Abstract
Infills can highly influence the seismic response of a Reinforced Concrete (RC) building: generally speaking, their presence leads to an increase in global stiffness and strength, but their brittle behavior can result in an increase of displacement demand if a certain threshold of seismic intensity is overcome. Moreover, presence of infills often leads to a change in the collapse mechanism compared with the bare structure, leading, for instance, to column-sway storey mecha- nisms characterized by a detrimental localization of inelastic displacement demand. In this paper, a numerical investiga- tion of the influence of infills on the seismic behavior of a case-study existing gravity load designed RC building is car- ried out. Different infill configurations are considered (Bare, Uniformly infilled and Soft-storey infilled). Seismic capacity assessment is carried out by means of Static Push-Over analyses, within the N2 spectral assessment framework. A sensi- tivity analysis is carried out, thus evaluating the influence of main material and model parameters on seismic response at different Limit States, namely Damage Limitation and Near Collapse, mainly due to the change in parameters as effective period of vibration, base shear and displacement capacity.
Highlights
A growing attention is addressed to the influence of infills on the seismic behavior of Reinforced Concrete (RC) buildings
Infills can highly influence the seismic response of a Reinforced Concrete (RC) building: generally speaking, their presence leads to an increase in global stiffness and strength, but their brittle behavior can result in an increase of displacement demand if a certain threshold of seismic intensity is overcome
Collapse is almost coincident between the Uniformly infilled and the Pilotis frame since the collapse mechanism involve in both cases RC columns at the 1st storey; a lower displacement capacity of the equivalent SDOF is observed in Fig. (22a), due to the lower modal participation factor Γ for the Pilotis frame
Summary
A growing attention is addressed to the influence of infills on the seismic behavior of Reinforced Concrete (RC) buildings. The beneficial effect of the increase in Ew, Gw and τcr is due to fact that in his case the distribution of lateral forces is closer to a uniform distribution (this is reflected by the decrease in the modal participation factor Γ), leading to a higher initial stiffness of the pushover curve, resulting in lower values of Teff and Sdy, whereas the displacement capacity Δcollapse does not change significantly and, μcollapse increases, leading to higher values of Sae,collapse and PGAcollapse.
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