混凝土箱梁日照温度效应研究

Effect Study on Sunshine Temperature of Concrete Box Girder

以衢宁铁路某大桥为工程背景,进行箱梁温度场及温度应力现场测试,总结箱梁顶板、底板和腹板的温度分布规律,拟合出适合该桥的箱梁竖向、横向温度梯度模式,并采用拟合的箱梁温度梯度模式分析箱梁日照温度应力,与实测温度应力对比,验证其准确性和适用性。结果表明:箱梁底板存在明显的呈非线性分布的竖向温差,在进行竖向温度梯度拟合时不能忽略;拟合的箱梁横向温度梯度模式考虑两侧腹板的横向温差,与箱梁实测横向温差分布更接近;考虑箱梁竖向和横向温差共同作用下的温度应力计算结果与实测温度应力吻合更好,在分析箱梁日照温度效应时,不能忽略箱梁的横向温差作用。

Taking some bridge of Quning Railway as an engineering background, the temperature field & temperature stress field test of box girder are carried out, the temperature distribution law of top, bottom & web of box girder is summarized, the vertical & transverse temperature gradient modes of box girder suitable for the bridge are fitted, and the sunshine temperature response of box girder is analyzed by using the fitted temperature gradient mode of box girder. The accuracy & applicability of the force are verified by comparing with the measured temperature stress. The results show that there is a distinct non-linear vertical temperature difference in the bottom plate of box girder, which cannot be ignored when fitting the vertical temperature gradient;the transverse temperature gradient model of the fitting box girder takes into account the transverse temperature difference between the webs on both sides, which is closer to the measured transverse temperature difference distribution of the box girder;and the combined action of the vertical and transverse temperature difference of the box girder is considered. The calculated results of temperature stress are in good agreement with the measured temperature stress. The transverse temperature difference of box girder cannot be neglected when analyzing the temperature effect of sunshine on box girder.