Systemized Structural Predesign Method for Selective Racks

Abstract

This paper presents a simplified stability-based method for practical structural predesign of down-aisle unbraced frames of selective racks. Given the uniformity of actual racks, only a single upright and its adjoining half beams were modeled, discretized with two-dimensional (2D) beam elements; the flexibility of the upright–beam and upright–floor connections was represented with linear springs. Such a model is used for linear buckling and second-order analyses. The proposed method consists of iteratively resizing the structural members according to cost and stability criteria (linear buckling analysis) until the serviceability limit state (SLS) and ultimate limit state (ULS) are satisfied (second order analysis). Specific procedures were developed to accelerate the computations. Two practical examples were analyzed to assess the performance of the proposed method. Compared with conventional design approaches for racks, the method was faster, and resulted in less-expensive structures. The simplification involved in the single-column consideration is sufficiently accurate. Some ideas about efficient methods of improving the stability of racks were presented.