UPGRADING THE DUCTILITY AND SEISMIC BEHAVIOR FACTOR OF ORDINARY RC FRAMES USING FIBER COMPOSITE SHEETS

The ductility and seismic behavior factor (R) are evaluated for an existing Reinforced Concrete (RC) frame that has been retrofitted with web-bonded Carbon Fiber Reinforced Polymer (CFRP) system. For this purpose, firstly using a nonlinear finite element analysis the flexural stiffness of FRP-retrofitted and original exterior and interior joints of the frame are determined. The obtained stiffness is then implemented into another software package in order to analyze the FRP-retrofitted frame using nonlinear static analyses. Then the R factor components including ductility reduction factor and over strength factors are extracted from pushover analyses. The results are compared with the results of the original RC frame and the same frame that has been retrofitted with steel bracings reported by other investigators. The results show that the ductility and the seismic behavior factor of the existing RC frame that has been retrofitted with CFRP sheets are better than the original frame, and upgrade the ductility of the ordinary RC frame to the Intermediate and even Special RC frame.

Keywords:

seismic behavior factor (R) , nonlinear static analysis , pushover , reinforced concrete frame , web-bonded CFRP-retrofitting , steel bracings