Simplified modeling and analysis method for skyscrapers with outrigger system

Abstract

In this paper, a simplified modeling and analysis method for skyscrapers with an outrigger system is introduced. The simplified method is mainly based on the superelements and dominant degree of freedom methods, and it is codified by using MATLAB software. The simplified method results are verified with analysis results of the ETABS detailed model, where static, modal, and dynamic analyses are conducted. The proposed method's applicability on different configurations of tall buildings with outriggers systems is also verified through a parametric study. A comparative study with some previous studies is conducted to prove the efficiency of the proposed method. It was found that the adopted simplified modeling method has good accuracy in predicting the lateral displacements and inter-story drifts in the linear and nonlinear analysis. Furthermore, the simplified model has good accuracy in predicting the first modal shape and its corresponding period, while it has less accuracy in predicting the higher modal shapes and periods. Also, it was found that the simplified model underestimates the Max and Min story acceleration in comparison with the accurate model. The parametric study confirmed the proposed method's applicability on different configurations and topologies of tall buildings with an outrigger system. As a result, the simplified modeling method gives a deep understanding of the outrigger system behavior and its parameters. Therefore, it is an effective tool for modeling and analysis in the preliminary design stage. However, further improvements on the simplified modeling method should be conducted in future studies to increase the accuracy and quality of the obtained results and avoid its disadvantages.