SEISMIC RESPONSE OF REINFORCED CONCRETE BUILDING WITH VISCOELASTIC DAMPER UNDER NEAR FIELD EARTHQUAKE

Near-field earthquakes are characterized by short duration pulses of long periods with large peak ground velocities and accelerations. Recent studies have shown that the performance of passive energy dissipation systems depends significantly on the characteristics of near-field ground motion pulses. This paper is focused on the viscoelastic (VE) dampers to be used as energy-absorbing devices in buildings. Detailed and systematic investigation on the performance of passive energy dissipation systems during near-field ground motions has been carried. The analytical studies of the model structures exhibiting the structural response reduction due to these VE devices are presented. In order to exhibit the benefits of VE dampers, a nonlinear time history analysis is carried out under strong ground motion records from near-field and far-field earthquakes for all case studies: (a) a 5-story, (b) a 10-story and (c) a 15-story reinforced concrete building. The top story relative displacements as well as the top story absolute accelerations and also the base shear values obtained indicate that these VE dampers when incorporated into the super-structure reduce the earthquake response significantly in proportion to the amount of damping supplied in these devices. Reduction response of structure in 5 and 15 story building is harmonic but in 10 story building, there is no harmony in response of structure. Overall, the highest reduction has been achieved in 5 story building with an average reduction of 100%. Additional viscous damping is suggested as a way to control very large displacements. In order to be effective for mitigating the effects of large near fault motions, large damping values would be required