钢管混凝土桁拱温差计算取值研究

以经实桥实测温度场验证的有限元方法,对一座钢管混凝土桁拱的计算合龙温度、有效温度取值进行了分析。分析表明,大气平均温度对钢管混凝土桁拱的计算合龙温度的影响最大,该拱肋的计算合龙温度大致为混凝土浇注后28 d内平均气温加3～5℃,冬季合龙取小值,夏季合龙取大值;日照作用对最低有效温度的影响不大,而对最高有效温度的影响很大,最高有效温度接近当地全年最高温度,最低有效温度接近当地最低日平均温度,弦管管径、钢管表面的辐射吸收率的影响都较为明显,而拱平面方位的变化和风速的影响不大。通过大量的参数分析,给出了福建省钢管混凝土桁拱的计算合龙温度和最高、最低有效温度的取值建议。

Research on Thermal Difference Magnitude of Concrete Filled Steel Tubular Truss Arch

By using finite element method which verified by the measured temperature field of one concrete filled steel tube (CFST) truss arch bridge, the closure temperature as well as the maximum and minimum effective temperatures were calculated. The results show that (1) The average ambient temperature has great influence on the calculated closure temperature. As to the arch rib being analyzed, the calculated closure temperature is about the average air temperature during 28 days after pouring concrete plus 3～5℃(the smaller value for closure in winter and the greater value for closure in summer). (2) Solar radiation has little influence on the minimum effective temperature, but great on the maximum effective temperature. The maximum effective temperature of the rib is close to local annual maximum temperature and the minimum effective temperature is close to local minimum daily average temperature. The diameter of steel tube and the radiation absorptivity of steel surface have distinctive influence on effective temperature, but the orientation of arch axis and the wind velocity have little influence. Based on numerous parametric studies, the suggestive values for the calculating closure temperature,  the maximum and minimum effective temperature of CFST truss arch bridges in Fujian Province were proposed.