Conventional approaches to layout design of block stacked warehouses assume perfect staggering of product inflow leading to perfect sharing of space among products. Since such an assumption is seldom true, we argue that warehouses designed using the conventional approach may result in choking situations with large quantities of inventory waiting outside the storage areas. On the other hand, liberal space allocation such as in dedicated policy might lead to under-utilization of space. In this paper, we take a fresh look at the block stacked layout problem, modeling the effect of imperfectly staggered product arrivals using queuing theory. Analytical expressions are derived for arrival time and processing time coefficients of variation using warehouse parameters and design variables. Further, we develop a bi-objective optimization model to minimize both the space cost and waiting time. Our approach provides design options over a total space cost-waiting time trade-off frontier as opposed to singular design points given by conventional approaches. Computational experiments are conducted to derive further insights into the design of block stacked warehouses.

块状堆叠仓库的布局设计的传统方法假定产品流入完全错开，导致产品之间空间的完美共享。由于这种假设很少成立，因此我们认为，使用常规方法设计的仓库可能会导致窒息，导致大量库存等待存储区域之外。另一方面，诸如专门政策中的自由空间分配可能会导致空间利用不足。在本文中，我们重新审视了块堆叠式布局问题，并使用排队论对不完全交错的产品到达的影响进行了建模。使用仓库参数和设计变量得出到达时间和处理时间变异系数的解析表达式。进一步，我们开发了一个双目标优化模型，以最小化空间成本和等待时间。与传统方法给出的单一设计点相反，我们的方法在总的空间成本等待时间权衡边界上提供了设计选项。进行计算实验以得出关于块状堆叠仓库设计的更多见解。