3003 W CASINO RD BLDG 45-12 2016-10-20

777X Static Test Building I 11 Use of On-Site Soil as Structural Fill Our explorations indicated that the near-surface site soil includes silty sand;this material may only be used for structural fill if it is near the optimum moisture content. Based on our laboratory testing,the material is near the optimum range for compaction and could likely be used during dry weather construction in areas outside of the building and structural slab footprint(e.g.,filling the stormwater pond). Any on-site soils used for structural fill should be free or organic and other deleterious material. The majority of the project grading consists of removing soil from the site. Temporary Cuts All temporary soil cuts associated with site excavations(greater than 4 feet in depth)should be adequately sloped back to prevent sloughing and collapse, in accordance with Occupational Safety and Health Administration (OSHA)guidelines. If temporary sloping is not feasible based on site spatial constraints,the excavation sides should be supported by alternate methods. Because of the variables involved, actual slope grades required for stability in temporary cut areas can only be estimated before construction. We recommend that stability of the temporary slopes used for construction be the sole responsibility of the contractor,since the contractor is in control of the construction operation and is continuously at the site to observe the nature and condition of the subsurface. Excavations should be made in accordance with all local, state,and federal safety requirements. The stability and safety of open trenches and cut slopes depend on a number of factors, including: ■ Type and density of the soil; ■ Presence and amount of any seepage; ■ Depth of cut; ■ Proximity of the cut to any surcharge loads near the top of the cut,such as stockpiled material, traffic loads,structures,etc.; ■ Duration of the open excavation; and ■ Care and methods used by the contractor. According to OSHA guidelines, loose granular soil and soft cohesive soil (Type C soils) require a cut slope inclination no steeper than of 1.SH:1V,while aslope inclination no steeper than 1H:1V is typically allowed for dense granular or medium stiff to stiff cohesive soils(Type B soils). At this site,the sand should be considered Type C material, and the glacial till should be considered a Type B soil. These guidelines are intended for planning purposes only. If groundwater seepage is encountered within the excavation slopes,the cut slope inclination may have to be flatter than 1.5H:1V. However, appropriate safe inclinations will ultimately depend on the actual soil and groundwater seepage conditions exposed in the cuts at the time of construction. It is the responsibility of the contractor to ensure that the excavation is properly sloped or braced for worker protection, in accordance with OSHA guidelines. ALK 19106-01 HAffCROWS ME May 29,2015