Analysis of Slab-on-Grade Floors Subject to Slab-Mounted Jib Cranes

Abstract

Free-standing, foundationless jib cranes mounted directly on unreinforced slab-on-grade floors are a common necessity in industrial settings for material handling purposes. Ensuring that existing slabs can support a jib crane is critical, as industrial floors are subject to stringent serviceability requirements. Sudden slab failure can result in dropped loads and the loss of life. The installation of such cranes is typically based on rules of thumb, and no design standards or guidelines currently exist. Slabs-on-grade are typically designed for vertical compressive forces stemming from vehicle wheel loads or storage rack posts; however, a slab-mounted crane transfers both compressive forces and an overturning moment to the slab. In this study, a parametric analysis was conducted by simulating finite element models to investigate the behaviour of unreinforced slab-on-grade floors under foundationless, freestanding crane loads. Statistical methods were used to develop a non-linear model capable of predicting the capacity of such slabs. In particular, for the range of practical values considered in the study, it was found that the slab thickness, concrete strength, and baseplate size were critical parameters greatly affecting the capacity of such slabs. This research provides more confidence and safety when checking the installation and operation of such cranes on plain slabs-on-grade.