Cyclic tests on seismically damaged reinforced concrete walls strengthened using fiber-reinforced polymer reinforcement

The paper presents, results from tests on low-slendmess reinforced concrete (RC) walls designed to modem code provisions, initially subjected to cyclic loading to failure, and subsequently conventionally repaired and then strengthened using fiber-reinforced polymer (FRP) jackets. Repair involved replacement of damaged concrete by a high-strength mortar and lap-welding of fractured reinforcement in the plastic hinge region, while strengthening involved wrapping of the walls with FRP jackets, a's well as the addition of FRP strips at the wall edges, to enhance both flexural and shear capacity. In addition to different arrangements of steel and,FRP reinforcement in the walls, a key parameter was the manner in which carbon FRP (CFRP) strips added for flexural strengthening were anchored; combinations of glass FRP (GFRP) anchors and anchoring strips, as well as anchoring steel plates, were used. Test, results have shown that the addition of steel plates to the GFRP anchors and strips leads to a more effective anchorage; strength increases of up to approximately 30% with. respect to a conventionally repaired specimen were measured when properly anchored FRP strips were used, but energy dissipation capacity of the original walls (designed to modem code provisions) could not be fully restored.