折线温差分布下倒虹吸横向温度应力计算

通过引进公路桥梁规范中的折线温差分布函数,推导了折线温差分布下倒虹吸横向温度自约束应力和框架约束应力计算公式,利用文章推导的公式,计算了倒虹吸处于停运状态时,突遇骤然降温作用时的温度应力,计算表明:倒虹吸内表面总应力是温差和壁厚的函数,当壁厚不变,温差减小50%时,其温度应力相应的也减小50%,当温差不变,壁厚减小50%时,其温度应力减小17%;采用相同的工程实例,按照折线温差分布函数和指数温差分布函数分别计算倒虹吸温度应力,发现前者计算值偏大,在设计时若按照折线温差分布模式考虑倒虹吸温度荷载,能提高倒虹吸抗裂性能。

Calculation of transverse thermal stress of inverted siphons under fold line distribution of temperature difference

Based on the fold line distribution function of temperature difference for highway bridges, we derived the calculation formulas for transverse thermal self-restraint stress and framework-restraint stress of inverted siphons. Using the calculation formulas, we calculated the thermal stress of inverted siphons in winter downtime when cold snap invades. Our calculations showed that the total stress of the inner surface of an inverted siphon is a function of the wall thickness and the temperature difference. When wall thickness is constant and temperature difference decreases by 50%, the thermal stress also decreases by 50%. When the temperature difference is constant and the wall thickness decreases by 50%, the thermal stress decreases by 17%. The thermal stress of inverted siphons calculated by the fold line distribution function of temperature difference was larger than that calculated by the exponential distribution function. If the temperature load of inverted siphons is considered on this basis in design, the crack resistance of inverted siphons can be significantly improved.