2205 BROADWAY 2016-01-01 MF Import

-1 � LSI - ADAPT Site Preparatlon and General Earthwork Consideratlons Subseq•icnt to sitc excavation and razing existing structurcs,we recommmd�that footing subgrade areas end slab or parking areas which will receive structural fill be compacted in place tc densify any loose or disturbed areas. Soil in any loose or soft ateas, if compacted and still yiclding,should bc over-excavated and roplaccd with structural fill to a depth that will provide a stable subgrade. Slab-on-grade subgrades shoi�id be similazly prepared. We recommend using a backhoe-mounted plate compactor to adequately densify the footing subgrades, and a smooth drum roller for the slab-on-grade or pavement areas. We anticipate site excavation could be accomplished using conventional earth moving equipment Based upon the soils encountered in the test borings, ovcrsize materials, exclusive of remnant building foundations, are not anticipated on the property. Remnant building foundations arc a.uicipated across the site, together with LII soi!s associated with prcvious site developmcnt. We recommend the existing foundations, subgrade walls, floors, and parking slabs be removed prior to fill placcment. The concrctc materials may be processed and ctushed, if desimd, and reused on the site for backfill. The decision to dispose of the coucrete debris or to crush and reuse the concrete as backfill can be baseci on economic considerations. The existing concrete will need to be ctushcd to a maximum 3-inc6 size for backfill use. We recommend the use of civshed concrete be limited to deeper sile excavations and the concrete debris fill be cappcd by at least 3 feet of mineral soil. We expect lhat grading at the subjcct site can be accomplished with convcnlional eartivnoving cquipmen[. The near surface site soils have a significant fines contcnt and are therefore moisture sensitive. These materials may be diflicult, if not impossible, to operalc on or compact during �vet wcather conditions. Thc operation of heary equipment at the site, except after an extended period of dry weather conditions, can be cxpected to result in consideraUle diswrbance of the cxposed subgrade soils. During wet weather conditions, we expect that operation of hea�y-wheeled cquipment at lhc site �vill be dif'ficult. We therefore recommend that carth�vork be undcrlakcn folloH�ing and during dry wcathcr conditions, if fca;iUle, to minimizc grading costs. Structural Fill Structural fill is defined as any compacted fill placed under buildings, roadways, slabs, pavements, or any othcr load-bearing arws. Shvctural fll ptaced under footings and floor slabs shculd bc placed in horizontal IiRs not cxcceding 12-inches in ioose thickness and compacted to a minimum of 95 percent of its laboratory maximum dry density, detertnincd in accordance e�ith ASTM Test Designation D-1557 (Modified Proctor). The fill materials should bc placed at or within 2 percent of the optimum moisture content. Fill undcr pavements and walks shoiQd also be placed in horizontal IifLc and compacted to 90 percent of maximum density, except ;or thc top 12-inchcs which shoulu be compacted to 95 percent of ma�imum density. During dry weather, most non-organic soils can be used as structutal fi!1. Generally, soil �vith more lhan 5 percent fines �an become unstable if cxposed to construction traffic in the presencc of excessive moisture, and compaction and grading will be difficult if the soil moisture increases significantly above its optimum condition. If consWction �ail1 6e completcd during wet�vcather LSI-ADAP7 Job No.WA02-8121 PaeB/3` August6,2D02