This article presents experimental study performed on a first-of-its-kind frame fabricated using crumb rubber concrete, that is, concrete with waste rubbers (crumb) as a partial replacement of fine aggregate (sand). A 20% volume of sand was replaced by rubber crumb. Free vibration and shake-table tests were performed on 1:3 reduced scale frame models, both conventional reinforced concrete frame and crumb rubber concrete frame. The dynamic properties (i.e. frequency/time period, elastic viscous damping, and floor acceleration amplification) and seismic response parameters (i.e. ductility and response modification factors) were obtained. In addition, lateral displacement demand was correlated with peak base acceleration to derive seismic response curves. The seismic performance of crumb rubber concrete frame was compared with the conventional reinforced concrete frame in order to assess the feasibility of rubberized concrete for building constructions in areas of active seismicity. The following were concluded on the basis of experimental study: the elastic damping reduced by 12%, the initial time period increased by 6%, specific weight of concrete reduced by 6%, maximum lateral load reduced by 20%, lateral maximum story drift capacity increased by 30%, displacement ductility ratio increased by 2%, response modification factor reduced by 24%, maximum peak base acceleration resistance corresponding the incipient collapse state increased by 40%.
Hybrid shake table testing method: Theory, implementation and application to midlevel isolation
