【作者】 赵大亮； 李爱群； 郭彤；

【Author】 Zhao Daliang Li Aiqun Guo Tong (School of Civil Engineering, Southeast University, Nanjing 210096, China) (School of Civil Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China)

【机构】 东南大学土木工程学院；

【摘要】 为了研究既有预应力混凝土结构在混凝土碳化后,结构在服役期间的使用寿命,分析讨论了混凝土碳化及与混凝土本身有关的内部因素(如水灰比、水泥品种、骨料品种与粒径、混凝土强度等)和与环境有关的外部因素(如环境湿度、CO2浓度、环境温度等)的影响．以混凝土的碳化深度作为一个随时间变化的随机过程,建立了一般大气环境下,混凝土强度的时变概率随机模型．并将混凝土强度、保护层厚度、荷载横向分布系数以及荷载增长视为随机变量,在此基础上,研究了在不修复的情况下五跨一联预应力组合箱梁主梁和结合面的使用寿命,结果表明结合面的失效概率要大于主梁．荷载增长对结构可靠度指标影响较大．给出了在不同服役年限时结构主梁和结合面的使用寿命可靠度水平,其结果对预测结构剩余寿命和经济、科学地安排养护维修时间具有重要参考意义．更多还原

【Abstract】 In order to investigate the service life of existing prestressed composite box girder on the condition of concrete carbonation, the mechanism of concrete carbonation and inner factors related to the concrete self(such as water-cement ratio, cement kind, aggregate kind and size and concrete strength etc.) and the outer factors related to the environment (such as environment temperature,CO2 density and environment humidity etc.) are discussed and analyzed. A time-varying probabilistic stochastic model of concrete carbonation are established by considering concrete strength, the concrete strength, the concrete cover thickness, the load-growth ratio and the transverse load-distributing factor as random variables in common atmosphere environment. Based on that, a five-span prestressed composite box girder is studied, the service life of the structural main beam and composite surface are studied in the different service period from reliability. The results show that the failure probability of the composite surface is larger than that of the main beam, the load-growth ratio affects the structural reliability index more significantly. The results can be used to predict the remaining service life and to develop reliability-based maintenance strategies.更多还原