Abstract:Dynamic characteristics of highrise buildings is analyzed in this paper with the help of shearflexural type cantilever beam model; and then, a structural characteristic parameter governing the mode of highrise buildings is given. Through the fitting analysis of fundamental mode shapes with different structural characteristic parameters, a simplified model of fundamental mode is obtained, which has a concise expression but can accurately reflect the prototype fundamental mode shapes of highrise buildings; at the same time, the method for determining the mode index which governs the shape of simplified modes is given. The simplified fundamental mode of this paper is applied in the windinduced vibration analysis of an actual highrise building; the result shows that, by using the simplified mode, the wind load distribution along the height of the building can be reflected more precisely and the computational accuracy of wind loads and windinduced responses of the building can be improved.