Effectiveness of strengthening RC beam-column connections in shear with vertical FRP strips

Abstract

Reinforced concrete (RC) connections, designed prior to the implementation of earthquake design standards around the world, may not posses sufficient shear strength to withstand a seismic attack. Such connections will therefore require strengthening. This paper reports the results of tests on two-dimensional RC connections which have been strengthened in shear with externally bonded fiber reinforced polymer (FRP) composite strips. FRP strips are an attractive strengthening solution as they are relatively simple to apply, and in this study they are orientated parallel to the longitudinal axis of the column (i.e. vertical strips). The tests reported in this paper serve to evaluate the effectiveness of the use of vertical FRP strips for strengthening and as a result, the test specimens are heavily instrumented in order to monitor not just the FRP but the connection as a whole. The hierarchy of strength dictates eventual failure in the joint region, even for the FRP strengthened connections, and all test specimens are subjected to monotonic or cyclic loading.