Rehabilitation of shear critical concrete columns by use of rectangular steel jackets

This paper describes an experimental research program on the use of rectang ular steel jackets for seismic retrofit of nonductile reinforced concrete f rame columns with inadequate shear strength. Eleven large-scale columns wer e tested to examine the effectiveness of various types of steel jackets for improving the ductility and strength of columns with inadequate shear resi stance. Response of the columns before and after being strengthened with st eel jackets was examined. Several types of steel jackets were investigated including rectangular solid steel jackets and partial steel jackets. The te st results indicate that a thin rectangular steel jacket can be a highly ef fective retrofit measure for reinforced concrete columns with inadequate sh ear resistance.