铁路56 m简支箱梁的碳化寿命预测

Prediction of Carbonation Life of Railway 56 m Simple Box Girder

为评估混凝土桥的耐久性与安全性,采用基于可靠度理论和热传导理论的2种碳化寿命预测方法,结合ANSYS热分析模块模拟分析混凝土碳化过程。基于热传导理论的碳化寿命预测方法从微观角度分析CO2扩散过程,以钢筋表面处单位体积混凝土吸收CO2的质量达到完全碳化所消耗的CO2质量为混凝土碳化寿命的判断标准。经验证,碳化深度的ANSYS模拟值与实测值吻合情况较好。采用2种碳化寿命预测方法预测银川机场黄河特大桥中的56 m简支箱梁桥的寿命,结果分别为135年和153年,表明在正常养护及运营条件下该桥的耐久性符合设计使用年限的要求。

In order to evaluate the durability and safety of concrete bridge,based on two carbonization life prediction methods of reliability theory and heat conduction theory,the carbonation process was simulated and analyzed with ANSYS thermal analysis module.The carbonation life prediction method based on the heat conduction theory analyzed the diffusion process of CO2 from the microscopic point of view.The mass of CO2 consumed by unit volume concrete on the surface of steel bar reaching the mass of CO2 consumed by complete carbonization is the judging standard of concrete carbonation life.It is verified that the simulated value of carbonation depth by ANSYS is in good agreement with the measured value.The service life of 56 m simple box girder bridge of Yellow River Bridge in Yinchuan airport was predicted by Niu Ditao model based on reliability life prediction and carbonization life prediction method based on heat conduction theory.The results are 135 years and 153 years respectively,which shows that the durability of the bridge meets the requirements of design service life under normal maintenance and operation conditions.