大型冷却塔结构的等效静力风荷载

Equivalent Static Wind Load of Large Cooling Tower

摘要:

采用刚性模型风洞同步多点测压试验获取非定常激励向量,并结合POD(经验模式分解)技术进行预测与重构处理,然后基于结构动力方程推导出仅广义共振模态位移和弹性恢复力协方差矩阵,再通过准静力分析方法计算出结构的共振和背景分量,最后通过线性三分量组合方法得到结构总的等效静风荷载.本文方法完全考虑了各共振模态间的耦合效应,且物理意义明确,从理论上适用于任意复杂结构的ESWL(等效静风荷载)计算.以国内已建成的亚洲最高、最大的冷却塔——宁海电厂超大型冷却塔为例,进行了该塔的风致响应和ESWL的计算,得出了一些对工程设计有益的结论,并验证了本文方法的有效性.

Abstract:

A new procedure is presented to calculate the equivalent static wind loads (ESWL) for the large cooling tower.Based on the synchronous multipressure measurement on the rigid building model,the generalized resonant modal displacement covariance matrix is obtained from structural equation of motion; then based on inertial wind loading(IML) method,covariance matrix of elastic restoring force containing the resonant components is obtained; the resonant response and equivalent static wind loads are calculated with loadsresponse correlation method.At last the total ESWL is obtained with linearity combination of background and resonant components.The proposed procedure avoids the integration process of calculating elastic restoring force with a full consideration of the modal coupling effects,which can be used to calculate the ESWL for any complex structures.The calculation of ESWL of the super large cooling tower of Ninghai Power Plant demonstrates the effectiveness of the present approach.