This paper deals with a methodology for the use of dynamic response as an inspection and surveillance tool for the damage in a structure. The method is based on finite element discretisation to identify the stiffness characteristics (related to cracking) starting from modal dynamic parameters (natural frequency and mode shape) derived from dynamic tests. Any damage in the structure alters its dynamic characters. The damage reduces the stiffness of the structure and increases its damping value, at the same time it will decrease the natural frequency and the corresponding mode shape changes. The present thesis work aims at detecting the cracks of a simply supported beam and to study the effects of cracks in its dynamic characteristics. The beam used here is a Reinforced Concrete Simply Supported Beam. Crack is induced by applying incremental load. Curvature Damage Factor (CDF) using curvature mode shape was used to locate the damaged positions.