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HomeMy WebLinkAboutGeotechnical Engineering Study 02.16.2010Tu*hBri unb þøøøúatvø CONSU LTING GEOTECHNICAL ENGINEERS AN D MATERIAL TESTING GEOTECHNTC/\L ENCINEERTNG STUDY STEEL BUTLDING, VAULTS, PONDS AND ON*SITE IND]VTDUAL SEWAGE DTSPOSAL SYSTEM CGRS PROJECT NO. L-L02i 0-1_L127 aa NE]./4, NË1 / 4 , SL'2, T7S, R93W RIFIJE, COLORADO Prepared for LLr.lf 5 PROJECT NUMBER: G09033cE FEBRUARY 16, 201.0 "Copyright @ Terra Firma Consultanls, Tnc. 2009" all rights reserved p.0. 80x 3986 GRAND JUNCTION, CO 81502 (e7o) 24s6506 FAx: (970) 248-97s8 P. O. BÕX 0043 MONTROSE,CO 81402 (e7o) 243-2154 F,Ax: (970) 249-3262 Tw*htúænil þøønúatw CONSULTING GEOTECI.INICAL ENG I NEERS AN D MATEH IAL TESTI NG CGRS P. O. Fort Box 1498 . Collins, Colorado 80522 February 16, 2010 P. O, BOX 0045 MONTROSE, CO 81402 (970) 249-21 54 FAXr (970) 24s-3262 Attention: Mr. Paul Sorensen, P.E PN: G09033cE Subject: Geotechnical Engineering Study for Lhe Proposed Steel Building, Vaults, Ponds and On*Sit.e Individual Sewagie Disposal System NEI-/4, NEI-/4, SLz, T7S, R93W nifle, Colorado Mr. Sorensen Lambert and Associates is pleasecl to present. our geotechnical enqineeríngr study for t.he subject projecL. The fietd study was completed on December 23, 2009. The laboratory study was complet,ed on Jart.uary 22, 20L0 . The analysi-s was perf ormed and the report prepared from .Tanuary 25 Lhrough February 1-6, 2010. Our geotechnícal engineering report is attached. We are available to provide material t.esLing services for soil and concrete and provide fourrdation excavation observat.ions during construction. We recomrnend that. Lambert and AssociaLes, the geotechnical engrineer, for t.he project provide material testing services to mainLain continuity between design and construction phases. If you have any quesLions concerning t.he geotechnical engineering aspect-s of your project please contact us. Thank you for the opportunity to perform thi-s study for you. Respectfully submiLLed, LAMBERT AND ASS Danie LamberL, P.E P. O. BOX 3988 GRAND JUNCTION, CO 8.f 502 (970) 245-6506 FAx: (970) 248-9758 2 c09033c8 TABLE OF CONTENTS 1.0 INTRODUCTTON Proposed Construct.ion Scope of Services CHARACTERISTTCS Site Location Síte Conditions Subsurface Conditions Sit.e Geology Seismicity 3.0 PLANNING AND DESIGN CONSIDERATIONS 4. O ON-SITE DEVELOPMENT CONSIDERATIONS 5. O FOUNDATTON SUPPORT CHARACTERÏSTIC 5.1 Swell Potential 5.2 Set,t,J-ement Pot.ential 5.3 Soil Support Characteristics 6. O FOInVDATION RECOMMENDATIONS 6.l- Drilled Piers 6.2 Spread Footing Foundations TNTERIOR FLOOR SLAB D]SCUSSION LEACH FIELD CONSTDERATIONS COMPACTED STRUCTUFAL FILL O LATERAL EARTH PRESSURES O DRATN SYSTEM O BACKFTLL O SURFACE DRAINAGE O LANDSCAPB TRRIGATÏON O SO]L CORROSIVITY TO CONCRETE O RADON CONSTDERATTONS O POST DESIGN CONSTDERATIONS l-7 .l- Structural Fi]l QualiLY L7.2 Concrete QualitY 1B. O I,TM]TATTONS MATERIALS TESTING CONCEPT ASFE PUBLICATION PROJECT VICTNITY MAP TEST BOR]NG LOCATTON SKETCH CONCEPTIONAI, SKETCH OF FOOT]NG SUBGRADE EMBEDMENT CONCEPT BACKFTLL ZONE OF INFLUENCE CONCEPT DRAIN SYSTEM FTELD STUDY KEY TO LOG OF TEST BORING LOG OF TEST BORTNGS LABORATORY STUDY SWELL_CONSOI,IDATTON TESTS GEOLOGY DISCUSSTON SOUTHWtrST COLORADO GEOLOGY GENERAL GEOTECHNICAL ENGTNEERING CONSIDERATIONS RADON FLOI^J CONCEPT Page L 1_ L ¿ a 3 3 4 4 4 5 '7 7 B a ôo I 11 L9 ¿¿ 24 26 21 zó 29 29 30 31- J¿ Figrure TREATMENT Appendix Figures A1 Figures A2 - A7 Appendix B Figures Bl- - 82 Appendix C Appendix D Figure Di lsmhert snù ßlggocinted L.L L.2 O SITE 2.L 1a 2.3 z.c)Ê, 7,0 8.0 9.0 10. 1_1-. L2. t-3. L4. 1EIJ. 1b. L7. l- aL 3 4 5 6 A CONSULIING GEOTECHNICAL €}IGINÊÉRS ANO ITATERIAL IESIING c09033cFl 1.0 INTRODUCTTON This report presents the results of the geotechnical engiineering st.udy we conducled for the proposed steel building, st.orag'e ponds,vaults and sepLic system. The study was conducted at the request,of Mr. Paul sorensen, P.E. CGRS, in accordance with our proposal- for geotechnical enqineering services dated sepLember 30, 2009. The conclusions / sugtgiestions and recommendatíons presented ínthis report are based. on the data gat,hered during our site andlaboratory study and on our experience with similar soil condi-Lions. FacLual data gat.hered during t.he f ield and laboratory workare summarized in Appendices A and B. 1-. 1 Proposed ConsLruction It is our understanding the proposed construction is to include an approxímate forty two (42) foot by eiqhty Eight (BB) foot slabon grade type building, several underground vaults, seveïal storage Lype ponds and an on-site domest,ic effluent. sewaqe disposal system. L.2 Scope of Services Our services included geotechnical engineering field and labora-Lory stuclies, analysis of the acquired dat.a and report preparation for the proposed site. The scope of our services is outlined below. The fielcl study consisted of describing and sampling the soil materials encountered in nine (9) small- díameter continuous f liqhl aug:er advanced t.est. borings. Two (2) tesL borings were located in the general vicinity of Lhe proposed storaqe ponds. Three (3) t.est boríngs were locat.ed in the greneral vicinity of the proposed building and vault.s. - We advanced one (1) profile test. boringr and three (3) shallow percolat.ion tesL borings within the general vicinil-y of the proposecl ef f l-uent. disposal system leach f ield area. The materials encounLered in the t.est borings \^/ere described and sampl-es ret.rieved for the subsequent laboratory study. The laboratory study included LesLs of select soil samples obtained during the fíeld study to help assess: l'smbert snb ãggscúetsd I I COIISULf ING GEOTECHNICAL ÉNGINEERS ANO MATÊR¡AL T€STING c09033GE the soil strength potential (inlernal friction angrle and cohesion) of samples tested, Lhe swell and expansion potential of the samples tesled, Lhe set.tlemenl/consolidat.ion potential of the samples Lested, the moisture conLent and density of samples tested, and t.he soil sulfate concent,ration of soíl samples LesLed. This report presents our g-eotechnical engineeríng commenLs, suggestions and recommendations for planning: and design of site development including : viable foundation types for t.he conditions encountered, allowable bearing'pressures for t.he foundation types, lateral earth pressure recommendat.ions for desígn of taterally loaded walls, geoLechnical eng,ineering- considerations and recommendations for concreLe slab on grrade floors, and geotechnical engineering considerations and recommendations for compacted sLructural fiIf ' Our comments, suggestions and recommendations are ]:ased on the subsurface soil and g¡round waLer conditions encountered duringt our siLe and laboraLory st-uclies' Our study did not. include any environmental ..i ^^,.^^ or geologic hazard 2 . O S]TE CHARACTERISTICS Sit.e characterist.ics include oÌ:served existing and pre-exLscrng site conditions that may influence the geotechnical engineering aspecLs of t.he proposed site development ' 2.L Site Localion The sit.e is located in the NE L/4 0f the NE i-l4 0f section Township 7s, Range 93W in Garfield" county, souLh of Rifle, colorado. A project vicinity map is presenLed on Figure 1-. flsmbert snù ß[ggocÍuteg 1) .) CONSIJLIING GEOTECHNICAL ËNGINEERS ANO I¡AfERIAL TÊSTING c0 9 03 3GE 2.2 Site Condition The site is currently a vacant tract of land. The area is relat.ively flat, vegeLated wit.h grass and weeds, and exhibits surface drainage toward Lhe east. The northeast portion of t,he site is current.ly occupied by a pigging station. North of the site is an existing compressor sLation. The site is bord.ered to the east. by a dirt access road. The site is bord.ered. tó the west and south by land. símilar in Lerrain to Lhe subject site. 2.3 Subsurface Conditions The subsurface exploration consisted of observing, describing and sampling the soil materials encountered in nine (9) small diameter auger advanced test borings. The approximaLe locations of Lhe test borings are shown on Figure 2. The logs describing the soil malerials encounLered in t.he test boringrs are presenLed ín Appendix A. The soil materials encountered wifhin the tesL borings generally consisted of silty, sandy clay material underlain by Wasatch FormaLion material. The formational maLerial was encounLered at approximate ciept.hs of Lwo and one-half (2-L/2) to six and one-half (6-1/2) feet. below existing site qrades ancl ext,ended to the depLhs explored, approximately nine t9) to twenLy-seven (27) feeL below exísting site surface grades. Free subsurface water was not encoun.Lerecl during the drilling operations. At Lhe time of our field study Lhe proposed development siLe was not irrigated. It has been our experience that. after the sit.e is d.eveloped and once landscape irrigation begins the free subsurface water level may tend Lo ríse. In some cases t.he free subsurface waLer level rise, as a result of landscape irrigation and ot.her d.evelopment, influences, can be fairly dramaLic and the water level may become Very shallow. IL is difficutt t.o pred,ict if unexpected subsurface conditions will be encountered during conslruction. Since such conditíons may be found, we suggest that the owner and the contracLor make provi- sions in t.heir budget and. construcLion scheclule to accommodate unexpecLed subsurface conditions . Lembert enù Ftrggstísted 3 CONSULTING GEOTËCHNICAL ENGINEERS ÀND MAÌERIAL TESTING A brief discussíon of the gerreral geology of the area near the site is presented in Append.ix c. The surface geology of the síte was determined by obseivation of the surface condiLions at the site and observingi t.he soils encounLered in t.he Lest borings on Lhe siLe. c0 9 03 3GE 2 .4 Sit.e GeologY '¿ .5 SeasmtcatY According Lo the International Building Cod.e, 2006 EdiLion, based on the subsurface condiLions encountered and the assumption that' t.he soils described in the t.est. borings are líkety representative of the top 100 feet of the soil profilel vre recommend Lhat the sj'te soil profile be So. 3.0 PLANN]NG AND DESIGN CONS]DERJ\TIONS A çteologic hazard study was not requesLed as part of the this report, however there are some conditions which were at the site durinq the field sLud.y which may influence the menL. scope of observed develop- may in kept Al1 of the suggtesLions and design parameters presented ín this report are based on high quality craftsmanship, care duringr con- struction and post construction cogni zance of the potentíal for swell or seLtlement of the síLe support materíals and appropriaLe post construct.ion maintenance' All construct.ion excavaLions should- be sloped to prevenL excavat.ionwa]-lcollapse.Wesuggestthatasaminimumthe excavalion walls should be sloped at an inclinaLion of one-and-one- halfQ_I/2)toone(1)(horizont'altovertical)orflat.ter.The area above the foundat.ion excavations should be observed at -east daily for evidence of slope movement during construction' I: evidence of slope movement is observed we should be contacLec immediaLely. we anticipate Lhat excavaLion and firl placement operations be associated with the proposed síte development. Excavatio::s the area which generale verLical or sloped exposures should be to a minimum. f.smbert nnù FlggnúEted 4 CONSULTING GEOIECHHICAL EHGINEERS ANO I¿ATERIAL TÊSTIÑG c0 9 03 3cE Excavations whi-ch result in cut. slopes with a vertical height.greater than about four (4) feet. or wiLh a slc;pe or struct.ure aboveshould be analyzed on a Site slrer-:i .ßic hasis. ,l,emporary excavrtio¡rcut slopes in competent material should not, exceed a one-and-one-half Lo one (t*1-/2 to 1-) (horizontal t.o vertical) inclination. A1lconstruction excavations should conform to OccupaLional safety andHealLh Administ,ration (OSHA) standards or safer. All permanent.slopes should have inclinaLions of t.hree to one (3 to 1) (horizontalto verLical) or shallower, Excavation cul slopes steeper t,han one-and-one*half to one (L-1,/2 t,o j_) (horizont,al to verLical) should beanalyzed on a per site basis. Slope and excavation and/or ot.her means Lo be allowed to cascade of any slope. surfaces should be prot.ected by vegietatíonprevent erosion. Surface runoff should notover Lhe top of a slope or to pond at the toe hie anticipate that some embankment, fill slopes will be construct-ed on lhe site. Fill slopes g.reater than abrout three (3) feetvertical heigrhL or fill slopes supporting structures wíll requireadclitional analysis' we reconìmend that each proposed f ill slope onthe sit.e be analyzed on a per site basis when the proposed siteconfiguration and fill material- has been determíned. rf fill slopeswill be constructed on site we should be contacLed to providegeotechnical eng"ineeringr review and recornmendaLions for the clesiç¡rnand construction of Lhe slopes. 4, O ON-S]TE DEVELOPMENT CONSIDERATIONS we anticipate that the subsurface water elevation may fluct.uatewith seasonal and oLher varying conclit.ions. Excavations mayencount.er subsurface wat,er and, soils that tend Lo cave or yie1d.rf water is encountered it may be necessary to dewater construct.ionexcavations Lo provide more suitable workinq condiLions.Excavations should be well braced or sloped to prevent, wal1 cof-lapse. Federal, stat.e and loca1 safety codes should bre obrserved.Al-l construcLion excavations should conform to occupational Safetyand HealLh Administration (OSHA) st.andards or safer. The site \^/ater away allowed Lo ated water construction surface should be graded to drain surfacefrom the site excavations. surface water should not beaccumulat.e in excavalions during construcLion. Accumul--could neg:at.ively influence the site soil condítions. T.smbert snù Flggstíeteø 5 CONSULIING GÉOTECXNICAL ENGINE€NS ANO MAIERIÀL IESIINC c09033cE Construction surface drainage should ínclude sv/ales, if necessary to divert surf ace v/ater away f rom Lhe const.ruction excavaLions. Organic soil materials were encountered in the Lest borings. The organic soil materials are not suitable for support of the struc* ture or structural components. The organic soil materials should be removed prior to foundation construction. It is our understanding that the site development. will include a domest,ic efftuent syslem which will include a leach field. The moisture from t,he leach field w111 ínfluence the moisture content of the site subsurface soifs. An increase in t.he subsurface mois- Lure content will decrease the strength of the influenced soi1s. The formational malerial encount.erecl in Lhe test. borings was very hard. IrVe anticipate that it may be possible to excavate this material ,' ho\nrever, additional effort may be necessary. We do not recommend blastinçr t.o aid in excavàtion of the material. Blasting may fracture t.he formational matería} which will reduce the support characterisLic integrity of the format.ional material. It. has been our experience that sites in developed areas may con- tain exist.ing subterranean st,ructures or poor qualÍty man placed fill. ff subLerranean sLrucLures or poor quality man placecl fill are suspecLed or encountered, they should be removed and replaced with compact,ed structural fill as discussed under COMPACTED STRUC- TURAL F]LL below The proposed builclinq site has been used in the recent past for agrrícultural purposes. We anticipate t.hat the near surface site soils may have been tilled to a depth of about twelve (L2) t.o eighteen (18) inches. Tilling typícally result,s in a loose l-ow density soil with low supporL characteristics and high sett.l-ement. characteristics. The foundations or any concreLe flat work should noL be supported t¡y tilled soils. The near surface tilled soils should be removed and replaced with compact ed struct-uraf fill in areas supporting structures, st,ructural components or concrete flat work. The soil materials exposed in the bott.om of the excavation may be moíst and may become yieldinq under construction traffic during construction. fL may be necessary tÕ use Lechniques for place¡nenL of fill material or foundation concrete which limits construci.ion t.raffic in the viciniLy of the very moisL soil mat.erial . lf yielding should occur during consLruction iL may be necessary co ![smbeut nnù ßlssocisteø 6 COHSULlING OEOÍECHNICAI FNG¡NFFRS ANO ÍATERIAL TCSfING c09033cE constrlrct a subqrade stabilizati.on fill btanket or simirar toprovide construct.ion traf f ic access. T'he subgrade stabilizat.ionblankel may includ.e over excavaf.irrg llre snhgrade soils orre (I) toseverar feet and repracing with aggregat,e subbase course Lypematerial-. The stabilization blanket may also include geotex¡ilestabilization fabríc at t.he bottom of the excavation prior topracement of aggregate subbase course stabilization fill. othersubgrade slabilizat.ion techniques may be avail-able. we areavailable to discuss this wilh you. 5. O FOUNDAT]ON SUPPORT CHARACTERTSTIC Two crj-teria for foundat.ion design which musL be saLisfiedsaLisfactory performance are : for r-)conlact stresses must. be 10w enough to preclude shearfailure of t.he foundation soils which would result. in lat.eralmovemenL of the soils from beneat.h t.he found.at,ion, and 2) settl-ement or heave of the foundation must be within amol.rntstolerable t.o t.he superstrucLure. The soil materials encountered in the test borings have varyingengineering characteristics LhaL may ínfluence the design and.construction considerations of foundations. The characteristícsinclucle swell pot,ential, settlement. potential, bearì_ngi capacity andthe bearing conditions of t.he soil-s support.ing the f oundalions.These are discussed below. 5.1 Swell Pot.ential some of the materi-als encountered in the test borings at theanLicipated foundation depths may have swell pot.ential. swellpotential is the tendency of the soil Lo increase in volume whenbecomes wetLed. The volume change occurs as moist.ure is absorbedinto Lhe soil and waLer molecules become aLtached to or adsorbedthe individual clay plat1et.s. Associat.ed with the process ofvolume change ì-s swell pressure. The swell pressure is the forcethe soils applies on its surroundings when moisture is absorbedinto t.he soil. Foundation design consideraLions concerningswelling soils include st.rucLure Lolerance t.o movement. and deaclload pressures to help restrict uplift. The st,ructure's toleranceto movement should be addressed by Lhe structural engineer and isdependent upon many facet,s of the design including the overallstructural concept and the buílding' material. The uplift forces or T.embert enù €lggseiflteø iL br¡ 7 CONSULTING GEOÍECIINICAL ÉNGINÉERS ANO I'AIERIAL IESTING c09033c8 pressure due to wetted clay soils can be addressed by designing' the foundaLions to account for swelling soils. 5.2 Settlement Potential Settlement pot,ent.íal of a soíl is the tendency for a soil to experience volume change when subjectecl Lo a load. Sett.lement is charact,erized by downward movemenL of all or a port.ion of the supporLed st.ructure as the soil particles move closer together resulLing in decreased soil volume. Settlement potential is a funct,ion oÊ foundation loads, depth of footing embedment, t.he widt.h of the footing and the selLlement potenlial or compressibility of the influenced soil. Foundation design considerations concerning setLl-ement poLent.ial include the amount of movement tolerable to the sLructure and t.he design and construction concepts to help reduce t.he potential movement. 5.3 Soil Support Characteristics 'l'ne sof I properLies width, the the lowest the amount bearing capacity is a function of the engineering of the soils supporting the foundalions, the foundaLion depth of embedment of the bottom of the foundat.ion below adjacent. grade, Lhe influence of the ground wat.er and of settlement tolerable Lo Lhe struclure. Foundat,ions for the structures should be placed on relatively uniform bearing conditions. Varying support characteristics of the soils supporLing the foundation may result in nonuníform or different.ial performance of the foundation. The influence of nonuniform bearingr conditions may be reduced by recognizing ancl accommodating during the site specific design. 6. O FOUNDATION RECOMMENDATÏONS Geotechnical engíneeri-ng consideraLíons which influence the foundat.ion design and consLrucLion recommendations presented below are discussed in Appendix o. We have analyzed drílled piers poLenLial foundation sysLems for are discussed below. and spread footing foundaLions as the proposecl struct.ures. These We recommend thaL the enLire st,ruct.ure be supporLed on only one foundaLion type. Combining foundation types wíl-1 result in differ- flsmhert snù Øggscisteg ö :t CONSULlIHG CEOTECHNICAL ENGINEERS AND MATERIAL TESTING c09033G8 enLial and unpredictable foundation performance between t.he varying -[ourrrlaLiutr Lypes. Wë recommend that t,he strucLure f ootprirlt not, be traversecl l:y l-Ìie cut./fill contacL which would result in a portion of the sfructure underlain by fill material and part of the structure underlain by materials exposed by excavaLed cut. ff Lhis conditíon will exist please contacL r.ls so that. v/e can revise our recommendations to accommodate the cut/f.Ll-I conLacL scenario. All of t.he design parameLers present.ed below are basecl on tech- nigues performed by an experienced compeLenL contractor and high quality craftsmanship and care during construction. We recommencl post const.ruclion cognizance of t.he volume change potential of t.he near surface soil materials and Lhe need for appropriate post const,ruction maintenance . The spread fooLing recommendations include recornmended design and const.ruction t.echniques to reduce t.he influence of movement of the soil materials supporting the foundation but should. not be interpreted as solutions for complet,ely mitiqating the potential for movement from the support soil mat,erial volume change. Exterior col"umn supporLs shoulcl be supported Lry foundatlons incorporat.ed into the foundation system of Lhe structure nol supported on flatwork. Column supports placed on exterior concrete flatwork may move if the support soils below the concreLe slab on grade become wetted and swel1 or freeze and raise or settle. Differential movement of the exLerior columns may cause stress to accumufate in the support,ed structure and translate int.o other porLions of the structure 6.1 Drilled Piers Drilled piers or caj-ssons that are drilled into the unweathered formaLional mat,erial may be used to supporL the proposed structure. The piers should be drilled a minimum lengt.h of fifteen (15) feet or a minimum of ten (10) feet into Lhe harcl unweaLherecl formational material, whichever ís deeper. The piers should be designed as end bearingi piers using a formational mat.erial bearing capacity of L7,000 pounds per square foot and a side friction of L,'700 pounds per square foot for the porLíon of bhe pier in t,he unweaLhered formational material. The drilled piers should be desigrned with a minimum dead load of 1,000 pounds per square foot.. Varying weathering and formational compet,ence may result in a shorter required penetrat.ion of the drilled piers inLo t.he formational material to provide the end bearing capacity discussed above. We le¡nbert snù Flggsciuteg : i 9 CONSULIING GEOTECHNICAL €NGINEERS ANO TTAÎERIAL IESfING c09033cE should be contacLed to observe the pier drilling operations and provide additional geotechnical engiineering suggestions and recommendatic¡ns for design bearing' capacíty and minimum penetraLi-on into the format.ional material as needed. There are differing theories on the use of side shear as part of tLie load carrying assessment of drilled pier foundation systems. The differences are related t.o the strain compatibility between end bearing and side shrear. One theory is t.hat mobilization of the drilled pier ís required to generate t.he side shear soil strength values. This mobilization would require the movemenL of the botLom of the pier which may not be a desirable characLeristic. Anot.her Lheory is t.hat. the support materials will develop staLic frictional- forces in contact with Lhe materials along- the surface of the pier. It is our opinion t.hat sufficient movement of the piers Lo mobi- lize skin friction for bearing supporL may resulL in undesirabl-e performance of the pier in Lhe form of settlement. We suggest consideration Lo the amount, of sett.lement tolerable Lo t.he struc- ture be íncluded in your assessment íf skin friction is used in your desigrn as part of the bearing support of the drilled pier. We suggest ttrat piers be designed using end bcarinq capacity only. The side shear in the formational material may be usecl for Lhe desig:n t.o resist uplift forces. When using skin friction for resistinq uplift we sì-rggest that you discount the upper porLion of the pier embedment in the formational material to a depth of at leasL one and one-half (L-L/2) pier diameters into Lhe formaLional material. The l:ott.om of the píer holes should be thoroughly cleaned to insure that all loose and clisturbed materíals are removed prior to placing pier concreLe. It is very important. to thoroughly clean Lhe botLom of the pier holes prior to placement. of the pier concret,e. Loose disLurbed material left. in the bott.om of t.he pier hole will likely result in long term settlement of the piers as Lhe disturbed material- consolidat.ed under the pier loads. The pier holes shoulcl be observed during the excavation and cleaning operation and" again immediaLely prior Lo placement. of pier co:rcrel-e aft.er steel reinforcemenL and any casinq materials have been insLalled Lo verify that material was noL dislodge into the pier hole d.uring steel reinforcement or casing placement' Because of the when unloaded by reboundinq poLential in t.he formational materials excavation and because of Lhe possibifiLy of [smbert anù flgsocinted 10 COHSULTING G€OÍÉCHNICAL ENGINEERS ÀNÛ I.lATEÍIIAL TÊ,51ING G09 03 3cE desiccation of the newly exposed mat,erial we suggest that. concretebe placed in t.he pier holes immediately after excavation and cleaninq. rf the piers are designed and constructed as discussed above weanLicípate thaL the post construction set.t,lement poLenLial of eachpier may be less than about one half (1"/2) inch. The portion of Lhe pier above the format.ional surface and in theweathered formational material should be cased with a sono tube orsimilar casing to help prevent flaring on the top of the pier holes and help províde a posit.ive separation of the pier concrete and t,headjacent soils. Conslruction of the piers should includ.e exLreme care Lo prevent flaring of the top of the piers. Enlarged port.ions of the drilledpier excavat.ion near the surface may perform similar t.o Lhe Lopflaring. Preventing flaring may be aided by casing the drirledpier excavalion with a sono Lube or similar casing. Reducingflaring is to help red.uce the pot.ential of swelling soils to imposeuplift forces which will puL the pier in tension. The clrilledpiers should be verLically reinforced to provide tensile strenqthin the piers should swelling on site soíls apply tensile forces onthe piers. The structural engineer should be consulted to provide strucLural desigri recoinmendations . Free grouncl water was moL encount.ered during the clril1ing operations, however, our experíence in the area indicates thatfractured layers may exíst in the formationa] material and t.hat. thefractured layers may carry or store water. If ground water is encountered during pier drilling, Lhe pier holes should be dewatered prior to placing pier concrete and nopier concrete should be placed when more than six ( 6 ) inches of waLer exists in t.he bottom of the pier holes. The piers should be filled \,^/ith a tremie placed concret,e immediately after t.he drittingf and creaninq operation is complet.e. rl- may be necessary to case the pier holes with temporary casinE to prevenL cavingl during pier const,ruction. Difficult c1ríl1ing condiLions were encountered with our drill rig cluring our fiel-d sLudy. We anticipate that pier drillíng equipment available in the area may have difficulLy drilling the format.ional material. ït may be necessary to obtain specialty drilling equip- ment, possibly not. available in western Colorado, Lo advance the drilled pier holes. We are available to discuss this with you. Lsmbert snù flggsrífltsd CONSUTTING GEOTÊCHI¡ICAL ENGINEÉRS ANO ll MATER!AL TESTING c0 9 03 3cE The contact between the weaLhered formaLional material and the unweaLhered formational material may be gradual and difficult' I'o identify. The minimum penetraLion of the drilled pier ínto the unweat,hered format.ional maLerial as discussed above is important, for the long term performance of the pier foundation. We should be contacted to observe the pier d.ríllíng operation t.o verífy the construction techniques used, the material encounLered during the drillinçt operalion and condition of the bott.om of t.he drilled pier hote prior Lo placement of pier concrete ' The structural engrineer should be consulted to províde sLrucLural design recomnendations for the drilled píers and girade beam founda- tion system. 6.2 Spread Footing Foundations In our analysis it was necessary to assume that the material encounLered in t.he test borings extended throughout the building siLe and to a depth below the maximum depth of t.he influence of the foundatíons. VrIe should be contacled to observe the soiL materials exposed in t.he foundatiorr excavations prior to placement of foundations to verífy the assumptions macle during our analysís ' The shale derived soil materials near Lhe surface and Lhe shale layers within Lhe formaLional maLerial are expansive. These materials are likely Lo be encounLered in the foundation excavations. Spread footingr foundations should not be supported on materials wiLh differing support characterístícs ' The site maLerials may vary from soil to sandstone to shale within the founclation excavaLion. These varyingr support material conoíUions will result in differing lonq term performance of the different areas of the spread footing. For this reason we Suggesl that if formational maLerial is encounLered only in portions of the foundation excavaLions at footing depth t.he foundation in all areas should be ext,ended to support. all foundalion members on the formational materíal. Overexcavation and placing of compacted filf material blanket, as discussed in this report, beneath the spread footing will somewhat mask t.he long term performance characLerisLics of t.he differingr support. materials. The bottom of the foundation excavations should be Lhoroughl-y cleaned and observed when excavated.. Any loose or disturbeC' maLerial exposed in the foundation excavaLion should be renoved prior Lo placing foundation concreLe' T,nmbert f,ilù Øggocísteg I :,. ¡ 1,2 cnNsurflNG cEolEci{NlcAL ENGIt{€ERS ANO I¡ATERIAL TEETII.¡G c09033cE The bottom of t.he foundation excavations shoulri he compacf.erlprior to placing compacted st.ruct,Lrral filt or foundation concrete.hle suggest thc mate¡rials exposed b'e cornpacLeú Lu aL leasL:rinety(90) percent of the materials moísLure content-dry density rela-Lionship (Proctor) tesL, ASTM Dl-557. Excavation compaction is tohelp reduce the influence of any disturbance that, may occur duringthe excavation operat,ions. Any areas of roose, low density oryielding soils evidenced during the excavalion compaction operaLionshould be removed and replaced with compacted structural fill.caution should be exercised during t.he excavat.íon compactionoperations. Excess ro1líng or compacting may increase pore pres-sure of the subgrade soil material and degrade the inLegrity of thesupport scils. Loose or disturbed material in the bottom of t.hefoundation excavatj-ons which are intended Lo support sLrucLural members will like1y result. in large and unpredictable amounts ofseLtlemenl., if the Loose or disturbed mat.erial is not compact,ed" The boLtom of any footíngs exposed t.o freezing temperatures shouLd be placed below the maximum depth of frost penetration for Lhe area. Refer t.o t.he local building code for d.etails. All footings should be appropriately proportioned. to reduce t.hepost consLruction differential settlement,. Footingis for largelocalized loads should be designed for bearing pressures and.footing dimensions in the range of adjacenL footings to red.uce Lhepotential for differential seLt.lement. We are avaílable to cliscussthis wiLh you. Foundalion walls should be reinforced for geotechnicar enqineering, purposes. The sLructural engineer should be consultedfor foundation design. The structural engineeringr reinforcingdesign t.ailored for t.his project will be more appropriate Lhan the suggestions present.ed above. The structures may be f ounded on spread footings. Vrle recommend.the use of a blanlcet of st,ructure fill material beneath the spreadfootíng foundation members. spread foot.ing's may be placed eitheron the natural undisLurbed soils or on a brankeL of compacted st,ructural fill. The blanket of compacted sLructural fill is tohelp provi-de uniform support. for the footings and Lo help reduce the theoretical calculaLed post. construct.ion settlement.. The theoretical calculated post construction settlement and associat.ed fill t.hickness supportingr the footings are presented below. {,smbert snù Øsøaú&tes ] t-3 CONSULIING GEOTECHNICAL ËNGINÊ€RS AI{D MATERIAL TESTING c09033GE We suggest that you consider Lhe foundation be supported on a blankeL of compacted structural fill at least one (1) foot thick Lo help mask the influence of volume change soil materials supporting the footings. The blanket of compact.ed structural fil1 will not prevent movement of the footings from volume change in the support- soil materials but will mask the influence of volume changes of the soils supportinq t.he foot.ings. If the footings are supported on a blanket. of compacLed sLructural fitl the blanket. of compact,ed structural fill should extend beyond each edge of each footing a distance at leasL equal to the filf thickness. This concept is shown on Figure 3. Geotechnical engineering recommendations for constructing compacted structural fill are presenLed below' AII footinqs should have a minimum depth of embedment of at leasL one (1) foot below the lowesL adjacenL grade when placed either on the naLural- und.isturbed soils or a blanket of compacted strucLural f ill. Deeper embedment will be need,ed for footings exposed t"o exteríor cflmaLe. The l:earing capacity wíll depend on the minimum depth of embedm- ent. of the boLtom of the fooLinqs below the lowest adjacent girade and Lhe support characLeristics of the soils supporLing the founda- tion. Ot.her characteristics may influence embedment. The emhed- ment. concept is shor¡rn on Figure 4. Bearing capacity and' associated minimum clepLh of embedment of the l:ottom of the footing below the lowest acljacent grade are presented below' SPREAD FOOTING SOTL BEARING CAPACITY CONTINUOUS ISOLATED L, 650 1-, 900 2 ,200 2 ,350 2,700 3, 100 ð ( feeL ) 0 I 2 A* Minimum clept.h of embedment for fooLinqs adjacent Lo level areas If deeper embedment is considered for increased bearing capacity greater t.han presented above, we should be conLacted t.o provide aclditional analysis and recommendations as needed' The bearing capacity design value is based on several considerations and these may change with dePth' T.smhert nuh ß[ggnrinteg CONSULf ING GEOTECHNICAL ENG¡NÊERS AND MATERIAL TESIING ! :. L4 c09033cE The bearing capacíty may be increased by about twenty (20¡percent. for transieuL loacls such as wind and seismic loads. rt is our opinion that footings exposed to frost or freezingground influences and all exLerior footings should. be embedded tofrost depLh or deeper. rnt,erior fooLings should have a minimumdepth of embedmenL of at least, one (1) foot on all sides to providea more predictable long Lerm performance of the footing. weunderstand Lhat consLruction techniques Lypically used in Lhe areamay result in some of the footings in the crawl space constructedwilhout signíficant embedment of t.he botLom of the footingr belowLhe lowesL adjacent grade. For this reason v/e have provided desiç¡'nval-ues for footings consLructed with little or no embedment. rt. ísour opinion that. the performance of footing consLructed without embedment may be influenced by erosion, temperature changes,moist,ure content chang,es, swell pot.ential of Lhe soil supportingrthe footings and weat,hering of t.he soils supporting the footingsand will have a less predictable settlement response Lhan footingswíth embed.ment. Exterior footíngs and footings \,úit.h uneven backfill may result inmovement of Lhe footings. Embedment of the footings on all sideswill help reduce the poLential for movement of footings with uneven backf il1. Vrle do not recofiìmend exterior f ootings or footings withuneven backfill be consLructecl wiLhout a minimum d.ept.h of embedmenLof the bottom of Lhe footinq below t.he lowest adjacent grade of atl-easl one (1) foot on all sides of Lhe footings. The minimum depth of embedment ís sufficient only t.o develop thetrea-ring capacity for desig"n prirposes and. does not account for frostínfluences - Actual design and construction should resulL ininterior foolings with one (1) foot or more embedment and exteriorfootings with frosL depth or more embed.ment. Typically deeper embedment will i-ncrease bearing capacity and decrease posLconst.ruction settlement and decrease the influence of expansivesoi1s. The soil sample tesled had a measured swell pressure ofapproximately 500 pouncls per square foot. and the actual swellpressrire of the support materials could be greaLer. when wetLedthe sit.e. soil materials have t.he ability to raise supported foundat.ion members wiLh loads less than Lhe swell pressure. The foundaLion design should be as rigid as possible wiLh as high of dead load as can be avaitable. The greater the dead load on thefootings the less the potential for movement from the foundation Lsmbert snù Hgøocistes a t-5 CONSULÍ IHG GEOTECHNICAL ENGIHEERS AND HAlERIÀL TESIING c0 9 03 3cE soils should Lhey become wetted. If t,he soils become wetled they will swell and will raise the foundation portions supported on the weLted soils. If the structure is supporLed on spread footings the owner musL realize that. post conslrucLion movement of the footings is likely. We are available to discuss the implÍcaLions of supporting foundatíons on swelling soils. Interior column loads supported on spread footingrs which are sLructuratly connected to the other foundation members will provide more uniform performance of the inLerior footings with respect Lo t.he other found.aLion members and will help reduce the potenLial differenLial seltlement between int,erior and exLerior foundation members. The f oundat.ion walls should be desigtned to act as beams t.o clist-ribute stresses associated with the swelling volume changies of soils. The beam design should be addressed by Lhe project sLrucLural engineer, Exterior column supporls should be support.ed by foundations incorporat.ed into the foundation system of the strucLure not support.ed on flatwork. Column supports placed on exterior concrete flatwork may move if the support soils below the concrete slab on grade become wetled and swe1l or freeze ancl raise or settle. Differential movemenL of the exteríor columns may cause stress to accumulate in the supported sLructure and translale inLo other porLions of the struclure. The calculated theoretical estimated posL conslruction seLtlemenL and swell potential may be reduced by placing the footings on a blanket of compacted sLructural fifl. The calculated ttreoretícal estimated post construction setLlement and associat.ed t.hickness of compacted structural fill are presenLed below. TH]CKNESS OF COMPACTED STRUCTURAL F]LL CALCULATED THEORETICAL ESTIMATED POST CONSTRUCTION SETTLEMENT FOR CONTINUOUS SPREJ\D FOOTTNGS ( TNCHES )STTPPORTTNG F'ÔNTNTNêS ì : 0 *B/2 B 38 /2 1"-L /2 1 3/4 L/2 -t tr CONSULTING GEOTECHNICAL ENGINEERS À¡ID MATSNIAL IESTING G09033cE THTCKNESS OF COMPACTEIJ STRUCTURAL FTLL CALCULATED THEORETTCAT, ESTTMATED POST CONSTRUCTTON SETTLEMENT FOR ISOLATED SPRE.â.D FOOTINGS ( TNEHE,C )sITppÔR1.TNt',l I.OO.FÏT\TGS 0 *B/2 B 3B/2 2-L/ 4 L_L/B 1 /1 1//. *B is equal Lo Lhe footing \^/idth The calculated theoretical estimat.ed sett,lement values above areappropriate for conLinuous spread foot.ings wiLh a \,,,/idth of abouttwo (2) feet or less and isolated spread foot.ings with a width ofabout four (4) feet or less. Larger footings should be analyzed, ona footing, load and width specific basis. Footings should be sized so thal each fooLingr is in a similarsize and load rang"e as nearby fooLings to encourag:e simi-larperformance. very large foot.ings or heavily loaded footíngs willinfluence the support soil materials t.o a deeper depth than smallor lighlly loaded footings and therefore will have different post const,ruction perf ormance . The calculated settlemenL estimat.es are theoretical only sett,lement could vary throughout the site and wiLh time. Actual If the footings are supported on a blankeL of compacted st.ructur-al fil1, the blanket- of compacted st,ructural fill should extend. beyond each edgre of each footing a clisLance aL leasL equal to thefill thickness. This concept i-s shown on Figure 3. CompactedStructural Fil1 is discussed in Section 9.0 below. The siLe soil samples tested have a measured swell pressure ofless than 100 pounds per square foot, however, the act,uar swellpressure of the support material could be g:reaLer. This swellpressure \¡/as measured for soils at the iniLial moisLure conte:rt ofthe soil sample tested. The swell pot.ential of the site soilmateriafs could vary significant.ly and. could be great.er than ihat. measured. The measured swell pressure may be influenced. by drstur- bance of the sample during' the sampling operation and the soii suction poLential and initial moislure conLenL. Changes in Lhe initial moist,ure cont'ent will ence the swel1 pressure of the sit.e soils. If sígnificantly influ- the initial moisture Lambert snù Øggstinteg I LI collSULTlNG GEOIÉCHNICAL ENGINE€RS ANO MATERIAL TESTING c09033Gtr conlent of t.he found.ation soils is less Lhan that of the test sample Lhe acLual swell pressures will likely be significantly higrher t.han measured.. If the ínitial moisture contenL of Lhe founclatíon soils is greater than that of t.he test sample the aclual swell pressures may be less than measured. The soil sample tested had a measured swell pressure of approximaLely 400 pounds per square fooL and the acLual swell pressure of the supporL materials could be greater. When wet-ted the site soil materials have the ability to raise supported f oundat.ion members with loads less than t.he swell pressure. The foundat.ion d.esign should be as rigid as possible with as high of a dead. load as can be availabte. The greater the dead load on Lhe footings the less the potential for movemenL from the foundation soils should. t.hey become wet.ted. If the soils become wetted they witl swell and will raise the foundation porLions supported on the wetted soils. If liqhtly loaded sLructure members are supporled on spread footings on expansive soil material then the owner musL realize Lhat post consLruction movemenl of t.he footings is 1ike1y. These ligrhtly loaded areas of the footing should be designed with sufficient structural int.egrity to resist the forces from swelling soi ls . Foundation members that will have significant.ly small or low dead loads, such as foundations beneaLh wall openingrs such as doorways, may be provided with positive separation between the foundaLion concreLe and. the und.erlying soil materials. That separation may be provicled by using commercial void form material. We recolÌlmend LhaL the struct,ural engineer be consulted concerning the void form design concepL. If Lhe void form desigrn concept is part of the foundation design we sug.gest that the foundation design may consider including a four (4) to six (6) inch corrugaled paper void form maLerial beneath the footinqs in the lightly loaded port,ions of the foundation. The corrugiated paper void forms provide temporary supporL for foundaLion concreLe during construction. The low strength of the voíd form material is intended to a1low the underlying soil materials to expand. into the void form thereby exerting Less or no uptift pressure on the foundation in the areas it is usecl' We are available to d.iscuss the implications of supporting foundations on swelling soils. T.amhert nnù Aøgsríflted CONçULTIN6 GEOTECIiNICAL ÊNGINEERS AND :J 1-B MATERIAL TESTING G09033GFl The bot.tom of the foundation excavations shouLd. be Lhoroushlyclearrecl and observed by the project Geotechnical Enqineer or hisrepreserlLdtive when exca,val-ed. Any o1d fil-l- or loose or disturbedmaterial exposed in the foundation excavatíon should. be removed orremedíed prior t.o additional construct.ion. we recommend LhaL we be contacled to observe the foundationexcavations and backfill operations during const,ruction ¡o verifythe soil support. conditions and. our assumpLions upon which ourrecoflìmendations are based. Tf necessary we may revise our recom-mendations based, on our observations. We are available t.o providematerial testing servíces during t.he const,ruct.íon phase of theproj ect. 1,0 TNTEF-TOR FLOOR SLAB DTSCUSSION It is our understanding that concret,e slab on grade floors may beinclucled in [he const.rucLion. The natural soils thaL will supportinterior floor slabs are stable at their natural moist.ure content.However, Lhe owner should realize that when wetted., the siLe soils may experience volume changes. The site soil samples t.ested had, ameasured swell- pressure of approximately 500 pounds per square foot.and an associat,ed magnitudes of o .7 to l_.I percent of the weLtedsoil volume at a surcharge load of 100 pounds per square foot. The recommendatj-ons in this report do not address a monolit.hicfloor slab/footing combination. The design and constructioncharact,eristics of the monolithic floor slab need geotechnical engineering design parameters cailored specifically for amonolithic slab and íntegral footing. Generatly this typefoundaLion/floor combination in Lhis area with these sitecondiLions does not. perform as well as oLher choices. Condit,ions which vary from those encountered during: our fieldstudy may become apparent during excavation. I¡le should be conLact-ed t.o observe the condirions exposed at concrete slab on gracle subgrade elevat,ion Lo verify t.he assumpt,ions made during thepreparation of this report. and to provide additional geotechnical engineering suggrestions and recommendations as needed. Engineering clesign dealing wit.h swelling soils is an art which isstill developing. The owner is cautioned Lhat the soils on this site may have swelling pot.ential and concrete slab on g'rade floors and ot,her liqhLly loaded members may experience movemenl when the l[.smbert anù €lggstí&teø L9 COHSULTING GÊOTÊCHNICAL ÉNGINÊERS AND ¡,tA1ÉRIAI TESIING c0 9 03 3cE supporting soils become wetted. We suggest you consíder floors suspended from the foundation sy.stems as structural floors or a similar design that will not be influenced by subg¡rade volume changes. If Lhe owner is willing to accept the risk of possible d"amage from swelling soils support.inq concrete slab on grade floors, Lhe followinq recommendations to help reduce the damage from swellingi soils should" be followed- These reconÌmendations are based on generalty accep¡ed design and construcLion procedures for construction on soils t.hat tend to experience volume changes when wetted and. are intended to help reduce the damage callsed by swell- ing soil materials. Lamberl and AssociaLes does noL intend that the owner, or the owner's consultants should interpreL these recorTìmend.at.ions as a sotution to the problems of swellinq soils, buL as measures to reduce the influence of swelling soils ' The shallow soil materials tested have a moderaLe volume change potential under lighL toading conditions ' concrete slab on grade floors may experience noticeable movemenL when slrpporLed by the natural onsite soils. concrete slab on grade floors will perform best if clesigned Lo tolerate movement inLroduced by the subqrade soil materi.al s. concrete f]atwork, such as concrete sl-ab on grade floors, should be underlain by compact.ed sLrucLural fill. The layer of compacLed fill should be at least one (1) fooL thick or thicker and con- structed. as discussed under COMPACTED STRUCTURAL FILL below' A one (1) foot thick or thicker blanket of sLrucLural fill maLerial beneath Lhe concrete flatwork is not sufficient Lo enLírely mask the set.tlement or swell potenLial of the subgrad'e soil maLeríal bul will only provide better subqrade conditions for constructíon' The concrete slab on grade should be desígned by a sLructural engineer Lo be compatible with the site soil conditíons ' The naturaf soíl malerials exposed in the areas supporting concreLe slab on grade floors should be kept very moist clurinq constructíon prior to placemerit of concreLe slab on girade floors ' This is Lo help increase the moísture regime of the potent'ially expansive soils supporting floor slabs and help reduce the expan- sion potentiat of the soils. we are available to discuss Lhis concept with You. concreLe slab on grad.e floors should be providecl with a positíve separaLion, such as a slip joint, from all bearing members and utilíty lines to allow their independent. movements and to help reducepossibledamagethatcouldbecausedbymovementofsoils 20 T'ambert nnÙ Øggocinteø CONSULTING ßEOTFCHNICAI FNGINCERS ANO t¡alcRlaL TrSl¡l¡c G09033c8 supporting inLerior slabs. The f loor slab should, be consL:n:ef.eri asa floating stab. All water and sewer pipe lines should be isolat.ed. f'c-rrrL Lhe slab. Any equipment placed on the floatingr floor slabshould be const.ructed with flexible joint,s to accommodate futuremovement, of the floor slab with respecl to the struct,ure. wesug-gest partitions constructed. on Lhe concrete slab on g,rade floorsbe provicled with a void space above or below the partitions torelieve st,resses induced by elevation changes in the floor slab. Floor slabs should noL extend over foundat.ions or foundationmembers. Floor slabs which extend over foundations or foundation members will likely experience post const.ruct.ion movement as aresult of foundalion movements. We are available t.o discuss t.hiswich you. The concrete slabs should be scored or jointed to help define thelocations of any cracking. we recommend that. joint spacing bedesigned as out]ined in ACr 224R. fn addiLion joinLs should bescored in t.he floors a distance of about three (3) feeL from, andparal1e1 to, the wal1s. It should be not,ed that when curing' fresh concrete experiencesshrinkage' This shrinkage almost. always results in some cracks inthe finishecl concrete. The actual shrinkage d.epend.s on the config-uration and strengrLh of the concrete and placing and finishingtechniques. The recommended joints d.iscussed above are inLended tohelp define the locatíon of the cracks but. should not beinterpretecl as a solution to shrinkage cracks. The owner musLunderst.and that concrete flaLwork witl contain shrinkage cracksafter curing and that all of the shrínkage cracks may not belocaLed in control joints. Some crackingr at random locations mayoccur. rf moisture migration t.hrough Lhe concreLe slab on gracle floorswill adversely influence the performance of t.he floor or floor coverj-ngs we suçÍgest t.hat a moisture barrier may be installed beneaLh the floor slab to help discourage capillary and vapormoisture rise through the floor slab. The moisLure barríer mayconsist of a heawy plastic membrane, six (6) mil or grreater,protecled on t.he top and bottom by clean sand. The clean sand willhelp to protect the plastic from puncLure. The layer of clean sandon the top of the plastic membrane will help Lhe overlying concreleslab cure properly. According to Lhe American ConcreLe Institute,proper curing requires at least three (3) Lo six (6) inches ofclean sand beLween t.he plastic membrane and the bottom of the Lsmbeut snù Elgøoc{eteg 2L CONSULTI}IG GEOIECHNICAL ENGIN€€RS ANO i{AÏÊRtAL TESTINC c09033cE concrete. The plastic membrane should be lapped and taped or glued and protected from punctures during construction' The Port.land CemenL AssociaLion suggesLs that welded wj-re rein- forcing mesh is not necessary in concrete slab on grade floors when properly jointed. It is our opinion that. welded wire mesh may help improve the int.egrity of the slab on grade floors. We suggest Lhat. concrete slab on grade floors should be reinforced, for geolechni- ca1 purposes, with at least 6 x 6 - w2.9 x W2.9 (6 x 6 - 6 x 6) welded wire mesh positioned midway in the slab. The sLructr.tral engineer shoul-d" be contacted for structural design of floor slabs. B. O LEACH FTELD CONSIDERAT]ONS PercolaLion tesLs were conclucted in three (3) t,est borings located within the proposed leach field area. The percolation tesLs \^/ere cond"ucLed to help idenLify the g:eneral percolaLion rate of the siLe soil materials. The logs of the soil- materials encountered in the profile test boring is presented on Figure A7 in Appendix A. The results of the percolation tests are presented in Appendix A and indicate a percolation rate ranging from twenty- eight (28) to t.hírty-six (36) minutes per inch' Groundwater was not encountered Lo the depths explored within the percolation profile borinq, approximately nj-ne (9) feeL. fnformalion provided in "Guidelines on Individual Sewage Disposal Systems" by Lhe Colorado Department of Health inclicates Lhat. a percolation rate between 5 and 60 minut.es per inch is acceptable for sLandard leach field disposal systems. If the percolation rate is less Lhan 5 minul-es per inch or qreater than 60 minuLes per inch or if free giround water is less than four (4) feet. below the boLt,om of the proposed leach field or if formational material is less than four (4) feet. below the bottom of the leach field Lhen the leach f ield" should be designed by a regiistered engi-neer. We are available to discuss the percol-ation test resulLs wiLh you. 9.0 COMPACTED STRUCTURAL FÏLL Material characteristics desirable for compacted sLructural- f:11 are cliscussed in Appendix D. Areas that are over excavaLed cr sliqrhtly below grrade should be backf illed to gracle with properl¡' compacted structural filt or concrete, not loose fill ma¡eriai' I: l,srTrbert snù Høgnústeß 22 CONSI¡I TING GEOTECHNICAL ENGINÊEÂS AND I¡ATERIAL fE6TII¡G c09033cE backfilled wiLh other than compacLed strucLural fitrconcrete there will be significant post constructionproportional- to the amount of loose material. material or settlement Because of the swell pot.ential of t.he on sit.e soils, it is ouropinion that the on site soils are less desirable for use as compacted st,ructural fifl than an imported non-expansive granular material as discussed in Appendix D. we anticipaLe Lhat. it may notbe cost effective to import non-expansive granular st.ruct.ural fitlmaLerial and t,hat the owner may prefer to use on site material- for compacted st.ruct.ural f il1. rf the on site soil materials are used as compacLed structuralfirl Lhe soí1s should be moisture cond.itioned to about two (z) t,ofour (4) percent wet. of oplimum moist.ure content and. compacted toat least ninety (90) percent but not more than ninety-fíve (95)percent of the maximum dry densiLy as defined by ASTM Dl-557, modif iecl moisture-density relat.ionship (proctor) test. The soil maLeríals should be placed in thin lifts about six (6) inches in compactecl Lhickness and compacted with a kneading type compactor such as a sheepsfooL t]æe roller. The on site soils may be veryclifficult t.o appropriately compact. Reconditioning and using theonsile soils for compacted struct.ural fill material may be more costly than using an imporLed granular non-expansive material. Weare available to discuss this with you. All areas to receive compacted st-ructural fill should be properly prepared prior to filr placement.. The preparaLion should inctude removal of all- organj-c or deleterious material. The areas toreceive fill maLerial should be compact,ed. after the organic delete-rious material has been removed prior t.o placinq the fitl material. The area may need t.o be moist.ure conditioned for compaction. Any areas of sofL, yieldÍng, or low clensity soil, evidenced during the excavaLion compact.ion operation should be removed. The area excavated Lo receive fill shou]cl be moisture conditioned to wet of opt.imum moisLure cont.ent as part of the preparation to receive filI. Fitl should be moisture conditioned, placed in thin lifts not exceeding six (6) inches in compacted thickness and. compactedto at least ninety (90) percent of maximum dry density as definecl by ASTM D1557, modif ied moj-sture content-dry density (proct.or) test. After placemenL of the structural fill Lhe surface should noL be allowed to dry prior Lo placing concrete or addiLional fill materi- al. This may be achieved by periodícally moistening Lhe surface of Lsûnbcrt snù FLggasíetos I :i ¿J COHSULTIIIG GÉOTÉCHNICAL ÉNGINEERS ANO MATERIAL IESTING c09033c8 the compacted sLructural fill as needed to prevent drying of the structura] fill. We are available Lo discuss this wit.h you. The soil materials exposed in t.he bottom of the excavalíon may be moist. an¿ may become yielding under construction t,raffic during construclion. It. may be necessary to use techniques for placement of fill materials or foundation concrete which limit construction traffic in the very moist soil materials. If yíelding should occur during const,ruction it may be necessary to consLrucL a subqrade stabilization fill btanket or similar to provide construcLion traffic access. We are available to discuss this with you. We recommend that the geot.echnical engineer or his be presenL during the excavaLion compaction and fill operalions Lo observe and Lest Llie mal-erial. representat,ive placement 10. O LATERAL EARTH PRESSURES Laterally loaded walls supporting soil will act as retaining walls and should be designed as such. Watls that are designed to cleflecL and mobíl-Lze Lhe internal soil sLrength should be designed for active earth pressures. Walls that- are resLrained so that they are not able to deflect t.o mobilize inlernal soil st.rength should be designed for aL-rest earth pressures. The values for the l-ateral eart.h pressures will depend. on the type of soíl retained b1z the wal-1, backfill configuration and construction technique. If the backfill is not, compacted the laLeral earth pressures wíll be very clif ferenL from Lhose noLed below' Lateral eart.h pressure (L. E. P. ) values are presented belo',v Level Backfill with on-site soils (nounds oer cu]:íc fo L Ðer foo[ oi clepth) Active L At-rest Pas s ive The soil samples tested have measured swe1l pressure of abouL 500 pounds per square foot. and the actual swell pressure of the backf i11 mat,erial could be gireater. Our experíence has sho-."n that the actual swell pressure may be much higher' If the retai:recl soils should become moistened af ter const.rucLion Lhe soil rnal' swell against retaining wal1s. The watls should be designed t.o resist T"srflbert snù Øggocisteg PE 50 65 ")? rì L.E.P L.E.P 24 CONSI¡I.ÍING GEOTECHNIçAL ENGI¡¡E€RS ANO MATERIAL TESTING G09033cE the swell pressure of the soil materials if these are used. as parLof t.he backfill within t.he zone of infruence. Tkre zone of i n f=l r,rencê côllcËpl_ is preeentod on Figure g . The above lat.eral- eart.h pressures may be reduced by overexcavat-ing Lhe wall backfíll area beyond the zone of influence and back-filting with crushed rock type material. The zone of influence concept is present.ed on Figure 5. The lateral earth pressure desígn paramelers may chanqe sígnifi-cantly if Lhe area near the wall is roaded or surcharged or issloped. If any of these conclítions occur we should be contacted foraddiLional design parameters tailored to the specific site and sLrucL.ure conditions . suggrested lateral earth pressure (L.E.p. ) values if Lhe backf i11is overexcavaLed beyond Lhe eone of influence and backfilled withcrushed rock are presented below. Level Backfill with crushed rock material- lnorrndq na r-r rkl icf oo1. ner fo o f clenlh )n{- Active L.E. P. At-resL L.E. P 30 50 rf t,he area behind a wall retaining soil material is sroped we should be contact.ed to provide lateral earth pressure design valuestailored for the site specific slopecl condiLions. Resistant forces used in t.he design of the walls wirl depend onthe type of soil that tends to resisL movemenL. we suggest that.you consicler a coefficienl of friction of 0.20 for the on siLe soí1. The lat.eral eart,h pressLlre values provided. above, for clesigrnpurposes, should be Lreated as equivalent fluid pressures. Thelateral eart.h pressures provided above are for level well drained b,ackfill and do not include surcharge loads or additional loading as a resufL of compaction of the backÊill. Unlevef or non-horizon- tal backfill either in front of or behind warls retaining soils will signif icantly inf luence t.he laterar eart.h pressure values. Care shoul-d be taken during consLruction to prevent construction and backfill techniques from overstressing the wa1ls retaining soils. Backfill should be placed in t.hin lifts and compacLed, as lsmbert snù Hgøseisted I 25 CONSULfING GEOIÊCHNICAL €NGINEÊRS AND I.IATERIAL IÊST¡NG c0 9 03 3GE discr:sserJ in this report to realize the lateral earth pressure vafues. Walls retaining soil shoutd. be designed and conslructed so that hydrostatic pressure will not accumulate or will not affect the integrity of the walls. Drainage plans should ínclude a subdrain behind the wall at the bot.t.om of the backfill Lo províde positive drainaçre. Exterior reLaining walls should be provided with perime- ter drain or weep holes to help provide an ouLlet' for collecLed v/aLer behind t.he wall. The ground surface adjacent to the wall should be sloped to permit rapid draínagre of rain. snow melt and irrigat.ion waLer a\^/ay f rom the wal1 backf í11. Sprinkler systems should nct be installed. directfy adjacenL to retaining or basemenL wa]1s. I-1.0 DRAIN SYSTEM A drain sysLem should be provided arouncl buitdingi spaces below t.he finished grade and behind any walls retaining soil. The drain systems are to help red.uce the pot.ential for hydrosLatic pressure to clevelop behind retaining walls. A sketch of the drain system is shown on Fiqure 6. Subdrains should consisL of a Lhree (3) or four (4) inch cliameter perforated rigid pipe surrounded by a fitter. The filter should consisL of a fílter fabríc or a graded material such as washed concrete sand or pea gravel. lf sand or giravel is chosen the pipe shoulcl be placed in the micldle of about four (4) cubic feet of âggregiaEe per linear f ooL of pipe. The drain syslem shoulcl be slòped to positive gravity outlets. ff Lhe drains are daylighLed the drains should" be provided wit.h all weather out.lets and Lhe outlets should be maintained to prevent them from beingr plugged or frozen. We do not recorffnend that. the drains be dischargred to dry well type strucLures. Dry well slrucLures may tend to fail if Lhe surrounding soil material becomes v/etLed and swells or if the ground water rises to a elevaLion of or above the discharge eleva- tion in t.he dry well. We should be callecl to observe the soil exposed in the excavations and to verífy the cletails of the drain sysLem. l'smbeü snÙ Øggseínted j I 26 COÑSIII TING GEOfECHNIçAL ÉNCIN€ÊRS ANÛ ¡¡ATER¡/\L IESf¡NG c0 9 0l 3GE 12. O BACKFILL R¿r-:k I i I I ä.reas and utí1it,1. ¡t"nch baclctítl should be constructedsuch Lhat the backfill will not seLLle after completion of con-struction, and t.hat the backfill is relaLively impervious for t.heupper few feet. The backfill material should be free of trash andother deleterious material. It should be moisture condit.ioned and compact.ed to at. least níneLy (90) percent relative compaction usinga modífied moisLure contenL-dry density (proctor) relationship Lest (ASTM D1557 ) . only enough u/ater should be added. to the backfillmaterial- to arlow proper compaction. Do noL pond, puddle, float. orjet backfill soil materials. fmproperly placed backfill maLerial will all-ow waLer migration more easily Lhan properly recompacted fill. rmproperly compactedfill is likely to settle, creating a 1ow surface area which further enhances water accumulaLion and subsequenL migration to the found.a*tion soils. rmproperly placed backfill will al-low water to migrat.e along theut.ility t.rench or backfill areas to gain access to the subgrradesupport soil-s with subsequent. mobilization of Lhe swell or settle- ment mechanism resulting in movement of Lhe supported st.ructure.l{oist,ure migration could al-so result in the inconvenience of freebiater in Lhe crawl space. Backfill placement t.echníques shoutd noL jeopardize the int.egrityof existing structural members. We reconimend recently constructedconcrete structural members be appropriately cured prior t.o adjacenL backfi llinq . 13.0 SURFACE DRATNAGE The foundation soil materials should be prevented from becoming¡wetted afLer construction. Post construction wetting of the soil support soil mat.erials can ínitíate swel'l poLential or settlement ¡:otential as well- as decrease the bearing capacity of the supportsoil materials . ProLecting the foundaLion from wet.Ling can be aiclecl by providing positive and rapid drainage of surface water away from t.he st.ructure. The final grade of the ground surface adjacent to the strucLure should have a well- defined slope av¿ay from the foundation walls on all sides. The ability to establish proper site surface drainaqe Lsilrhert euù $øgocíeteg I I ì a.-l CONSULTIHG G€OTECHNICAL ENGINËÊRS ANO I¡tATÉRIAL TEST¡NG c09033G8 a\day from the st.ruclure foundation sysLem may be influenced by t'he existinq Lopography, existing structure elevalions and the grades and elevations of Lhe ground surface adjacenL to the proposed sLructure. We sug'gest, where possible a minimum fall of the surface grade away from the sLructure be t.hat which will accommodate other project- grading" constraints and provide rapid drainaqe of surface water av/ay from the structure. If there are no other project constraints we sugigesL a fa1l of abouf: one (1) foot in the first Len (10) feet away from the sLructure foundation. Appropríate surface drainage should be maintained for the life of the project- Future landscaping plans should. j-nclude care and attention to the potential infl-uence on t.he long term performance of the foundalion and/or crawl space if improper surface drainage is not maintained' Roof runoff should be collect.ed in appropriate roof drainage collection devices, such as eve gutters or similar, and directed Lo discharg'e in appropriate roof drainage sysLems. Roof runoff should not be allowed to fall on or near foundations, backfill areas/ flatwork, paved areas or other sLrucLural members. Downspouts and faucels should discharge onLo splash blocks t.hat extend beyond the limits of Ehe backfilf areas. Splash blocks should be sloped away from the foundation walls. Snow storage areas should noL be located next to the struc¡ure. Proper surf ace drainage should T:e tmirrLained from the onset of construcLion Lhrough the proposed project life' If significant. water concenlration and velocity occurs err:sir:n may occur. Erosion proLection may be considered to reduce soil erosíon potential. A lanclscape specialist or civil engineer should be consufted for surface drainage desigin, erosion protecLion and landscaping cons iderations . 14. O LANDSCAPE TRR]GATION An irrigaLion system should. not be installed next Lo foundations, concrete fl-atwork or paved areas. If an irrigation system is in- stalled, Lhe system should be placed so t.hat. the irrigation waLer does not fall or flow near foundations, flat.work or pavements . The amounl of irrígat.ion water should be controlled' We recommend. t.hat wherever possible xeriscaping concepLs be used' Generally, the xeriscape includes planning and design concepts r';hich will reduce irrigation waLer. The reason we suggest xeriscape concepls for 1andscapinq is because the reduced lanclscape water will decrease the pot.ential for waLer Lo influence the long Lerm 2B lumbeut snb ØsgotíEtÊd I CONSULlINß GFNIFCHNICAL ENGINÊERS ANO MATENIAL TESTING G09033c8 performance of t,he sLrucL,ure foundations and flaLwork. Manypublications are available which discuss xeriscape. Colorado St.ateUniversity Cooperative Extension has several useful publications and mosL landscape architects are familiar with the subject. Mon¡roseBotanical Society has a Botanical Gard.en, 1800 pavilion Drive, sout.hof Niagara Drive, Mont,rose, colorado, that. has a very good exhibitwíth examples and information regardingi successful xeriscape concepts. Due to the expansive nature of the soils tested we suggest that t.he owner consíder landscaping, with only native vegetation whichrequires only natural precipitation to survive. AcldiLional irrigra*tion waLer will greatly increase t.he likelihood of damage to the sLructure as a result of volume changes of the material supporLing t.he structure. Impervious qeoLextile mat,erial may be incorporatedproject landscape clesign to reduce Lhe potent,ial for water Lo influence the foundation soils. into the irrigat ion ].5. O SOIL CORROS]VITY TO CONCRETE Chemical tests rvere performed on a sample of soil obtained during Lhe field study. The soíl sample was t.ested for pH, waler soluble sultates, ancl total dissoLved salt.s. The results are presented" in Äppcndix B. The test resulls indicate a water solul:le sulfate content of 115 parts per million. Based on Lhe American ConcreLernstituLe (ACI) information, a waLer soluble sulfate content of l-1-5parts per million indicates negligible exposure to sulfate altack onconcrete. We suggest sulfate resislant. cement be used in concrete which will be in conLact. with Lhe on site soils. American Concrete InstituLe recofitmendat.ions for sulfate resistant cement, based on the water soluble sulfate contenL should be used. The American Concrete Institute (aCr¡ does not slate a recoñtmended maxímum water/cement ratio for concrete where negligible exposure will occur, however, ACf does recornmend a maximum water/cement ratio of 0,50 for concrete where moderat,e exposure to sulfate attack will occur. ]-6. O RADON CONSIDERATIONS Our experience Colorado procl.uce inclicates that many small quantities of of Lhe soils in wesLern radon gias. Radon gas may tend {embert snù Øggstigte$ ?o CONSULTING GË.OTECHNICAL ENGINEERS ANO MATERIAL TESIING c09033cE Lo colfect in closed poorly ventj l.ated structures. Radon consider- alions are presented in Appendix D. 1-1 . O POST DESIGN CONSTDERATTONS The project g:eotechnical engineer should be consulted during construction of the project to observe siLe conditíons and open excavations during construction and to provide maLerials Lesting of soil and concrete This subsurface soil and foundation condit.ion study is Ì¡ased on limited sampling; therefore, it is necessary to assume that the subsurface conditions do not. vary g"reatly from Lhose encountered in the field study. Our experience has shown that. significanb varia- t.íons are likely t-o exist and can become apparent only during additional on site excavation. For this reason, and because of our familiarity wit.h the projecL, Lambert and Associates should be retained to observe foundation excavations prior to foundation constructíon, to observe the geotechnícal engineering aspects of the construcLion ancl to be available in the event any unusual or unexpected condit.ions are encounterecl. The cost of the geotechnical engineering observations and maLeríal Lesting during construction or aclditionat engineering consultatíon is not íncluded in the fee for this report. We recofiìmend that your consLruct.ion budget ínclude site visits early during' construct.ion scheclule for the project geotechnical engirreer Lo observe foundaLion excavations ancl for aclditional site visits to test compacted soil. We recommend that the observaLion and mat.erial t.esting services d"urinq consLruction be retained by the owner or the owner's engineer or architecL, not the contractor, to maintain third party credibility. We are experienced and available Lo provide material t.esting services. We have included a copy of a report prepared by Van Gilder Insurance which discusses Lest.ing services during con- sLruction. It is our opiníon that Lhe owner, architect and engineer be familiar with the informaLion. If you have any questions regarding this concept please contacl us ' We suggest that your construct.ion plans and schedule include provísions for geotechnical engineering observatíons and material tesLíng during construction and your budget reflect t'hese provi- sions. Lsmhert nnù Øøgsritttts 30 CONSULTING GEOTECHÑICAL ÉNGIN6€RS ÂNO MAI hRIAL TESlIHG c0903lcE It is difficult Lo predicL if unexpected subsurface conditionswill be encountered during construction. Since such condiLíons maybe fr:rund, we suggest. that Lhe owner and the contractor make provi-sions in Lheir budget and const,ruction schedule to accommodate unexpecLed subsurface conditions . L1.L Structural Filt euality It is our understanding that, the proposed development may include compacted structural fill. The quality of compacLed. sLructural flllwirl depend on the Lype of mat.erial used as st.ructural fill, filllift t.hickness, fill moisture condition and compactive effort. usedduring construct.ion of the structural fí1I. Engineering observationand Lesting of structural fill is essential as an aid t.o safeguardthe quality and performance of the structural fill. Filf maLerials placed on sloped areas require special placement techniques Lhat key the fill materials unLo the underlyingr supportmaterials. These t.echniques include a Loe key at the toe contact of Lhe slope filr and benching the fill/natural contact up the slopej-nto the competent nat,ural material-. The placing technique will al-so inclucle subd.rains at several l-ocaLions Lo inLercept subsurfacev/ater and route it away from the fill materials. We are available t.o discuss these Lechniques with you and your earthwork contractor. TesLing of the st.ructural fill normally includ.es tesLs t.o d"eLer- mine the grain size distribution, swcll potential and moist.ure- clensiLy relationship of t.he fill material to verify the materialsuitabilicy for use as structural fill. As the material is placed the in-place moisLure cont.ent. and clry densit,y are tesLed to indicatethe relative compaction of the placed structural f ilf . Ilrle recommend" t.haL your budget. include provisions for observatj-on and testing ofstructural fill during construction. Testing of the compacted fitl material should include tests of themoisture cont,ent. and density of the fill mat,erial placed and compacted prior t,o placement of additional fill mat,erial. We sugqest that a reasonable number of densíty tests of Lhe fillmaterial can best be determined on a site, materíal and construcLion basis although as a guid.eline we sugigest one tesL per about each 300to 500 square feet, of each lift of fill mat.erial. Utility trench backfill may need to be tested about. every 100 linear feet of lift of backfill. Lsmbert snù flggocietgd 31 CONSTJLTING GEOTECHNICAL ENGINE€RS ANO 'TAIÊRIAL TÊSTING c09033GE 17.2 Concrete Qualitv ït is our und.erstandingi current pl-ans include reínforced struc- tural concreLe for foundaLions and walls and may include concrete slabs on grade and. pavement. To insure concreLe members perform as intended, the structural engineer should be consulted and shou]d address facLors such as design loadings, anticipated mowement and deformations. The quality of concrete ís influenced by proport.ioning of the concreLe mix, placement, consolidation and curing. Desirable qualit.ies of cåncrete include compressive sLrengLh, waLer tightness and resisLance to weathering. Enqíneering observations and testing of concreLe during' construction is essential- as an aíd to safeguard t.he quality of the completed concrete ' Testing of the concrete is normalty performed to determine com- pressive strength, entrainecl air contenL, slump and temperalure' we recofttmencl that your buclget íncluc1e provisions fOr testing of concrete during construction. We suglgest LhaL a reasonable frequency of concreLe tests can best be deLermined on a site, materials and const'rr.].ctíonspecificbasisalthroughasaguidelineAmerican concrete InsLitute, AcT, suggests Ône Lesl' per about each fifty (50) cubic yards or portion thereof per day of concreLe maLerial placed' ].8.0 LTMITATIONS It. is Lhe owner'S and the oln/rter's representaLíves' responsibility Lo reacl Lhis reporL and become famitiar wit.h the recommendations and sugqesLiorr= pr"=ented. we should. be contacted íf any guestions arise concerning the geotechnical engineering aspects of this project as a result of t.he information presenled in thís report' ThescoSfeofservicesforthisstud.ydoesnoLincludeeither =på"iri"rirv or by implication any environmental or biological as mold, fungi, bacteria, etc') Assessment of the site or iclent.ificaLion or prevention of pollutants, hazardous materials conclitions. If thã owner is concerned abouL the potenLial f'or contamination or pollution, oLher stud-ies should be performed' The recommendations outlined above are based on our understanding of the current.ly proposed construction. Inle are available to discuss the details of ãLr, r""ommendations with you ancl revise them where necessary.Thisgieotechnicalengineeringreportisbasedonthe a')JA Lsmhert nnb ßggocínteg ( such or such CONSULTING GEOfECHNICAL EHGINÊERS ANO MATERIAL fESTING c09033c8 proposed site developmenL and scope of ser\¡ices as provideci lr: us byMr' Paul sorensen, p.E. CGRS, on the type of construction planned,existing sile conditions at the time of the field stud.y, arrd" on ourfindings. should the planned, proposed use of the site be altered,Lambert and Associates must be contacted, since any such changes maymake our suggtestions and recommendations inappropriat.e. This r"porlshould be used. oNLy for Lhe planned development for which thisreport was tailored and prepared, and ONLy to meet. informat.ion need.sof the owner and the o\¡iirrer ' s represent.atives. In the event that anychanges in the future design or location of the buitding areplanned, the conclusions and. recommendations contained in thisreport shal1 not be considered valid unless the changes are reviewed.and conclttsions of Lhis report are modified or verified in writing.rL is recommended t.hat, the geot.echnical engineer be provided Lheopportunity for a general review of Lhe final projecL desígn and.specificat.ions in order that. t.he earthwork and foundaLion recolnmendations may be properly int,erpreLed. and implemenLed in thedesiqn and specif ícat,ions. This report does not. provide eart.hwork specífications. we canprorride guidelines for your use in preparing project specificearthwork specificat.ions. Please contact. us if you neecl these foryour projecL. This reporL presents boLh suggiestions and. recommendat,ions. Thesuggestions are presenLed so that t.he owner and L,he owner'srellrcscntat.ives may compal:e t.he cost. Lo Lhe poLent-ial risk orbenefit for Lhe sugg,esLed procedures. This report contains suggestions and. recommendations which areintended Lo work in concert with recommendaLions provided by theother design t,eam members to provide somewhaL predictable foundationperformance. ff any of L,he recommendations are not included in Lhedesign and construction of the projecL iL may result inunpredictable foundation performance or performance different thananticípated. We recommend t.hat we be requested t.o provide geoLechr nica] engineering observation and maLeriars tesLing during theconstruction phase of Lhe project as discussecl in t.his reporL. Thepurpose for on sit.e observation and LesLing by us duringi construc-tion is Lo help provide continuity of service from Lhe planning ofthe project through Lhe construction of the projecL. This servicewill also allov/ us to revise our recommerLdations if conditions occuror are discovered during- construcLion Lhat were not evid.enced during Lhe init.ial st.udy. I¡7e suggest thaL the owner and the contract,or l'smbert anù €[ggocictes 33 CO}ISULTING GEOIECHNICAL ENGIHEÊRS AND MATERIAL IÉSTING c09 03 3GE make provisions in ule to accornmodaLe DanieI LamberL, P.E Geot cal Engineer their consLruct.ion bud.get. and construction sched- unexpecLed subsurface corrditions' We represent that our services were performed within the limits prescribed by you and with the usual Ehoroughness and compeLence of Lh" "rrrrenL acãepted practice of Lhe geotechnical engíneering pro- fession in Lhe area. No vi/arranty or representation either expressed or implied is included or int,ended ín this reporL or our contract. we are available to discuss our findíngs with you. rf you have any quesLions please contact us. The supportíng data for this report is included in the accompanying figures and appendices. This reporL is a product of Lambert and Associates ' Excerpts from Lhis report, used in oLher documenLs may not convey the intent or proper concept,s when taken out of conLext, or they may be misinterpreted or used incorrectly. Reproduction, in part or whole, of Lhis document wíthou| prior written consent of Lambert and Associates is Prohibited. This report ancl information presented can be used only for Lhis site, for Lhis proposed. development, and only for the client. for whom our work was performed. Any other circurnstances are not' appropriate applications of this information. Other developmenl plans wilL require project specific review by us' We have enclosed a copy of a brief discussion al¡out geotechnícal engineerinq reports published. by AssocíaLion of Soil and Foundation Engineers for Your reference ' Please call when are reguireci. further consultation or observations and tests If you have any questíons concerning this reporl or if we may be of further assistance. please conLact us' Respectfulty submit ted; LAMBERT AND ASSOCIA Reviewed Denni Geotechníca1 Engineer f.smbeff nnÙ ßlggotíntefi TL, P. E DRL/nr 34 CONSIII fIÑG 6EOTEÇHNICAL ËNGINÉÉRS ANû IIATERIAL IÉSTING ::,::;: zÌ r na Frr1gr. ,, h,lft .', O tnaicates approximate projeci location N This map is intended to present geotechnical engineering data only PROJECT VICINITY MAP NO SCALE ? l0l,annbcrt flnù gÍficirtrr rUþtrl|lrv)/-oþUoFJ(fzgâ1FfJ)P-L!FJ(_)(nztnL0-)>,oo>- cü!(d!'r302 00o0)äEc'&)Od'j: c)tr(Ú:1 L)Çí Irrc)-ÕoE80(J=EÃ)oöLkÈo.9oûcú'O>c)r'È(-) ()0)É.n u)ØFızano(úOoÞoko-o(t)oo()t<d)Í).IJ(dÊxotqÊ.e.6Ja/)0,H()o__rØooÞoko.orJ7c)0-)F.xokÊØ0_.,(Je', l,:t.ll --.',''-".*''I *- ,-r --.ij-lao>. -l^ rts__.l ohñ ilvC\¡IIIIÁtrrf+.cE\-t¿CTËðËE'Ë6+aù¡ù¡lllE6rrl c)Õz,C¡ra.D{crVr2(m{tl-o.,|]Tlo()fz.ç)ttc@l)p(Jm+ærn{3mz,IMaximum Depth ofStream ScourHáxîmum Depth ófStream ScourCompactAbutment- Còmpacted-Backf i-Abutme- Backf intr-AA--ùl-Iral FilAcomÞactedlilatiJral SoilsICompacNOT TO SCALENatural Soi l sB = Foot ing t/idth,4 = Compacted Structura I F¡ I I Th icknessand Fil I W¡dth Beyond Footín9.Ed9ê,.: ,,..D = Footing Embedment Betorr, toùre;t',¡ãJacd¡Grade :, . ¡..j,FIÞ3r*DãgnËÇrIfrDË,I1 .""úr;:¿ú Con c re te Fi n i shed Floor SIab or lnterior Grade Exisling Exterior GracJe Foundation \{all Concrete Floor SÌab or Finished lnterior Grade l'1ini mum [mbedmen t f1i n mum trnbed::en t EIlBEDIlTNT COI.ICEPT oundation'l/all þ1al I Backfi I I 't I I L. Foot i ng Foot i ng Lnmbart flnù f[.sgottstss Foundat ion,/Reta in i ng' Wall Zone of I nf I uence Concrete s I ab:on-grador finished elevation tr 60 BACKFILL ZONE OF INFLUENCT CONCEPT Foot i ng , tl,smt?ü ffiù gÍrocl¡trr , : iI Low Foun da t i on/ Re ta i n i ncl l¿Ja I I I I I I Dermeabilitv BackFi I I 1,1âteriai l Comnacted Backf i I I Dra inage B I anket Concrete S i ab-on-Grade I Geo techn i ca I Fìlter Fabric l- ree Dra i nrng' Filter rialerial I Perforaled Drain Pipe SIoned to 0u t let Hoislure ßarrier Tlr is sketch is to shcu¡ concent only ' The text of our reDort shouid be consul ted for addi tional information' CONCEPT I ONAL SKETCH OT FOUNDAT I ON DRA I II SYSTEM GrG il fl,e¡nhsrt nnÙ ltwdffet nÇilder NEWsLETTER lnsurance Corporation Brokers since 1905 . 7@ Broadway, suite 1035, Denver, co g0200 " 303/gs7-g500 THE PROFESSIONAL LIABILIW PERSPECTIVE Vol" 8, No" I @yrigt¡t 19SB Ar¡gust f98B TIHO TIIRES TTIE TESTTNG LA.BORå.TORY? It is one of those relatively small details inthe overall seheme of things. Independenttesting may be required by local building !o9-9r: or it may be insisted upon by lenders-. Additional testing can usually be oidered bythe design team during construction. What-ever the souree of the requirement, malyowners perceive it to be an unnecessslvburden-a¡ additional cost imposed principal-ly for someone elsets benefii. What does this have to do with you? you may be the only one in a position to in-fluenee the use of testing and inspection serviees so they beeome more, rather than less likely to contribute to a suceessful out-eome. There seems to be an a_lmost irresist-ible incünation on the part of some ownersto eest aside their potential value to theproject in favor of tne administnative andfinancial convenience of plaeing, responsibili-ty for their delivery into the hands of thegenerai contractor. Resist this inelination where you ean. It isnot in vour eüent's best interests, and it is certainly- not in yours. There are impoctant issues o-f quality and even more important issue5 of lif e saf ety at stake. In the complexenvironment of today's eonstruction arena,it makes very little jense for either of yoú !9 fiu. up your contnol of quality control.Yet it happens aitogether too often. Whatts Behfuld this Missdventr¡re? the idea that millions eould be saved byeliminating the jobs of Federal workers en_gaged in construction inspection. The pro_eurement model used to support this strokeof genius was the manufactuiing segment ofthe eeonomy, where producers ıf gıoOs pur- chased by the Government had bee-n requìredfor ¡rears to conduct their own quality assur-ence pnograms. The result w&s a trendy new eoneept in Federal eonst¡uetion knowñas Contraetor euality Control (CeC). It was L dumb idea. Costs were simplyshifted from the Federal payrolt to capiiai irnpnovement budgets. Government eontrae-tors, selected on the basis of the lowest bid,were handed resourees to assure the quatityof thei¡ own performance. Some cíiO so; many did not. AII found themselves eaughiup in an impossible eonfliet between the demands of time and eost, on one hand, andthe dictates of quality, oR the other. CQC was opposed by the Associated GeneralContractors of America, by independent testing laboratories, by the design profes- sions, and by those charged with fnont-Iineresponsibility for quatity control in theFederal Agencies. Eventualiv. even the General Accounting Office camé'to the con- clusion that it ought to be abandoned, But, once set in motion and fueled by the per- vasive infiuence of the Federal Government,the idea spread-first to state and local governments; finaUy, to the private seetor. i i: j ': The culprit seems to be the Federal Govern- Why would the private seetor embrace suchment. In the 1960's, someone eame up with an ill-conceived notion? Because so ms.ny Binder Key: Professional practiees VoL I, No.8 owners view testing and inspection as an undertaking which simply duplicates some- thing they are entitled to in sny event. They are confident they will be prctected by eontraet doeuments which eover every detail and eontingency. They look to local building inspectors to assure eompliance with codes. And they fully expect the design team to fulfill its obligation to safeguard the quality of the work. A Fox in the Henhouse If testing is pereeived as little more than an 'unneeessary, but unavoidable expenset why not make the general eontraetor respon- sible for controlling the cost? It may pro- duce a savings, and it certainly eliminates an adminstrative headache. If eontractual obligations dealing with the projeet sehedule and budget can be enforeed, surely those governing quality can be enforeed, as well. Possibly so, but who is going to do it? Some testing eonsultants wÌll not aecept CQC work. The re&sons they give eome from firsthand experienee. They include: 1) inadequate to barely adequate seope, 2) selection based on the lowest bid; 3) non- negotiable contract teri'ns inappncpriate to the delivery of a professional serviee;4) intimidation of inspeetors by field super- visors; and 5) suppression of low or failing test results. This ought to be fair warning to anSr owner. Keepirg Both Hands on the lYheel The largest part of the problem, from your point ol view, is one of artful persuasion. If you eannot eonvinee your elient of the value of independent testing and inspeetion, no one e&n. Yet, if you do not, you are Iikely to find yourself responsible for an assuranee of quatity you are in no position to deliver. How can you keep quatity control where it belongs and, in the process, prevent the owner from eompromising his or her interests in the project as well as yours? Consider these suggestions: 1. Put the issue on an early agenda. It needs your attention. Anticipate the ownerts inclination to avoid dealing with testing and inspection, and explain its importance to the sueeess of the project. - fer¡lst, if you ean,until your client agrees to hire the testing laboratory independently and to establish aiadequate budget to meet the anticipatedcosts. A testing eonsultant hired by the owner eannot be fired by the generai con-traetor for Brodueing less than favorable results. Page 2 1988 2. Tailor the testing rem ents carefullv. Scissocs and paste can be your veny worst enemies, Speeify what the job requires, retain controi of seleetion and hiring, make certain the eontractorrs responsibilities fornotifieation for seheduling purposes are elear, and require that copies of all reports be distributed by the laboratory directly to you. 3. Insist on a ruction testin eon- f erenee,ean 8.n esse ment oãTfffie eoordination, Inelude the owner, the general contraetor, major subeontrac- tors, the testing consultant, and the design team. Review your requirements, the pro- eedures to be fol-lowed, and the responsibili- ties of eaeh of the parties. Have the testing consultant prepa.re a eonf erence m emoran- dum for distribution to all participants. 4, Monitor tests and inspections closely. Make certain your field répresèntãtive is present during tests and inspections, so that defieiencies in proeedures or results can b€ reported and aeted upon quiekly. Scale baek testing if it becomes elear it is appropiateto do so under the eireurnstances; do not hesitate to orden additional tests if they are requi red. 5. Ffq4!yrJ99p_y!-q client informed. With- out your lælp, he or she is not likely to understand what the test results mean, nor will your eetions in response to them make mueh sense. If additional testing is catled for, explain why. Rememben, it is en unex- pected and, possibly, u'rbudgeted additional eost for whieh you will need to pave the wey. In this sense, índependent testing and inspection can serve an important, secondary purpose. You might view it as a eommunica- tions resouree. Use it in this way, and Ítjust may yield unexpected dividends, THË PROFESSIONAL ¡.IABILITY PERSPECTIVE IMPORTANT INFORMATION ABOUT YOUR GEOTECHNICAL ENGINEERING REPORT More construction problems are caused by site subsur- face conditions than any other factor. As troublesome as subsurface problems can be. their frequency and extent have been lessened considerably in recent years. due in large measure to programs and publications of ASFE,/ The Association of Engineering Firms Practicing in the Ceosciences. The follorving suggestions and observarions are offered to help you reduce the geotechnical-related delays, cost-overruns and other costly headaches that can occur during a conslruction proiect. A GEOTECHNICAL ENGINEERINC REPORT IS BASED ON A UNIQUE SET OF PROJ ECT-SPECI FIC FACTORS A geotechnical engineering report is based on a subsur- lace exploration plan designeC to incorporate a unique set of project-specific factors. Thesc rypically inciude: the general naiure ol the structure in,,'olved, its size and configuration: the location of the structure on the site' ancJ its oricntation; physical concomitants such as access roads. parking lors. anC underground utilit¡es, and the level of aciditional risk ivhich the client assumed by virtue of limitations imposed upon thc explorarory program. To help avoici costl¡r problems. consult the geotechnical engineer to derermine horv any factors which change subsequent io the date of rhe report may- af fect its recom menclations Unless your consulting geocechnical engineer indicates otherwise, ¿iotrr,tcph'cf¡ri¡ al tnqintrriui rrporl siruulc{ rrot lir.'trS¿r'1: " When the nature of the proposed structure is changed. forexample. if an office building will be erectecl ìnstead ol a parking garage. or if a ref riger- atecl warehouse lvill be built insteacl of an unre- frigerated one: . when the size or conf iguration of the proposecl structure is alrered. . rvhen rhe loca¡ion or orientation of the proposed struc(u rL1 is modi f ied : ' r,vhen there is a change of o',,,'ncrship. or . for application to an adiacent sire. CcolcrliI ica f ¡rr,,ir¡¿t'rs c ú n nL)t Ll ( ( c pt rcsporr S ifii ft l y l tlr p rù(]lffi $ n'l\ich ntttl tlev¿l¡p i[ lttc. arc not ct¡tsulter.l after ftrctors corrsid- ered in lhtir rcporl s rirurlt4: ment lww cftcrrr4rri. MOST CEOTECHNICAL''FINDINGS" ARE PROFESSIONAL ESTI MATES Site exploration identif ies actual subsurface conditions only at those points where samples are taken. when they are taken. Data derived through sampling and sub- sequenl laboratory testing are extrapolated by geo- technical engineers who then render an opinion about overall subsurface conditions, their likely reaction to proposed construction activiry, and appropriate founda- tion design. Even under oprimal circumstances actual conditions may difler from those inferred to exist, because no geotechnical engineer, no matter how qualified, and no subsurface exploration program, no matter how comprehensive. can reveal what is hidden by earth. rock and tìme. The actual interface between mare- rials may be far more gradual or abrupt than a report indicates. Actualcondirions in areas not sampled may differ from predictions. Notliirrg can be done to prevent thi wnnltipated. bul stcps un þe tttlun to help mininíze theîr impctcl. For lhis reason. nittsl euperienced owners relaín their ¿lrotcilriicttl ro¡rsull¡rrls tirrouqh lle' ror¡strlctio n slage. to iden- tify variances. conducr ¿ddirional tesrs which may be needed. and to re.commend solutions to problems encounterecl on site. SUBSURFACE CONDITIONS CAN CHANCE Subsurface conclitions rne!,Ðe modified by constantly- changing natural forces. Because a geotechnical engi- neering report is based on conditions rvhich existed at thc. timc of subsurface erploration. couslruct¡(ln decisíous slro¿rlrT rrol lr.'li¿tsrd orr ti gr'oiiilì;iictrl cnqineerinq rtporlwlnse art'r¡rruu rriru lii,tut lc¡l ¿1ff¿'¡tc,ï ¡iy {irrr. Speak rvith the geo" technical consultant to learn il addi¡ionai tests are aclvisable be[ore construction starts. Construction operations at oi'ad¡ace;rt to rhc site and n¡tural evl-nls such as floods. earthqual(es or ground- r,v¡ter f lucruations ma!' ai:c alfect subsurÍace conditions ancl. thus. the continuing a¡requåcy- cí a geotechnical rel)ort. l'hr" geotechnicai engineer should be kept appriseci c'rl ðrn,.' such eveîis ancl sho'licl be consulted to determine il ¡clclition¡l tes:s are necessarv CEOTECH N ICAL SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES AND PERSONS CL.otechni(¿|l enginecrs reports are crep:reci to meet thL. specif ic needs ol siìecií;; incirvid..l¡ls A report pre- prrecl for a cc,nsulting ci'. il engineer ira)- nol be ade- qu:tc- for ô construction contractor. or even some other consulting civil enginær Unless indicated otherrvise. this report wes prep¿red expressly for the client involved anil expressll' for purposes indicateC by the client. Use b¡- any other persons for an;,' purpose. or by the client for a different purpose. ma'; result in problems. No iir,li- r,'irlrral otl¡r lli¡rr llì¿ r:li¡rrl sirori[l rrp¡lrr llris repL'rrt l0r ils inl*nitd prrrpdsr u'itltt ul frsl ¡,.aftrrrig rll(lr lllr gleoteúrnicul enlinrcr. Ntr p{rsorr slroul,i ,t¡'¡ly tftis rcporl f0r ctng plttpose ollicr llrarr llicrt ori4írrrrlly i(rrrl.'rirpl¿rl.'.1 u'¡¡,1rul frrst conl..rrín,J u'itJì lfc dcolcclìrrii¿tl rrrgirrccr: der the mistaken impression that simply disclaiming re- soonsibilitv for the accuracy of subsurface information ui*rys insúlates them from altendant liability. Providing the best available information lo contractors helps pre- vent costly construction problems a¡d the adversarial attitudes which aggravate them to disproportionate scale, READ RESPONSIBILITY CLAUSES CLOSELY Because geotechnical engineering.is based extensively on iudgmãnt and opinion, il is far less exact than other design disciplines. This situalion has resulted in wholly unwãrranted claims beìng lodged against geotechnical consulrants, To help prevenl this problem, geotechnical engineers have developed model clauses for use in wril- ten transmittals. These are not exculpatory clauses designed to foist geotechnical engineers' liabilities onto soméone else. Rather they are definitive clauses which idenrify where geotech nical engi neers' responsibilities begin and end. Their use helps all parties involved rec- ogñize theìr individual responsibilities and take appro- priate action. Some of these definitive clauses are likely to appear in your geolechnical engineering report. and iûu ãre encouraged to read them closely Your geo- iechnical engineer rvill be pleased to give full and frank answers to your questions. OTHER STEPS YOU CAN TAKE TO REDUCE RISK Your consulting geotechnical engineer will be pleased to cliscuss other techniques which can be employcd to mit' igate risk. ln addition. ASFE has developed a variety of rñaterials which may be benelicial Contact ASFE for a complimentary copy ol its publications direclor-v. A GEOTECHNICAL ENGINEERING REPORT IS SUBJECT TO MISINTERPRETATION Costly problems can occur when other design profes- sionais-develop their plans based on misinterpretations of a geotechnical engineering report. To help avoid thesã problems, the geotechnical engineer should be retained to work with other appropriale design profes- sionals to explain relevant geotechnical findings and to review the adequacy of their plans and specifications relative to geolechnical issues. BORINC LOGS SHOULD NOT BE SEPARATED FROM THE ENGINEERING REPORT Final boring logs are developed by geotechnic.al engi- neers baseã upbn theìr interpretalion of lield logs {assemblecl by site personnel) and. laboratory evaluation of field samples. Only finalboring'logs cuslomarily are included in geotechnical engineering reports. these [ogs shou[d not tmder anlt circumsttuces þe retirarvn [or inclusion in architectural or oihcr design drawings, because clrafters may commit errors or omissions in lhe transfer process' Atrhough photographic reproduction elimjnates lhis probleri ii doeinothing lo minimize the possibility ol ¿ontraclors misinterpreting the logs during bicl prepara- tion. When this occurs. delays, dispules and unantici- paled costs are the all'too-frequenl result. To minimize the likelihood of boring log misinterpreta- tion, give ,on¡¡,7¿tttrs readg access to the complete g.eotechnical enqinitrurcl report preparecl or authorized for their use' those who clo not provide such access may proceed un- Puf'l¡slìd,l f'U ,/5¡FE THE ASSOCIATION OF ENGINEERING FIRMS PRACTICING IN THE GEOSCIENCES BBìl Colewille Road/suite G lgólsilver spring, Maryland 20910/(301) 565'2733 079,r'llt G09033G8 The field field study encounL.ered of the test encount.ered through 47. Ij APPENDIX A study was performed. on December.22 anð.23, 2009. TheconsisLed of logging and sampling the soilsin nine (9) test borings. The approximate locationsborings are shown on Figure 2. The 1og of the soilsin t.he test borings are presented on Figures A2 The test borings were logged by Lambert and Associat.es andsamples of significant soil types were obtained. The samplesv/ere oblained from t.he test borings using a Modified CaliforniaBarrel sampler and bulk disLurbed samples v¿ere obtained.Penetration blow counts were determined using a 140 pound hammerfree falling 30 inches. The blow count,s are presented on thelogs of the tesL boringrs such as 16/6 where l_6 blcws with thehammer \^/ere required. to drive the sampler 6 inches. The engineering field d.escription and major soil classificationare based on our interpretation of.the materials encountered andare prepared according to the Unified Soil Classification System,ASTM D24BB. The descript.ion and classifícation which appear onuhe test boring logr is inLended to be that which most accuratelydescribes a qiven interval of the test. boring (frequently anint,erval of several feet). Occasionally discrepancies occur inthe Unified Soil ClassificaLion System nomenclature between aninterval of Lhe soil log and a particular sample in the int,erval.For example, an int,ervar on t,he t,est boring logr may be identj_fieclas a silty sanci (Su¡ while one sample Laken wiLhin the intervalmay have individually been iclentified as a sandy sitt (ML). Thisdiscrepancy is frequenlly allowed to remaín to emphasize t.heoccurrence of local t,extural variat.ions in the interval. The stratification lines present.ed on Lhe logrs are intend.edpresent, our interpretation of the subsurface conclitions encor.r.ntered in Lhe test boring. The stratification linesrepresent the approximat.e boundary between soil types and thetransition may be gradual. lsmbert nnù Øggscíırtsg to ì A1 CONSULIING GEOf ÊCHNICAL ENGINEERS ANO HAIERIAL TESIIhC KEY TO LOG OF TEST BORING Borlng Number: Elevatlon: Date Drilled: Location: Diameter: Field Engineer: Total Dopth:Depth to WatsratTirne of Dtilling: ' ı¡¡ E v, g CLoo 0 5 10 15 20 25 Sample Soil llescription Type N Sand, silty, medium dense, moist, tan (sM)L Unified Soil Classifi cation lndicates Bulk Bag SampleB c lndicates Drive Sample lncicates Sampler TYPe: C - Modified Califomia St - Standard SPlit SPoon H - Hand Sampler 7t12 lndicates seven blows required to drive the sampler twelve inches with a hammer that weíghs one hundred forty pounds and is dropped thirtY inches. BOUNCE lndicates no further penetration occuned with additional blows with the hammer NR: lndicates no sample recovered CAVED: lndicates depth the test boring caved after drillinq Y lndicates the location of free subsurface water when measured CLAY Note: SYmbols are ofren used only to helP visuallY SILT identifY the described information Presented on SAND the log. GRAVEL CLAYSTONE SANDSTONE Laboratory Teet Resutts Notes in thís column indícate tests performed and test results if not plotted^ DD: lndicates dry density in pounds per cubic foot MC: lndicates moislure content as percent of dry unit weight LL: lndicates Liquid Limit PL: lndicates Plastic Limit Pl: lndicates Plasticity lndex ru W - ProjectName: CGRS No. 1'10270-1172Jaa FrojectNumber: G09033GE $mnherf mrh $'*snrinicx CO NSU LTINO OEOTECHN ICAL ENGI N EERS AND MATERIAL TESTI NG Figure: A1 T-o(Dc)z.À¡3PC)C)xØzIoN){o{lv--lft)0)1laoor)7EIt(Dt'tG)o(oO(¡CJ)C)m-nı'IgN)HgttdirtÉrt+gr+ç.{vÞHÞtrr"{ r&toùþozU)ct-_Jzoomo-tmc)TzC)f-mzL.,zmmnØz.o{m7FF-ìmCNJzoÐrc,i'o ÂtãßÉoFo:v!.! .. ı-Ø(Dorı"NøN-ãtoN)f-O:fo(o(ooofÐ!l-o:f .Ígı'3ãıDr3'd.bãG)3o-TT{umëU,'{IÐrr9ãô N't-ò='zd(O ^o-t¡,aZ3ETo:':5'c)oø-loÐgoîtN)(Doootão€!¡o:g¡-l3ooE_4,='çzoa{Dm=c)ocooo-SymbolDepthØ!J¿aı-f,ôJfD-É(tci5løn:$='oı=ísØ=ìo--.ã3$o=-a;'oa'.= ct9ıl-<fU'gÐoQÕ=,UeorÞJoaq¡oa-{(DVtnoUI;¡oc)(oo)Oi O)zililc)<5É-s*SooFãã]S.^O6üí=ô Il.¿äqã,q,Qf,q)o.-<Øı'oIilililil1ilililililltililililtililililililililil1illlil tllilEo7ocØOJIèd'o To(Dozqi3f?TU)z*oI\J-.1O*-¡NJ--lolOJT-.9.(Doz3u(D.oO(ooG](,rCImllEtfq(jHtlrù+Ëlrtssgt++-ìwÞHÞt1FllItöNc)aìz.acr-{zrFJfnc'ïz(lT-mzazmm7Øz(]{mntt'-{mQ)-lzUTEä'O a)=o4l¡Jre(D*r-tãio:í,r .. ı-*5 0r)_.o¡or3a'¡¡o(4ñØ'NlUÕ Ì\)=.O-O{ı (oo_orxl)U=.oo'of.n5= O(ct\ìñ[rrd3d.'os ão3OT-.19mF PqE, ...|:r tDä__oÉ*HnÃJ:iãò='z- *(El Fro¡ooU/lErio olo ].:l+tc,| -¡. 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Date Drilled: Location: Diameter: LOG OF TEST BORING 12122t2009 Field Engineer: DRL Boring Number: 4 See test boring location diagram Elevation: 4 inches Total Depth: 14 feet Depth to Water at Time of Drilling: None Encountered , o -a E U) OJo Sample Soil Description Clay, silty, sandy, stiff, moist, brown, tan, approx. 2 inches organic (CL) Laboratory Test Results Direct Shear Test: DD: 119 pcf MC: 5.9% Type N 39/6 50/6 Wasatch Formation - Claystone, Mudstone, Sandstone and Conglomerate Boitom of Test Boring at 14 feet CGRS No. 1 -1 0270-1 1727 aa Project Number: G09033G8 Figure: A5Project Name: Wffiuhwlûnù þøør'rr¡des CONSULTINGGEOTECHNICALbNGINËERSANDMAIbRIALItSIING LOG OF TEST BORING Date Drillecl: 12l22l2)Ag Field Engineer: DRl, Boring Number: 5 Location: See test boring location diagram Elevation: Diameter: 4 inches Total Depth: 14 feet Depth to Water at Time of Drilling: None Encountered o.o E Ø o. 0)o Sample Soil Description Clay, silty, sandy, stiff, moist, brown, tan, approx. 2 inches otganic (CL) Laboratory Test Results Swell/Consolidatíon Test: DD: 101 pcf MC',9.2% Type N 16/6 20t6 Wasatch Formation - Clavstone, Mudstone, Sandstone and Conglomerate Bottom of Test Boring at 14 feet Project Name: CGRS No. 1-10270-11727aa Project Number: G09033G8 Figure: A6 WffihwtffiIù bsø,ssrúex 1 ,1 I CONSULTING GEOTECHNICAL ENGINEERS AND MATERIAL TESTING i : Date Drilled: Location: Diameter: LOG OF TEST BORING 1212212009 Field Engineer: DRL Boring Number: Percolation Profile See test boring location diagram Elevation: 4 inches Total DePth: I feet Depth to Water at Time of Drilling: None Encountered -o E U) l)o Sample Soil Description Clay, silty, sandv, stiff, moist, brown, tan, approx. 2 inches organic (CL) Laboratory Test Results Type N Wasatch Formaiion - Clavstone, Mudstone, Sandstone and Conqlomerate Botlom of Test Boring at I feet CGRS No. 1 -1027 O-1 1727 aa Project Number: G09033G8 Figure: A7 Wg,lø'¡beúanù þxxøfifújjø CONSULTING GEOTECHNICAI FNGINEERS AND MATËRIAL TESTING Project Name G09033c8 APPENDIX B The laboratory sLudy consisted of performing: Moist.ure cont.ent and dry density Lests, Swell-consolidation tests, A Direct Shear Strength test, and Chemical t,ests. It should be noted LhaL samples obLained using a drive type sleeve sampler may experience some disturbance during t.he sampling operations. The t.est results obt.ained. usingi Lhese samples are used only as indicators of the in siLu soíI characterisLics. TESTTNG MoisLure Content and Dry Density Moisture contenL and dry density \^/ere deLermined for each sample tested of the samples obt,ained. The moisture cont,enL was determined according t.o ASTM Test MeLhod D22L6 by obLaining the moisture sample from the drive sleeve. The dry density of Lhe sample was det.ermined by using the wet. weighL of t.he entire sample tested. The result,s of the moisture and dry density determinat,ions are presented on t.he logs of borings, Figiures A2 througrh 47. Swell Test Loaded swell- tests were performed on drive samples obtaíned cluringr Ehe field study. These tesls are performed in general accordance with ASTM TesL Method D2435 Lo the extenL Lhat the same equipment and sample dimensions used for consolidation tesling are used for the determinat.ion of expansion. A sample is subjected to static surcharge, water is introduced to produce saturation, and volume change is measured as in ASTM Test l¿Iethod D2435. Results are reported as percent change in sample herght.. Consolidation Test One dimensional consolidation propert.ies of drive samples \^/ere eval-uaLecl according to the provisions of ASTM Test Met.hod D2435. Lembert enù €trgsoci$teg B1 CO'{SULTING GEOIECHN¡CAL €IIGITIEÉRS ANO gATERIAL IESTING c0 9 03 3GE Water was added in all cases during the tesL. Exclusive of special readings during consolid.atíon raLe tesLs, readings during an increment of load \^iere taken regularly until the change in sample height was less than 0.001- inch over a Lwo hour period. The results of Lhe swell-consolidation load Lest are summarized on Figures 81 and 82, swell-consolidation tesLs' It should be noted consolidaLion data is in axial load. As a be illustrated. that the graphic PresenLation of a presentation of volume changTe with change result, boLh expansion and consolidaLion can Dírect. Shear Strength TesL Direct shear strength properties of sleeve samples were evalua¡ed in general accordance with Lesting procedures defined by ASTM Test Method D3080. Two (2) direct shear strength tests was performed on samples obtained. from Test Boring Nos. 3 and 4 aL depLhs of four (4) and nine (9) feet, respectively. An int.ernal angle of friction of 22 degrees and a cohesíon of 250 pounds per sguare foot were used for the silty clay soil materials and an interna.l. angle of friction of 32 degrees ancl a cohesion of 11_2 pouncls per square foot, were used for the formational maLerials in our analysis ' Chemical Tescs chemical l-ests for water soluble sulfates and pH were perfornred on select sampl es obtairLed during the field sLudy' The resulcs oi che chemical Lests are tabulateo below' Test Boring Depl,h 4-5 feet 8.70 water soluble sulfates 11-5 ppm I,s¡nbert snù ß[ggocisteg 3 pH B¿ CO'.ISULf IIIG G€OÍÉCHNICAL EN6INÊÊRS ANO TAI ÉRIÀI TÉSÎING 10 PRESSURE (pouxus ern sqùRne roor) 100 1000 000 2 )0 2 3 oì(¡) 4 5 N o Þ! B U) Èoo 6 7 Sweì I Undcr Constant Presgure Due To Wetting t j'water oddtd lo somplc SUH'IARY ff I"ESÏ RESULTS Diamtlcr(in ) *tçll Pr¡tture(PS E) [+{cistura Cc¡rttcnl PAI Dry Dtnsily (P.C.E ) Hrright ( in.) Edng No. 3 ct,pth 9-10 ft. 1t?_n 1-q¿rlnilìol12.8 1_C) 1R e roL 500 tFÍtnlllq_n qÁR Was:frh Format inn-f ¡åv<fônê-Muclctone- Sanrlctone end%ìl Dtscriølion j Conglomerate Oal.:2/l 6/ 10 Fígura: BlLambert rnù Çl.ssoeisteg slvELt - corJsot lDATtoN rESr ftojoct Ho.; M9033GE 10 PRESsURE (POUHOS PER SqUARE TOOT) 100 1000 1 0,000 )0 2 3 ¡ì U) 4 q Ico Þ-l¡ ìg)so() 6 7 Swel I Under Constant Pressure Due To Wetting t * t, Wolor oddtd lo somPlo \ SUMFIARY 6 rEST FESULTSBdng No. 5 4-ft.*kÅsturc Crshnt loAI Dry hnsìly(Þc.E ) Htight I in.) Diomtter (in. ) SFr/l Prç¡¡sre(P.S.E) lnitiol 500 t Fìtøl 9r,il D.sciípîion Mo9o33GEÊojrcl No.L- CONSOLIDATION TESTSWEL 2/16/ 1oOata : Figurc t 82I,smhert tnb ß,s'goctateg' c09 03 3cE APPENDÏX C GEOLOGY DISCUSSION SOUTHWEST COLOFÀDO GEOLOGY SouthwesL Colorado exhibit,s many geologic features formed by a multitude of geologic processes. Regional inundation, uplift, volcanism and glaciation are responsible for some of t.he complex geology of the region. Many theories and speculations concerning the mode of occurrence of the regions's gieology have been presenL.ed over the years. This cursory discussion of the g'eology of southwesL Colorado presents some t.heories accepted by the geologic communit,y, but is only intended to introduce t.he basic concepts and restraints that arise due Lo geologic activity. Prior to t.he formation of the Rocky Mountains souLhwest Coforado v/as a primarily a flaL lying region with litLle topographic expression. The North American continenL was experiencing many episodes of deposition. The Transcontinental Sea was transgressing and regressing:'across the continent, these transgressions and reg:ressions are the cause for such diverse rock types. The st.ratigraphic column in souLhwesLern Colorado expresses rock LX)es from variable clepositional environmenLs. LimesLones are formed in deeper water, sandsLones are formed in beach and Lidal flat environments, while arkosic sandsLone and conglomerates are formed in allur.ial plains and fans. Parlicle size and mineraloqic cont,ent in rock units are related to the deposit.ional environment. A sandstone or conglomeraLe would not, be likely to form in a deep sea environment because there would not be enough energy to carry such larqe particles a grreat distance from the source lands. As one observes the stratigraphic column of southwesL Colorado a siltstone may be overlain by a sandstone which is in turn overl-ain by a silLstone. This represenLs a regressional Lhen Lransgressional sequence. Many such sequences or combinaLions of olher rock uníts are exhibiLed throughout southwest Colorado. The final reg-ression of the sea may have been caused by orogenic activity and uplif t. This uplif t l¡/as not conf ined to Colorado, it was a regional uplift that" occurred in many stages. The uplíft is what caused the formation of Lhe ancest.ral rockies. The Larimide Orogenic episode is responsible for the formation of the San Juan dome. (Note: The San Juan dome theory is not accepLed by the entire qeologic community. It is used here for descripLive purposes). The San Juan dome \^/as essentially an upv¿arp of the sLratigraphy formed by sedimentation during t,he Transcontinental Sea. An actual dome probably never existed due to erosion cluring the uplift. The idea being that. a dome of sediments and rock uniLs T,smhert snù fløgotíuteø cl_ CONSULIING CEOTECHNICAL ÊNGINE€RS ANO ÍdATERIAI IESTING G0 9 03 3cE i I Ì The orientation of beddínq planes forms a radial pattern around the San Juan region which seems t.o vindicate this Lheory; The stresses need to "Llp\^Iarp" this large areA were obviOUsly tremendous. Localll¡ occurring sLresses may not.be suffícienL to move this quantíty- of material, global tecLonics, directly or inclirectly, *ry nán" been involved. Compressíon of the entire North American plate could have occurred. The magnitude of the stresses and thä deep seated origín of these stresses also have ;;;=¿á extensive volðanism. Colorado has many large remnants of Calderas that *"". active during the oroqenic activiLy' The silvert.on and Lake city calderas are the largest in t'he san 'Juan ,ãgi""- Activi¿t in the Sílvert.on Caldera has been estimated (rädiclmetrically) to have occurreð' 22 miltion years ago' Calderas of this maqnituäã are believed to have formed by the collapse of epierogeniı magma chambers. Volcanic and meLamorphic rock bodies u.?. "ori*on in the San Juan region' many of these units are relaLed to the orogenic activity in the region' Faults associated with local orog"enic activity are anoLher coÍìmon geologic feaLure found in southwesLern Colorado ' As stated previouãly, exLreme stresses were probably associated wil-h the formaLion of t.he san Juan Mountains ancl may be responsible for ãå.p*="uted volcanic and metamorphic processes. These slresses had to be released,- ifr" geoloqic mod.e for stress release is faulLing' niastrophic ..ti.rity" i., the area today is quite 1ow, Lhe lack of seismic activiiy inåicates that sLresses are not currenLly being released. An -ä*pf "trrtíon for the loss of stresses is througrh faulting. The lasL. episode of reqional geologic activity in the area was glaciation. The most recenL period of glacial act.ivity ended approximately 10,000 years ago. Glaciat, activity is responsible for much of the'topojraphic expression in the area. "U-Shaped" ,ãifãv=, morainè ¿"p"ãit", tarns, (glacial formed lakes), and rock glacíers are Lhe mosL promínent features which are found in southwestern colorado as a result of glacíal activity' The valley ãonfigurations are a result of the erosional acCivity of the glaciers. ¡torainã deposits developed during thre g:1acial- activity' Rock glacíers ãru *o.iing masses of rock which are Lhought- Lo have an ice core wfricfi may bã the Last remnanL of glacial ice' As the subsurface ice core moves and melts, t.he overlyinq mass of rock also moves. i[.umhert nnù ßlgøocínteg C2 COH3ULftNO OEOTECIINICAL E¡¡OI'¡EER6 AIIO MATÉRIAL TESTING c09033cE APPENDIX D GENERAL GEOTECHNICAL ENGINEERING CONSIDERATIONS D1. O TNTRODUCTION Appendix D present,s general geoLechnicat engineering consideraLions fof -¿esign ana construction of slrucLures which will be in contacL wiCh soiis. The discussíon presented in this appendix are referred to in the text of Lhe report and. are inlended as tutorial and "uppf"mental ínformation to the appropriale secLions of the texL of the report. D2 . O FOI.]I\DATION RECO}IYIENDATIONS Two criteria for any foundatíon which musL be sat.isfíed for satisfactory foundaLion performance are: . conlact stresses must be low enough to preclude shear failure of the foundation soils which would result in lateral movement of t'he soils from beneaLh the foundat,ion, and . setLlemenL or heave of the foundation must be within amounts Lolerable to Lhe superstructure ' The soils encounLered during our field study have varyingt engineering characteristics thaC may influence the desígn and consLmction considerations of tfre fçuñdations. The characLeristics include swell potentiat, settlement potential, bearing capacity and the bearing coådirions of Lhe soils supporLing the foundations ' The éã"ur"r aíscu=siot below is int.ended to increase the readers Éamiliaricy wiLh characterisLícs Lhat can influerice any sLrucLure' D2.L Swelt Potential Some of the materials encounLered during our field study at the anticipaLed f oundat.ion depth may have swelI potent'ial' swell potentiaf is Lhe tendency of the åoif to increase in volume when iL becomes wetted. The volume change occurs as moisture is absorbecl into the soil and water molecules bðcome atbached to or adsorbed by Lhe individual clay platlets. Associatecl with the process- of volume chanqe is sweti þr.==1r.r*. The swell pressure is the force the soi: ãpprí"" on it.s -"üirorrndings when mois{ure is absorbed int'o Lhe soil ' Foundation desiın conside?ations concerning sr,velling soils inclucle structure tolerance t.o movemenL and dead load pressures to help D1 {.embert enù €Iggsúateg CONSULIIHG GEOTECHNICAL ÊNGIHEERS ÀNO I{AÍERIAL IÊSIING l' c0 9 03 3GE restrict uplifL. The structure's t.olerance to movement should be add.ressed by trre struct,ural engineer and. is depende,nt upon many facels of the desigrr- incfuAing LhJ overall sLructural concept and the build.ing material.--tit" üplift..forces or pressure due to wetted clay soils can be addressed.by designing the foundations with a minimum dead toad u"di;;-;lãåit s* tlt. fıundãtions on a blanket of comtr¡acled sLrr-r.ctural f itl. The compacLed structural f itl blanket will increase Lhe dead. load ott tfr"-=wetiingi foundations soils and will increase t'he separation of iü"-i",-.rtdation f rom the swelling soirs ' sug:gestions and recomrnen¿ations tor d.esign dead- load and compacted sLructural fill btanker are " p;;;;Lud below. Compacted structural f irr recoï'ftmendat.ions are presented under COMPACTED STRUCTURAL FILL below' D2.2 Sett.lement PoLential Settl-enrent potent.ial of a soil is Lhe tendency .*p*ti.rl." .rofr.r*. change when subjecLed to a load' chäracterízed by downward movement of all or a supporLed strucinte as the soil particles move råã"fti"q in decreased soil vol-ume' Settlement function of; . foundation loads, , depth of footing embedmenL' . thã width of the footing, and . the settfeÃãn|-óoi"tttia-l or compressibitiLy of the influenced soil. FounclaLion desiqn considerations concerning settlement poLential inclucle t.he amount. of movemenL tolerable Lo the strucLure and the desiqn and consLruction concepts to help reduce the potential movement. The settlement potenii-f of the ioundation can be recluced by reducing foundation pressures and/or by placing Lhe foundations on a blanket of àà*pactåd sLructural filt ' The anticipated posL consLruction settlemenL poLentiat and suggested compacLed filr thicknes" r."o**endationã .tá based ott siCt specífic soil condiLions and are presented in t'he text of the report ' D2.3 Soil Support CharacterisLics The soil bearing capacity is a function of; . the engineering properties of the soil material supporting the foundations, the foundaLion width, the depth of embedment of t'he boLLom of the lowest. adjacenL grade, the influence of the ground water' and ihe amount of settlement tolerable to the s D2 ![.nffibert nnù ßggocÍsteø for the soil to SettlemenL ís portíon of Lhe closer Logether potential is a foundation below the trucLure. COÑSULTING GEOTÉCHNICAL ËNGIÑÉËRS ÀNU TIAlERIAL IESIINO c09033cE Soil bearingr capacity and associaLed minimum depth of embedment are presented in the t.ext of the report.. The foundation for t.he st.rucLure should be placed on relatively uniform bearing conditions. Varying support clraracLerisLics of the soí1s supporLingr the foundation may resulL in nonuniform or differential performance of the foundation. Soils encount.ered at founrlation clepLhs may contain cobbl.es ancl br:ulders. The cobbles and boul-clers encountered at foundation dept,hs may apply point. loads on the foundation resulting in nonuniform bearing condit.ions. The surface ot Ene rormarlonal material may und.ulate throughouL the building site. If this is Lhe case it may result in a portion of the foundation for the sLructure being placed on Lhe formational maLerial and a porLion of the foundation being placed on the overlying soíls. Varying supporL materíal will result in nonuniform bearing condít.ions. The influence of nonuniform bearing conditions may be reduced by placing Lhe foundation members on a blanket of compacted structural fill. Sugqestions and recommendaLions for constructing compacted sLructural fíll are presented under COMPACTED STRUCTURAL FILL below and in Lhe text of the report. D3. O COMPACTED STRUCTURAL FILL Compacted sLruct.ural fill is typicalty a maLerial which is consLruct.ed f,or clirect support of structures or sLructural components. There are several material characLeristics which should be examined before choosinq a maLerial for poLential use as compacted structural filf. These characteristics include; the size of the larger ParLicles,the engineering characterísLics of Lhe fine grained porLion of material malrix, the moisture conLenl that Lhe maLerial witl need to be for compaction with respect to the exist.ing init.ial moisture conLent, the organic conLenL of the material, and t.he ilems thaL inf luence the cosL t,o use the maLerial. CompacLed fill should be a non-expansive material with Lhe maximun agqregate size less than about two (21 inches and less than abouc twenty five (25) percenL coarser Lhan t.hree quarler (3/4) inch size. The reason for the maximum size is that largier sizes may have too qreat an influence on the compaction characteristics of the material ánc1 may also impose point loads on the footings or floor slabs :he: are in contact with the maLeríal. Frequently pit-run materia-r cr crushed aqgregaLe maLerial is used for sLructurat fill maLerial ' Pit- run materiãt *ay be satisfact,ory, however crushed aqgregrate material laffibert snù FLøgsrieteg ì' L ,:. D3 CONSULTING GEOTÊCHNICAL ÊNGIN€ERS ÀNO HÀTERIAL TESI¡NG c09033G8 If you have radon, PIease 3030 withangulargrainsispreferable.Angularpart'iclestendto inLerlock with ""åï- ottrãr t.tter than rounded particles ' Thefinegirainedportionofthefillmaterialwillhavea sisnificanl i"Ëi;;;;. oï tr."-putiãt*t""" of the fill' Material which has a fine giraio"ã *"trix comfro=ãã-tf silb and/or clay which exhibits expansive "irrrå"J.iistics "üã"fA ¡. avoid"ed fot Llse as sLructural f ill. The moi-sture conLent "Ì-ir." maLerial should be monitored during construction ;"d - maintain"ã -ãá"i optimum moisture content for ãompaction of the maleríal ' Soilwithanappreciableorganicco-nLentmaynotperformaclequately for use as struci'urãf filt malerial due to Lhã compressibil-iLy of t'he maLerial and ultimaLely An. fo-Jft. decay of the organíc portion of the material. D4. O RADON CONSIDERÀTTONS Informationpresented.in.,RadonReductioninNewConstruction,An Interím Guide, î:pÁ-gf -009 by l.:he [nvironmcntal Protecf inn Agency dated August 1-g87 indicates that cuirent.ly there are no sLandard soil tests or specific stããàar¿s for coirelating Lhe results of soil tests äL a buildinq site with sun=.que-rrJ-inOoır radon levels ' Actual indoor levers can be affected nv .orrãtructíon techniques and may vary qreatly f rom soil radon Lest result=. -ih;¿fore it is recommended that radon tests be condu"t"a in the strucLure after construction is complete Lo verify t.he acuual radon leve1s in the home ' WesuggesEthat'youconsiderincorporatingconslrucLiontechniques into L.he development to t"ãr-,"à tádon levets in the residential structures and. provide r"i-i"trof ittinq equipment f or radon gas removal if it becomes necessary Measures to red.uce rad.on levels in strucLures include vented crawl spaces with ";;;; barrier ãt- tir* surface of the crawl space to restrictradongasflowintothesLructureoraventedgravel-ayer with a vapor uriri"iieneatt a concrete slab-on-qrade floor to allow venting of radon gas collectåa beneath ¡he floor and to restricL radon gas frow throuãir-irr" slan-onlgrrade floor into the sLrucLure' These concepts .re shown on Fígure Dl- ' any guesLions or would like more informaLíon about conLacL us ot tft" State Health DepartmenL at 303-692- t: T.sûnbert mnù flggurinted D4 CONSULTING GEOTÉCHNICAL ENOINEERS ÂI¡O I¡ATERIAL fESIING I I Fan Medium pressure zone ssure zoneLow Radon RadonHigh pressure zone This figure was excerpted from an EPA manual rrRadon-resistant Construction Techniques for New Residential Constructiont'and reproduced here for reference only RADON FLOW CONCEPT I turct fla: G 2 )1 r' Lambert anù ÍIgtotútt?Í