基于AR模型的大跨悬索桥脉动风速时程模拟

Time-history simulation of fluctuating wind speed for long-span suspension bridge based on AR model

为了解决风荷载的输入问题,分析桥梁风致振动响应,提出了基于AR模型的脉动风速时程模拟方法.基于线性滤波法的AR数值模型,依据AIC准则确定了模型的阶数,利用MATLAB语言,采用Kaimal谱编制了随时间和空间变化的脉动风速时程模拟程序;对某大跨悬索桥的主梁、主缆及主塔表面的风速时程进行数值模拟,根据工程实际确定了特定参数的取值,运用功率谱密度函数及互相关函数,考虑空间相关性,对结果进行验证.结果证明,本文方法简便快捷,模拟值同目标值吻合,能够较好地解决风荷载的输入问题.

In order to solve the problem of the input of wind load and the analysis of wind-induced vibration response of bridge,a simulation method for the time-history of fluctuating wind speed based on AR model was proposed.In terms of the AR numerical model using the linear filtering method,the order of model was determined according to the AIC rule.With the MATLAB language and Kaimal spectra,the simulation program for the time-history changing with both time and space of fluctuating wind speed was compiled.In addition,the surface wind speed time-history of main beam,main cable and main tower of a long-span suspension bridge was carried out by numerical simulation.According to the actual project,the values of specific parameters were determined.The results were verified with the power spectral density function and cross-correlation function,considering the spatial correlation.The results show that the proposed method is simple and efficient,the simulation values are identical to the target values,and the proposed method can substantially solve the problem of wind load input.