沥青铺装高温摊铺时钢箱梁温度分布

Temperature Distribution in Steel Box Girder during High Temperature Paving of Asphalt Pavement

为获得沥青铺装高温摊铺时钢箱梁温度分布特征,以某长江大桥为研究对象,在桥面板底部横向和横隔板竖向布设25个温度传感器,测试浇注式沥青混合料摊铺时钢箱梁内部主要构件的温度,通过数据分析和模拟,获得钢箱梁最不利温度梯度,并建立桥面顶板底部最高温度的预测公式。结果表明:桥面板底部最高温度达到84℃,最大升温幅度达到67℃,平均升温速率达到0.83℃/min,局部时段上升至2.10℃/min;温度的影响范围主要分布在摊铺范围内周边1.2 m,最不利横向和纵向温度梯度分别为58℃/m和10℃/m,而竖向温度梯度可采用指数函数模拟;桥面板底部最高温度可由气温、混合料摊铺温度和厚度进行预估。由分析结果可见,沥青铺装摊铺高温使钢箱梁在局部区域形成较大的温度梯度,可作为温度应力分析的依据。

For getting temperature distribution property in steel box girder,25 temperature sensors were planted along bottom of bridge deck transversely and diaphragm vertically in a certain Changjiang bridge,so temperature of steel box girder’s crucial components were tested while Gussasphalt mixture paving.Basing on datum analysis and simulation,the worst temperature gradient was got,and formula for predicting the maximum temperature of the bottom of steel deck was created.Results show the maximum temperature under steel deck and the maximum rise extent of temperature can reach 84℃and 67℃respectively.Temperature can rise at 0.83℃/min averagely and 2.10℃/min in special period.The influence range of paving temperature is 1.2 m around paving area,and the worst transverse and longitudinal temperature gradient is 58℃/m和10℃/m respectively.Vertical temperature gradient can be simulated with exponent function.The maximum temperature under steel deck can be predicted with air temperature,paving temperature and thickness of mixture.It is concluded that relative high temperature gradient occurs in local area of steel box girder when asphalt pavement is to be paved at high temperature,and which can supply reference for thermal stress analysis.