Seismic damage assessment of steel storage racks subjected to subduction earthquakes using a simplified method

Abstract

The incremental dynamic analysis is procedure highly used in the evaluation of structural systems and seismic design parameters for the linear design methods traditionally used in current building codes. The use of this methodology has been extended to industrial structures; however, in the case of steel racks subjected to subduction earthquakes such as the one in Chile, the procedure presents limitations in the post MCE scaling stage due to the high seismic demand, which does not allow its use. In this research, the seismic evaluation of steel storage racks is studied using a dynamic decremental analysis (DDA). The numerical research aims at a methodology proposed to evaluate seismic damage in steel storage racks, considering operational continuity, life safety and collapse prevention levels. A total of 4840 nonlinear models were performed to establish the performance levels, supported by the principles of the IDA according to FEMA P695. The MCE is used to scale the seismic records, however, a decremental scaling process is applied to identify the performance gap between the design intensity and the MCE intensity. The results obtained showed that the archetypes with lower load levels and lower height exhibited higher performance levels in the down-aisle direction compared to the transverse direction. In addition, the proposed methodology allows obtaining a performance level considering the seismic forces scaled to the MCE level through a methodology on steel racks, which had not been possible to evaluate using the IDA. Finally, the main problem in the study of steel racks design is to ensure the stability in the cross-aisle direction and stability of the stored goods in that direction.