平潭海峡公铁两用大桥双线64m节段拼装简支梁创新技术

Innovative Technology of 64 m Assembled Simply Supported Box Beam of Pingtan Strait Combined Bridge

平潭海峡公铁两用大桥是新建福州至平潭铁路的关键控制性工程,受海洋大风环境的影响,建设条件异常复杂。平潭侧引桥采用双线64 m预应力混凝土简支箱梁,节段预制造桥机整孔拼装施工。为适应桥址恶劣的大风环境,研发了SPZ2700×2/64型箱梁节段拼装双孔连做造桥机,采用先进的风速预警系统及设备自动化控制系统的集成技术,提高了节段梁定位精度与拼装效率,降低了台风期间工程安全风险;针对海洋腐蚀环境对桥梁结构耐久性进行研究,对梁体节段预拱度和线性控制进行了分析,确保梁部节段拼装施工质量可靠、线形精准。介绍复杂恶劣海洋大风建设环境下,双线64 m大跨度简支箱梁结构设计、节段预制施工、线形控制及耐久性等创新技术,对推动我国铁路混凝土桥梁预制拼装技术的提升,复杂海洋环境下桥梁结构耐久性技术的应用有借鉴意义。

Pingtan Strait combined bridge is the key control project of the new Fuzhou Pingtan railway.The construction conditions are extremely complex under the sea gale environment.To solve this problem,double-line 64 m prestressed concrete simply supported box beam is adopted for the approach bridge at Pingtan side.Segment prefabrication technology,bridge building machine,and whole hole assembly techniques are applied for the construction of the box beam.To deal with the severe wind environment of the construction site,the SPZ2700×2/64 box beam section assembly double hole continuous bridge building machine is developed.Moreover,the advanced wind speed early warning system and the integration technology of equipment automatic control system are employed.As a result,the positioning accuracy and assembly efficiency of the section beam are improved,and the engineering safety risk during the typhoon period is reduced.The durability of the bridge structure under the marine corrosion environment is studied.The pre-camber and linear control of the segment are analyzed to guarantee the reliability and the linear accuracy of the beam segment assembly construction.This paper systematically introduces some innovative technologies such as structural design,segmental prefabrication,linear control and durability of 64 m long-span simply supported box beam with double track under the complex and severe sea gale construction environment.This project can provide some references for promoting the prefabrication and assembly technology of railway concrete bridges in China.It also serves as an paradigm of the application of durability technology of bridge structures under the complex sea environment.