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Phelan Development Holly Master Plan - Buildings H & 1 15188.000.006 Geotechnical Exploration 7.0 SLABS-ON-GRADE 7.1 INTERIOR CONCRETE FLOOR SLABS We anticipate that the operation of the distribution facility will include forklift and rack loads on the interior concrete floor slab. While no loading information was provided, we developed our recommendations assuming a lightly loaded industrial concrete floor. This would include only small racks and forklifts. Prior to construction of the slab, the surface should be proof-rolled with heavy equipment to check that the base material is uniformly compacted and does not deflect under equipment loads. Prior to placing the base material, the building subgrade should be prepared in accordance with Section 7.1.1. 7.1.1 Lime-Treated Subgrade Due to the high expansion potential of the near-surface soil, we recommend that the upper 18 inches of the building pad, and to 5 feet laterally beyond, should consist of imported low-expansive fill with a Plasticity Index less than 12. Alternatively, the upper 18 inches of the finished building pad and to 5 feet laterally beyond can be chemically treated to reduce the expansive potential of site soil. If chemical treatment is selected as an alternative to importing non-expansive fill for building pad construction, the type of chemical admixture (lime, quicklime, or cement) and percentage of chemical additive should be based on testing of actual foundation soil after mass grading is substantially completed. Based on our experience, for estimating purposes, we suggest chemical treatment with approximately 4 percent lime (by dry unit weight) may be appropriate to reduce the plasticity of the onsite soil. For quantities estimating, we suggest using a soil unit weight of 110 pcf. Chemical treatment should be performed by a specialty contractor experienced in this type of work. In addition, excavations performed in chemically treated soil, such as for utility trenches, should be stockpiled and protected for reuse in the upper backfill area to match the treated section. 7.1.2 Slab Thickness We recommend consideration be given to providing concrete floors with a minimum thickness of 6 inches; a thicker section may be needed depending on the actual loading conditions. Adequate slab reinforcement should be provided to satisfy the anticipated use and loading requirements. The structural engineer should provide final design thickness, concrete strength, and additional reinforcement for any structural loads, including forklift or rack loads. The contractor should notify and consult with the structural engineer if slab-on-grade floors will be subject to construction traffic or equipment loads. Additional slab thickness or reinforcement may be needed if the slab-on-grade floors are subject to construction loads. Post-construction cracking of concrete slabs-on-grade is inherent in any project. Adequate slab reinforcement and control joints should be provided by the structural engineer to satisfy the anticipated use and loading requirements. ENGEOPage 118 December 13, 2021 Expect Exceltence