环境温度对单薄壁墩连续刚构0#块水化热的影响

On the Effect of the Ambient Temperature on the Hydration Heat of Block 0# of a Continuous Rigid Frame with Thin-Walled Piers

以重庆市某单薄壁墩连续刚构桥为工程背景,采用Midas FEA建立0#块实体有限元模型,研究了不同平均环境温度和温度变化幅值下单薄壁墩连续刚构0#块的温度场和应力场,分析了此条件下0#块水化热的变化规律。研究表明0#块的拉应力区域主要出现在通人孔附近、横隔板与箱梁腹板和顶板交界的位置、横隔板内部中心区域以及横隔板位置对应的翼缘板,横隔板内部中心区域拉应力范围最大,通人孔附近通常出现拉应力峰值;横隔板内部的主应力大致表现为先压后拉;平均环境温度的改变对横隔板内部的主应力影响不大,温度变化幅值越大横隔板内部的主拉应力越大;平均环境温度和温度变化幅值越大通人孔倒角位置的主拉应力峰值越大。

With a continuous rigid frame bridge with thin-walled piers in Chongqing as the engineering background, the entity finite element model of Block 0# is established in the present paper with the help of the Midas FEA.The temperature field and stress field of Block 0# of the continuous rigid frame with thin-walled piers under different environmental average temperatures and temperature variation amplitudes are studied,with the changing laws of the hydration heat of Block 0# under such conditions analyzed. It is shown in our research that the tensile stress region of Block 0# mainly appears near the manhole, the position where the diaphragm and the box girder web and the top plate meet, the inner central region of the diaphragm, and the flange plate corresponding to the position of the diaphragm.The tensile stress range is the largest in the inner central region of the diaphragm,and the tensile stress peak is usually present near the manhole.The principal stress inside the diaphragm is generally shown as the pressure first and then the tension.The change in the average ambient temperature has little effect on the internal principal stress inside the diaphragm.The larger the temperature variation amplitude,the larger the main tensile stress inside the diaphragm. The larger the average ambient temperature and the temperature variation amplitude,the larger the peak value of the main tensile stress at the chamfering position of the manhole.