某PC单箱三室箱梁温度梯度效应研究

以某高速铁路单箱三室箱梁桥为背景,通过对国内外几种典型的温度梯度及不同的温度梯度在相同的温度特征值下的温度效应进行比较,重点分析了在不同的温度梯度下箱梁的温度应力及位移的变化规律.结果表明:纵向位移最大值在箱梁两端,呈线性变化,竖向位移最大值处于中跨跨中,呈抛物线变化;应力与位移的关系表现为下缘应力与位移呈对应关系,下缘应力大对应的位移也大;温度梯度将会引起很大的温度应力,且不同的温度梯度引起的应力和位移相差较大.因此,在设计时选择合理的温度梯度是非常重要的.

Study on the effect of temperature gradient in single box and triple cells of PC box-girder bridge

Under the setting of a single box and triple cells of high-speed railway box-girder bridge, The paper compare several typical temperature gradient at home and abroad and the temperature effects of different temperature gradients under the same temperature characteristic values, With the focuses on the variation of temperature stress and displacement under different temperature gradient box girder. The results show: Maximum longitudinal displacement is on both ends of box girder and changes linearly, Maximum vertical displacement of bridge is at mid-span and shows parabola changes. Relationship between stress and displacement is correspondence in the lower edge of bridge, If the stress of lower edge is large, the displacement is also large. Temperature gradient will cause a lot of temperature stress, and the stress and displacement caused by different temperature gradients have a larger difference. So it is very important for bridge design to choice reasonable temperature gradient.