Effect of longitudinal steel on ductility of a R.C. flexural member: a direct approach

The objective of the present paper is to identify the ductility that can be achieved with the reinforcement details of existing structures and develops guidance to ensure adequate ductility in new structures. The effect of longitudinal reinforcements on ductility of a flexural steel concrete composite member is presented. Under any transverse loading condition, the member undergoes strains and consequent stresses. By assigning predetermined values of strain and using stress–strain relationship curve of steel and concrete, the expression for thrust and moment at a section has been calculated. The corresponding rotations against these thrusts and moments are obtained from the strain undergone. The ultimate rotation capacity of the member is calculated from the ultimate strain of concrete. Parametric studies show the importance of the amount and position of the longitudinal reinforcement on ductility and collapse load.