مدل بررسی لرزه ای سازه های بتن مسلح قدیمی مقاوم سازی شده

Abstract:
In seismic areas, a majority of old RC buildings have only been designed for gravity loads or
according to outdated seismic codes. Before1970s, smooth rebars were also extensively used
in RC structures. As these buildings are still functioning, they need to be reassessed against
seismic demands. Load bearing behaviour of concrete structures reinforced with smooth
rebars is considerably affected by the slip deformation of the plain rebars. In this study, a
specific finite element model has been proposed for evaluating the seismic performance of
these structures. The slipping characteristics of smooth rebars have been incorporated in this
model. For this purpose, a tailored stress-strain property has been assigned to the steel fibers
in tension. The model has then been calibrated/verified against several sets of experimental
results from others. In general, satisfactory correlations have been noticed between the
experimental results and the predictions from the proposed fiber element model. The model
has also been used for a full seismic assessment of an existing RC building, having smooth
rebars. In addition, the structure has been retrofitted with steel bracing, viscose dampers and
base isolators' schemes and their nonlinear seismic performance has been evaluated using the
proposed model.