SEISMIC BEHAVIOR OF REINFORCED CONCRETE FRAMES RETROFITTED BY PRESTRESSED STEEL STRIPS

Failure of RC columns under a combination of axial compressional load and seismic moments could result in the collapse of RC frames during severe earthquakes. This paper presents a new technique for retrofitting RC columns by wrapping them with pre-stressed steel strips. Previous experimental studies have proved this technique to be effective and promising. A previously introduced stress-strain model is used to obtain moment-curvature diagrams for retrofitted columns using a nonlinear analysis. Subsequently, these diagrams were employed in nonlinear pushover analyses to study the seismic performance of retrofitted RC frames as compared with the normal frames. The results indicate that this retrofitting approach enhances the seismic performance markedly by increasing the ductility of the columns, and hence, reducing the level of damage. In particular, this retrofitting technique replaced the undesirable failure of the columns by the rather more desirable failure of beams.