预应力混凝土连续箱梁桥温度效应研究

Research on Temperature Effects For Prestressed Concrete Continuous Box-girder Bridges

温度变化不但会产生温度应力,而且也会产生变形。结合工程实例,在中跨离墩中心线5 m、1/4跨和1/2跨处布置温度计和应变计,并对其温度和应变进行现场一昼夜观测。根据所观测的温度数据,取用最不利时刻温度进行温度分布曲线的拟合。运用Midas/Civil软件建立模型,计算出该温度模式下的理论温度应力和温度变形,比较实测值和理论值的差异。结果表明,温度拟合曲线符合实际的温度分布,可为该地同一时期其他桥梁提供一个温度计算的依据;并且由分析数据可知在最不利温度时刻,温差使箱梁顶板产生压应力,底板产生拉应力,随着往跨中的移动,应力值逐渐增大,因而,严格控制合拢段的预张拉应力是至关重要的。

The changes of temperature not only can produce temperature stress,and also can produce deformation. Combined with engineering instance,decorate thermometer and strain gauge in pier across from the centerline of 5 m,1 /4 and 1 /2 cross,and observe the temperature and strain during day and night on the spot. According to the observed temperature data,and taking the most unfavorable moment on temperature distribution curve fitting. To calculate the temperature stress and temperature deformation under the temperature mode theory according to Midas / Civil software,compare the difference between the measured values and the theoretical value. The results show that the temperature curve fitting is in line with realistic temperature distribution and provide a temperature calculation basis for other bridges of the region. In the same time,analysis data also shows that the difference of box girder temperature brings about compressive stress in the roof and tensile stress in the floor,and with the move to midspan,the stress increases in the roof and floor. So it is crucial to control the pretension folded of section.