200 W MARINE VIEW DR Geotech Report 2025-08-07

October 16,2020 Project No. T-8221 5.7 Drainage Surface Final exterior grades should promote free and positive drainage away from the building areas. We recommend providing a positive drainage gradient for a minimum distance of ten feet from the building perimeter. If positive drainage cannot be provided in paved locations provisions for collection and disposal of surface water adjacent to the structure in trench drains should be made. Subsurface In our opinion,with the area immediately adjacent to the structure paved,and positive surface drainage maintained, perimeter foundation drains would not be necessary. If the grade is not positively drained away from the structure or is landscaped,perimeter foundation drains should be installed. 5.8 Utilities Utility pipes should be bedded and backfilled in accordance with American Public Works Association(APWA),or City of Everett specifications. As a minimum,trench backfill should be placed and compacted as structural fill, as described in Section 5.2 of this report. Most inorganic native and existing fill soils excavated on the site should be suitable for use as backfill material during dry weather conditions. However, if utility construction takes place during the wet winter months, it may be necessary to import suitable wet weather fill for utility trench backfilling. Depending on final utility grades, the utility contractor should also be prepared for encountering unstable soils below the pipe invert elevations. If not removed from below the pipe and replaced with crushed rock or additional bedding material,pipe deflections will occur as a result of the soil yielding and compressing in response to loading imposed by the trench backfill. 5.9 Pavements Pavement subgrades should be prepared as described in Section 5.2 of this report. Regardless of the degree of relative compaction achieved, the subgrade must be firm and relatively unyielding before paving. The subgrade should be proofrolled with heavy rubber tired construction equipment such as a loaded 10 yard dump truck to verify this condition. The pavement design section is dependent upon the supporting capability of the subgrade soils and the traffic conditions to which it will be subjected. We expect traffic at the facility will consist of cars and light trucks,along with heavy traffic in the form of tractor-trailer rigs. For design considerations,we have assumed traffic in parking and in car/light truck access pavement areas can be represented by an 18-kip Equivalent Single Axle Loading (ESAL) of 50,000 over a 20-year design life. For heavy traffic pavement areas, we have assumed an ESAL of 300,000 would be representative of the expected loading. These ESALs represent loading approximately equivalent to 3 and 18,loaded(80,000 pound GVW)tractor-trailer rigs traversing the pavement daily in each area,respectively. Page No. 9