Numerical investigations on seismic performance of steel buildings

The performance-based approaches in current seismic codes based on the plastic deformations of structural elements. Thus, member damages can be assessed and total/partial collapse of structures can be prevented. However, the post-earthquake reconnaissance reports and studies have shown that if the residual drifts in buildings exceed certain limits, buildings may become unusable. Therefore, it is crucial to evaluate the performance criteria in current approaches in conjunction with residual drifts. In this study, the adequacy of performance targets stipulated in the 2018 Buildings Earthquake Code of Türkiye (BECT) was evaluated in terms of residual drifts for steel buildings designed according to the code. The evaluations were performed on two, four, and eight-story steel building models. The structural systems of the buildings consist of moment-resisting frames (MRF) in one direction and concentrically braced frames (CBF) in the other direction. Performance criteria described in the BECT were used for the evaluations and ASCE/SEI 41-17 modelling properties were used for nonlinear analysis.The buildings were analyzed using nonlinear static procedure (NSP) and nonlinear dynamic procedure (NDP) for design level earthquake and maximum earthquake level. The performance targets of the BECT were satisfied for all buildings. In general, the plastic deformations in the bracing members of the CBFs of the buildings were effective in determining the global performance level. Plastic deformations in the MRFs of the buildings were obtained quite low compared to those of CBFs even at maximum earthquake level. It was concluded that the performance criteria in the BECT were adequate in respect to the residual drifts at the design level earthquake. However, there is a risk of exceeding the residual drift limit for the MRFs of the buildings the at maximum earthquake level.