Influence of floor system on seismic behavior of RC buildings to forward directivity and fling-step in the near-fault region

Abstract

The pernicious effect of far-fault and near-fault earthquake records on the seismic behavior of concrete structures has been studied widely. In addition, several research works have been carried out to investigate the influence of forward-directivity and fling‐step, as unique characteristics of the near-fault motions and not observed in the far-field, on the seismic response and damage of high-rise buildings. This paper focuses on seismic response demand and damage of building structures having different floor systems and subjected to two types of near-fault records with pulses. For this purpose, three-dimensional nonlinear finite element models were developed in ETABS. In addition, fourteen earthquake motions, with characteristics representing forward-directivity and fling-step, are selected to excite the developed models using nonlinear time-history analysis. Two damage models are employed in the study to capture the damage indices associated with each type of slab and earthquake. The compared results from the analysis revealed that floor system significantly influences the induced story responses as well as the level of damage of the buildings. Regardless the type of floor, findings from the study also revealed that response demand and damage index values were magnified for fling-step rather than forward-directivity motions leading to more severe damage to buildings.