Ductility may be defined as the ability to under-go deformation without a substantial reduction in the capacity of the member141. The curvature ductility factor is a fare more meaningful index for duc-tility demand that is because once plastic hinge has commerced in a structure, the deformations concentrated at the plastic hinge posi-tions by rotation of the plastic hinge. The fundamental information needed by the designer concerns the required member section behavior at the plastic hinge expressed by the curvature ductility factor and its variation with the type of steel used and the ratio of the com-pression reinforcement.
The study of the flexural ductility was carried out mainly through a series of tests on simply supported beams under pure bending. The principal test variables were the compression reinforcement ratio and the type of steel reinforcement.