Geotechnical Engineering Report 12 10 2024 submission

Mavis Store #2296 December 10, 2024 ECS Project No. 44:2100 Page 14 Prior to re-use of on-site soils, representative bulk samples (about 50 pounds) of the material should be submitted to ECS for laboratory testing, which will typically include Atterberg limits, natural moisture content, particle-size distribution, and moisture-density relationships (i.e., Proctors) for compaction. Compaction requirements for on-site soil re-use will be the same as Structural Fill compaction requirements stated above. 5.2.4 Excavation Considerations All excavations and slopes should be constructed and maintained in accordance with OSHA excavation safety standards. The contractor is solely responsible for designing, constructing, and maintaining stable temporary excavations (both sides and bottom of the excavations) and slopes. The contractor’s responsible person, as defined in 29 CFR Part 1926, should evaluate the soil exposed in the excavations as part of the contractor’s safety procedures. In no case should slope height, slope inclination, or excavation depth, including utility trench excavation depth, exceed those specified in local, State, and Federal safety regulations. ECS is providing this information solely as a service to our client. ECS is not assuming responsibility for construction site safety or the contractor’s activities; such responsibility is not being implied and should not be inferred. 5.3 EARTHWORK AND FOUNDATION OBSERVATIONS Subgrade and Engineered Fill: Due to the presence of very loose and loose subgrade, some of the soils at the project site are anticipated to be unsuitable. As such, it is important to have ECS observe proofrolling and test subgrade compaction prior to engineered fill placement to document the soil conditions and the extent of any undercutting necessary. Additionally, it is important to have ECS observe, test, and document the as-placed moisture content and density of engineered fill on a full-time, lift-by-lift basis for conformance with our recommendations. Footing Subgrade: To ensure the soils at or below footing bearing elevations are to be suitable for support of the new building, it is important to have ECS observe, probe, and test the footing subgrade prior to placing

o ensure the soils at or below footing bearing elevations are to be suitable for support of the new building, it is important to have ECS observe, probe, and test the footing subgrade prior to placing foundation concrete to document the bearing soils are what was anticipated and the extent of undercutting necessary. As previously noted, the existing fills are most likely not suitable for support of foundation elements, therefore, the bearing materials will need to be carefully evaluated prior to concrete placement to confirm the bearing materials meet the requirements provided herein. Protection of Foundation Excavations: Exposure to the environment may weaken the soils at design subgrade elevation if the excavations remain open for too long a time. Therefore, foundation concrete should be placed the same day that excavations are made. If the bearing soils are softened by surface water intrusion or exposure, the softened soils must be removed from the foundation excavation bottom immediately prior to placement of concrete. If the excavation must remain open overnight, or if rainfall becomes imminent while the subgrade is exposed, a 1 to 3-inch thick “mud mat” of “lean” concrete should be placed on the subgrade soils before the placement of reinforcing steel. 5.4 UTILITY INSTALLATIONS Utility Subgrades: The soils encountered in our exploration are expected to be generally suitable for support of utility pipes and conduits. The subgrade for utility excavations should be observed and probed for stability by ECS. Any soft/loose or unsuitable materials encountered at the subgrade elevation should be removed and replaced with suitable compacted Structural Fill or bedding material. Utility Backfilling: We recommend granular bedding material (e.g., AASHTO No. 57) be at least 4 inches thick, but not less than that specified by the civil/site engineer’s project drawings and specifications.