基于贝叶斯理论的钢管混凝土劲性骨架拱桥收缩徐变效应分析

Analysis of Creep and Shrinkage Effect of CFST Stiffened Skeleton Arch Bridge Based on Improved Bayesian Theory

钢管混凝土劲性骨架拱桥施工程序复杂、施工周期长,导致混凝土收缩徐变效应十分显著,极大地影响桥梁的正常使用性能,严重时甚至威胁结构的安全。同时受收缩徐变不确定性的影响,结构的应力和位移表现出明显的离散性,使桥梁的设计施工工作变得更为困难,结构实际变形偏离其设计值的情况时有发生。为了缓解这种困难,首先改进贝叶斯方法,使其对似然函数分布与先验分布较远的情况同样适用。然后基于此方法,对北盘江大桥模型桥施工期间收缩徐变效应进行分析得到后验预测结果,并通过实测数据进行检验。计算结果表明:基于改进贝叶斯方法得到的后验预测结果与实测数据吻合良好,相较于先验预测结果,数据离散性得到明显改善。

Concrete-filled steel tube stiffened skeleton arch bridge is characterized by complicated construction procedure and long construction period,which leads to obvious shrinkage and creep of concrete and affects greatly the normal service performance of the bridge and even threatens the safety of the structure. What ＇s more,due to the uncertainty of concrete shrinkage and creep,the stress and displacement of the structure show obvious discreteness,which makes the design and construction of the bridge more difficult and the actual deformation deviating occasionally from the design value. To alleviate such difficulties,Bayesian Method is improved to apply to the condition that the likelihood function distribution is far from the prior distribution. Then,based on this method,the concrete shrinkage and creep effect of the Beipan River Bridge model during the construction period is analyzed and the posterior prediction result is thus produced andverified through measured data. The calculation result shows that the posterior prediction result based on the improved Bayesian Method matches the measured data quite well and the data discretization is much improved compared with the prior predication result.