组合梁斜拉桥桥面板滞后施工可行性研究

泰东河大桥为主跨270m的城市宽幅组合梁斜拉桥,桥面全宽40. 5m,边跨采用支架拼装施工,中跨采用悬臂整拼施工。由于工期需求以及桥面起重机空间位置,桥面板需在前移起重机后采用汽车式起重机进行安装。由于组合梁斜拉桥成桥受力状态与施工过程密切相关,结合本桥超宽幅桥面的特点,为保证施工和运营阶段结构受力性能的安全性,开展了桥面板滞后安装对结构受力状态和变形影响研究。研究表明,桥面板滞后安装会引起钢主梁应力有一定增加、桥面板压应力减小,对施工累计变形也有较大影响,通过合理的施工控制,将其对施工及运营期的影响控制在可接受范围内。     

非对称独塔斜拉桥施工监控斜拉索张拉方案研究

由于斜拉桥结构较为复杂,为了使桥梁实际施工状态接近于理想状态,桥梁在施工建设过程中必须进行严格的监测与控制。本文以浙江省金华市金婺大桥为研究背景,该桥为非对称独塔斜拉桥,桥塔两侧主梁跨径及材料不同,在斜拉索张拉过程中,主梁空间效应显著且易产生不平衡力矩。对斜拉索张拉方案开展研究。研究结果显示,相比于斜拉索一次张拉方案,采用二次张拉方案时,桥梁的应力状态、索力等指标较好,满足施工监控要求。     

斜拉桥Π形结合主梁施工过程剪力滞系数变化规律

斜拉桥中的Π形主梁宽高比很大,剪力滞问题非常突出。针对斜拉桥施工过程中结构、荷载与位移边界条件等不断变化的情形,提出一种能同时考虑结合梁剪力滞变形与弯曲变形耦合影响、适用于复杂荷载与边界条件的每节点两个剪力滞自由度的Π形结合梁单元。在单元公式推导中,假定钢梁与混凝土翼板纵向位移沿横向为3次抛物线分布,相同横向坐标的钢梁翼缘板和混凝土桥面板呈相似的剪力滞位移曲线变化规律。按悬臂施工过程中的动态结构和动态剪力滞边界条件分析了在桥面板自重荷载、斜拉索张拉荷载及二期恒载等作用下的Π形结合梁斜拉桥中主梁截面剪力滞效应及其随施工过程变化的规律,并将计算结果与现场实测数据进行对比,结果表明:斜拉桥中结合梁主梁截面的剪力滞效应随施工过程荷载及位移边界条件的变化呈正负剪力滞交替变化,相较于桥面板自重等竖向荷载,斜拉索张拉荷载对主梁剪力滞效应的影响更明显;与靠近悬臂前端梁段截面的剪力效应相比,靠近桥塔附近梁段截面的剪力滞效应亦更加明显;随着施工步骤增加,Π形结合梁主梁截面剪力滞系数变化逐渐减小。相对斜拉桥成桥阶段,悬臂施工阶段的剪力滞效应更值得关注。     

淮北长山路斜拉桥主梁支架法施工技术

通过淮北长山路斜拉桥预应力钢筋混凝土主梁的施工技术研究,解决了在复杂地形条件下搭设膺架,并通过理论分析指导和实时监控,确定了主梁预应力和斜拉索张拉次序及张拉力值等关键工序,解决了主梁在脱架前受力不明确等技术难题。     

大跨度叠合梁斜拉桥施工控制参数敏感性分析

为深入研究大跨度叠合梁斜拉桥施工控制参数的敏感性,以临海高等级公路灌河大桥为背景,采用有限元软件MIDAS Civil建立全桥三维有限元模型,分析了各设计参数对大跨度叠合梁斜拉桥主梁成桥线形和主梁应力的影响。研究结果表明:桥面板重量、钢主梁梁重以及斜拉索弹性模量对该桥主梁成桥线形和主梁应力有显著影响;桥面板弹性模量和钢主梁弹性模量对该桥成桥状态影响不大。     

组合梁斜拉桥桥面板抗裂性研究与工艺控制

总结了组合梁斜拉桥混凝土桥面板裂缝的类型及成因,从钢主梁和钢横梁的连接程度来研究它们对桥面板抗裂性的影响,提出了三种湿接缝钢筋可行的连接形式,通过试验探索组合梁斜拉桥混凝土桥面板湿接缝处裂缝的产生机理,进一步优化湿接缝钢筋的合理构造设计。     

港珠澳大桥组合梁建造技术

结合港珠澳大桥组合梁桥的工程概况、结构特点及难点,系统介绍港珠澳桥组合梁的总体施工方案设计,以及桥面板预制的质量控制措施、钢主梁制作技术、预拼装、桥面板叠合,组合梁节段的装船、运输、吊装、桥位连接、体系转换等,并重点对钢主梁制造过程中采用的自动化、机械化施工工艺和无码组焊、线形控制等技术进行了阐述,表明:组合梁总体施工方案合理可行,施工质量、几何精度及线形等控制措施得当。     

独塔单索面部分斜拉桥非对称施工技术

依托余姚中山路斜拉桥项目,针对独塔单索面部分斜拉桥的结构特点,并结合该桥的周围环境,主桥主梁采用支架现浇和悬臂浇筑结合的非对称施工方法.根据悬臂现浇对称性施工原则和力学原理,建立不利条件下一侧挂篮一侧支架法现浇施工的新工艺,在支架侧先行施工一个节段,为菱形挂篮提供配重,经过体内预应力和体外斜拉索张拉,可有效保证结构安全...     

大跨度组合梁斜拉桥主梁安装技术研究

针对大跨度组合梁斜拉桥主梁的结构特性,结合工程实例,通过对某大跨度组合梁斜拉桥主梁吊装阶段的力学分析和计算,得出相对优化的施工安装方案,对同类型桥梁的主梁安装施工具有一定的参考价值。     

南昌市朝阳大桥通航孔桥主梁设计特点及关键技术

南昌市朝阳大桥为国内第一座主梁采用波形钢腹板混凝土组合箱梁的多塔斜拉桥。主要介绍在设计过程中,针对主梁的结构布置特点、受力要求,结合全桥施工方案,提出包含波形钢腹板结构、斜拉索锚固及挂篮施工的设计方案。可对今后波形钢腹板混凝土组合梁桥的设计有一定借鉴意义。     

安康七里沟汉江大桥环氧钢绞线斜拉索安装工艺

斜拉索为环氧喷涂钢绞线拉索体系,其优点是可以使用轻便施工设备、有效地完成斜拉索的安装和张拉,但技术含量高,在斜拉索的安装施工中对索力控制精度高。通过介绍陕西安康七里沟汉江大桥矮塔斜拉桥斜拉索的安装施工,详细阐述了环氧喷涂钢绞线拉索的安装施工工艺,以及单根钢绞线等值法张拉控制的方法,供施工人员借鉴。     

高寒地区组合梁斜拉桥施工阶段温度效应研究

以青海地区主跨560 m的海黄大桥为依托工程,基于桥位附近气象站近5年气象数据,采用热传导原理对海黄大桥的钢梁、混凝土桥面板、斜拉索和桥塔温度场进行模拟,提取并分析了不同部件温度作用。基于此,采用杆系模型计算了组合梁斜拉桥在最大双悬臂和最大单悬臂2个关键工况下的温度效应。结合施工误差控制范围,给出了各部件施工控制的最佳时间段。研究结果表明:不同季节太阳辐射作用下,钢梁、桥面板、斜拉索和桥塔的有效温度和等效竖向线性温差变化规律相似,但数值相差较大,夏季最高,冬季最低; 部件温差较大,混凝土桥面板与与斜拉索最大温差为10.8 ℃,在斜拉桥设计细则规定的范围内; 拉索与主塔的最大温差为10.2 ℃,大于规范建议的温差值; 组合梁的等效竖向线性温差可达14.9 ℃,超过中国规范取值; 温度作用下,主梁位移日变化最大可达87 mm,主梁标高控制宜在19:00—6:00进行; 塔顶偏位可达54 mm,塔顶偏位监测宜选择凌晨2:00—10:00; 索力变化值达施工控制索力的4.4%,在施工控制中应当避开8:00—20:00; 在海黄大桥施工控制过程中,充分考虑了温度作用的影响,取得了良好的施工控制效果。     

天兴洲桥700t架桥机在边跨纵移的解决方案

针对武汉天兴洲公铁两用长江大桥为双塔三索面斜拉桥,主桥钢桁梁采用整体节段架设工法,在2号主塔墩边跨混凝土结合板桥面区间,700 t架桥机不能正常纵移的情况,根据架桥机纵移原理并结合边跨混凝土结合板桥面区间钢桁梁整体节段的特点,提出了架桥机在该区间纵移的解决方案,并作了阐述,以供参考。     

Longterm sensor-based monitoring of an LRFD designed steel girder bridge

The new AASHTO LRFD bridge design specifications allow the use of the arching action mechanism in concrete slabs to design lightweight bridge decks. The Star City Bridge in Morgantown, WV is designed according to the LRFD code and measures 306 m over 4 spans. In an effort to demonstrate the long-term performance of in-service light-weight bridge decks, the bridge was heavily instrumented with over 700 sensors that record the response of main superstructure elements to various loading parameters. Data are being recorded every 20 min and provide continuous monitoring and evaluation of the performance of the bridge since construction in 2003–2004. This paper describes the instrumentation system installed on the Star City Bridge and demonstrates the performance of the steel superstructure over 4 years from the time of deck pouring. The expansion and contraction of the superstructure at one end contributed to the relief of environmentally induced internal stresses in the longitudinal direction. Bearing movement constrains on the other end introduced normal forces in the steel girders that are not taken into consideration in deck designs. Straining action variations due to environmental loading amounted to 20% of their initial values after pouring the deck. Temperature data shows development of a non-linear gradient across the bridge width, which explains an additional build-up of stresses found on diaphragm members at the outside girders. Compared to the LRFD specifications, the measured maximum positive temperature gradient across the bridge superstructure was found to have close values, while the maximum negative temperature gradient recorded a higher profile.     

Erneuerung von Großbrücken im Zuge hoch belasteter Autobahnen – Randbedingungen und Lösungsansätze am Beispiel der Urselbach‐Talbrücke

Renewal of highly frequented large‐scale motorway bridges. The bridge over the Urselbach – edge conditions and solutions. The newly built bridge across the Urselbach, which has a total length of 332 m, is part of the Federal Highway A5 near Frankfurt. The construction is composed of two bridges, one for each carriageway. Each superstructure consists of two steel box girders. Over these steel box girders, and resting on their top flange, is a cast‐in‐place concrete slab that becomes a part of the roadway. For a future renewal of the concrete slab it is requested that eight traffic lanes still have to remain during reconstruction. As one superstructure is passed by maximum six traffic lanes, the other must still be partly passable during its renewal. That's why the concrete slab can be demolished partly and afterwards concreted if it's necessary. Therefore the composite construction offered many advantages. The form of composite construction of the bridge across the Urselbach results from the combined action of structural steel and a concrete deck slab, which has the function of a replaceable structural member under traffic use. This conception was achieved by a structural analysis taking the substantial influences into account and the arrangement of some additional structural parts. The found solution should give some ideas on the way to a technical guide‐line for dimensional and structural design of concrete bridges with replaceable deck slabs.     

铁路钢桁斜拉桥挂索施工技术

通过计算斜拉索无应力索长和挂索牵引力,提出了短索和长索分别采用软、硬牵引相结合的技术进行挂索,并巧妙利用了桥面展索和脱空展索相结合的工艺,在斜拉索桥面展索与梁端安装时采用桥面门架与桥面牵引相结合的方法,提高了斜拉索的安装效率和质量。     

大型有限元计算在叠合梁安装中的应用

开口钢箱叠合梁,开口钢箱在下部,砼桥面板在上部,受力非常合理,其充分利用了钢材抗拉性能和砼抗压性能,而且减轻了桥梁的自重。由于开口钢箱叠合梁安装过程受力复杂,可能会引起砼的开裂,因此开口钢箱叠合梁在安装过程需要验算砼桥面板的应力。该文通过大型有限元软件计算分析,验算2跨连续开口钢箱弯桥在安装过程中是否会开裂。     

Das große Viadukt von Millau – Stahlbau und Montage mit hochfesten Feinkornbaustählen

The Millau Viaduct – Steel construction, fabrication and erection with high‐strength fine grain steel. 16^th of December 2004 the Millau Viaduct, a 2460 m long multi cable‐stayed bridge, was opened of traffic in the Southern part of the French Massif Centrale mountains. This bridge comprises 6 main spans of 342 m length respectively and two side spans of 204 m length respectively. The steel superstructure consists of an orthotropic box deck of 27.75 m width and a maximum height of 4.20 m aerodynamically optimised due to the enormous wind loads in the valley. The deck is fixed to the 7 steel pylons via 22 stay cables per pylon in a height of up to 270 m above the river Tarn. Thus this viaduct represents the highest bridge in world with a total height of 343 m, even more than the Eiffel Tower in Paris.     

巴河特大桥斜拉索安装施工关键技术

矮塔斜拉桥作为一种介于传统斜拉桥与普通连续梁桥之间的斜拉组合体系桥,具备跨度大、刚性强、造型美、成本低、施工简便等诸多特点,遂近几十年间于世界各地广为兴建。本文结合巴河特大桥项目施工实际,就矮塔斜拉桥的斜拉索安装施工关键技术展开全面探讨,以期可对类似桥梁施工项目有所借鉴参考价值。     

公轨两用钢主梁斜拉桥的施工仿真计算

以公轨两用钢主梁斜拉桥——上海市闵浦二桥为工程实例,给出了采用悬臂拼装施工方法的公轨合建钢主梁斜拉桥的施工仿真计算方法。按照实际施工过程,采用Midas/Civil程序,建立了闵浦二桥主桥的空间计算模型得到主塔偏移变形、主梁内力以及主梁各节段的制造预拱度与施工预拱度。经仿真所得计算结果,为此类型桥的施工控制提供参考。