Analysis Outrigger Structural System Subjected to Lateral Loads

Abstract

The advances in structural systems and material technology made it possible to design light and slender structures satisfying economical and architectural requirements. In tall buildings, lateral loads caused by wind and earthquake actions are often resisted by a system of braced-frame and shear wall-frame. However, such structures face the problems of vibration induced by the wind load and inconveniences may be caused to the occupants of the building due to excessive deflection and acceleration. In order to limit the wind drift to acceptable limit and to maintain human comfort with optimum utilization of material, the core-outrigger and belt truss structural system is developed. The magnitude of the reduction in drift and core moment depends on the location of outrigger and relative flexural rigidities of the core, outriggers and columns. In the present paper simplified analysis of structure under lateral uniform wind pressure is presented to understand the behaviour of the outrigger structural system. Further effect of location of outrigger in tall building is illustrated. A 50-story reinforced concrete building is considered for study. Modeling and analysis of building is carried out using ETABS software. In present study an outrigger is provided at different level to obtain optimum location for the one outrigger structure system. Response of building under uniform lateral load in terms of displacement, drift, core moment are studied for building with and without outrigger.