|
Abstract
|
Structures in earthquake-prone areas are not subjected to a single seismic event, but also
to a seismic sequence consisting of mainshock and several aftershocks. However, the influence
of seismic sequence on performance of structures has not been addressed in majority
of existing seismic codes. This paper investigates the effect of repeated earthquakes on performance
of steel buckling restrained braced frames. For this purpose, 4-story and 10-story
prototype buckling restrained braced frames, designed according to Iranian building codes,
are exposed to five seismic sequences. Nonlinear time history analyses are conducted and
the responses of frames are measured in terms of maximum inter-story and residual drifts.
Furthermore, Park–Ang damage indices and global ductility factors are obtained for braced
frames under examined mainshocks and mainshock–aftershock sequences. From the results
of this research, it is found that the seismic sequence has the potential to increase the interstory
drift, residual drift, damage index and global ductility factor of buckling restrained
braced frames. It is also highlighted that the spectral acceleration of mainshock–aftershock
sequence, in comparison to that of single event mainshock, considerably affects the performance
of buckling restrained braced frame under repeated earthquakes.
|