塔体刚体运动对其地震载荷的影响

THE SEISMIC LOADING OF A COLUMN MOVING AS A RIGID BODY IN THE WAVE FIELD

本文指出：在计算塔设备的地震载荷时。若塔高Ｈ远小于地震波长，应考察塔体在地震波场中作为一个刚体的运动。此时塔体绕空间某一瞬时不动点摆动。过此点的塔体横截面将承受最大的水平剪力，因而是最危险的承载截面。假定塔体是等径均质的，在地震开始瞬间进行推导。得知该不动点位于０．６４４Ｈ高度处、激振频率约在０．１～０．５Ｈｚ范围内。

This paper shows that a column should be considered as a rigid body in the wave field when its height is far less than the wave length in earthquakes. It may swing around a point which is above its mass center. The section containing this point is the most dangerous one which withstands the maximum horizontal shear stress. Calculation shows this this point is at the height of 0.644H where H is the height of the column and the frequency of excitation is about 0.1～0.5Hz Provided that both its section area and wall thichness are unchanged.