预应力混凝土斜拉桥收缩徐变效应的概率分析

预应力混凝土斜拉桥及其所处的环境存在大量的不确定因素,因此其收缩徐变效应具有明显的随机性.常用的随机分析方法(如摄动随机有限元法和蒙特卡罗法)很难直接应用于预应力混凝土斜拉桥收缩徐变效应的随机分析.为此,文中提出了以响应面拟合技术和蒙特卡罗试验为基础的响应面-蒙特卡罗法,得到了单个计算参数引致的收缩徐变效应的标准差,以评估该参数对收缩徐变效应的影响程度.在随机分析的基础上,引入区间估计的概念,获得了收缩徐变效应在不同置信度下的置信区间.将所提出的概率分析方法应用于广州绕城公路甘竹溪大桥,所得结果验证了文中方法的有效性.

Probability Analysis of Shrinkage and Creep Effect of Prestressed Concrete Cable-Stayed Bridges

As the commonly-used stochastic analysis methods such as the perturbation stochastic finite element method and the Monte Carlo method are inapplicable in analyzing the random shrinkage and creep effect of the prestressed cable-stayed concrete bridge subjected to a large number of uncertain factors,a response surface-Monte Carlo method(RSMCM) that combines the response surface fitting and the Monte Carlo simulation is proposed.By the RSMCM,the standard deviation of the shrinkage and creep effect varying with each parameter is obtained,and the corresponding significance of each parameter to the effect is evaluated.Then,by introducing the concept of interval estimation,the confidence intervals of the shrinkage and creep effect corresponding to different confidence degrees are determined based on the stochastic analysis.The proposed method has been applied to the newly-built Ganzhuxi Bridge on the South Circular Highway in Guangzhou,China,with its feasibility being verified.