2410 RAILWAY AVE Geotech Report 2023-04-06

Penske Truck Leasing—Proposed Service Facility,2410 Railway Ave,Everett,WA Mar.8,2019/Rev.Feb. 25,2020 Geotechnical Engineering Report P1493-T18 Bearing Pressures: In our opinion, for static loading, footings that bear on properly prepared, structural fill bearing pads 2 feet thick can be designed for a preliminary allowable soil bearing pressure of 1,500 psf. A one-third increase in allowable soil bearing capacity may be used for short- term loads created by seismic or wind related activities. ' FootingBackfill: Toprovide erosion protection and lateral load resistance,we recommend that all footing excavations be backfilled on both sides of the footings and stemwalls after the concrete has cured. Either imported structural fill or non-organic onsite soils can be used for this purpose, contingent on suitable moisture content at the time of placement. Regardless of soil type,all footing backfill soil should be compacted to a density of at least 90 percent(based on ASTM:D-1557). Lateral Resistance: Footings that have been properly backfilled as recommended above will resist lateral movements by means of passive earth pressure and base friction. We recommend using an allowable passive earth pressure of 225 psf for and an allowable base friction coefficient of 0.35 for site soils. 4_4 Augercast Pile Foundations Based on the soil conditions disclosed in the supplemental test borings, the planned structure can also be supported on augercast piles installed to depths of 35 feet below the existing ground surface in the medium dense to dense sand layer. The following tables provide estimated allowable design capacities for 14-, 16-,and 18-inch-diameter augercast concrete pilings installed to this embedment depths: TABLE 2 RECOMMENDED ALLOWABLE PILE CAPACITIES 14-,16-,AND 18-INCH-DIAMETER AUGERCAST CONCRETE PILES Pile Diameter Embedment Depth Downward Capacity Uplift Capacity (inches) (feet) (tons) (tons) 14 35 30 11 16 35 37 13 18 35 45 15 The allowable pile capacities presented above apply to all long-term live and dead loads and may be increased by one-third when considering short-term loads such as wind or seismic influence. The allowable pile capacities are based on the strength of the supporting soils for the penetrations indicated and include a factor of safety of at least 2.5. The allowable uplift capacities indicated for augercastpiles maybe usedprovided that a reinforcingbar is installed the entire length of the pile. g g This bar should be centered in the pile. Down drag loads could reduce the above pile capacities if 2 feet or more of fill is placed to raise site grades during or after pile installation. We recommend that all site fill be placed well in advance of pile installation. Pile settlements are expected to be essentially elastic in nature and occur as loads are applied. Total settlement of piles constructed as recommended are not expected to exceed 1 inch,while differential Migizi Group, Inc. Page 11 of 17