渡桥电厂冷却塔倒塌的塔型因素分析

针对渡桥电厂冷却塔倒塌原因中的塔型因素，建立与之同壁厚、同高度、同筒底直径和相同人字柱的双曲线型冷却塔，分析两者动力特性的差别，比较自重、规范平均风荷载和风洞试验脉动风荷载作用下响应的差异。研究表明:渡桥冷却塔比双曲线型冷却塔的基频低30%；风荷载作用下渡桥冷却塔的径向位移比双曲线型冷却塔大很多，壳体扭曲程度较大；渡桥冷却塔迎风面的子午向薄膜力随塔高减小而迅速增大，最大拉力比双曲线型冷却塔大40%以上。渡桥冷却塔的塔型不如双曲线型合理，塔型不合理是构成渡桥电厂冷却塔倒塌的一个因素。

ANALYSIS OF TOWER SHAPE FACTOR IN THE COLLAPSE OF THE FERRYBRIDGE COOLING TOWERS

In order to determine whether the tower shape is a contributing factor for the collapse of Ferrybridge cooling towers,a hyperbolic cooling tower with the same shell thickness,height,diameter on the bottom of shell and supporting columns is used for comparison.The difference of dynamic characteristics of two towers is analyzed.The different responses of these two towers under gravity loading,mean wind loading obtained from the code and dynamic wind loading obtained from the wind tunnel test are compared.The results show that the first frequency of Ferrybridge tower is 30% lower than that of the hyperbolic tower.The radial displacements of Ferrybridge tower under wind loading are much larger than those of the hyperbolic tower,and more significant twist distortion can be found in the shell of Ferrybridge tower.The meridian membrane forces on the windward face of Ferrybridge tower under wind pressure increases significantly with the decrease of height and the maximum value is over 40% greater than that of the hyperbolic tower.It is concluded that the tower shape of Ferrybridge tower is not as good as that of the hyperbolic tower,indicating that the tower shape is a contributing factor for the collapse of Ferrybridge cooling towers.