梁使用注意事项 (36)

3.5 本章小结 (36)

第4章顶推施工全过程仿真分析 (38)

4.1 顶推施工整体模型建立 (38)

4.2 顶推施工阶段划分 (39)

4.3 顶推施工过程应力分析 (41)

4.4 顶推施工过程变形分析 (45)

4.5 顶推施工过程支座反力分析 (48)

4.6 顶推过程桥梁稳定性计算 (57)

4.6.1 立柱1反力最大工况 (57)

4.6.2 立柱2反力最大工况 (57)

4.6.3 立柱3反力最大工况 (58)

4.6.4 立柱4反力最大工况 (59)

4.6.5 立柱5反力最大工况 (59)

4.6.6 立柱6反力最大工况 (60)

4.6.7 立柱7反力最大工况 (60)

4.6.8 立柱8反力最大工况 (61)

4.6.9 立柱9反力最大工况 (61)

4.6.10 立柱10反力最大工况 (62)

4.6.11 立柱11反力最大工况 (62)

4.6.12 立柱12反力最大工况 (63)

4.6.13 立柱13反力最大工况 (63)

4.7 本章小结 (64)

第5章顶推施工钢箱梁局部受力分析 (66)

5.1 钢箱梁承受的最大反力 (66)

5.2 局部模型建立 (66)

5.3 局部分析结果 (68)

5.3.1 顶板应力结果 (69)

5.3.2 底板应力结果 (69)

5.3.3 底板加劲肋应力结果 (70)

5.3.4 腹板应力结果 (70)

5.3.5 横隔板应力结果 (71)

5.3.6 横梁应力结果 (71)

5.4 本章小结 (72)

结论和展望 (73)

1、结论 (73)

2、展望 (74)

致谢 (75)

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西南交通大学硕士研究生学位论文第V页参考文献 (76)

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第1章绪论

1.1 引言

近年来，我国经济的快速发展对交通运输能力提出了越来越高的要求，国家大力推进交通运输体系：2013年提出了“一带一路”发展战略，旨在以交通运输体系为基本媒介进一步增进跟世界的联系；2017年出台了“十三五现代综合交通运输体系发展规划”，目标为2020年基本建成安全、便捷、高效、绿色的现代综合交通运输体系，基本实现交通运输现代化；之后的中共十九大报告更是提出要建立“交通强国”，将高速铁路的发展作为一个重点。随着城镇化的进一步发展，我国对公路建设、铁路建设以及城市市政道路的建设会有较大的需求，因此势必会出现大批跨越大江大河的桥梁，桥梁作为交通运输体系的重要节点甚至是控制点，其安全性对整个交通运输体系来说至关重要。在众多桥梁型式中，钢拱桥具有外形雄伟壮观、跨越能力大、结构轻盈、承载能力高、便于施工等优点，同时可以适应高速铁路对桥梁刚度的要求，因此越来越受到设计者的青睐，目前已建成的特大跨度钢拱桥包括重庆朝天门大桥、上海卢浦大桥、重庆巫山长江大桥、重庆万州长江大桥、菜园坝长江大桥、广州新光大桥、和南京大胜关长江大桥等。随着国家交通网络的不断扩大及完善，跨线路桥梁越来越多。作为桥梁施工的一种重要方法，顶推施工法成本较低，对环境很友好，设备相对轻便，适用于深水、山谷和高墩工程，也可用于坡桥和弯桥; 梁体可以连续作业，并且制造精度有保障，作业人员工作强度不高，现场便于施工管理，更重要的是顶推施工不影响既有通航或通车；但顶推法因为是逐段施工，随着施工的进行，梁体要承受反复的应力变化，对梁体受力不利；且对预制场地强度、刚度、稳定性及对施工设备的工作性能有较高的要求；

此外，顶推施工过程中还存在箱梁“爬行”、滑板损坏的问题。

目前国内外有关顶推施工技术的研究大多是围绕混凝土桥进行，有关钢拱桥顶推施工尤其是大跨度钢桁架拱桥主梁拱上顶推的研究较少，因此，本文以上承式钢拱桥作为研究对象对顶推施工技术作进一步的探究具有一定的理论意义和实际意义。

1.2 顶推施工技术发展概况

顶推法是通过在桥梁两端或者一端设置预制场，预制组拼梁体然后借助顶推设备使梁体移动到设计位置的施工方法。本节将分国内与国外分别介绍顶推施工方法的发展历程。

1.2.1 国外顶推施工技术发展概况

1959年，在修建奥地利的Ager桥时，前联邦德国的鲍尔教授和莱昂哈特博士首次运用了一种由早期钢板梁拖拉法发展而来的施工方法，人们将这种施工方法称为顶推

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