宽幅连续刚构承台大体积混凝土早期温度场仿真分析及现场实测研究

Finite element simulation and field measurement of initial temperature field of mass concrete for bearing platform in wide continuous rigid frame

龙溪嘉陵江特大桥是重庆三环高速公路合长段的控制性工程,同时也是重庆首座高速公路和市政道路合建桥梁,其8承台为圆端形,平面尺寸为44.5 m×14.5 m×5 m,其横桥向44.5 m的宽度是同类型桥梁承台中的最大尺寸。通过8承台施工水化热的有限元仿真分析及现场实测,研究了大体积承台的内部温度场及应力场,根据计算结果制定了温控标准和相应的温控措施,优化了冷却管道布置。对8承台进行了现场水化热温度实测,以避免温致裂缝,从而确保8承台混凝土的施工质量。从温度监测数据结果来看,浇筑后温度采集数据正常,通水降温与表面养护都基本满足大体积混凝土的要求。混凝土在浇筑完成后温度升值为43.4~45.6℃,小于50℃,且芯部最高温度低于75℃,温降曲线平缓,混凝土内部与表层温度差值满足规范要求。

Longxi Jialingjiang super large bridge is a control project of Hechuan Changshou section of Chongqing third ring expressway.It is the first highway and municipal road bridge in Chongqing.Its No.8 bearing platform is round in shape with plane size of 44.5 m×14.5 m×5 m.The width of 44.5 m is the largest in the same type of bridge caps.Through the finite element simulation and field measurement of hydration heat of mass concrete of No.8 bearing platform, the internal temperature field and simulated stress field of mass concrete of bearing platform were calculated.According to the calculation results, the temperature control standard and corresponding temperature control measures were formulated, and the layout of cooling pipeline was optimized.In order to ensure the construction quality of No.8 bearing platform concrete, the field measurement of No.8 bearing platform was carried out.From the analysis of test data, the temperature collection data after pouring is normal.The water cooling and surface maintenance after concrete pouring basically meet the requirements of mass concrete.The temperature rise of concrete after pouring is 43.4 ~ 45.6 ℃,not more than 50 ℃,and the maximum temperature of core is not more than 75 ℃.The temperature drop process is gentle, and the temperature difference between the internal and surface of concrete meets the relevant requirements.