3606 W MUKILTEO BLVD 2016-01-01 MF Import

Gcotechnical Engincering Gvaluation Mukilteo Boulevard Dcvelopment EvcrMt, Washington March 31, 2003 NGA Filc No. 3G(50; Pngc 12 condition. Activic earth pressures and at-rest carth pressures can bc cakulated based on equivalent tluid density. Gquivalcnt fluid densitics for activc and at-rest carth pressurc of 35 pounds per cubic foot (pc� and GO pcf, respectivcly, mny be used far dcsign of a rctaining wall with a Ievel backfill. These values assume that granular soils arc uscd for wall backfill nnd that ihc backfill adjncent to the wall is ��ell-compacted and drained. 'I�he preccding values do not includc thc cfTects of surcharges such as those duc to foundation loads, vchicic loads, or othcr surfacc loads. Surchargc cffccts should bc considcrcd whcrc appropriatc. All wall backfill should be well-compactcd. Care should be taken to prevent the buildup of e�cess Interal soil pressures duc to ovcrcompaction of thc wall backfill. This can bc accomplishcd by placing wall backfill in 8-inch lifts within a distance equal to onc-half the hcigh[ of the wall. Compaction close to the �vnll shoidd bc accomplishcd with small, hnnd-operated compacrors. Pcrniancnt drninagc systcros should bc installcd for rctaining walls as describcd in the Subsurfacc Dr.�inagc subsection. SIa6s-on-Grudc Slnbs-on-gradc should bc supportcd on subgradc soils prcparcd as dcscribcd in thc Sitc Preparation nnd Grading subsection of this rcport. Wc reconunend that all tloor slnbs be underlain by at Ie�st 6 inches of frco-draining sand or gravcl for use as a capillary break. Wc recommend that the capillary brcak bc hydraulically connected to the footing drain system to allo�� fine drainage trum under the slab. A suitablc vapor barricr, such as henvy plastic slucting (6-mil minimum), should bc pinccd ovcr thc capillary brcnk matcrial. An additional 2-inch-thicl, sand blanket may be uscd to cover the vapor barrier. This sand blanket is to protcc[ thc vnpor barrier mcmbranc and to nid in curing the concrcte. I! will nlso prevent ccmcnt pastc lcaking do��n in�o thc capillar}� brcak through thc joints or tcars in thc vapor barricr. I'uvement Subgr•rdc I'avetnent subgrade prcparation, and structural filling �ehere rcquired, should be complcted as rccommended in the Site Prcparation anJ Grading and Structural Fill subsections of this report. 'fhc subgrade should be prooGolled ��ith a hcavy, rubbervtired picce of cquipment to identify soft or �icldiue arcas tliat requirc repair prior to placing thc pa��ement scction. Arcas that arc observed to pump or weavc NELSON GEOTECHNICAL ASSOCIATES, 1IYC.