Outrigger system for interconnecting three dimensional multi-stories buildings

Abstract

In tall buildings design, lateral loads induced by wind or earthquake forces are often resisted by an outrigger system. This system is often chosen as its function by tying the structural components together to provide sufficient lateral stiffness to the structure and control the excessive drift due to the lateral load. This thesis is to analyze the behavior of two 30 stories residential buildings that interconnected by a link bridge which acted as an exterior outrigger system at different heights and also the outrigger system location optimization. A total of five models with different configuration of exterior outrigger system which interconnecting the two multi-stories buildings had been analyzed by using ETABS software program. There is one model with no outrigger system is applied, three models with outrigger system interconnected at different height locations which are level 10, level 20 and level 30 of the buildings respectively, and last model with outrigger system is applied at three levels which are level 10, 20 and 30. The modeling process was carried out in such a way that the behavior and performance of the structure was within the limitations suggested by BSI (2001) CP 3: Chapter V-2: 1972. From the results, the percentage of reduction in lateral displacement is directly proportional to the number of level of outrigger system applied to the multi-stories buildings. By comparison, it is structurally efficient to locate an exterior outrigger system at the top of a building. Study has shown that it is indeed helpful in reducing the lateral displacement of building structure by applying the outrigger system as an exterior structural system for interconnecting between the multi-stories buildings.