Discussion on Crack Control in Road Bridge Design and Construction

In recent years,China's social economy is in a period of rapid development which has also made great progress in the construction of roads and bridges.Roads and bridges as basic building facilities provides strong support for local transportation and socioeconomic development in China.At this stage,roads and bridges are the basic guarantee for the development of the national economy,so great attention must be paid to the quality of their construction and engineering design.At present,the main factor affecting the quality of road bridges in China is the problem of bridge cracks.There are various reasons causes for cracks they must be controlled by effective measures to better improve the quality of road bridges.This article will discuss crack control in road bridge design and construction.

Design and Construction Strategy of Arched Continuous Rigid-frame Bridge

With the current rapid development of urbanization in China,people's living standards have been greatly improved.In the context of such a development background,the requirements for road traffic are getting more stringent,especially for bridge projects.The arched continuous rigid-frame bridge was developed under this social background.The advantage of the bridge lies in the design of a bridge model that integrates various functions such as transportation,landscape,and sightseeing.Based on the above,this paper first refers to the case to analyze the design and construction strategy of the arched continuous rigid-frame bridge,in hope of providing a valuable reference for relevant personnel.

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.

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.

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.

Design and construction of super-long span bridges in China: Review and future perspectives

Super-long span bridges demand high design requirements and involve many difficulties when constructed,which is an important indicator to reflect the bridge technical level of a country.Over the past three decades,a large percentage of the new long-span bridges around the world were built in China,and thus,abundant technological innovations and experience have been accumulated during the design and construction.This paper aims to review and summarize the design and construction practices of the superstructure,the substructure,and the steel deck paving of the long-span bridges during the past decades as well as the current operation status of the existing long-span bridges in China.A future perspective was given on the developing trend of high-speed railway bridge,bridge over deep-sea,health monitoring and maintenance,intellectualization,standard system,and information technology,which is expected to guide the development direction for the construction of future super long-span bridges and promote China to become a strong bridge construction country.

Structural Design of Roadbed and Pavement in Transition Section of Roads and Bridges

As the lifeline of social development,road and bridge projects are the main channel to realize resource transportation and economic circulation.Ensuring the quality of road and bridge project construction is crucial for the development of society,the economy,and people’s livelihoods.This paper studies the design of roadbed pavement structures in road and bridge transition sections.It aims to provide technical references and significance for China’s road and bridge engineering design and construction units,promoting scientific and standardized design in these actions.This will contribute to the safety and stable operation of road and bridge projects,offering effective technical support.Furthermore,it seeks to foster the sustainable and healthy development of China’s road and bridge engineering on a macro level.

Particle swarm optimization model to predict scour depth around a bridge pier

Scour depth around bridge piers plays a vital role in the safety and stability of the bridges.The former approaches used in the prediction of scour depth are based on regression models or black box models in which the first one lacks enough accuracy while the later one does not provide a clear mathematical expression to easily employ it for other situations or cases.Therefore,this paper aims to develop new equations using particle swarm optimization as a metaheuristic approach to predict scour depth around bridge piers.To improve the efficiency of the proposed model,individual equations are derived for laboratory and field data.Moreover,sensitivity analysis is conducted to achieve the most effective parameters in the estimation of scour depth for both experimental and filed data sets.Comparing the results of the proposed model with those of existing regression-based equations reveal the superiority of the proposed method in terms of accuracy and uncertainty.Moreover,the ratio of pier width to flow depth and ratio of d50 (mean particle diameter)to flow depth for the laboratory and field data were recognized as the most effective parameters,respectively.The derived equations can be used as a suitable proxy to estimate scour depth in both experimental and prototype scales.

大倾角钢箱提篮拱桥总体设计

考虑施工技术、经济性和景观效果等方面,陕西蔡家坡渭河特大桥主桥采用(35+210+35) m大倾角钢箱提篮拱桥。该桥采用摩擦摆和环向钢丝绳阻尼支座综合减隔震约束体系,以降低结构的地震响应。拱肋为单室等宽钢箱截面,采用主、副拱肋2条悬链线,主、副拱肋共面,设计为横向内倾20°的大倾角,在提高桥梁景观效果的同时,又有效提高了结构的整体稳定性;拱肋设钢-混结合段连接拱脚与混凝土拱座。桥面系采用自重较轻的正交异性钢桥面板结构。吊杆采用抗拉强度1 860 MPa的环氧柔性钢绞线。基础采用Φ2.5 m的钻孔灌注群桩,以抵抗软弱地质条件下荷载的竖向及水平作用力。该桥总体采用先梁后拱的施工方案。整体及局部有限元分析结果表明,桥梁结构力学性能均满足规范要求,设计安全可靠。

异形塔混合结构斜拉桥设计参数对成桥状态的影响研究

为研究异形塔混合结构斜拉桥相关设计参数对成桥状态的影响,进而支撑该类桥梁优化设计及施工质量控制,以某跨径组合为(2×30+2×60+2×30)m的异形塔混合结构斜拉桥为依托,建立空间有限元模型,研究主梁容重、主梁刚度、环塔刚度、拉索弹性模量、拉索初拉力、温度等参数对主梁线形、环塔线形、成桥索力的影响规律。结果表明:主梁容重、温度、拉索初拉力对成桥主梁线形的影响明显,其中,主梁容重对成桥主梁线形影响最大,其次为温度、拉索初拉力;温度、环塔刚度、拉索初拉力对环塔线形的影响明显,温度的影响最大,环塔刚度、拉索初拉力次之;拉索初拉力、温度对成桥索力的影响最为明显。

山区钢桁梁斜拉桥设计和工程应用研究

随着交通强国和乡村振兴等国家战略的实施,我国山区桥梁建设的数量和规模与日俱增。文章调研世界范围内2113座山区桥梁(含中国1521座),分析山区桥梁的建设难点和应用现状,阐明山区斜拉桥的关键设计技术,研究山区钢桁梁斜拉桥主梁、主塔及斜拉索的方案选型及构造设计,探讨适用于山区条件的新型斜拉桥施工方法。结果表明:我国是世界上山区桥梁建设最多的国家,贵州省又居我国首位(34.4%)。山区斜拉桥通常具有大跨径、高塔墩、小边主跨比和结构不对称等特点,运输施工易、装配程度高、抗风性能好、抗震性能优和景观造型美的结构设计成为山区桥梁的主流趋势。钢桁梁比钢箱梁斜拉桥更适应于山区的建设条件,公路钢桁梁斜拉桥一般采用两片主桁,N形桁式,主桁高度为6~9m,节间长度为6~12m,梁上标准索距为12~16m。主桁横向联系采用华伦式,桥面系常用板桁组合体系,斜拉索则主要采用钢绞线斜拉索。新开发的缆索吊机法和节段纵移悬拼法解决了山区斜拉桥主梁整节段起吊、运输和拼装的难题,可供类似桥梁借鉴和参考。

装配式桥梁顶升调坡关键技术研究

以广深高速公路改扩建项目中需纵面抬升的多跨32.5m简支桥面连续T梁桥为背景,为解决此类装配式桥梁顶升设计、顶升高度界限值等关键技术问题,提出了此类桥梁竖曲线拟合分析方法、不同墩柱高度采用不同的断柱接头设计方案,确保顶升过程中桥梁结构安全,提高施工精度;根据小偏心受压理论,以新、老支座垫石交界面处不出现拉应力为控制标准,确定垫石的加高限值并结合桥墩加高盖梁限值分析,得出3种抬升高度界限值使用不同方案的结论;同时,结合桥梁拆除、建筑物移位等新技术,研究了桥梁顶升与抬升设计方案,分析2种施工工艺优缺点,得出其不同适用性,拓展了桥梁调坡改造技术思路。

场景理论视域下城市高架桥下空间的维度建构与更新设计策略研究

城市高架桥下空间能够作为“城市名片”直观地展示城市形象,而现今的城市高架桥下空间建设同质化、使用消极、难以与人群形成互动等问题层出不穷。场景理论揭示了城市公共空间转型发展的内在机制,可从提供“文化消费”新视角、整体性与交互式思维等方面为城市高架桥下空间更新设计工作提供科学指导。基于场景构成要素,构建了城市高架桥下空间的五维度分析框架,据此调研分析了城市高架桥下空间利用的现状及问题,进而提出了相应的更新设计策略,即物理维度:利用形式活态化,更新设计整体化;活动维度:形式生活化,增加人群场景互动;社群维度:共同参与、通力协作、成果共享;制度维度:完善监管制度,增强后续跟进;价值观维度:尊重在地人文,提升空间品质。通过采取上述更新设计策略,有助于打造兼顾多元属性、满足多方需求的城市高架桥下空间,促进城市高架桥下空间更新工作的有力有序进行。

公路桥面径流收集系统构造设计与选型分析

为进一步完善和规范公路桥面径流收集系统,延长其服役寿命,先针对桥面径流收集系统的构造形式,对比分析了现有纵向排水管道固定构件的适应性,提出了不同桥梁截面形式所对应的最合理的排水管道悬挂附着方式;后针对桥梁伸缩缝位置、主桥与引桥截面变化处等的排水管道构造及设计问题,深入分析并提出了这些特殊位置处排水管道的连接方式。结果表明,针对不同桥梁截面形式,排水管道应采用不同悬挂附着方式,在桥梁结构特殊处应采用伸缩节或软管连接的方式。

嵌岩低桩承台锁口钢管桩围堰设计与施工技术

昌九高铁扬子洲赣江公铁大桥西支主桥为(48+144+320+144+48)m无砟轨道钢箱桁组合梁斜拉桥。桥塔墩位于通航河道内,桥位处河床覆盖层浅,基岩强度高,基础由大直径钻孔桩和矩形嵌岩低桩承台组成,承台采用锁口钢管桩围堰施工方案。G33号主墩围堰平面设计尺寸54.56 m×28.52 m,锁口钢管桩采用Q345B材质∅1020 mm螺旋钢管,长28 m,钢管桩之间采用C-T形锁扣连接;围堰设置4层内支撑,单层内支撑设3道对撑,内支撑四角设型钢斜撑;基底设置混凝土垫层参与围堰结构受力。围堰采用XR360旋挖钻机在岩层中引孔,孔内换填细砂后插打钢管桩,钢管桩壁内、外两侧换填砂采用高压旋喷注浆加固。围堰设置智能化监测系统,对围堰受力、变形等进行实时动态监控。实践证明,该桥围堰结构安全可靠、止水效果良好、施工快捷高效。

基于海绵城市理论的道路排水系统优化设计与施工要点

快速降水产生的城市洪涝灾害和径流污染影响重大,需要在市政工程建设中融入多种控制技术,达到渗透、过滤、限流、存储等作用。论文从总体设计思路、排水横断面设计、组合排水设计、外部空间衔接设计等方面出发,分析了道路排水系统优化设计策略,研究了融入海绵城市理论的道路排水系统建设典型案例,总结了基础施工、储水箱施工、透水盲管安装、绿地施工等关键环节的施工要点,有利于提高设计与施工的衔接效果。

海上拌合平台设计与施工关键技术

结合舟岱跨海大桥工程施工特点,设计了一种全“装配化桩式型钢”拌合平台,在其上设置混凝土拌合站,实现离岸工程混凝土持续供应,并运用空间有限元计算软件MIDAS/Civil对拌合平台进行力学性能分析,在浪流作用下,水平侧向位移小,结构整体安全。在海上拌合平台应用中,总结一些具有实际工程意义的施工关键技术。

大型市政工程深基坑支护设计优化与应用研究

市政工程深基坑支护设计优化多偏重于缩减构件尺寸和数量等直接成本,而忽视缩短工期带来的间接效益。以湖北省武汉市黄孝河CSO调蓄及强化处理设施深基坑项目为背景,详细阐明了从结构平面、支护体系、支撑体系和降排水等方面的优化思路,打破了传统“流程式”的设计思路,为深基坑支护创造敞开式作业条件,以便各专业施工作业,可从多维度节省工期,其产生的经济效益、社会效益和环境效益显著。

联李大道顶进框架桥下穿铁路咽喉区方案设计与施工技术

框架桥下穿施工因其安全可靠且不影响既有线路运营等优点,在立体交叉工程中得到广泛应用。联李大道顶进框架桥下穿铁路咽喉区位于深圳市龙岗区南湾街道,需依次下穿跨越广深铁路平湖南编组站南咽喉区、平湖南综合物流枢纽铁路货场及其集1、集2线、广深铁路Ⅰ、Ⅱ、Ⅲ线等众多重要线路,工程复杂,难度极高。介绍了穿越铁路咽喉区所面临的复杂地质条件、顶进框架桥设计、线路加固方案和施工步骤、关键技术和解决思路等重点内容,并利用Midas GTS有限元程序对工程各个施工阶段的稳定性分析,建立三维实体有限元模型进行数值模拟计算,量化基坑开挖过程对既有线路的影响,可为同类项目提供有意参考和科学依据。

高速铁路桥梁墩柱新型塑料模具的优化设计及应用

针对高速铁路桥梁墩柱钢模具自身质量大、拼装和拆卸困难,以及户外易生锈等问题,本文设计制造了新型塑料桥梁墩柱模具。根据新型塑料模具的结构特征、受力规律和墩柱施工工艺,对新型塑料模具结构进行有限元分析,确定了模具主要材料、抱箍配置结构、组装工艺和新型塑料模具结构。结合钢模具的施工工艺和新型塑料模具结构特征,确定新型塑料模具现场拼装和拆卸方法、桥梁墩柱施工工艺和该模具的墩柱质量验收标准。仿真计算结果表明:新型塑料模具的模板、箍带和螺栓满足强度要求。现场应用结果表明:在保证桥梁墩柱施工质量的基础上,该模具自重小,能够降低拼装和拆卸难度、维护难度,提升了桥梁墩柱成品外观质量和桥梁墩柱施工效率。在降低桥梁墩柱施工难度和施工总成本的同时,实现了高铁建设施工节能降耗和绿色环保。