Nonlinear response analysis of different retrofit strategies

Abstract

The major objective of this study is to evaluate different retrofit strategies for a typical, existing reinforced concrete building in Istanbul under a non-linear response methodology and performance based design procedure. Calculation of the capacity spectrum of the system and demand spectrum of the design earthquake and the resulting performance points based on FEMA-356 and ATC-40 documents, using SAP2000. Evaluated building is found to be inadequate in terms of strength and stiffness demands of the design earthquakes as defined in the current Turkish Earthquake Code. Capacity curves and performance levels of the building retrofitted with shear walls and concentric braces are obtained and results are discussed. A two-dimensional frame is retrofitted by eccentric braces, concentric braces and steel plates. Ductility and seismic load reduction factors are calculated based on ATC-19. A preliminary cost analysis is also performed and compared for the retrofit strategies used