Enhancement of lateral capacity of damaged non-ductile RC frame using combined-yielding metallic damper

Abstract

Non-ductile reinforced concrete (RC) frames are vulnerable to severe damagesor complete collapse under seismic excitations. Several such deficient RC frames are prevalent in the moderate-to-high seismic regions of India. In order to improve theirseismic performances, suitable strengthening schemes should be adopted. The use of passive energy dissipation devices in the seismic strengthening technique is consideredas an efficient and cost-effective solution. In this study, a reduced-scale single-bay single-storey damaged RC frame specimen was retrofitted with the combined-yielding metallic dampers (CMD). In addition, the damaged beam and columns were strengthened using steel elements. The retrofitted frame was experimentally investigated under aconstant gravity load and graduallyincreased reversed-cyclic loading. The test specimen was tested up to 6.0 % drift level. The RC frame exhibited better hysteretic respons with mild pinching. Unlike other metallic devices, CMD was capable of dissipating hysteretic energy through the flexure and shear yielding of metallic plates. The main parameters investigated are lateral strength, ductility and hysteretic response Test results showed that the proposed strengthening technique significantly enhanced the lateral strength and ductility.