Evaluation of the efficiency of single-outrigger structural systems in tall buildings

Abstract

This study investigated the seismic behaviour of the single-outrigger frame systems and proposed the optimum location of outrigger in tall buildings compared to conventional approaches. For this purpose, a pushover analysis was carried out on different forms of the single-outrigger braced high rise buildings to capture the seismic response. An innovative Stiffness Ratio Method (SRM) technique has been utilised for small-scale 3-D modeling using Finite Element Modeling (FEM) in Abaqus/CAE software commercial program. The performance of single-outrigger systems under uniform loading was measured through lateral displacement and drift. The results confirm that by changing an outrigger's position throughout the height of the building, the strength and stiffness will experience significant changes. Placing an outrigger at the top level of the building termed Cap model led to a reduction in lateral drift by 72 percent, while it reached 84 percent, where it placed at 0.4 height of the building hereinafter called Optimal model. Overall, the results showed that the optimal form of the single-outrigger systems' efficiency is 17 percent higher than the conventional model (Cap model) in the reduction of the top displacement of the building under lateral loads.