304 SE EVERETT MALL WAY PANERA BREAD Geotech Report 2025-07-25

KA No.092-12004 August 24,2012 Page No. 14 Wall Design Criteria "At-rest"Conditions (Lateral Earth Pressure) 55 pcf(Equivalent Fluid Density)(Triangular Distribution) "Active"Conditions(Lateral Earth Pressure) 35 pcf (Equivalent Fluid Density)(Triangular Distribution) Seismic Increase for"At-rest"Conditions 15H* (Uniform Distribution) (Lateral Earth Pressure) Seismic Increase for"Active"Conditions 6H* (Uniform Distribution) (Lateral Earth Pressure) Passive Earth Pressure on Low Side of Wall Neglect upper 2 feet, then 250 pcf(Equivalent (Allowable,includes F.S.= 1.5) Fluid Density) Soil-Footing Coefficient of Sliding Friction 0.35 (Allowable; includes F.S.= 1.5) *H is the height of the wall; Increase based on one in 2,500 year seismic event (2 percent probability of being exceeded in 50 years) The stated lateral earth pressures do not include the effects of hydrostatic pressure generated by water accumulation behind the retaining walls or loads imposed by construction equipment, foundations or roadways (surcharge loads). To minimize the lateral earth pressure and prevent the buildup of water pressure against the walls, continuous footing drains (with cleanouts) should be provided at the bases of the walls. The footing drains should consist of a minimum 4-inch diameter rigid perforated PVC pipe, sloped to drain, with perforations placed down and enveloped by 6 inches of washed gravel in all directions and filter fabric to prevent the migration of fines into the drain. The backfill adjacent to and extending a lateral distance of at least 2 feet behind the walls should consist of free-draining granular material. All free draining backfill should contain less than 3 percent fines (passing the U.S. Standard No. 200 Sieve)based upon the fraction passing the U.S. Standard No.4 Sieve with at least 30 percent of the material being retained on the U.S. Standard No. 4 Sieve. It should be realized that the primary purpose of the free-draining material is the reduction of hydrostatic pressure. Some potential for the moisture to contact the back face of the wall may exist, even with treatment, which may require that more extensive waterproofing be specified for walls, which require interior moisture sensitive finishes. We recommend that the backfill be compacted to at least 95 percent of the maximum dry density based on ASTM Test Method D1557. In-place density tests should be performed to verify adequate compaction. Soil compactors place transient surcharges on the backfill. Consequently, only light hand Krazan&Associates,Inc. Eleven Offices Serving The Western United States