INTERACTION DIAGRAMS AND DUCTILITY CURVES FOR HOLLOW CIRCULAR AND DOUBLE-D SECTIONS

Abstract

This thesis presents the interaction diagrams and ductility curves. for hollow circular and double-D sections. In preparation of these curves Fe 415 grade of steel and M25 grade of concrete were selected. The cross-sectional dimensions were selected by studying some practical cases of bridge sub-structures and chimneys. Limit state method with simplified stress-strain curve for steel and concrete as per IS:456-1978 is used in the analysis. Several percentages of steel were considered in preparation of these curves to suit to the practical design needs. Ductility curves are intended to provide the information regarding curvature ductility of the section which could be used to estimate the reserve capacity for higher than design values of seismic coefficients. The positions of the neutral axis and the stress in the bars nearest to the tension face are also indicated in the curves.