四川5.12地震楼顶钢塔破坏浅析

本文对四川5.12地震时楼顶塔普遍遭到破坏的鞭梢效应进行了分析。高楼对楼顶塔的水平地震作用起了放大作用。楼房顶部在水平地震作用下产生的加速度,使楼顶钢塔底部产生与其反向的惯性力,这个惯性力就是激励楼顶钢塔顶部桅杆鞭梢效应的动力荷载。由于桅杆的质量和刚度比塔架小得多,因此它所产生的加速度和位移比塔架大得多,于是导致弯折破坏。据此,为以后高楼建塔提出了相应对策。

Superficial Analysis of the Damage of Steel Towers on Top of Buildings under Earthquake on 5.12 in Sichuan

The whipping effects on damage of most of the towers on the top of buildings under the action of earthquake happened on the 12th of May in Sichuan were analysed. The high buildings played the role of magnifying effect for the towers on the top of the building under horizontal earthquake action. The acceleration conducted by the influence of horizontal earthquake on the top of the buildings shall cause a sort of inertial force contrary to its direction on the bottom of the steel tower. The sort of inertial force is considered as impetus load activating the top mast of the steel tower to conduct its whipping effect. Because the mass and rigidity of the mast is much less than that of the tower truss, so it conduct so large acceleration and displacement that cause the folding damage. As a result, the relevant methods should be put forward for the towers built on high building later.