An Evaluation of P-Delta Effect in High-Rise Building

High-Rise structures of rigid joint frame system are increasing day by day to accommodate growing population and infrastructural needs in metropolitan cities. However multi-storied rigid frame RC structures are prone to collapse under severe displacement, axial force and moment, if the second order effects are not included or ignored in analysis and design phase. P-Delta is one of important second-order effects. P-Delta is a non-linear effect that occurs in every structure where elements are subjected to axial load. It is associated with the magnitude of the applied axial load (P) and a displacement (delta). The second order effects are analyzed in much softwares like Etabs, Staad Pro, SAP 2000 etc. , this study evaluates the difference between displacements and bending moments for second order effects performed analysis by ETABS and STAAD PRO. In this research the plan with dimensions 15 x 40m was considered and varied the stories of the building 15, 20 and 25 was modeled and earthquake load is applied on model of structure as per IS-18939 (2002) for zone III. Then by trial and error method suitable cross-section are provided for unsafe building to bring within acceptable limit by increasing stiffness of a building. Bending moment and story displacement with P-Delta effect was considered and compared for all the models. The result shows that it is essential to consider the P-Delta effect for all multistoried buildings.