Geotechnical Engineering Report 12 10 2024 submission

Mavis Store #2296 December 10, 2024 ECS Project No. 44:2100 Page 7 4.0 DESIGN RECOMMENDATIONS 4.1 SHALLOW FOUNDATIONS A site grading plan including the proposed FFE was not provided and should be provided to ECS to confirm the recommendations included herein; however, we have assumed the FFE will be within 1 to 2 feet of existing grades. Provided subgrades and Structural Fills are prepared as recommended in this report, the proposed building can be supported by shallow foundations including column footings and continuous wall footings. We recommend the foundation design use the following parameters. DESIGN PARAMETER COLUMN FOOTING WALL FOOTING (1) Net Allowable Bearing Pressure 3,000 psf 3,000 psf Stratum II with SPT N- Stratum II with SPT N- Acceptable Bearing Soil Material value ≥ 5 bpf value ≥ 5 bpf or new Structural Fill or new Structural Fill Minimum Width 24 inches 24 Inches Minimum Footing Embedment Depth 36 inches 36 inches (below slab or finished grade)(2) Estimated Total Settlement (3) Less than 1-inch Less than 1-inch Less than 0.5-inch Less than 0.5-inch Estimated Differential Settlement(3) between columns over 50 feet Notes: (1) Net allowable bearing pressure is the applied pressure in excess of the surrounding overburden soils

between columns over 50 feet Notes: (1) Net allowable bearing pressure is the applied pressure in excess of the surrounding overburden soils above the base of the foundation. (2) Minimum footing depth recommended for frost protection. Interior foundations located within permanently heated portions of the structure may be established at conventional depths below the floor slab, provided that they are established within the intended bearing stratum. (3) Based on an assumed maximum column load of 50 kips and wall load of 3 kips per foot. When final design loads are determined, ECS must be contacted to update foundation recommendations and settlement calculations. bpf = blows per foot Potential Undercuts: As indicated in the above table, shallow foundations may be supported by Stratum II materials provided the material at bearing depth is homogeneous with at least an SPT N-Value of ≥ 5 or newly placed Structural Fill. It is important to have ECS observe and test footing subgrade prior to placing foundation concrete to confirm soil conditions are as anticipated (granular soil with SPT N-value ≥ 5 bpf) and consistent with our recommended foundation design parameters. The existing fill materials on the site do not appear to be suitable for support of the building foundations as they appear to be variable in both composition and strength (based on SPT N-values), therefore we recommend these materials be removed below foundation elements. As stated in the Executive Summary, it may be beneficial to perform test pitting within the building footprint to further evaluate the existing fill materials. Generally, existing fills are not suitable for support of foundations as the method of their placement and compaction effort (or lack thereof) is unknown, therefore, they maybe prone to settlements which are unpredictable. If existing fills, soft or unsuitable soils are observed at the footing bearing elevations, the unsuitable soils should be undercut and removed. Any undercut should be backfilled with lean concrete (f’ c ≥ 1,000 psi at 28 days) up to the original design bottom of footing elevation; the original footing shall be constructed on top of the hardened lean concrete.