桥梁构件风致动态内力回归估算方法

Wind-induced dynamic stress estimation method for bridge elements utilizing linear regression algorithm

为弥补全桥气弹模型试验无法直接测量结构动态内力响应的缺陷,选取江东大桥悬索桥吊杆为例,采用风洞试验和随机振动时域有限元分析相结合的手段:首先对两者的位移响应进行校核;然后根据正交风随机有限元分析中加劲梁中跨跨中位移响应和吊杆内力响应的高度相关性,采用线性回归算法获得回归方程,并对中跨跨中位置在多个风偏角下的位移响应进行全桥气弹模型风洞试验取样;最后通过回归方程,估算悬索桥吊杆在不同风偏角下的风致动态内力响应.研究表明:该回归算法得到的线性回归方程在95%置信区间内的回归效果显著;算法克服了气弹模型风洞试验无法测量结构内力响应的缺陷,也可避免随机振动斜风有限元计算需多组风偏角气动参数和复杂计算框架等问题.

The present paper concentrates on overcoming the deficiency of whole bridge aero-elastic wind tunnel test in the acquisition of dynamic stress of bridge elements.Based on both the whole bridge aero-elastic wind tunnel test and finite element method,some research is implemented with the hanger of Jiangdong Bridge as an example.Firstly,verification analysis for displacements is made on results derived from the above two approaches.Thereafter,regression equation is deduced from finite element method under zero yawed angles since the mid-span vertical displacement time history keeps high correlations with the hanger axial forces.Furthermore,displacement time histories of the mid-main span are sampled from wind tunnel test under different yawed angles.Lastly,with the help of regression equation and wind tunnel test results,the hanger＇s dynamic stresses are obtained.Research shows that the regression equation in this paper has a significant regress effect in the 95% confidence interval.It is concluded that estimation method in this paper makes up the shortcoming of wind tunnel test for not being able to get structural stresses,and avoids several procedures in finite element method analysis under skew wind excitations,such as the identification of aero-elastic parameters and its complicated framework.