预应力混凝土连续梁日照温度效应研究

A Study of the Effect of the Sunshine Temperature on a Pre-Stressed Concrete Continuous Girder Bridge

结合大跨度预应力混凝土连续梁在施工中线形和应力受日照温度效应影响较大的特点,通过日照温度场测试,得到了箱梁竖向温度梯度的拟合公式,并将拟合公式加载到有限元模型中进行计算,计算的线形与应力变化均与实测值基本一致。研究结果表明:10:00以后标高变化较大,呈现为整体下挠的状态;在下午16:00时,梁体线形下挠值最大,悬臂端部达到12.9mm。在日照温度梯度作用下,梁体顶板应力变化明显,而梁体底板应力变化较小。可为后续施工阶段探究日照温度对梁体线形和应力的影响提供参考。

Upon the basis of considering the characteristics of the sunshine temperature having a comparatively great effect on the alignment and stress of a long-span pre-stressed concrete continuous girder,the fitting formula of the vertical temperature gradient of the box girder is obtained through the sunshine temperature field tests.And the fitting formula is loaded into the finite element model to help perform the calculations.The calculated values of both the alignment and the change in stress are found to be approximately in agreement with the really tested ones.The results show that after 10：00 a.m,the elevation changes greatly with the whole beam in a down-deflection state.At 16：00 p.m,the down-deflection value of the alignment of the beam is the greatest,and reaches 12.9 mm at the end of the cantilever.Under the action of the sunshine temperature gradient,the change in the stress of the roof of the girder is obvious,but the change in the stress of the beam bottom is comparatively small.The paper may serve as a useful reference reference for exploring the effect of the sunshine temperature on the alignment and stress of the beam in subsequent construction phases.