TWO NEW TYPES OF ELASTIC-SUBGRADE BEAMS AND THEIR APPLICATIONS IN THE SIMPLIFIED ANALYSIS OF SUPER TALL BUILDINGS

Two new types of mega-beam elements with elastic subgrade have been developed for the simplified analysis of super tall buildings. A simplified computational method is thusly obtained. The method can be applied by employing the commonly used computational program for computing the space frames after the stiffness matrices of the two elastic-subgrade elements are obtained. In the calculation of the elastic subgrade of the mega column, the bending rigidity of subsidiary frames within the mega frame is considered. Thusly, a new mega beam element solely of shearing deformation supported elastically is developed. Also the axial rigidity of the subsidiary columns within the mega frames is recognized, which contributes to the stiffness of the elastic subgrade of a generalized Winkler elastically-supported mega beam. Therefore, another new beam element of a generalized Winkler spring elastic support is acquired. It is observed that the simplification for the new elastically-supported beam elements is reasonable and effective. The accuracy of the results from the new simplified method is close to those of the exact solutions if any.