Seismic Reliability of a Steel Rack Structure with Various Mass Eccentricities

摘要

The paper examines the seismic reliability of an existing externally braced steel frame rack structure and analyzes the effects of mass eccentricity on the seismic response of such structures. The seismic performance has been analyzed by using nonlinear dynamic analysis, while the effect of mass eccentricity has been parametrically studied by means of nonlinear static (pushover) analyses. Various asymmetric variants with different realistic distributions of the payload mass and levels of occupancy have been considered. The results have shown us that certain mass eccentricities might increase the level of seismic risk, because they obtain considerable levels of damage in the supporting columns of the rack structure, which can lead to local instability of some essential structural parts. The paper concludes that a certain accidental eccentricity in correlation with the design occupancy level must be taken into account in the analysis and design of such structures.