薄壁墩混凝土水化热及收缩徐变分析

鄂西某汉江特大桥主桥为60 m 110 m 110 m 60 m预应力混凝土连续刚构,桥墩采用了双薄壁形式。墩身施工后,现场人员发现在与承台相接的部位有裂缝产生,大桥施工被迫停止。结合实例,利用理论计算和仿真模拟两种手段同时对裂缝进行了分析,其结果和裂缝实际状态非常吻合,判定是由大体积混凝土结构在养护过程中的水化热及收缩、徐变所致。

Analysis of Concrete Hydration Heat, Shrinkage and Creep of Thin-Wall Piers

The main bridge of a bridge over Hanjiang River in the west of Hubei Province is a prestressed concrete continuous rigid-frame structure with span arrangement 60 m 110 m 110 m 60 m and with piers of double thin wall structures. Upon completion of the shafts of the piers,the construction crew at site found that cracks appeared at the joint parts between the pier shafts and pier bases,and the construction of the bridge had to suspend.In this paper,in the light of the specific examples,the cracks are analyzed by means of both theoretic calculation and computer simulation.The results of the calculation and simulation coincide exactly with the actual situations of the cracks,and it is therefore judged that the cracks are caused by the hydration heat,shrinkage and creep in the curing of the massive concrete structures of the piers.