使用碳纤维板加固的RC梁桥服役过程可靠度指标分析

基于大气环境下混凝土强度的衰减模型和钢筋的锈蚀模型,考虑材料性能、几何参数和计算模式的不定性,建立了服役RC桥梁加固前和加固后的抗力时变模型。并结合一座实桥运用JC验算点法,计算出了服役50年的桥梁在加固前和加固后的可靠度指标,加固前可靠度指标降为3.576 4,通过碳纤维板加固后可靠度指标提升至4.611,满足了规范对可靠度指标的要求,且在今后50年服役中都能满足可靠度要求。算例分析表明该加固方案是可行的。最后对恒载的变异系数和活载的变异系数进行了分析,发现汽车活载对可靠度指标的影响最大,验证了交通量的变化是影响目前桥梁结构功能退化的主要原因这一结论。

Reliability index analysis of the service process of RC beam bridge reinforced by carbon fiber

The corrosion model of concrete strength under atmospheric conditions and atten-uation model based on reinforcement,considering material properties,geometry parame-ters,calculating the uncertainty of model,established the service for RC before and after reinforcement of bridge strengthening the time-dependent model,combining with a real bridge using JC checking point method to calculate the reliability index of bridge in service for 50 years before reinforcement and after reinforcement,reinforcement of reliability index dropped to 3.5764,the carbon fiber sheet reinforced,reliability index to 4.611,meet the standard for reliability requirements,and served in the next 50 years to meet the reliability requirements.Example analysis shows,the reinforcement scheme is feasible.Finally,the coefficient of variation,coefficient of variation of dead load live load analysis,found the live load effect on the reliability index of the maximum,to verify the change in traffic volume is the maj or factor influencing the function of bridge structure degradation.