IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308 __________________________________________________________________________________________ IC-RICE Conference Issue | Nov-2013, Available @ http://www.ijret.org 111 EXPERIMENTAL BEHAVIOR OF CIRCULAR HSSCFRC FILLED STEEL TUBULAR COLUMNS UNDER AXIAL COMPRESSION H. Ravi Kumar 1 , K.U.Muthu 2 , N.S.Kumar 3 1 PhD Scholar, Assistant Professor, Sir M.Visvesvaraya Institute of Technology, Bangalore 2 Dean, Brindavan college of Engineering, Bangalore 3 Professor & Director (R&D-Civil), Ghousia College of Engineering, Ramanagaram hrkmvit@gmail.com Abstract This paper presents an outlook on experimental behavior and a comparison with predicted formula on the behaviour of circular concentrically loaded self-consolidating fibre reinforced concrete filled steel tube columns (HSSCFRC). Forty-five specimens were tested. The main parameters varied in the tests are: (1) percentage of fiber (2) tube diameter or width to wall thickness ratio (D/t from 15 to 25) (3) L/d ratio from 2.97 to 7.04 the results from these predictions were compared with the experimental data. The experimental results) were also validated in this study. Keywords: Self-compacting concrete; Concrete-filled steel tube; axial load behavior; Ultimate capacity. ----------------------------------------------------------------------***-------------------------------------------------------------------- 1. INTRODUCTION Concrete-filled steel tubular (CFST) columns possess excellent earthquake-resistant properties such as high strength, high ductility, and large energy absorption capacity. In recent years, the possibility of using thin-walled HSS columns filled with self-consolidating concrete (SCC), or self-compacting concrete, in practical engineering has been of interest to structural engineers. Self-consolidating concrete, as it is sometimes known, arrived as a revolution in the field of concrete technology The self-compactability of concrete refers to the capability of the concrete to flow under its own weight and fill in the formwork in cast processing. Due to its rheological properties, the disadvantage of vibration can be eliminated while still obtaining good consolidation. Apart from reliability and constructability, advantages such as elimination of noise in processing plants, and the reduction of construction time and labor cost have been cited as arising from the self-consolidation function of SCC. The literature review points out that the reputed investigation of thin walled structural steel sections with SCC fill are less numerous. fibre reinforced concrete (FRC) is used as an in-fill material, as it has greater flexural strength and tensile strength than plain concrete. The purpose of this study was to examine the effects of FRC on the strength and behaviour of composite columns. However it is to be noted that the addition of fibres in the concrete will enhance the load carrying capacity because the infill material has greater flexural strength and tensile strength than plain SCC. Therefore the lack of information on the behaviour of HSS Columns with SCC & Fibres as infill necessities the need for research in this area The relationship between workability and strength and co-relation between compressive and tensile strength of self compacting concrete have been established in the earlier studies.(1,2). The present study is an attempt to study the possibility of using high strength self-compacting concrete and steel fibres in thin walled HSS columns. The objectives of present study are: - 1. To develop High Strength self-compacting concrete by adopting Nan-su method, this is regarded as the simplest method of mix design. 2. To study the acceptance characteristics of SCC by measuring filling ability, passing ability and segregation resistance by using different test methods like Slump flow, U- box, L-box, Orimet and V-funnel test. 3. To compare strength parameters (compressive strength, Tensile strength and Flexural Strength) of normal Self- compacting concrete and fibre reinforced self-compacting concrete. 4. Analytical method formulated (7) is used to predict the failure load is examined with the experimental value observed .The formula for calculating the theoretical value is P the = C A c f c +A s f y, where C=1.18 (7) A c =Area of Concrete, f c =compressive strength of concrete, A s =Area of steel, f y =Yield stress of steel. The final objective was to evaluate the possibility of using High strength self-compacting concrete with fibres (HSSCFRC) in thin-walled HSS columns in practice.