Seismic Analysis of High Rise Steel Structure with Outrigger Braced System
01 Jan 2021-pp 37-45
TL;DR: In this paper, the effectiveness of outrigger system at various locations along the height of the high rise structures in resisting lateral loads is discussed, and the effect of the proper position of the outriggers especially at 0.6 H and at top floor enhances the seismic performance of the buildings.
Abstract: Urbanization, increase in population and lack of living space in urban areas lead to development of the high rise structures and this situation is unavoidable in the twenty-first century. The constant evolution of high rise structures is very essential for the development of developing nations like India. However, designing and construction of high rise building is a challenging one because as the height of the structure increases the structural stiffness and resistance of building against lateral loads become the crucial considerations. For high rise structures, the major dominating lateral forces are wind loads and seismic loads. Therefore, minimizing the lateral displacement and inter-storey drift of high rise structures is a demanding factor. There are many lateral load resisting systems available for high rise structures such as shear walls, diagrids, braced frames and outriggers are used in recent decades. In this study, the effectiveness of outrigger system at various locations along the height of the high rise structures in resisting lateral loads is discussed. Time history analysis is carried out on three models of 20 storey steel frame structures for this study such as (1) model with outrigger at 0.3 H and at top floor, (2) model with outrigger at 0.45 H and at top floor and (3) model with outrigger at 0.6 H and at top floor. It is found that the proper location of outrigger especially at 0.6 H and at top floor enhances the seismic performance of the high rise structures.
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TL;DR: In this paper, the structural performance of different bracing systems in high-rise 2D steel buildings is compared. But, the results show that the different braced frames performed well in terms of storey displacement, inter-storey drift ratio, base shear and performance point.
42 citations
19 Sep 2017
41 citations
TL;DR: In this paper, a nonlinear static pushover analysis was carried out on different outrigger braced high rise steel buildings of 20, 25, 30, and 35 storeys to capture the seismic response.
35 citations
01 Jan 2009
TL;DR: In this article, a 50-storey building was investigated and three different peak ground acceleration to peak ground velocity ratios in each category of earthquake records were incorporated in this research study to provide a consistent level of approach.
Abstract: Tall building development has been rapidly increasing world wide introducing new challenges that need to be met through engineering judgment. In modern tall buildings, lateral loads induced by wind or earthquake are often resisted by a system of coupled shear walls. But when the building increases in height, the stiffness of the structure becomes more important and introduction of outrigger beams between the shear walls and external columns is often used to provide sufficient lateral stiffness to the structure. In general, earthquake ground motion can occur anywhere in the world and the risk associated with tall buildings, especially under severe earthquakes, should be given particular attention, since tall buildings often accommodate thousands of occupants. It is conceivable that structural collapse of such buildings can lead to disasters of unacceptable proportions. When adopting outrigger beams in building design, their location should be in an optimum position for an economical design. A range of different strategies ha s been employed to identify the optimum location s of these outrigger beams under wind load. However, there is an absence of scientific research or case studies dealing with op timum outrigger location under earthquake loads. This study aims to identify the optimum outrigger location in tall buildings under earthquake loads. A 50 storey building was investigated and three different peak ground acceleration to peak ground velocity ratios in each category of earthquake records were incorporated in this research study to provide a consistent level of approach . Response spectrum analysis was conducted and the behaviour of the building was determined considering response parameters such as lateral displacement and inter storey drift . It has been shown from this study that the structure is optimised when the outrigger is placed between 22-24 levels. Therefore it can be concluded that the optimum location of the structure is between 0.4 4-0.48 times its height (taken from the bottom of the building).
32 citations
01 Jan 2009
29 citations