Experimental studies on the seismic behavior of reinforced concrete beam-column joints strengthened with basalt fiber-reinforced polymer sheets

In this research, six reinforced concrete (RC) interior beam-column joints, including one reference specimen and five specimens strengthened with basalt fiber-reinforced polymer (BFRP) sheets in different ways, were tested under the cyclic load. Results obtained from the test showed that: (1) the seismic performance of joints were significantly improved after strengthening with BFRP sheets with proposed strengthening schemes; (2) no evident debonding of BFRP sheets was observed in the test indicating that a good interface behavior between the BFRP and concrete, as well as the limited influence of the practical RC slab on the strengthening scheme could be found; (3) the load bearing capacity and ductility of joints increased by strengthening with BFRP sheets, among which larger increasing degrees of specimens strengthened with three layers of BFRP sheets could be found; (4) the stiffness of joints increased after strengthening with BFRP sheets, while the initial stiffness of specimens strengthened with BFRP sheets in the core areas exhibited larger values than those of other strengthened specimens; (5) the energy dissipation capacity of joints improved by BFRP, and more effects by increasing the layers of FRP sheets or strengthening with FRP sheets in whole lengths could be obtained.