THE EFFECT OF HORIZONTAL IRREGULARITIES AND BASE ISOLATION CONFIGURATION ON SEISMIC RESPONSE OF RC BUILDINGS

2022-2-22
Yazıcıoğlu, Eylem Bilge
This study aims to evaluate the effect of horizontal irregularities and base isolation configuration on the seismic response of reinforced concrete base-isolated buildings. A set of structural models with varying re-entrant corner geometric properties has been utilized to make evaluations with respect to square-symmetric ordinary form. In addition to this set, alternative models with non-uniform mass distributions in the plan have also been employed to expand the building set. Elastic response spectrum-based analyses have been performed to design the seismic isolation systems of the selected buildings with an iterative procedure considering the same target period and displacement. After finalizing the design stage, strong ground motion record suites compatible with three different target spectra have been compiled and utilized to perform nonlinear time history analyses. The numerical results of these analyses have been processed to display and assess the effects of horizontal irregularity and mass concentration on selected fundamental engineering demand parameters. It has been shown that as the level of irregularity increases, the fundamental engineering demand parameters –monitored in the irregularity direction- tend to increase as well, whereas this trend is not clear in the symmetry direction. Worsening site characteristics reflected via the target spectra and compatible ground motion records tend to amplify the responses. In addition to horizontal irregularity and mass concentration, the isolator configuration, which is deemed to have crucial interaction with horizontal irregularity effects, has been also examined for a specific building case selected from the main set. Alternative isolator schemes have been considered to reveal the group effect on the selected engineering demand parameters. The general conclusion of this study is that the base isolation system significantly reduces the adverse effects of irregularity on seismic response of the buildings, as apparently observed in fixed-base structural systems, yet it cannot completely eliminate them, especially at the roof level of the buildings.

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Citation Formats
E. B. Yazıcıoğlu, “THE EFFECT OF HORIZONTAL IRREGULARITIES AND BASE ISOLATION CONFIGURATION ON SEISMIC RESPONSE OF RC BUILDINGS,” M.S. - Master of Science, Middle East Technical University, 2022.