CONCRETE OR FRP JACKETING OF CONCRETE COLUMNS FOR SEISMIC RETROFITTING

Experimental and analytical work is reported for jacketed concrete columns, including short lap splices at the base. 45 rectangular columns with smooth or ribbed vertical bars are subjected to cyclic flexure with constant axial load. Test parameters are the presence and length of lap splices and the type of retrofitting: concrete jackets over the whole column, or CFRP wrapping of the plastic hinge region at varying number of layers and height of application from the base. A 0.7:1 scale two-storey space frame was also pseudodynamically tested before and after retrofitting. Test results are supplemented with past data, to develop expressions for the yield moment, deflection at yielding and ultimate deflection in cyclic loading, for columns with concrete or FRP jackets, as a function of jacket parameters and the length of lap splice.