COMPARATIVE ANALYSIS OF A TALL BUILDING FRAME UNDER LATERAL LOADS USING FINITE ELEMENTS AND SIMPLIFIED METHODS

Abstract

In this research the analysis of tall building under lateral load is carried out, and the structural systems that use in tall buildings are presented. The main objective is to carry out the comparison between the simplified and FEM methods of analysis of tall buildings. The representative tall building System chosen for comparison is Rigid Frame The proposed structure was modeled in square plan area of 25×25𝑚2and 25 stories. Then model was analyzed using simplified methods (portal and cantilever methods) in addition to that finite element structural analysis program ETABS. A simple analysis program was developed using Excel spread sheet for both cantilever and portal methods. Wind load was applied to the proposed structure according to British Standard 6399. The analysis using ETABS was carried out, and analysis results for simplified and computerized were compared at four different building heights. Results of analysis were submitted in tables and graphical formats. The portal and cantilever methods are considered to be appropriate for the preliminary analysis of reasonably tall building frames. The finite element method is more accurate than the portal and cantilever methods but it is not economical for everyday design works, When results of two programs were compared it shows the cantilever method is more close to the results of finite element method but the values of bending moments and shear forces in external columns are more close than portal method.