结构风振响应极值估计方法比较

A COMPARATIVE STUDY ON METHODS FOR ESTIMATING EXTREME WIND-INDUCED RESPONSE OF STRUCTURES

为考察基于高斯分布假定的工程极值估计方法对结构风振响应极值估计的准确性,以单层球面网壳结构为例,首先通过重复采样风洞实验和重复风振响应分析,获得了超过1000个以上的结构风振响应时程样本;其次利用经典极值理论根据大量样本确定结构风振响应的极值准确值,作为评价标准;然后分别采用几种常用的工程极值估计方法,包括峰值因子法、改进Hermite模型法和Sadek-Simiu法,仅根据单个样本确定极值;最后通过对众多极值估计值进行统计分析,系统考察了不同方法极值估计结果的稳定性和准确性。结果表明,峰值因子法估计结果的离散性较小,但数值多数偏低;改进Hermite模型法估计结果的离散性较大,且数值多数偏高;Sadek-Simiu法的离散性介于二者之间,且估计结果与准确值较为接近,因而建议在进行工程极值估计时采用。

To evaluate the accuracy of some engineering methods for estimating the extreme values of wind induced response, which are usually based on the Gaussion distribution assumption, repeated wind tunnel tests and wind-induced response analysis with over 1000 samples were carried out on a single-layer spherical lattice shell structure, and more than 1000 samples of the structural response time-history were obtained. Secondly, the extreme value of the structural response was analyzed by the method of classical extreme value theory based on the large number of samples, and can be regarded as the reference value. Then, the Peak Factor method, the Modified Hermite Model method, and the Sadek-Simiu method are used seperately to estimate the extreme values of structural response based on only one sample. Finally, statistical analysis is carried out on these estimated values, and the stablity and accuracy of these three methods are investigated. The results indicate that the estimation results from the Peak Factor method have small deviation, but most are underestimated; the estimation results of the Modified Hermite Model method vary greatly, and most are overestimated; the estimation results of the Sadek-Simiu method are close to the reference value. Thus in practice it is recommended to estimate extreme values by the Sadek-Simiu method.