港珠澳大桥混凝土连续梁施工期裂缝控制技术

发布时间：2018-06-29 00:52

本文选题：跨海大桥 + 连续梁桥　；参考：《桥梁建设》2017年02期

【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。
[Abstract]:The connection bridge of Hong Kong-Zhuhai-Macao Bridge is (3 脳 65 40) m prestressed concrete continuous beam bridge. The main beam is constructed with large segment cast-in-place construction. The concrete pouring capacity of each section is 1 248 ~ 1 726 m ~ (3). In view of the construction of mass prestressed concrete, combined with the actual situation of the bridge, the main causes of four kinds of cracks (stress crack, temperature crack, plastic crack and restrained shrinkage crack) during the construction period are analyzed. According to the different causes of the cracks and the characteristics of the bridge structure, the stress cracks are controlled by reasonable design of the support, preloading and reasonable pouring sequence of concrete, and the temperature cracks are controlled by the mix ratio of concrete, the temperature of the mould and the reasonable maintenance measures, etc. The plastic cracks are controlled by means of reasonable setting of the blanking points and vibrating points, and the confined shrinkage cracks are controlled by the pre-tensioning technique of partial prestressing tendons. Through the implementation of the above various crack control techniques, the cracks in the construction period are well controlled, and the durability of the structure is ensured.
【作者单位】：中铁大桥局集团第四工程有限公司;中铁大桥局集团有限公司;桥梁结构健康与安全国家重点实验室;
【分类号】：U445.57

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