J_2024 05 09_West Orange Stormwater Management Plan

August 8, 2022 File No. 26.0092704.00 PSE&G – West Orange, NJ Page 12 Proactive by Design It is our opinion that foundations designed and installed in accordance with our recommendations would experience post-construction settlements of 3/4 of 1 inch, or less. Seismic Considerations: Based on the regional geology, the subsurface conditions encountered in the explorations at the site and published geologic information, it is our opinion that the foundations for the proposed improvements can be designed using a Site Class “C” as determined by the International Building Code 2018, New Jersey Edition. Concrete Slab Design Criteria: Following the previously described site preparation procedures, any atgrade concrete slabs could be supported by the controlled compacted fill installed atop the natural soils. Due to potential variations within the existing fill materials, the existing fill would not be suitable for direct slab support and should be removed and replaced as necessary. We recommend that a minimum 6-inch-thick layer of porous fill consisting of clean 3/4-inch stone be placed beneath the slabs to provide a capillary break between the subgrade soils and the bottom of the concrete, and to help provide a stable working base during construction. A subgrade modulus of 150 pounds per cubic inch (pci) would be appropriate for design of slabs established atop the native clayey and silty soils, while a modulus of 200 pci would be appropriate for design of slabs established atop properly placed granular controlled compacted fill. We estimate that maximum post-construction settlements of lightly loaded slabs will be less than 1/4 of 1 inch. More heavily loaded transformer pads (if any are proposed) could experience greater total settlements which are estimated to be about 1 inch or less but could be confirmed when loads are available. An Equal Opportunity Employer M/F/V/H