Design and construction of Sutong Bridge tower

Sutong Bridge tower which is 300.4 m is the highest one in the world.The tower anchor area uses the steel-concrete composite structure,its structure and the stress mechanism are complex,so it must be paid more attention to the structure durable issue.The 300 m height makes the tower quite sensitive to the environmental factors such as wind and temperature.The wind resistance safety of tower in construction stage is especially important.In this paper,the design of composite structure is introduced.The key technologies of tower geometry control and wind resistance in construction stage are analyzed.

Assistant pullback technique for main span closure of Sutong Bridge

Sutong Bridge is a cable-stayed steel box girder bridge with a main span of 1 088 m. The erection of upper structure adopts geometry control method and requires no change to the unit＇ s size and the structure＇ s none-stress geometry. Before main span closure, the cantilever of girder reaches 540.8 m, the structure state is noticeably influenced by extemal circumstances, the main span closure face great difficulty. By abstracting the advantage of the pullback method abroad and the domestic temperature-cutting method, a new assistant pullback method have put forward and bring into practice actually. In this paper, the analysis key point of practice conditions, key parameter of practice, main measures of the method and the performance is introduced.

Design and construction of Sutong Bridge deep-water main-pylon foundations

This paper,from three aspects including construction conditions,foundation design and construction,introduces some considerations in the designing of main-pylon foundations and some practical measures to deal with certain unfavorable construction conditions,such as deep water,tidal effect,soft stratum and heavy traffic,during the construction of main-pylon foundations.

Study on dangerous collision area of ships out of control in Sutong Bridge area

Motion state of ship out of control in bridge area was analyzed.Motion procedure after losing control was divided into two steps.One is drift step within stopping period.The other is drift step without inertia,which is induced by wind and current.Mathematical model for motion of ship out of control,considering wind-induced drift,current-induced drift,stopping ability,etc.,was established.Dangerous collision areas for main pier and auxiliary piers were analyzed according to different calculation conditions.

Key technology and innovation of Sutong Bridge

Sutong Bridge is a cable-stayed bridge across Yangtze River with the main span of 1 088 m. This article outlines technical challenges,key technology and innovation in the design and construction such as scour protection,lowering steel cofferdam,construction platform establishment,construction and control of pylons,fabrication and damping of long cables,erection and control of steel box girders.

Cultivating technical capabilities of enterprises is an important task of the Sutong Bridge project

The paper analyzes existing state of innovation system in the field of public infrastructure construction in China and elaborates on the duty and role of owner in establishment of a technical innovation system with enterprise as the main body following the process of production-education-research.This paper also claims that the key project construction is an important resource to enhance national capability of innovation and accordingly puts forward an effective approach to cultivate the core competitiveness of leading enterprises on the basis of practice in the Sutong Bridge project.

Construction and control technology of the main bridge superstructure of Sutong Bridge

The Sutong Yangtze River Bridge(short as Sutong Bridge)is now the largest span cable-stayed bridge in the world.The construction of the superstructure of the middle bridge covered several stages including erection of the big block girders for the side span,assistant span and tower area,erection of standard girders and closure of the middle span.The big block girders were hoisted by a floating crane,and the standard girders were hoisted by a double crane system on the deck.The pushing assistant method was adopted for the middle span closure construction.Furthermore,key technologies and innovative methods used in the processes of girder erection and cable assemblage in all stages were expatiated systematically.An all-stage self-adaptive geometry control method was used in the construction process.By accurately controlling the unstressed dimensions and shape of all structural components in each step,and realization that the control system and the controlled system adapt to each other,the goal was to make control of the final line shape and inner force of the bridge structure achievable.Two solutions,including GPS based and total station based dynamic geometry monitoring systems,were used to resolve the measure problem under the wide-range of wind-induced vibrations in the long cantilever state.Finally,research on the wind-induced vibration of the superstructure during the construction period was executed.Buffeting response analysis to the longest single and double cantilever states were carried out.The analysis and evaluation of wind resistance safety of the main girders under the longest single cantilever state was made,and corresponding wind resistance measures were suggested.The as-built geometric error and cable force error were controlled in a required design range,and this whole technological achievement can be a benchmark for construction of other large span cable-stayed bridges in the future.

Study on complexity of Sutong Bridge's objectives system and its meta-synthesis management

Objectives define the boundaries of complex engineering system.It is a hard work to identify the specific objectives of a complex engineering system.The objectives system development needs a complicated process,from nix to prototype,and to final definition.The total process will cover the following course:from chaos to well-ordered;from qualitativeness to combination of quantitativeness and qualitativenss,then from qualitativeness to quantitativeness(a recurrent process),expert experience and theoretical science,rationality and sensibility,synthesis analysis and meta-synthesis,routinization and non-routinization.Such process is explicit in phase development yet overlapped;mutually confined yet mutually independent;permeated conflicts yet pregnant in harmony.This article explores the complexity of Sutong Bridge's objectives development and the process of meta-synthesis in the Sutong Bridge engineering.

Research on the special lifting devices for steel box girders of Sutong Bridge

Sutong Bridge is a cable-stayed bridge with a steel box girder and a main span of 1 088 m.The steel box girder of main span includes five portions:back span large unit,large block of pylon,standard girder,back span closure girder and middle span closure girder.Each back span large unit is fabricated by welding several deck segments together in factory,and is erected by floating crane.As navigational clearance of the main bridge is high,the traditional truss lifting device can't satisfy the requirement of domestic lifting cranes for this kind of lifting height and weight.Hence,a kind of lighter lifting device for the erection of back span large units was accepted for this bridge.In this paper,the design and use of this lifting device is introduced.The upper structure used lifting gantry to install the standard girder segment by cantilever method.Because the bridge's navigation clearance is high,and the girder segment is wide and heavy,the meteorology and hydrology condition of the bridge district is abominable,and the requirements of long cable girder side pull-in,structure and performance propose high request to the lifting gantry.In this paper,the design and use key point of long cable pull-in angle adjustment device integrate into lifting gantry is introduced.

Stress and noises of steel box girders in Sutong Bridge

Sutong Bridge is a cable-stayed bridge with a main span of 1 088 m. 370 high-precision stress monitoring measured data show that in the process of hoisting the steel box girders,the stress of the main girders is in the fluctuant and complex state and many meteorological factors,such as sunshine radiation,temperature and wind,have important influence on the change of stress of the steel box girders. According to the real-time weather data,the stress data after the process of wavelet denoising from representative measuring points in different weather conditions is picked to establish the stress response brought by meteorological factors with Layered Separation method,thereby basically eliminating the influence of meteorological factors on the stress of main girders,so that accurate and reliable stress data can be got for steel box girders adjustment and cable-tensioned construction control.

Design and construction of scour protection for deep-water group pile foundation structures of two pylons in the Sutong Bridge project

Sutong Bridge,as a world-record cable-stayed bridge with its main span exceeding 1 000 m constructed in Yangtze River estuary region in China,is located at a site with complicated hydrologic conditions and poor geotechnical conditions and therefore,scour protection will be a decisive factor for ensuring smooth and successful construction of this bridge.This paper,starting from structural description of deep-water group pile foundation,analyzes impact to the bridge safety introduced by scour and its protection and further presents different solutions of scour protection for foundation structures of this bridge.

Dynamic Geometry Monitoring System and Its Application in Sutong Bridge Construction

The construction period of large cable-stayed bridges is long, and the structure deformation is complicated. Any error during construction will potentially affect the cantilever alignments and the internal forces. In order to ensure safety during construction and exactly determine the cantilever alignments, dynamic deformation monitoring is needed immediately when the con struction of the superstructure starts. This paper aims at the requirement of deformation monitoring during the Sutong Bridge construction, and introduces the realization and observing schemes of the GPS and georobot based on remote real-time dynamic geometrical deformation monitoring system, then researches the data processing methods and enumerates some of the application achievements. Long-term operation during the Sutong Bridge construction indicates that the system runs steadily and the results are reliable.

过江通道围堰绕流场流速分布特性与紊流宽度影响研究

施工期围堰绕流场分布特性是船舶通航安全评估需要考虑的主要问题。选址确定后,围堰绕流场分布特性与来流速度和围堰形状密切相关,研究来流速度和围堰形状对围堰绕流场分布特性的影响对围堰设计与船舶安全通航具有重要意义。文章建立了围堰绕流数值计算模型,采用物理模型试验验证了数值计算方法和网格尺寸的合理性和准确性,针对围堰绕流问题及其对船舶通航安全的影响,分析了围堰形状和来流速度对围堰绕流场流线分布、纵向与横向流速分布特性的影响规律,得到了矩形、哑铃形和圆端形三种围堰形状的导流能力以及施工期桥区船舶安全通航所需的通航净宽。研究结果表明:矩形围堰紊流宽度最大,哑铃形围堰次之,圆端形围堰最小,紊流宽度随来流流速的增大而增大。通航侧碍航紊流宽度介于1.3 D~2.1D。

苏通大桥施工期几何监测系统的建立与应用研究

大型斜拉桥施工过程复杂、控制要求严格,施工期各种不利条件均可能对成桥内力、线型造成潜在的影响。为准确评价结构的阶段线形、受力与安全,有必要在施工期进行几何、物理监测。结合苏通大桥施工期动态几何监测需要,介绍自主研发的基于GPS和测量机器人的远程实时动态几何监测系统的实现方法及其观测方案,并列举本系统的部分应用成果。依托工程的长期运行情况表明,系统稳定、可靠,与常规测量方法相比较体现出独特的优越性,保障工程建设的技术要求。

大型复杂工程管理的方法论和方法：综合集成管理--以苏通大桥为例

通过对大型工程系统复杂性的分析,根据复杂性管理思维,探索关于大型复杂工程的具有中国情景的综合集成管理的方法论与方法。综合集成管理的基础是复杂系统理论,方法论是综合集成,其本质是通过构建一个新的复杂系统来驾驭复杂被管理工程系统,关键是主体的选择、接口的构建、能力的涌现和过程的综合控制。并以苏通大桥为例,分析了工程综合集成管理的主体、内容和过程。

特高压GIL故障定位超声衰减特性及试验研究

苏通气体绝缘金属封闭输电线路(gas-insulated transmissionline,GIL)综合管廊工程单相GIL长度接近5.8 km,在运行过程中一旦发生内部击穿将会对电网安全运行造成极大隐患,超声波原理故障定位方法可以快速和准确查找故障位置以便开展检修更换,难点在于超声波在特高压GIL上传输衰减特性及传感器的布置方法,其决定了故障定位的精度。为达到苏通工程故障定位到GIL气室的要求,研究了超声波在特高压GIL中衰减特性,开展了特高压GIL故障模拟试验和真型故障定位试验,获得了超声波经过特高压GIL直线单元、气隔盆子和伸缩节的衰减规律,得到了苏通工程GIL单个气室直线单元传感器布置方法,并对后续研究工作提供了一定建议。研究结果表明,超声波经GIL直线单元36 m传播后衰减约60%,经气隔盆子和伸缩节衰减约70%和89%,苏通工程单个气室布置2~3个超声波传感器即可达到故障定位到气室的精度要求。

台风作用下超大跨度斜拉桥抖振响应现场实测研究

大跨度桥梁抖振响应的现场实测研究,对桥梁风工程的发展具有重要意义。2008年7月,"凤凰"台风突袭江苏,本文以遭受该台风袭击的世界第一大跨斜拉桥——苏通大桥为工程背景,综合利用现场实测风特性数据和该桥结构健康监测系统(SHMS)中加速度传感器实时采集的数据,采用频谱分析和统计方法对超大跨度斜拉桥的抖振响应进行了现场实测案例研究,主要研究内容包括桥址区的强风特性分析、主梁和拉索振动响应特性分析、振动与风速的关系、上下游拉索的振动特性对比以及斜拉索阻尼器的减振效果分析等。研究结果可用于验证现有抖振理论分析方法的可靠性,同时可为超大跨度斜拉桥的抗风设计提供参考。

大直径超长钻孔灌注桩桩端后压浆机理探讨

在分析大直径超长灌注桩实时应力监测资料的基础上,从力学机理入手分析桩端后压浆对基桩承载特性的影响.分析结果表明:桩端后压浆主要通过渗透固结、挤密充填等作用,改善桩端及桩周地层土的物理力学性质,消除桩端虚土对承载力的影响效果明显;由于扩底和劈裂泥皮作用,基桩桩端承载面积及桩体的有效长度与侧摩阻力均得到明显的提高.

基于小波变换的台风激励下千米级斜拉桥模态参数识别

为了给大跨桥梁结构损伤识别和安全性评价提供现实依据,采用小波变换(WT)方法进行千米级斜拉桥的模态参数识别研究.以"海葵"台风激励下的苏通大桥为研究对象,基于结构健康监测系统(SHMS)采集的数据,采用WT方法共识别出包括频率和阻尼比在内的主梁前4阶竖弯模态参数、前2阶扭转模态参数和第1阶侧弯模态参数,并将结果与相关文献提供的模态参数进行对比;在此基础上研究了海葵台风期间该桥主梁模态参数的全过程变化情况.结果表明:基于WT的模态参数识别方法稳定可靠;随着时间的变化,主梁各阶模态频率均较稳定,而模态阻尼比的波动则较明显.

斜拉桥的拉索纵桥向风荷载计算方法研究

介绍了苏通大桥在设计过程中专门对斜拉索进行的测力试验情况,并与国外相关研究成果进行了对比,提出了斜拉索纵桥向风荷载阻力系数计算公式。该研究填补了我国桥梁抗风设计规范的空白,已被纳入《公路桥梁抗风设计规范》(JTG/T D60-01-2004),具有很高的实际指导意义。