DRAFT <br />The following sections of this report provide our preliminary geotechnical <br />recommendations for design and construction of new foundations for the project. These <br />recommendations will be updated when additional foundation design information is <br />available, where appropriate. <br />5.4.2 Spread Footings <br />In our opinion, spread footings established in the gravel and cobbles that mantle the site <br />can be designed using a maximum allowable bearing pressure of 7,000 pounds per square <br />foot (psf). This value applies to the total of dead load plus permanently and/or frequently <br />applied live load and can be increased by one half for the total of all loads: dead, live, and <br />wind or seismic. All spread footings should be established at a minimum depth of 2 feet <br />below the lowest adjacent finished grade. The footing width should not be less than 4 feet <br />for isolated footings and 3 feet for continuous footings. Adjacent footings should typically <br />be provided with a minimum center-to-center spacing of at least two footing widths (clear <br />spacing of at least one footing width), and any footings in closer proximity should be <br />reviewed by GRI on a case-by-case basis. We estimate the total settlement of isolated and <br />continuous spread footings designed and constructed following the recommendations <br />provided herein and supporting permanently applied loads of up to 600 kips and 40 <br />kips/foot, respectively, will be less than about 1 inch. Differential settlement between <br />adjacent, comparably loaded footings should be less than half the total settlement. Our <br />experience indicates settlement will occur relatively quickly as load is placed on the <br />footings. <br />5.4.3 Mat Foundations <br />In our opinion, mat foundations measuring up to 50 feet wide that are established in the <br />gravel and cobbles that mantle the site can generally be designed using maximum average <br />and peak allowable bearing pressures of 2,500 psf and 4,000 psf, respectively. However, <br />the actual allowable bearing pressures used for design will depend on the distribution of <br />loading on the mats and tolerable settlements, which should be reviewed by GRI during <br />design. These values apply to the total of dead load plus permanently and/or frequently <br />applied live load and can be increased by one half for the total of all loads: dead, live, and <br />wind or seismic. All mat foundations should be established at a minimum depth of 1.5 feet <br />below the lowest adjacent finished grade. Any mat foundations with a significantly greater <br />embedment depth should be reviewed by GRI on a case-by-case basis, as a lower <br />allowable bearing pressure may be appropriate based on settlement considerations. <br />Depending on the actual distribution of permanently applied loading on the mats, we <br />estimate the total settlement of mat foundations designed and constructed following the <br />recommendations provided herein will be on the order of 1 inch, which should be reviewed <br />by GRI during design. Differential settlement between adjacent, comparably loaded mats <br />could be up to about half the total settlement. Differential settlement across individual <br />GRI #6497-A - 2.M0 Indoor Football Practice Facility Page 14 <br />August 26, 2021 <br />