港珠澳大桥混凝土连续梁施工期裂缝控制技术  

Techniques for Crack Control of Concrete Continuous Girder of Hong Kong-Zhuhai-Macao Bridge at Construction Stage

作　　者：杨海鹏[1] 潘军[2,3] 

机构地区：[1]中铁大桥局集团第四工程有限公司,江苏南京210031 [2]中铁大桥局集团有限公司,湖北武汉430050 [3]桥梁结构健康与安全国家重点实验室,湖北武汉430034

出　　处：《桥梁建设》2017年第2期106-111,共6页Bridge Construction

摘　　要：港珠澳大桥珠澳口岸连接桥为(3×65+40)m预应力混凝土连续梁桥,主梁采用大节段现浇施工,每段混凝土浇筑量为1 248~1 726m^3。针对大体积预应力混凝土施工,结合该桥实际情况,分析了施工期4种裂缝(受力裂缝、温度裂缝、塑性裂缝、约束收缩裂缝)产生的主要原因。根据裂缝的不同成因及桥梁结构特点,通过支架合理设计、预压及合理的混凝土浇筑顺序控制受力裂缝;通过混凝土配合比、入模温度及合理的养护措施等控制温度裂缝;通过下料点及振捣点合理设置、二次抹压及大面积覆膜锁水技术控制塑性裂缝;通过部分预应力筋早期预张拉技术控制约束收缩裂缝。通过以上各种裂缝控制技术的实施,施工期的裂缝得到了良好控制,确保了结构耐久性。The Connecting Bridge of the Zhuhai and Macao Ports of the Hong Kong-ZhuhaiMacao Bridge is a prestressed concrete continuous girder bridge with span arrangement(3×65+40)m.The continuous girder of the bridge was constructed by casting in situ in large segments and the casting amount of the concrete for each segment was up to 1 248~1 726m^3.In the light of the massive concrete construction and the other related situations of the bridge,the main causes leading to the 4types of the cracks(i.e.the loading cracks,temperature cracks,plastic cracks and constraint shrinkage cracks)in the continuous girder at the construction stage were analyzed.In consideration of the different causes leading to the cracks and the structural characteristics of the bridge,the loading cracks were controlled by the rational design,preloading of the scaffoldings and the formulating of the rational casting sequences of the concrete.The temperature cracks were controlled by the proper mix proportioning,casting temperature setting in the formwork and the rational curing of the concrete.The plastic cracks were controlled by the rational arrangement of the batching points and vibrating points,second time plastering of the concrete and the covering of large area water-keeping plastic membrane on the concrete.The constraint shrinkage cracks were controlled by the early pre-tensioning of part of the prestressing tendons.With all the mentioned techniques for the crack control,the cracks in the continuous girder at the construction stage were well controlled and the durability of the structure was ensured.

关 键 词：跨海大桥 连续梁桥 预应力混凝土结构 受力裂缝 温度裂缝 塑性裂缝 约束收缩裂缝 桥梁施工 

分 类 号：U448.35[建筑科学—桥梁与隧道工程] U443.35[交通运输工程—道路与铁道工程]