劲性骨架拱桥施工阶段应力不确定性及敏感性分析

Analysis of Stress Uncertainty and Sensitivity of Stiffened Skeleton Arch Bridge During Construction Stage

劲性骨架拱桥应力受各种随机因素的影响在施工期间就表现出较强的不确定性,确定性分析已不能满足计算精度的要求。本文通过北盘江大桥模型试验,研究劲性骨架拱桥施工期间应力的不确定性及敏感性,结合贝叶斯方法引入早期应力观测数据对不确定性分析结果进行修正,得到结构应力后验概率分布。研究结果表明:结构应力在施工前期离散性较小,后期逐渐变大;经过贝叶斯修正的结构应力后验概率分布离散性得到明显改善;各变量敏感系数在施工期间均有不同程度的波动,徐变模型敏感系数最大,收缩模型敏感系数在施工前期较大,后期较小。

Stress of stiffened skeleton arch bridge is uncertain,because it＇s influenced by many random factors during construction stage,certainty analysis cannot satisfy the calculation accuracy.Based on the model test of Beipan river bridge,the stress uncertainty and sensitivity of stiffened skeleton arch bridge during construction stage were studied in this paper.Bayesian theory was introduced into the prior stress observation data,the posterior probability distribution of stress was obtained by modifying the results of uncertainty analysis.The results showthat the discreteness of stress is small in the early construction stage and become large later.The discreteness of the posterior probability distribution of stress is improved by Bayesian modification.The sensitivity coefficient of variables fluctuate during construction stage,such as the sensitivity coefficient of creep model is the largest,the sensitivity coefficient of the shrinkage model is large at first and become small later.