International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395 -0056
Volume: 04 Issue: 05 | May -2017
p-ISSN: 2395-0072
www.irjet.net
COMPARATIVE STUDY OF OUTRIGGER AND BELT TRUSS STRUCTURAL SYSTEM FOR STEEL AND CONCRETE MATERIAL Prajyot A. Kakde1, Ravindra Desai2 1Post
Graduate Student, Department of Civil Engineering, Walchand college of Engineering, Sangli, Maharashtra, India 2Associate Professor, Department of Applied Mechanics, Walchand college of Engineering, Sangli, Maharashtra, India ---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract
–Rapid growth of infrastructure to accommodate modern civilization is demanding tall structures in cities. As the buildings are becoming taller the problem of their lateral stability and sway has to be tackled by engineering judgment. Structural system development has evolved continuously to overcome the problems related to lateral stability and sway, one such structural system is outrigger and belt truss structural system. The outrigger and belt truss structural system has proved to be most promising structural system in resisting problem related to lateral stability and sway. The present study is conducted for 70 storied high rise building with core shear wall. High rise building with floor plan of 30 m x 30 m in addition with core shear wall of 10 m x 10 m is considered with building aspect ratio of 7.Wind analysis is carried out to study parameter’s maximum storey displacement, inter storey drift and base shear to compare building with application of concrete and steel outrigger at various position varying with the height of building and the software used for this analysis is ETABS of 2016 version.
may be centrally located or it may be located on one side of the building with outriggers extending to the building columns on one side. The basic structural response of the system is based on very simple concept. When structure is subjected to lateral loads, the columns on which the outriggers rest combining the column restrained by outrigger resist the rotation of the core, causing the mitigation in magnitude of lateral deflections and moments in the core in comparison to the freestanding core alone resisted the loading. The external moment is now resisted by combined action of the bending of the core and the axial tension and compression of the exterior columns connected to the outriggers. As a result of this effect the strength of the structure for resisting bending is increased when the core acts as a vertical cantilever, by the development of tension in the windward columns and compression in the leeward columns. The column located at periphery also help in distributing the moments and reducing the rotation of outriggers, which can happen by combining the exterior columns with bracings commonly referred to as a “belt truss,” around the building. The belt truss is the bracing around the building at the same floor which are located between adjacent columns. The belt truss and the outrigger together combined stiffens the building and mitigate the rotation of the core, storey displacement and storey drift. This method is aimed to reduce obstructed space compared to the conventional method. The outrigger and belt truss system has solved the problems of other structural system so the use of outrigger in recent tall structures has increased tremendously. Outrigger and belt truss is economical in comparison to other structural system and is simple in terms of its arrangement and technical background.
Key Words: outrigger, belt truss, shear wall, lateral stability, sway, storey drift, storey displacement, base shear, wind.
1.INTRODUCTION In today’s modern era it has become need to undertake development in tall structure to accommodate the present population as the cities are growing fast and land availability is becoming lesser for human beings, so there is need for development of tall structures, but with development of tall structures there is need to tackle the problems related to it .Outrigger and belt truss structural system has proved to be efficient and economical solution for the problems related to tall structure development.
1.1.
1.2 Concept of Outrigger
Outriggers have been effectively used in the sailing ship industry for long time which were used to resist wind. The slender mast was connected with horizontal outrigger, the above mentioned arrangement can be imagined as the core treated like the mast, the outriggers like the spreaders and the exterior columns like the shrouds or stays. Engineers had observed this behavior of sail boats in resisting wind and so it was implemented in buildings which further was studied and used as outrigger and belt
Outrigger and belt truss structural System
The outrigger and belt truss system comprises of a main concrete core connected to exterior columns by relatively stiff horizontal members such as bracings termed as outriggers. The bracing can be of different shape. The core
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