**InternationaleJournals**

**NON-LINEAR ANALYSIS OF CONCRETE FILLED COMPOSITE SHORT COLUMNS**

**Jagdish Chand ^{1}, S.M. Gupta^{2} and Babita Saini**

^{1}A.P., HCTM Technical Campus, Kaithal, E-mail: jckamboj.17@gmail.com

^{2}N.I.T. Kurukshetra, E-mail: sm_gupta85@rediffmail.com

^{3}Babita Saini: N.I.T.Kurukshetra. E-mail: babitasaini6@gmail.com

**ABSTRACT**

Composite columns offer a number of advantages over conventional reinforced cement concrete (RCC) columns, hence making their application more varied and versatile. Larger cross sections required both, extra space and material. Steel columns in-filled with high strength concrete provide a solution to tackle this problem. In the present study, an effort has been made to reduce the cross-section of composite columns and to achieve higher load carrying capacity. Two methods have been evolved for computing the ultimate strength of concrete in-filled columns. Thickness, length and eccentricity are the constant parameter while perimeter, aspect ratio and grade of concrete are varied. It is assumed that the behavior of reinforcement either inside or outside has no effect on the stress-strain properties of concrete. It is concluded that the load carrying capacity of a concrete filled square column is 15% higher than that of rectangular column of same perimeter. The percentage increase in load carrying capacity of composite steel columns is 10% to 15% with increase in grade of concrete from M-20 to M-40. Further percentage increase in load carrying capacity varies from 73% to 86% for a change in columns perimeter from 800mm to 1200mm. Thus, the desired load carrying capacity of section can be achieved with a lower grade of concrete and lower perimeter by choosing the most efficient aspect ratio making the section more economical.

**Keywords: **composite columns, ductility, local buckling, reinforced concrete, steel sections and ultimate load

**International
eJournal of Mathematics and Engineering**

**Volume 4,
Issue ****3,** **Pages: ** 2256 - 2268