Studies on RC and Ferrocement Jacketed Columns Subjected to Simulated Seismic Loading

It is known that large inelastic deformation limits of individual members allow entirestructures to endorse severe ground motion while dissipating significant levels of seismicenergy. Plastic hinge formations associated with lateral displacement excursions is favoredin beams and girders rather than in columns to ensure that the overall structural integrity is not compromised. Plastic hinges can occur in columns, however, particularly at the base of multistory frames and bridges where incurred, damage acts to dampen seismic forcesconsiderably. Ductile behaviour is hence essential at these crucial sites to prevent complete structural collapse under sustained loading. The structural response during earthquakes have indicated that the majority of the column failures was caused by high shear stresses, insufficient transverse reinforcement rendering those members ineffective at dissipating seismic energy and inadequate ductility rapidly leading to failure. Typical procedures to compensate for the deficiencies involve external retrofitting of these columns. Recent research works1,2) have indicated that ferrocement jacketing may be used as an alternative technique to strengthen RC columns with inadequate shear strength. The present objective is to complement the earlier work of the authors3,4,5), on the use of ferrocement jackets for seismic retrofit of non-ductile reinforced concrete columns with inadequate shear strength. The response of R.C and ferrocement retrofitted columns to seismic loading was examined under three different axial load ratios.