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以荆州至松滋一级公路某预应力混凝土连续梁桥为背景,研究其最佳合龙时间和温度。当箱梁处于最大悬臂结构状态下,选取晴朗一天进行24小时跟踪观察,研究箱梁最大悬臂状态时的结构温度效应;根据现场实测的箱梁结构温度场,拟定箱梁分别在早晨、中午及下午三时段合龙,结合有限元模型分析不同时段下合龙的结构温度效应,确定箱梁最佳合龙温度。结果表明,预应力混凝土连续梁桥在悬臂浇筑阶段,受日照温差的影响,结构产生自应力,竖向发生明显变化;在合龙状态下,结构属于超静定,日照温差使结构产生了次内力,结构应力发生明显变化;在桥梁施工控制中,为了确保箱梁合龙后的成桥状态符合设计理论状态,悬臂箱梁结构合理合龙温度宜选凌晨一点至六点间。
Taking the Jingzhou-Songzizi highway prestressed concrete continuous girder bridge as the background, the best closing time and temperature were studied. When the box girder is in the state of maximum cantilever structure, the weather temperature of the maximum cantilever of the box girder is selected for a 24-hour follow-up observation day. According to the temperature field of the box girder measured in the field, Closing in the afternoon at 3 o’clock, the finite element model was used to analyze the structure temperature effects of the clogging at different time intervals to determine the optimal closing temperature of the box girder. The results show that the structure of the prestressed concrete continuous girder bridge is affected by sunshine temperature difference during the cantilever pouring stage, and the structure is self-stressing and vertically changing obviously. Under the closure condition, the structure belongs to statically indeterminate, and the sunshine temperature difference causes sub-internal force , Structural stress changes significantly; in the bridge construction control, in order to ensure the completion of the box girder into the state of the bridge after the theoretical design theory, suitable temperature synthesis cantilever box beam structure should be between 1 am to 6:00.