02-16-2016 Planning Commission Packet

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land ventures I,uC Land Ventures I,LLC Project B14-0B095 Projea 814-08095 Nwem6er 19,2014 Novemher 19,201a Page 8 Page 9 D.2.b. Subgrade lmprovement . Tabic 2.Compactton RecanmendaNma Summary Atthough fat clay sops were only encourroered by Boring ST-2,thesQ solfs can alsa be found In other parts Relative tompadian,percent Molature tontent VarixKe from of the ske.These so)Is are consldered wsteptible to valume diange with change in mo[sture rnnter�.If pefennae (ASTM o 698-dtand�rd Pmctor} Oprimun,perc�patRcs they remafned oonfined below at least 2 feet o{lean day or ather mineraf sdl,and heve suflkient Below faindatfons,kss than -1 ta+3 fa clay soiFs 10 feet of fill 95 t 3 for sandy soils sttuctural strength,these sotls wUl ISkely be sultable to leave in place below arry structures.However,ff eelow foundatbns,grea�r than � -1 to+3 for clay sals �5O�e�P�xM�hin 2 feet of future faotings or slabs,Mey shouid be removed and replaced 14 feet of ftM t 3 for sandy sdls with lean clay or uttier mineral sal such that e 2-foot separetbn remalns betwee�the fat day pnd 9elaw slabs gg -i to+3 tor clay soils bottom oE house foatfngs. t 3 for sardy sdls eelow pavements,within 3 feet 1� -1 to+2(or clay so11s ff a small amount of groundwater Ls present wiUtin the footing excavatloq,or if tfie fpotlng subgrade soils of top of subgrade elevaYwns t 3 fa sandy soils becpme disturbed prior to placf�g forms or reinforoement,uye recommend subcutting the soR or wet eelow pavemencs,more than 3 feet 95 -1 m+3 for clay soils clay and plaang a 5-to&Inch layer of clear rock.The clear rock wfll rwide a sbbie worMng surface,and bebw subgrede elevatlons t 3 for sandy soils p -3 to+5 for cla soils« will altow fnr the flow of water to a drain tlle or sump pump. Below lands�ped surfaces' �' t 5 for sandy soils 'ERrytforwellbaddll.SeeSectbnD.3ofMlsreport. D.Lc NetAllowable8earingp�essure We reoommend sizh�spread footl�s to exert a nei allawab{c bearing pressure of up to 2,000 pounds ff flll depths exceed 10 feet,the minimum compacdon requireme�rt stwuld be lncreased to 98 percent.As per square foot(psfJ.This value indudes a saftty fac[or of at least 3.0 with regard to bearing capatity noted above,If filf depths exceed 10 fcet,a constructEon delay may also be necessary to allow the flll to failure.The net alfowable bearing pressure can be lncreased by one-third its value for ocwsianal consolidate under Its ovm welght.Constructbn delays can rartge from 3 to 6 months or longer, t��m loads,but nat for repetitive loads due to trafflc,or for other live loads from snow or accupancy, deperding on the depth and type of fili plated.We recommend Qladr�settlert�ent plates on lots wherc a constnution delay fs roquired to alfow for perlodk monitoring.We recommend monitoring tlx �•Z•d Settlemerft settlement plates once a week during thc first mortth,once every other week for the secnnd month,a rd We estimate that total arxt differential setdements among the footings w(II amoum to te.ss than 1 and once a month tl►ereafter until the settkment rate has declined to within tolerable ranges. 1/2 inch,respedhrely,under the assumed bads. In areas where more than�0 Teet of flll are plxed, greater settlements could occur it a constructlon detay is not o6served. If the construdfo�schedule is such that a rnnstnxtlon delay cannot be tokrated,sand tontalning tess than 12 percent of fine-graaud mater{al(slk or clay},can be placed to within SO feet of the bottom of �•3. Basemerrt Walls footing elevation.Sar�soils consolidate much quidcer than day soils,and the majority of consolidation will likely be comp{eted during construction of the lot. The fallowing sections address soii parameters for basement wall design_Although oorrstruct�on of retaining walls has not been specifted for this proJect to date,the folbwing recommendatlons pn aLso be used for retaining wail design. o.z. spread Footiags D.3.a. Drainage Corrtrol D.2.a. Embedment Depth We recommend installing subdrains behind the basement wa115,adJacent to d�e wall footiregs,below the For frast protection,we recommend embedding perimeter footl�s 421nches below the lovvest exterlor slab elevatlon.preferebfy the subdrains should rnnsist of perforated pipes embedded in washed revel, grade.interiorfootlngs may be placed diredly below floor siabs.We recommend emhedfing buildirig P footings not heated during winter constrt►cti�,and other unheated footkigs associated witt�porches, which in turn is wrapped in hlter fatrric.Perforated pipes encased in a fltter"soclt and embedded in washed gravel,however,may also be considered.We recommend routlng the subdrains to a sump and dedcs or stoops 60 inches below the lowe.st exterior grade. pump capable ot routing any accumulatad groundwater to a sukable disposal site.