Ductility Factor Evaluation of Concrete Moment Frame Retrofitted by FRP Subjected to Seismic Loads

Most of the reinforced concrete buildings that have been constructed are not earthquake resistant or have not sufficient and acceptable resistance. Therefore, these buildings need retrofitting with reliable, simple, and cost-effective retrofitting methods, particularly against lateral loads. Since a significant number of vulnerable buildings have already been designed, raising their seismic resistance in different ways can lead more or less to functional challenges and structural design changes. Building industry researchers have always tried different approaches to fix defects in concrete structures. Today the use of advanced composite polymer materials to reinforce and strengthen structures is developing. One of the most important goals of seismic standards for structures is to provide enough ductility, because under such conditions the structure will be able to dissipate a sufficient amount of earthquake energy. This article describes the role of polymeric fibers enhanced by the fiber-reinforced polymer (FRP) in reinforcing reinforced concrete structures. Therefore, the most fundamental steps to achieving this goal is an evaluation of the response modification factor (R) and the ductility coefficient (μ). Due to this important need, this study will present a formula that calculates the amount of plasticity in concrete structures. Three concrete moment frames of 3, 6 and 12 floors with and without composite FRP have been tested for finding this coefficient. In SAP2000, nonlinear static analysis (Push-Over) of the frames has been performed, and then factors of ductility and response have been determined from the base shear and the roof displacement curve.