Case Studies

With a strict deadline to deliver a detailed cost-estimate for a 20,000 SF mat slab foundation for a single-story industrial storage facility, Audet & Knight, contacted StructurePoint Engineering Services team for a simple, quick and accurate turnaround.

The structure utilizes multi-level racks to store materials weighing up to 40 kpa. Due to limited soil bearing capacity at the construction site, a pile supported foundation system was proposed: a design in which the foundation is a suspended concrete slab supported by augered concrete piles spaced closely under the slab. The rack loading (40 kpa) presents a significant challenge for two-way punching shear design due to the substantially heavy nature of the loading. A detailed evaluation of various structural options to support the load while optimizing member slab dimensions is required to achieve a cost-effective system.

spSlab was utilized to analyze and design the suspended mat slab using two design strips in each orthogonal direction per Canadian Standard (CSA A23.3-14). spMats was also used to model the entire mat slab to compare the Equivalent Frame Method (EFM) solution from spSlab to the Finite Element Method (FEM) solution obtained from spMats. Essentially, using both spSlab and spMats facilitated a comparative assessment of the suspended mat slab excluding the effect of soil support. The punching shear check feature of both programs allowed quick and accurate determination of the necessary slab thickness. Finally, the pile reactions calculated by spSlab and spMats were entered into spColumn to design the cross-sectional dimension and required reinforcement of the piles.

Despite limited soil bearing capacity and a substantially heavy load, StructurePoint Engineering Team utilized their software to propose an optimal foundation system for a multi-level rack by allocating strength where it is most effective resulting in a strong and nimble structure.