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Home My WebLink AboutSubsoil Study for Foundation Design 12.09.2020LKP CIVIT/GEOTEEHMCAL SOIL A¡ID FOUNDATTON II{VESTIGATION FOR A PROPOSED RI,SIDENCE LOT 3E, CERISE RANCH ST}BI}IVISION, PIIASE 2 27 LARKSPT]R DRIVE, CARBONDALE GARFIELD COTINTY, CO PROJECT NO. 2A-¡,473 DECEMBER 9,2A20 PREPARED FOR: SEAIï & CHRISTINA DUT'FY 5 ELEMENTS ELECTRIC INC. 2OO UTE TRAIL CARBOFIDALE, CO 81623 Engineering, Inc.RECEIVED JUL ? ü ?il?t GARFIELD COUNTY cımruu Htrv DEVELoPMENT P.O. Box 7 24, Eaglc, CO I I 63 I T el (97 0| 39A-A307 www.LKPEn gineering. com SITE ÞESCRJPTION.. TABLE OF CONTENTS EXECUTIVE SUMMARY SCOPE OF STI.'DY GRAIN-STZE DISTRIBUTTCIN PERIME.TER DRAIN ÞETAIL 2 2 ,, 3 3 3 4 5 5 6 6 7 7 PROPOSED CONSTRUCTION .,...... FIELD INYE STIGATION,,.,...,,.,. SUBSURFACE SOIL AND GROTJND1VATER CONDITION FOUNDATION RECOMMENDATIONS .,,..,.,..,.... SLAB CONSTRUCTION .,,., RETAINING WALLS,,.. {JNDERDRAIN SYSTEM' SITE GRADING AND DRAINAGE LAWN IRRIGATION LIMITATION FIGURES LOCATION SKETCH ,DRAWINGNO. 1 SUBSURFACE EXPLORATION LOGS.FIGURE NO's 1-2 ,FIGURENo's.3-6 .FIGURE NO. 7 LKP Engineoring,Inc 2 EXECUTIVE SUMMÀRY The proposed rcsidence should be supported with conventional type spread footings, designed for an allowable soil bearing pressure ofry_ptÍ.They should construct the footings on the undisturbed silty-gravelly sand with some cobbles. See Foundation Recom mcnd alíons, SCOPE OF STUDY This report presents the results of a subsurface Soil and Foundation Investigation for a proposed rçsidence to be constructed on f,ot 38, Cerise Ranch Subdivision, Phase 2,27 Larkspvr Drive, Carbondale, Garfield County, Colorado. The purpose ofthe subsurface soil and foundation investigation was ûo detenuine the engineering characteristics of the foundation soil and úo provide recommendations fsr the foundation desigu, grading, and drainage. Geologic hazard studíes øre oußide of our seope of services. SITE DNSCRIPTION Lot 38 is a 4.15?-acre lot on the north side of Larkspur Drive, about 850 feet west from the roundabout and the intersection with Bluesfem CourÇ af 27 Larkspur Drive in the Cerise Ranch Subdivisior, Garfield Counfy, Colorado. The lot variable moderate topography with a steep bank up from the road then moderate slope for the next 200 to 300 feet (or to the north LKP Ëngineering,lnc. J edge of the building envelope) and then steep slope again- The vegetation on the lot consisted of wild grass, cacti, shrubbery, cottonwood trees along the old irrigation ditch, and juniper trees on the upper, steep slopes. Drainage is ûo the south and southwest. Along the south side of the lot is Larkspur Drive. To the east and west are existing residences, and to the north are vacant lots of the White Cloud Subdivision. Lot 3E is also vaçant. PROPOSED CONSTRUCTION We understand that the proposed residence will be a one story, wood frame construction on a concrete foundatíon,without a basement. We anticipate loads to be light, typical of residential construction, If the finalized plans diffsr significantly from the above understanding, they should notiff us ûo reevaluate the recommendations of this report. FIPLD INVESTIGATION The field investigation, conducted on December 3, 202A, consisted of excavating, logging and sampling two test pits. The excavation of the test pits was done with a John Deere 310SK rubber tire backhoe. The test pits' locations are shown on Drawing No. 1. We show the soil profile of the test pits on the Subsurface Exploration Logs, Figure No's I and2. Soil samples for laboratory soil analysis and observation were taken at selected intervals. Geologic hazard srudies are outsicle of our scope of servÍces. ST]BSURT'ACE SOIL A¡ID GROI'NDWATER CONDITION The soil profiles eltcount€red in the fwo ûest pits were similar. Test Pit No. t had about one foot of topsoil over light brown, silty-clayey, sandy gravel with basalt and sandstone cobbles LKP Engineering,Inc 4 and boulders over sílty-clayey, gravelly sand, calcareous with cobbles and few boulders, üo the maxímum depth explored of I feet. The soil was less gravelly in the last couple of feet. Test Pit No. 2 had about 1.5 feet of topsoíl over of blocþ clay, over siþ-gravelly sand, calcareous, gypsiferous with some, ûo the maximum depth explored of 8feet, Ground water was not encountered in eíther test pit. We sampled the soil in the test píts at random intervals. The soil samples were tested in our laboratory for natural moisture content and grain size disribution The test results are shown on Figure No's 3 üo ó. FOUNDATION RECOMMENDATIONS The proposed residence should be supported with conventional type spread footings, designed for a maximum allowable soil of 1500 The entire foundation should be constructed on the undisturbed silff-gravelly sand with some cobbles. We recommend a minimum width of 16 inches for the continuous footings and .? lþl:!r the isolated footing pads. Continuous foundation walls should be reinforced top and bottom ûo span an unsupported length ofat least 10 feet. We recommend a minimum of 48 inches of backfill cover for ûost protection of the footing subsoils. Iåe excøvãtion should be observed by the undersigned engineer to verify that the soil condítions encountered durìng annsrruction sre as anticipated in this repon. The foundation excavation should bo free from excavation spoils, frost, organics and standing water. We recommend proof-rolling of the foundation excavation. Soft spots detected during the prooÊrolling, should be removed by overexcavation. Any overexcavation within the proposed foundation should be backfilled, in I inches loose level lifts and compacted to l00o/o ofthe maximum dry density and witbin 2 percent of the optimum moisture content as determined in a laboraúory from a Standard Proctor test (ASTM D-698). A structural fill, placed under footings should be tested by a qualified professional on regular basis. LKP Engineering,Inc. 5 SLAB CONSTRUCTION The natural on-site soíls, exclusive of ûopsoil and organics, are suitable to support lightly loaded slab-on-grade consfuetion. The subgrade for the slab-on-grade construction should be proof compacted to detect and remove soft spots. They should backfill overexcavated soft spots and other underslab fill with the sn-sito soil, free from topsoil and organics, or other suitable matEriaL compacted úo a minimum of 95 percent of the maximum standard Proctor density (ASTMD-698). Suitable maþrial shouldbe free from topsoil, organics and rock fragments greatar than 3 inches. The concrete slab should be constructed over a 4-inch layer of clean gravel consisting of -}l4-inçhgtravel with at leastS0o/o retained on the No. 4 sieve and less than 3 porcent passing the No.200 sieve. They should reinforce the concrete slab-on-grade and score control joints according to the American Concretp Institute requirements and per the recommendations of the designer to reduce damage due ûs shrinkage. The concrete slab should be separated from the foundation walls and columns with expansion joints to allow for independent movement without causing damage. RETAINING \ilALLS Foundation walls retaíning earth and retaining structures that are laterally supported should be designed to resist an equivalent fluid density of 55pcf for an uat-rest" condition. Laterally unrestrained structuros, retaining the on-site eart[ should be designed to resist an equivalent fluid density of 35pcf for the oactive" case. The above design rocommendations assume drained backfill conditions and a horizontal LKP Engineering, Inc. 6 backfïll surfaco. Surcharge loading due to adjacent structures, weight of temporary stored construction materials and equipment, inclined backfill and hydrostatic pressure due to undrained back{ill should be incorporated inthe design. They should try to prevent the buildup of hydrostafic pressure behind the retaining wall. Passive earth pressure of400pcfcan be used for the lateral pressure against the sides of the footings. Resistance to sliding at the botfonn of the footings can be calculated based on a coefficient of frictisn of 0.6. Undismrbed soil or a structural fill eompacted to 100 percent of the maximum dry density and within 2 percent of the optimum moisture content will be used to resist latoral loads at the sidos of the footings. UNDERDRAIN SYSTEM To reduce tho risk sf surface watm infiltrating the foundation subsoil, we recommend installation of a foundation perimeter drain (see Figure No. 7). The foundation perimeter drain should consist of a 4-inch diameter, perforaüed pipe, sloped ûo a suiøble gravity outlet, or to a sump pump location, at a l/4 iuch per foot for flexible or at a 1/8 of an inch for rigid pipe. The bottom of the trench adjncentto the footing should be lined with filter fabric. The drain pipe should be covered with a minimum of ó inches of -314-nch freedraining granular material. Geotextile (Mirafi l40N or equivalent) should be used to cover the free-draining gravel to prevent siløtion and clogging ofthe drain. The backfrll above the drain should be granular material to within 2 feet of the ground surface to prevent a buildup of hydrostatic pressure. SITE GRADING AND DRAINAGE The following recommendations are general. Exterior backfill should be compacted at or near the optimum moisture csnúent to at least 95o/o of the maximum standard Proctor density under pavement, side.walk and patio areas and to at least gÙo/o of the maximum standard Proctor LKP Engineering, lnc 7 density under landscaped areas. They should use mechanical methods of compaction. Do not puddle the foundation excavation. The site surrounding the building struchue should slope away from the building in all directions. A minimum of 12 inches in the first l0 feet is recommended in unpaved areas, and three inches in the first 10 feet in paved areas. The top of the granular foundation backfill should be covered with a minimunr of I foot of relatively impervious fill to reduce the potential of surface water infïltrating the foundation subsoils. Surface lryat€r naturally draining toward the proposed building site should be diverted around and away from it by means of drainage swales or other approved methods. The roof drains and downspouts should extend and discharge beyond the limits of the backfill. LAWN IRRIGATION It is not recommended to introduce excess water to the foundation soils by installing sprinkler syst€ms next üo the building. The installation of the sprinkler heads should ensure that the spray from the heads will not fall within 10 feet of foundation walls, porches or patio slabs. Lawn inigation must be controlled. LIMITATION This report has been prepared according to locally accepted Professional Geotechnical Engineering standards for simil¿r methods of testing and soil conditions at this time. The option to test the soil with a backhoe pits verses with test borings drilledwith a drill rig, was selected by yau. There is no olher wørrønty eíther expressed or implied. The findings and recommendations ofthis report are limited to the depth of the test pits investigated due to the type of equipment selecfed by the owner for the soils and foundation investigation. The above recommendations and based on field exploration, laboratory testing of LKP Engineering, Inc I samples obtained at the specific locatíons shown on the Location Sketch, Drawing No.l and on assumptions stafed in the report. Soil conditions at other locdions may vary, which may not become evidcnt untíl the foundation ørcavation is completed. If soil or water conditions seem different from those described in thÍs report, we should be contacted immodiately to reovaluate the recommendatioos of this report. We are not responsible for technical interpretation by others ofthe data presented in this report. This report has bçen prepared for the oxclusive use of Sean and Christina Dufff, for their proposed residonce, úo be constructçd on Lot 38, Cerise Ranch SuMivision,Phase 2,27 Larkspur Drive, Carbondale, Garfield County, Colorado. Sincerely, LKP ENGTNßERING,INC. LuvaPetrovska, PE J:\ WP X4-tKn 2A2A\20-347 3çRAVSNDPITS.DOCX PË ñ Iül ' É,høhù,,t'\ LKP Engineering,Inc. uaàø?Ë<'Øo$oFÚ!¡J Dt<Þ@oô2zQøk=ËsJ:TH>tðUCbÈu{IeStw/tIItII,III9çS*tJ.tO'O¿þ*8.ar,raotqÐ¿î to76t JAt-l-^¿--l--/Í/./Íy',/r'IilI"qiIlto$''1I!f--*--tÌ.ãt ,/;ffi<4/,$-7*F-t////lt/{.ôt /.æ //l-nfL---r-*--;sr-----."ûIãd*u{*/ssqøE¡.Ë"/lwts'Ê,l-/u,/.u/l-.ûrIitFl)lirHlrjäÊiFrFrsotlcal\rtcâ¿c\¡ı¡ôllI2ilR23Ëe qð,8!83ãÈÈHgEËii"ÊËgdFI-ÈiqñFI\\aq)Ft\'hlÞr.l{-ltas.H\ì¡t.aÞ2EIC¡ÈËEC'EÊ)oFao5('¿)0'ÐþN{l\¡xÒ&dû-hc,no¡êa ÐA'lE æSERì/EÐ: DECEÌIBER 3' 2O2O ELEVAÏION: Te¡t Pit # I DEPIH FEET s YuI o L s A$ P L E ÐæmPng{ tr HAlffilÃL ÅNO SAIIPLE LOCANON LABæATONY ÏEST RESULI5 REIIARKS ü _10 -tt _9, ,V a I Íopaoll, forcst llttt *zd hcouy rootc Líght brovn, cllt¡t-c-lo¡oy, candy gravcl vlth cúbl¿s afld bwldea, botqdt and sandatona owr Sìltfdat y, wlth cobblce grovdlï rottd, colearwtg and fcv bouldcrs ìlC:4.ÍE -2OA-138 MC:S.52 -20CI:2Q.62 lesa growlly near thc bottom Battom of TcEt Plt at I fsçt No Ground Water Fncwntved LEGENDS trt DD HC -200u PI ew - 2-lnch O,D, CollfarnlE Llncr Sampte - Eulk Sømpls - Natural Dry Donslty (pcf) - Naturd Holsturç Cøltã,t (X) - Parcent Paselng No, 200 Siçw - Llquld Umlt- Plottlclty lndcx - ãround wotsr IJ(P ENGINEEBIT{C, INC.ST'BST'NTACE EXPil)AATTON LOC "xtÆÍ;t tw:20-3473 1 flgÆre: DAIE OËSER\¡ED: ÐECEMBER 5, 2O2O ELEVAÏON: Tect Pit # Ê DEPfII FEET s Y HI o L .9 A H P L E ÐEæfrIPNW ff 'TÃ\ERIALÅND SAMPLE LOCATTON LAESATARY ÏEST RESULTS REIIARKS ı .-to -13 -N ^r t I Topeall, ønd raob ovx bloc*y døy Tan, sttfwvclly cørd, colcorcous-g¡pclfcrous v[th soma cobblac MC=5.Jß -20(Þt798 llC=5.28 -2OO:18-11 Bottom of Tcst Plt at E fsct No Grwnd Jlater Encqtntæcd I.EOENI}: tr - 2-lnch O,D, Colllornla Uncr Sompla¡ - Sulk 9anplcDD - Naturol Dry Dcnslty (pcf) t C - ilaturot llolctarc enht (ß) -2O0 - Percent Passlng Na, 240 SlewLL - Llquld LlmltPl - Ptaatlclty lndcxeW - êround woter I,XP ENOINEEBINC, II{C.SUBSUNFÀCE SIPIÍ}RATIÛN LOG Fñq€a;r rc.t 20-347J tDliFm.2 rIE.$þIfr$ìffiÞù*RìJP({FnA¡t' fcaú lúsf Ptf I at I (¿ctu.3 stTpÍü$¡EæAtpIúmESC 1t 2þ t.r,nouc'mrl¿F t 1 a aþ nß n æAm mtærtftrgnogot)mf',!$-q€rosS¡onroto,oæ&ìsro$ægCq60qF709æfioilo1æ50t05î 0.5o.î o.o50,Ø6 o.(n'ttut¡l: SOllF}a'qs: l3.OÍ\\\\\\\\\\\\flt ø Ctay&rrd&tcmdþmaodFc&adfrraoo¿ntcCoÉ¡å/ælloîehre Ccrltæt: LlÍ&vvd: ã77Daecrþtfut: *tydaycy, gravúy fu?d $r$Þ(4tqìtgI$sE.$ssf¡FROII: H Pît l{a , øt 7 Íaclt|l5 Sr¡rt$usEFffitrutst I J tt , *{¿s sf7uflp slE.ttrãst* ¡ 1 C tr0 14ß n &$fi TorürQñ,'lûftr890æ70$uo!$-EQøFS¡onroot0ngrro$ngr60qFzogæ9A10o100wæto5I O.8ø.t o,æa.æ50.ættulû 6e2,\\\\tI\\\\\Sf,t * CIaySo/rdfutcmadkxnooøngit&vrãlfup60øì9üCoâölssllø¡*glturtc Contat: 5.5Í@atd¡: 112ÍDæaþtìaa: fltfdany, gzvdy futdFFlæ: 24.65 r.a t 1 a tto larg æ &.nûmtúraflot0ã,&Trogn)Ëi¡q60qF7096090owIOQ fltæ105ta5at aolta,oa,0.dltFnún* fcrl Plt Na. 2 øa 5 fc']t¿¿s 5í7¡mlp srFcffif mEa 1t tlt t çrrs, srlmræ sEEtmr,rañ*ESry,á 64Af90&,70f',3$-q€+oFÈ¡anroto\\\\\\\\\\\\rhflt or CloySondftpmdùrncodt¡cævwlftteâam3tØHæf.næ: 17.9tÐæþtkrt: Slty, gravdly Sætd&avC: 17.12tloleturc Cøúglû 5.JfrIE.$Irfr$IIþNB*gOl $=IñÞv,IÈqì{POtr$a5$tssffFß(I* Icet Tæt PÍt 2 at I îrp¡t¿rs st¡tfla/tp sElF æÞaF fú tËGtt a I 2þ. t.rt¿s' SAJorp SF[rer.¡r J 4 I alO Kt û l|íOæ ml&Fl0øI,loK5EoI&,70ï-t$*qQrotS¡onro,ot0fr&,rro$*Ëdq60qËrogæ90otæ5Ø1æ EO,o5ta5o.î o.æa0Ø aættutA æ.1Í\\\\\\\\\\\\SIt t Clayfurdftiamdftntoaø¡stqTgfrp6øø1¡tØHætloþtt¿tp futtgrrt 5.8O?rd.' 2J.24Dæþtba: flty, gmwlly SandFþtæ: 16.108 AWAY FROM BUILDING BACKFILL WÍTH A MINIMUM OF ONE FOOT OF RELATIVELY |MPERV|O{,SSO|L FABRIC (MlRAFl 140N OR EAUTVALENT) 3|/+INCH DIAMETER, COARSE, CLEAN CRUSH ROCK 30 MIL MINIMUM THICKNESS.ÐIAMETER PERFORATET} PIPE SLOPED TO PLASTIC LINER, GÍ-UET' TO A DAYLIGHT LOCATION AWAY FROM THÊ FOUNT}ATION AT 1/4.INCH PER FOOT FOR FLEXIBLEÁND I/&INCH MINIMUM FOR RIGIÐ PIPE FOUNDAÏION WALL cMrlctoTucEMcAL Engineering, Inc. P.û. Box 724, Édql., çÕ Et63t Iel (970) 59O-O:K'7 rww.LXPEngÌneering.com LKP PEBTMETER DßAIN 20-u73LOT38, CERISE RANCH, PHASE 2 27 L,ARKSPUR DRME CARBONDALE GARFIELÐ æUNTY, COLORAT}O N.T.S. 7