An analytical optimization study on the core-outrigger system for efficient design of tall buildings under static lateral loads

Abstract The location and number of outriggers in a core-outrigger lateral resisting system have a major influence on the tall buildings' performance and the design's cost efficiency. In this study, an analytical procedure was performed to produce a general equation of the top lateral displacement of a core-outrigger system (up to four outriggers) due to various static lateral loading distribution forms (uniform, triangular and parabolic). Moreover, the optimal positions of outriggers that produce the maximum top displacement reduction are determined in this research. On the other hand, this work proposes the maximum height of a tall building corresponding to displacement limit criteria, number of the outrigger and outrigger positions. For practical use, this study offers curves for use at the preliminary design stage to allocate the top displacement and the number of the required outriggers in terms of the building height and a proposed rigidity factor which shows to have a great influence on a core-outrigger system in a tall building.