太阳辐射对混凝土箱梁温度效应的影响

Solar Radiation Affection on Concrete Box Girder Temperature Effect

摘要:

介绍了影响混凝土结构温度效应的太阳辐射强度和太阳辐射吸收系数的一般特性.利用有限元程序进行混凝土简支箱梁的温度效应计算,分析了太阳辐射吸收系数对梁的跨中挠度变化幅度、轴向变形变化幅度以及梁内最大拉应变的影响,并给出了相应的等效温差.根据混凝土表面性状的不同,太阳辐射吸收系数在0.4~0.8之间变化.计算结果表明,太阳辐射吸收系数的变化对混凝土箱梁结构的温度变形影响明显.在工程中建议采取在混凝土表面刷浅色涂层、采用整体式定型钢模板等措施减小温度效应.

Abstract:

The paper presents a discussion on the characteristics of the solar radiation intensity and solar radiation absorption coefficient.An analysis is made of the thermal behavior of a simply supported concrete box girder with the finite element program.The paper also presents an analysis on the affection of solar radiation absorption coefficient on the variant range of mid-span deflection,axial deformation and max tensile strain of the box girder.The corresponding conclusions are obtained in the form of equivalent temperature difference.For different concrete surface properties,the solar radiation absorption coefficient varies between 0.4 and 0.8.The calculating result shows that the solar radiation absorption coefficient greatly influences the deformation of concrete box girder.Light color and set-shaped steel formwork are proposed to be used to reduce the temperature effect in practical project.