Seismic evaluation of joints before and after retrofitting

Earthquakes have shown that seismically deficient RC frames are particularly vulnerable to seismic action. Direct observation of damaged structures has shown that damage occurs usually at the beam-column joints with failure in bending or shear, depending on geometry and reinforcement distribution and type. After earthquake structures were classified as slightly damaged, thus being uneconomic to replace them, at least in the short term. For this reason suitable means of repairs of the beam column joint area are being studied. This book highlights the cyclic tests carried out on beam-column joint specimens, with different configurations of steel reinforcement detailing and strengthening by external FRP wrapping. One specimen was designed to comply with gravity load design code and the other with ductile detailing. Analytical modeling of the same was done with the help of the FEM package and its behavior with the actual one is compared. Strength and ductility of the undamaged and retrofitted specimens were compared. Behavior of confined specimen is also compared with the unconfined one. Effect of FRP wrapping is discussed as a viable option for restoring the strength of joints.