FRP retrofit for collapse mitigation of RC frames with URM infills: 3-D computational modeling of an as-built and retrofitted one story building

December 30, 2009
Publication: Improving the Seismic Performance of Existing Buildings and Other Structures - Proceedings of the 2009 ATC & SEI Conference on Improving the Seismic Performance of Existing Buildings and Other Structures, p 1086-1092
Author(s): Naguib, Wassim I. Talaat, Mohamed M. Citipitioglu, Ahmet

Abstract: Structural systems of reinforced concrete (RC) frames with unreinforced masonry (URM) infill walls are common building systems, especially for historical buildings. In this study a one-story reinforced concrete building was simulated until collapse scaled records of ground motion, before and after retrofitting the URM infill wall using Fiber Reinforced Polymer (FRP) bars. The nonlinear behavior of the URM-infilled RC frame was modeled using the general purpose finite element (FE) software ABAQUS, to shear-deformation behavior of the infill walls. The infill walls were then idealized using a calibrated strut-and-tie model of the wall. The infill walls were then modeled, along with the RC frames, using the open source FE code OpenSEES (Open System for Earthquake Engineering Simulation). The OpenSEES (Mazzoni et al, 2004) modeling uses a direct element removal procedure which accounts for sudden loss of brittle elements taking into account dynamic equilibrium and the transient change in thestructural system kinematics. Static and dynamic analytical simulations were conducted, on the one story building model, to study the effect of retrofitting the infill walls on the overall behavior of the building system. Finally, the overall building performance after retrofitting was compared to the as-built building system. This study concludes that, after retrofit of the infill walls with FRP bars, the overall displacement ductility and the building system performance were enhanced, without significant increase in the stiffness of the lateral resisting system.

Services: Materials Design