Seismic Performance Assessment of Soft-Story RC Frame Buildings

Year 2016, Volume: 11 Issue: 3, 241 - 248, 30.09.2016

Roberta Apostolska Golubka Necevska-cvetanovska Julijana Bojadzieva Elena Gjorgjievska

Abstract

Soft-story buildings are characterized by an inadequate stiffness or flexibility of the ground
floor, which is less resistant to horizontal seismic forces than the upper storys.
On the other hand, such inadequate stiffness causes disproportional
displacement focused on that story. As a result, the ground floor becomes weak
and susceptible to partial or complete damage to its structural elements, which
in turn, results in collapse of the entire building. The results obtained from
the performed linear and nonlinear push-over analyses show that the flexible story
may result in a drastic change of the period of vibrations, which will further
lead to a change of the seismic design force, the maximal relative story drifts
and ductility of the considered structure. Within this paper, the effect of the
flexible story on seismic performance of building has been explored through
comparison between a structure with regular story heights and a structure with
a flexible story. The effects of upgrading the critical story by appropriate structural interventions like enlargement of the base
columns cross-section and/or insertion of RC walls are also investigated.

Keywords

soft-story, seismic resistance, relative displacement, story stiffness, “pushover” analysis, strengthening, upgrading

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