This study proposes an investigation into the effect of stiffeners where local stiffness varies on the vibration characteristics of I beams. The main focus is to finding out the proper perforation for reducing the deflection that is caused by vibration characteristic of the beam. Based on the study, considering a castellated beam with hexagonal opening is taken as an example to locating the stiffeners where the local stiffness is reduced in the beam. The castellated beam with web openings and they gain its advantage due to its increased depth of section by cutting the beam into two pieces and welded it together to make hexagonal web openings. Hence, due to increase in depth of beam, variable load carrying capacity of the beam is getting increased. The increase in depth of castellated beam leads to local residual stresses in web openings and lateral torsional buckling failure when these beams are subjected to loading. There are many modes of failure like shear buckling, flexural failure, and rupture of the welded joint in a web post. In order to avoid all these failures stiffeners were introduced in the hexagonal castellated beam
