1010 N BROADWAY STARBUCKS Geotech Report 2025-07-24

Geotechnical Engineering Evaluation lierracon Broadway& 10th Starbucks Everett, WA January 9, 2014 -- Terracon Project No. 81135080 Also, final site grades should be sloped so that surface water flows away from the building rather than ponding near the foundation walls. Drainage Discharge: All water collected by the interceptor drain, foundation drain, catch basins, and other on-site systems should be conveyed to an off-site municipal storm drain, sewer, or other appropriate discharge location. As previously mentioned, the subsurface soils do not appear suitable for on-site infiltration of stormwater. 5.6 Pavement Sections We anticipate that some combination of flexible and rigid pavements will be used in new parking lot and drive-through lane. Up to 3 feet of existing granular fill soils were observed in our borings throughout the site. Fill by nature can be highly variable and could vary greatly between sample locations, though due to the granular composition and limited depth encountered in our explorations, in our opinion recompaction of at least the upper 12 inches of existing fill materials would be sufficient to mitigate the risk of excessive and differential pavement settlements. The following comments and recommendations are given for pavement design and construction purposes. Soil Design Values: Soil conditions can be defined by a California Bearing Ratio (CBR), which quantitatively predicts the effects of wheel loads imposed on a saturated subgrade. Although our scope of work did not include a CBR test on the existing surficial granular fill soils, we infer from our limited textural testing that a CBR value of 10 to 15 would likely be appropriate for pavement design purposes if the existing fill soils are left in place and the upper 12 inches are compacted prior to placement of additional fill or base course. A CBR value on the order of 20 would be appropriate for base course and pavement sections constructed directly on the native glacial till soils. Traffic Design Values: Traffic conditions can be defined by a Traffic Index (TI), which quantifies the combined effects cf projected car and truck traffic. Although no specific traffic data was available at the time of our analysis, we estimate that a TI of 3.0 to 4.0 would likely be appropriate for the drive-through lane or adjacent parking areas. A slightly higher TI of about 5.0 appears appropriate for an access driveway subjected to daily deliveries by small freight trucks, but this does not accommodate frequent use by heavy freight trucks. Flexible Pavement Sections: A flexible pavement section typically comprises an asphalt concrete pavement (ACP) over a crushed aggregate base (CAB) over a granular subbase (GSB). Although the GSB can be omitted in certain cases, we infer that it is beneficial at this site in order to mitigate the moisture-sensitive subgrade conditions. Our recommended minimum thicknesses for flexible pavement sections, which are based on the aforementioned design values and a 20-year lifespan, are shown below. Reliable Responsive 4. Convenient - Innovative 11