Optimal design of conventional warehouse floors: concrete flooring solutions and racking anchors

In modern industrial warehouses, the concrete flooring slab is one of the main total cost components. Thus, designers of these structures are under a constant pressure to reduce the total slab cost, while maintaining the expected functionality and durability of the slab. Due to technological progress in last decades and innovations in the concrete industry, it is now possible to produce steel fibre reinforced self-stressing concrete (SFRSSC) floors, which are far thinner, while providing various advantages and performance improvements compared to traditional concrete floors [1]. One key aspect of warehouse floor design impacted by reductions in slab thicknesses is the design and detailing of anchors for warehouse racking systems. Commonly available design aids for anchors from suppliers have focused on embedment of anchors in traditional concrete floors, ignoring any potential benefits from embedment in SFRSSC floors. As reported in reference [2], a large series of anchor pull-out tests was recently completed on SFRSSC samples to develop characteristic design values for this new material combination. These results are utilized in this paper to complete a technological and economic comparison of alternative design solutions for three different example warehouse situations. For all examples, 20200 square m storage warehouses are assumed with load levels varying from a “lightly loaded” (60 kPa) warehouse, a ‘heavily loaded’ (160kPa) warehouse, and a high-bay warehouse. In the design examples, floors are designed according to the guideline TR34 for fibre reinforced concrete and ACI standard for plain concrete floors. Anchor pull out capacity data are obtained from tests and the Fastening Technical Manual (FTM). As presented herein, overall costs for the SFRSSC floor provide significant economic advantages due to reduced volume of concrete and associated reductions in production costs provided by a reduced slab thickness for the same loading. Comparison of the racking anchor detailing includes a limited direct cost impact of SFRSSC floors. Shorter anchors used for SFRSSC floors allow for faster installation per anchor.