Seismic behavior of three dimensional reinforced concrete structures under multiple earthquake excitations

Earthquakes that occurred in Turkey and in many other regions in the world showed that many foreshocks and aftershocks occur before and after an earthquake. According to conventional codes, one earthquake scenario is taken into consideration and related design is established. Experiences reveal that even if structures provide required performance level during main earthquake, they cannot provide required strength and rigidity during aftershocks. Moreover, as a result of carried studies, it's seen that materials of structures which were exposed to effects of an earthquake, don't show the same behavior as they did before the earthquake. Within the context of this study, six buildings, three of which is regular and the three other of which are irregular, are evaluated under 11 March 2011 Tohoku earthquake series. Two different material models, which take into account stiffness degradation and strength deterioration, were used during the structural modeling. In addition, structures modeled with the material models, which have non-degrading effect. Comparison and assessment of the results of regular and irregular structures, was carried out with different material models under multiple seismic excitations.