混凝土桥梁承载力综合评价体系研究

Study on concrete beam bridge bearing capacity comprehensive evaluation system

为准确评估在役混凝土桥梁的承载力,首先,选取影响桥梁结构承载力的平均锈蚀电位、氯离子含量、混凝土相对炭化深度、裂缝平均宽度、混凝土截面损失率和混凝土实测强度推定值等6个主要因素,基于模糊数学理论和非确定性层次分析法(AHP),将影响因素分级,构建各因素模糊关系矩阵,同时,采用改进的实数遗传算法,确定各因素的最优权重,计算得出承载能力综合折减系数,构建承载力综合评价体系;然后,选取10片损伤程度不同的室内缩尺梁,开展破坏试验,验证所建立的承载力综合评价体系的有效性。结果表明:相比于现行规范中的承载能力评价方法,采用综合评价体系计算得出的承载能力折减系数与实测值更为接近,计算结果更为可靠。

Six main factors,including average corrosion potential,chloride ion content,carbonation depth,average crack width,concrete section loss rate and concrete measured strength value were selected as the research object,the influencing factors were classified based on the fuzzy mathematics theory by non-deterministic AHP,and then the fuzzy relation matrix of each factor was established.The improved real genetic algorithm was used to determine the optimal weight of each factor to calculate the bearing capacity comprehensive reduction factor,and a comprehensive evaluation system of bearing capacity was established.Ten experimental beams with different damages were utilized to carry out destructive tests to verify the effectiveness of the comprehensive evaluation system.The results indicate that compared with the standard beating capacity evaluation method,the reduction coefficient calculated by the comprehensive evaluation system is closer to the measured,and the results are conservative,which is more conducive to the assessment of the bearing capacity of the existing concrete beam bridges.