Study of Seismic Behavior on Multi-Storied Buildings with Composite Columns

Abstract

The present work seeks to investigate the seismic behaviour of typical SMRF framed structure with two types of composite columns. The main objective of this paper is to evaluate the comparison of composite columns i.e., Concrete filled steel tube (CFST) and Concrete encased I section (CES). This paper is mainly emphasis on structural behaviour of multi-storied structure with different vertical geometric irregularities with two different composite columns. The present work deals with the seismic behaviour of 15 storey building assessed through dynamic analysis (response spectrum method) as per IS 1893:2002 for seismic zone IV and soil type medium, using ETABS 2015 software package. It is also to compare and find which composite column is more effective against lateral loads. The models were analysed and results are tabulated and compared for various parameters like time period and frequency, storey displacement and storey drift. Keywords: Concrete filled steel tube, Concrete encased I section, vertical irregular buildings, Response Spectrum analysis, Time period, Storey Displacement, Storey Drift. I. INTRODUCTIONThe buildings in India are constructed with RCC and the adoption of steel structures is generally confined to industrial buildings, which have acquired prominence by adopting composite structural elements. The most important and most frequently encountered combination of two materials steel and concrete, with the application in multi-storey commercial buildings and factories, as well as in bridges. These materials can be used in mixed structural systems, for example, concrete cores encircled by steel tubes, as well as in composite structures where members consisting of steel and concrete act together compositely. These essentially different materials are completely compatible and complementary to each other, they have almost the same thermal expansion, they have an ideal combination of strengths with concrete efficient in compression and the steel in tension, concrete also gives corrosion protection and thermal insulation to the steel at elevated temperatures and additionally can restrain slender steel sections from local or lateral-torsional buckling. However, in recent times, the composite columns are gaining popularity for use in multi-storey buildings by virtue of their excellent static and earthquake resistant properties such as lower mass, high strength, rigidity and stiffness, significantly high toughness and ductility, large energy dissipation capacity. Due to these reasons, composite members are gaining importance for the making of sky-scrapers, infrastructure growth and especially for high rise structures of seismic regions in the world. A steel-concrete composite column is a compression member, comprising either a concrete encased hot-rolled steel section or a concrete filled tubular section of hot-rolled steel and is generally used as a load-bearing member in a composite framed structure. The load carrying capacity of composite columns is more than that of the bare reinforced column ...