MITE ELEMENT ANALYSIS OF CONFINED CONCRETE COLUMNS

Abstract

Behavior of concrete columns under uniaxial loading has been a subject of study for ages. It is an well established fact now that, concrete columns, when confined by suitable reinforcement arrangements, results in increase in both the strength and ductility. With the increasing consciousness of designing earthquake resistant structures, the factors like gain in strength and ductility becomes much more important. This is more important in the case of high strength concrete columns, as high strength concrete has a much brittle post-peak behavior. Various researchers have proposed different empirical models to predict the behavior of confined concrete columns under uniaxial loading. But very little work has been done for the finite element modeling of confined concrete columns. In this thesis, a three dimensional nonlinear finite element analysis of confined concrete columns has been carried out. Material models have been formulated for both concrete and reinforcements. Geometric modeling of both reinforcements and concrete has also been done. The material model has been validated against experiments carried out by researchers. A parametric study has also been carried out to study the effect of different parameters on the behavior of confined concrete columns. Concrete compressive strength, reinforcement configuration, spacing of tie steel and strength of reinforcements are the parameters considered for the study. This parametric study has been carried out with a view to find out the deficiencies in the Indian Standard regarding the specifications of confining reinforcements.