S Bozorgmehrnia - Student of Structure Engineering (M.Sc), University of Guilan, Rasht, Iran
M.M Ranjbar - Assisstant of professor, University of Guilan, Rasht, Iran

Many opportunities are becoming available for using composite materials to strengthen/upgrade existing reinforced concrete (RC) structures. the objective of the rehabilitation is to upgrade the shear strength of these joints andreduce the potential for bond-slip of the bottom bars of the beam. Fiber reinforced polymer (FRP) sheets are wrapped around the joint to prevent the joint shear failure. The FRP plates provide flexural strengthening, whereas the lay-up laminates provide confinement and shear strengthening. Along with the modeling of such upgraded connections to assess the increase of strength and/or ductility provided by the composite reinforcement, an experimental program was planned and it is being undertaken. A preview of it is given in this paper together with an explanation of its philosophy; furthermore, interesting preliminary results are presented and discussed. It appears that the proposed upgrade method will have a significant impact of the engineering practice in the near future

Seismic retrofitting, RC beam-column, FRP plates