高温条件下连续刚构桥合拢施工技术

Closing Construction Technology of Continuous Rigid Frame Bridge at High Temperature

宜昭高速公路洛泽河特大桥连续刚构最大跨度达150m,洛泽河特大桥原设计合拢温度为15±5℃下进行合拢,但根据工程实际进度安排,合拢时间为7—9月,历史平均高温接近30℃,温差大,高温合拢后当温度降低时墩顶将产生水平位移和合拢口产生竖向位移,导致结构产生附加内力。另外,合拢时温度高,混凝土水化热大,合拢段混凝土在附加内力和温度应力等作用下容易出现裂缝,通过建立的洛泽河特大桥主桥模型,分析了温度对合拢的影响,并采取了相关的措施,避免了裂缝的产生。

The maximum span of continuous rigid frame of Luozehe Bridge on Yizhao Expressway is 150m.The original design closing temperature of the Luozehe Bridge is 15±5℃.However,according to the actual schedule of the project,the closing time is July to September,the historical average high temperature is close to 30℃,and the temperature difference is large.When the temperature decreases after high temperature closure,the pier top will generate horizontal displacement and the closure opening will generate vertical displacement,resulting in additional internal force of the structure.In addition,when closing,the temperature is high and the hydration heat of concrete is high.The concrete in closing section is prone to cracks under the action of additional internal force and temperature stress.In this paper,the influence of temperature on the closure is analyzed by establishing the main bridge model of Lozehe Bridge,and relevant measures are taken to avoid the generation of cracks.