The URL can be used to link to this page

Home My WebLink Aboutsoils test.pdf Geclitech SUBSOIL STUDY ro R FOUNDATION DESIGN PROPOSED RESIDENCE LOT 5, FILING 2,POTATO PATCH 73$SANDY LANE VAIL, COLORADO JOB NO 135 347A AUGUST 25, 2015 PREPARED FOR: HOLM CONSTRUCTION, INC- ATT N: CLAES HOLM P.O.BOX 536 VAIL, COLORADO S I6SS (hc mnu iIC' irr..iI,iuiii) TABLE OF CONTENT PURPOSE AND SCOPE OF STUDY...:... .. ... .. .. .......... .,:.- I - PROPOSED CONSTRUCTION :::.. .:. .. .. ... ...- ] - SITE CONDITIONS. ... :::..,::: .:.-.--_. .. .. ....... - 2 - ROC KFALL HAZARD._,.. . : ::: :,,: :,::..-- . •--_... ....- 2 - FIELD EXPLORATION.:: ..... .. . .......--.:..._...._..__... .. - 2 - SUBSURFACE CON.D TION .................... .. . .....-„-,::._. .. .. .__- 2 - DESIGN RECOMMENDATIONS .. :..-...,.. . . .. . .. ....:.- 3 - FOUNDATIONS .. .... ...... ... .. ... ......_.. ... .. ......- 3 - FOUNDATION AND RETAINING WALLS :..,, ,,: ..- 4- FLOOR SLABS ... . .. .... ...... ........ . ... .... .... :::__.- 5 - l.]NDERDRAIN SYS'T`EM.:: :: :.... . ... - 6 - SITE GRADING. .. .......... ... _..... .......... ... ........ __- 6 - SURFACE DRAINAGE .. :.: .:: ... .. ... . ....... .. ...... 7 - LIMITATIONS..:: ::__,-:.. ... .__.:.__.:. .. .. 7 - R.EFERENCE . ..... ... .................................. ... ............ ... - 8 - FIGURE I - LOCATION OF EXPLORATORY PITS FIGURE ? - LOGS OF EXPLORATORY PITS FIGURE 3 - GRADATION TEST RESULTS TABLE E- SUMMARY OF LABORATORY ORY TEST RESULTS l�sb ND I L3 347A PURPOSE AND SCOPE OF STUDY This reps ri presents the results ora subsoil 4tudy fr,r a proposed residence to be located on Lot 5, Filing 2, Potato Patch, 738 Sandy Lane, Vail, Colorado, The project site is shown on Figure I. The purpose of the s[iody was Lo develop recommendations for the foundation design. The study was.conducted in accordance with our agreement for professional services to Holm Construction, Inc, dated July 2$, 20]5_ A field exploration program consisting of exploratory pits was conducted to obi ai rk information Oil kh subcurfLrcc Gond iiions, Samples of the subsoils,obtained during the field exploration were tested in the Laboratory to determine their class ificatiort and other engineering characteristics_ The rein Lr ti of the field exploration arid laboratory testing Wet'e analyzed to develop recommendations for foundation types, depths and allowable pressures for the proposed building foundation. This report summarizes Lhe data obtained during this study and presents our conclusions, design recommend tt Goon; and other geotechnical engineering cam i deratiort_'based on the prop 'icd construction and the subsurface conditions encountered. PROPOSED CONSTRUCTION Plans for the residence were conceptual at the time or our study and we urs demand that our findings will be considered in the purchase! cif t he lot, The proposed res ide nre wiI generally be a one to two std structure with a walkout base me nt Located between the exp]uraLory pits shown orr Figure I. Orou n d flexr will. be Blab-on-grade_ Grading for the structure k assn rued rc) be relatively minor with cut depths between about 3 to 10 feet_ We assume relatively light foundation. d i ngs, typical of the proposed type of consirucrion. If by i]ding loadings, location or grading plans change significantly from those described above, we should he noLi lied to re-cvaloatc the recommendations contained in this reporL, TL N,x I 153. ?A Ganachi SITE CONDITIONS The for wr a5 vacant at the time of our field explorariori and the grotiri 1 su ridcc appnred most iy natural. The site is partly located on a topographic bench of a south facing hillside. The ground surface is gently to moderately sloping down to the soutltiweat with about 13 feet of eleva[ion difference across the lot. Vegetation on the Lot consists of aspen trees and assorted grasses, weeds,and brush, ROCKEALL HAZARD The extreme, 'uphill northern ix,rner of the lot (as-slimed to he outside (a F building =a] is mapped as the lower limit of a medium severity rockfall hazard zone {Town of Vail, 2000), If additional ek alua[i on of the rock fall hazard to the lot is desired, we should be contacted, FIELD EXPLORATION The field ex.ploration for [he project was conducted on August 4, 2015. Two exploratory pits were c cavai ed at the locations shown on Figure I to evaluate the subsurface conditions. The pits were dug with a traclrttoe provided by the client_ The pits were k}gged by it rep reserktat iv ra 1 Hepworth-Puwlak Ot technica], Inc, Samples of the subsoils were taken by disturbed sampling methods_ Depths at which the samples were takers are shown on the Logs or Ex ploratot + Pits, F cure 2. The samples were returned to our laboratory for review by the project engineer and testing. SUBSURFACE CONDITIONS Graphic togs of the subsurface i.onditions a rIcouritered at the site art shows, on Figure 2_ The suhsoils consist of about 21 3 to 3 feet of topsoil overlying relatively dense, clayey sand and gravel with scattered cobble=s and boulders Co the pit depths of about 9 feet. Laboratory resting performed ort samples obtained rrom the pit; included natural moisture eontcn[ and vadat ion analyse.s. Results o f gradat iron analyses performed on disturbed - ,143 Alis 1 13 347A - 3 - hulk samples of I he coarse granular subsoils are shown on Figure 3. The laboratory testing is summarized in Table I Free water was generally not encotLrLrCred in the pi t s at the time or cxeavat ion and the subsoils were typically moist Soils within pit I were very moist below 6'i feet where slight seepage + a5 encountered, DESIGN RECOMMENDATIONS FOUNDATIONS IONS Considering 1 he .subsurface conditions encountered m the exploratory pits and the nature of the proposed construction, we recornrrbend the building be founded with spread footings bearing on the natural granular The design and construction criteria presented below should he ohoerved for spread foc ti n g foundation system, Footings placed on the undisturbed natural granular soils should be designed for an allowable bearing pressure of 2.500 psi._ Based on experience, we expect set tlernc rLt of footings designed and constructed as discussed in this section will be about 1 inch or less_ 2) The footings should have a minimum width of l6 inches for con ti rLuou s walls and 2 feet for isolated path:. 3) Exterior footings and footings beneath unheated areas should be provided with adequate soil cover above their bearing e]e w.1 ion for frost protection, Placement of foundations a least 48 i ridhcs below exicrior grade i typically used in this area_ 4: Continuous foundation walls should be reinforced top and bottom to span local anomalies such as by assuming Un urtsu fiported length of at least. 12 feet, Foundation walls acting as retatni ng structures should also be designed to resist lateral earth pressures as discussed in the "Foundation and Retaining Walls" sect teal of this report. �nf�td 1 1.3 I47A GeTriErch -4 - 5 The topsoil and any loose or disturbed soils should be retrio ed and the footing bearing level uxrenrcd down to the relatively dense natural granular soils.. The exposed soils in footing area shots kl then be moisture adjusted to near optimum and compacted_ if water seepage is encountered, the footing areas sht}u ld be dewatered before concrete placement. A rcpresentatiae of i he geotechn ica] engi neer should observe ail F oci rtg excavations prior to.concrete placement lo evaiunic hearing conditions. FOUNDATION AND R STAINLNG WALLS Foundation wills and retaining structures which are laterally supported and can be expected to undergo ory a slight amount of deflection should be designed for a lateral earth PressiArC computed on the bsNi s of an equivalent fluid unit 'weight c]f at 'cast 50 pcf for hack rill consisting of the on-site granular ar soils. Cantilevered retaining structures which are separate front titre residence and can be expected to deflect suIiiciently to mobilize the fu]l active earth pressure condition should be designed for a Iareral earth pressure computed on the basis of an equivalent fluid stair weight of at least 45 pcf for back rill consisting of the on-site granular soils_ Backlit! should not etmrain organics or rock larger than about 6 inches in size, All foundation and retaining structures should be Litgigne,d for appropriate hydrostatic and surcharge presstrrr such as adjacent foot irlgs, 1 ra ffic, construction materials arid egtti pmen t_ The pressures recommended above assume drained conditions behind the +N alts and a horizontal back CO! surface_ The buildup of water behind a wall or an upward sloping back f tI I surface will increase the latera pressure imposed on a found aLion wall or retaining structure. An underdratin should be provided to prevent hydrostatic pressure IttildUp behind walk. Backfill should he placed in uniform lifts and compacted to at least 90% of the rtta%i m.rn standard Proctor density al a moisture content near optimum_ Back fill placed in pavement and walkway areas should be compacted to at least 95%of the maximum standard Proctor density_ Cane should be taken not to overcompdct the hackfill or use Jct.No 115 3447A r-rp - 5 - large equipment near the wail, since this cou bd cause excessive !mend pressure on the will. Some settlement of deep foundation wall backfill should be expected, even if ilk material placed correctly,and could result in distress to. facilities constructed on the back iI I. The lateral resislanee of fourrdar i on or retaining wall footings wi kl be a cvEribination cif[he sliding resistance of the filing On t he foundation materials and passive earth pressure against the side of the footing. Res istartee to sliding at the 'bottoms of the footings can be. calculated based on a coefficient or met ien of 0.45. Passive pressure of compacted hack fill against the sides of the footings con he calculated using an equivalent fluid unit weight of 375 pd. The coefficient cient of Neikirk and passive pressure values recommended above aSsu rrMe ultimate soil strength_ Suitable factors of safety should beincluded i n the design to limit the. strain chic h will occur at the uI Li m rte strength, para iculariy in the case of passive resistance.. >'IU placed against the sides of the footings to resist lateral 3oads should be a gr`zu-tu]or Material corpaactcd Lo at least 95% of She maximum standard Proctor density at a moisture content near optimum_ FLOOR SLABS The natural on-site sai ts, excLIOsi ve of topsoil, arc suitable to support lightly loaded slab- on-grade cousrrut1 iof. To reduce the effects of some differential movement, floors L ih should he separated from all beating walls and columns with expansion joints which art I oma, urLrestr-aincd crl i cal movement_ Floor slab control joints should to user to reduce damage due to shrinkage cracking. The requirements for joint spacing and slah rein foreerntil should he established by the designer based on experience and the in Lendcd slab use. A minimum 4 inch layer or free-draining gravel should t placed beneath basement level slots to Reil if:Mte drainage_ This material should consist of minus 2 inch aggregate with at least 50% retained on the No. 4 sieve and less than 27i pa ri erg the 2o_ 201) sieve. All fill materials for support of floor slabs should be corripaled to at Least 95% of maximum standard Proctor density at a rno isture canton near optimum_ Required tit' curt consist of the on-rile granular soils devoid of vegetation. topsoil and oversized rock. lob No I(5-3617A - 6 - k]N DERDRA1N SYSTEM Minor seepage was aricou niered i r1 Pit I during our exploration and it has been our experience in the area that perched groundwater cart de we]up during times of heavy precipitation or seasonal runoff. FrCIacn ground during spring runoff can create a perched Coad i:Eion. We recommend below-grade constriction, such as retaining waits,cr wJspac e and basement areas, be protected from wet[ing and hydrostatic pressure buildup by an underdrain system. The drains should consist of drainpipe placed in [he bottom of the wall haokfi II surrounded above the invert level with free-draining granular material. The drain should be placed at each level cel excavation and at least 1 fool below lowest adjacent finish grade and sloped 21 a minimum I% to a suitable gravity outlet. Free•draining granular ina1e ria I used in the u ndcrd ra in system should Contain less than 2% passing the No. 20(1 sieve, less than 50% passing the No, 4 sieve and have a mai imam size Of 2 inches. The drain gravel backfill should be at Least I V foci deep and ex tc ndi up to any seepage in [he cut face. SITE GRADING The risk of eoustrtieL k[t-irtiduued slope instability at the site appears low provided the building is located in the toss steep part of the JOE as planned and cut aid fill depths arc limited. We assume the cut depths for the basement level will not exceed one level,shoal 10 to 12 feet, Ells should be limited io about S to 10 feet deep. Embankment rills should be compacted to at least 95 of the maximum standard Proctor clew i[y near optimum moisture Corti kert[, Prior to fill placement, the subgnide should be carefully prepared by removing all vegetation tation and topsoil and compacting to at bier 95%, of the maximum standard ProC[or density, The 1`i]C should he benched into slopes [hat exceed 20% grade. Permanent t fret lined cuE and fill slopes should be graded at 2 horizontal to 1 Vertical or flatter and protected against erosion by revegetation or other means. The risk of slope instability will be increased if seepage is encountered in Cuts and flatter slopes may he Necessary, If seepage is encountered in permanent cuts, an investigation should be • !ab No 15 147A -- - 7 - conducted to determine if the seepage will adversely affect the cut stability_ This office should review site grading plans for the project prix,r to construction_ SURFACE DRAINAGE Positive surface dmimage is an important aspect of the project to pre}crk[ u ct Ling or the hearing rroattrials. The following drainage precautions should be obs r eed during .r or struction and maintained at all ti nits after the residence has been completed; I) inundation of the foundation t`xeaVati.ns and u nide r fab areas should be avoided during construction. 2) Exterior back Fi]L should be adjusted to near optimum. rootsturc and compacted to at least 95% of!Fre maximum standard proctor density in pavement and slab arca5 and to at least 90% of the maxi mum standard Proctor density in landscape areas_ 3) The ground suriiee surroundi n the ex to rior of the building should be sloped to drain ;sway from the foundation in all directions_ We recommend a minimum slope of 12 inches in the fist 10 feet in unpaved areas aid a minimum slope of 3 inches in the first !O fit in paved areas_ Free-draining wa]I backlit! should be capped with at least 2 feei ref the on site finer graded soils to reduce surface water infiltration. 4) Rnor downepou[s and drains. shout discharge well beyond the limits u f ail backlit!. 5) Landscaping which requires regular heavy irrigation should be !waled u !east 5 feet from foundation walls. LIMITATIONS This study has been concluded in accordance with genera[]y accepted geotechnical eng i mteri ng principles and practices in [his area at this time_ We make no warranty either express or implied. The conclusions and rccornmendatioris submitted in [his report are based upon the data obtained from the exploratory pi rs excavated I she !mations indicated on Figure I, the assumed type orCOM-trilieliOn and our eX perierice ill the area. Ow-s r'ices do not i nc I adv determining diii presence, prevtnEi on or possht]ii w of mold or 115 5-t7 A _... G to - 8 - Our. 'i±eg do no; inc lute dhtcrni Gni ng the presence,prevention or possibility of mold or other biological con tarn]rlaUts (MOBC) developing in the future. If the client ig concerm d about MOBC, then a professional i n This special field of prac[icc should be consulted_ Our findings include i rrterpolation and extrapoEation or the suhAurIaie conditions idcnti Fred at the exploratory pits and variations in the subsurface conrdiiioni may not bc«me evident until excavation is performed. If conditions encountered during construct i o appear different front those described in this report, we should be notified so Ilial re-evaivati on of the rcco nmcnd ations may be made- This report has heel. prepared for t he exclusive use by our client for design purposes. We are not responsible for lee hnical i nlerpretatio'ns by others of our in rormation- As the project evolves, we should provide continued consultation and field services during construction to review and monitor the implementation of our recommendations, and to verify that the recommendations have been appropriately interpreted_ Significant design changes may require additional analysis or mod i ficatitkn s to [he rec4}rnmcndution presented herein. We recommend on-site observation of excavations arid foundation bearing strata and lest ing of structural fill by a representative of the geotechnical engineer. Respectfu tly Submitted., H E PW TH - PA ILA K GEOTECHNICAL, INC- Dj'r'id A. YOUri , F. E. Reviewed bY= r �tit'� �5y 4rj r :71,111 1.PZ Steven l.._ Paw '. 1 6222 It' 2 01 DAYWks* {'i, .' • ..... ,, , NEE .. G1 • Tow•u of Vail, 2000, Ofiri rl Rockfafl Hazard Map, T ii'n Er/Vurtl: Prepared by the.Town of Vail, Vail.,Colorado (Adopted by the Town Council nn October I?, 2 CI), —-- INri 115 347A 'Ch i._ .. ..—,...„„,.......,,_,„,, r?-. P.• \ \ \ \ \ \ APPROXIMATE SCALE 1 3d I, 1 \ T t 1 I l -"- -- II \ — :[' — — ' 11) I 1 if 1(4-- ! I 1, } { i ( ILOT t I 17 8.pAN Y L4,NE I 4% E b N I Jr 1 + �1 / I AREA 1 I ~ ~ •- - LOTS. 1 ,r t _ II \ \N. \ -- ---, p i'2 •••• • LOT 4 \ \' I 1 , ti ti 4 1 1 4 SONO V LANE i 115 34.A lir itedi j LOCATION OF EXPLORATORY PITS Figure 1 H t�.varrri+P,�WLAN aECITE f ,.� PIT 1 PIT 2 0 d _ POP —1 iii !' ; — — -- we lin `•~ . j +4 25 . '4 5 '.' 0 _ ] 33 5 - 4. ft- o s..„; 5'4' t I ;+l a WC 151 :a `, _—I +4 51 - 1 to -2001 t3 1D LEGEND: ETOPSOIL; silty. clayey, sand with scattered cobbles and bcw olars. mi st, dark Lrmen I it SANK)AND GRAVEL (S GC ; ctayrey,with Cobbles and small boulders.dense, mo St lo veal most, brown plastic tinafi J• Disturbed bulk sample. ---— IndiCe1es seepage daserwed al gime c1 excavrtiprr NOTES: 1. Explwatoryr Os were excavated on/ugu sl 4, 201$with a tra khoe. 2. Locations of explora1ary pits were rneaSured approx,malely by pacing from reaiures shown on the site plan prcroided, 3. Elevations of exploratory pits ware noc measured arid vie log9 or e40ratoryr pits are dirawrt to depth, 4 The exploratory pit loeatiortis ehOuld be Con. idEred accurate only to the degree implied by the method used. 5. The limes between meiterials shown on the exploratory pis logs represent the approximate boundaries bietwee rriaterial types and rf rtisitiorl5 may be gradual 6. Water seepage was encountered in Pik 1 a time of excavation No free water was encountered in Pit 2 at the time of monavatjn.g. Flucit at n In water leveret may or.mr w.ith.time. 7 Laboratory Testing Results: WC - Water Content (4} —4 = PerCanl relai led on the No.4 sieve -200 = percent passing No. 200 siege 1"1 115 347A LOGS OF EXPLORATORY PITS 7 Figure 2 1-L'Ellmei011r11.11r1.11wL xR Gutcr+sar.nr� - S d �v r • _I�roRaraTEa+44 5 E+�l'4='— TIME - �� l�1 AI REr�E]Ih LR� [ u$ ST 5E $ I CLEA9 SO.JIIFiE OPENIH13S 43 k11h 15 MN 64PANIISMINI 4 k#Fy :MN 0244 fi Ig(F g v 0:20 i~1 s £a pa —te ' 1.4• 1 JP .3' 5-6' 6— d .....„.... �_-- ---.-.. .-ii—ii -1� i iii - -r . a � . . 1I Mil—mil--- 54ii y� —• - — ila�� iu ��i ��Irlmg I CI �!•` R.M J iii +� 1—Y til.. *l . •iimrrii` dpi✓ i�ia�i�r� -��•iwow m.. i'- i — -- EA — Y M-- US I �+U., 1��1_ i —.— __!_ Jrii� +Ii !i_ .} I � i��.—#iii �i �l� # Y. 50 i.--...i7'''•• •--.. -.4..... .....A..—...._..._.ir _ ._!..I • EA) i----- ii ----—i--i— w Ir — T+, i__—i i��i��l_J•i_�_i—_i�_L__ 1 Ieg ii!��i�Yr _ i iy�� '1�JY-1li ! 7 I i 1i. 'ii--i .ilri� —TE.!IMml __ —iii'-ii—ii ii�ir�Fl.� ��y}�Misi iii.�ii i�li� I W �i 1-,......... 1 au• ?r ad aea 419 w; V. 1m. .VE EV 1'i 154 +*7 As }s .91 ='a IR1 OJAMETEA OF PARTICLE iN!I UJMEYi=RS I- s n} GP' I:1-w'-Q gI - 4r LYil•• ._I.u�r r y F I GRAVEL 51 % SAND 36 % ILT ASD CLAY 13 % u0i...I0 LIMIT % FUNSTICITY INDEX % SAMPLE OF: CFayreyr Sandy Gravel PROM: Pi[ 1 ar 8 le 9 Fest ►i'rDR 1lSS �_ 1 aNa, I TIME REpt lin _.5 • l.kS STN ARD SERIE �S CLEM SO• E oc ENN $ • - i +$ 15 MIN P lIH yMIN 4 MN 1 MIN S24a 'ICC' /1O a 4.1 I.1 �`.w.� X34 16 #8 ^J 1II r 3 B co� i��.. ii-- fir_ 1 — -----i—i.i. ...�1!Jilin 10 - • �.-a --i • k .. E911 ! — i — ! Eli _ l iMgr- --11! MN lip, .1.l. O iii——ii --i—ii_i_ !---Y— W 11 =iiiY ^� W 70 i�� ---T•llii�� i1 ---- --�---TIS —�.. i iii.1_ii� ii_��.. LinLLLUUU I_f_^Eii ',�` i fi CC ii��i�� i-Iii i .r.` 50 •cr i��i—ii—i•ai�. —mo �. .- .el 1�—i_r_�i--__—ai��i .. .. iia_ z ii �_ CC 61) �i�^ .ilei--—l_ii.��i- _`�!i A 40 YTS iirtiii��i��.lir ��ryry I. ' ai ll7�i i i��k— EL E.=1== i —._---i EV `i — _.ii ....i=.M i�1�i ii yJi—=— =.1 •••• . —ii.a� ...., — 1 ��ii �r -lam li ___i_—= l 1051 m — ..--ice! —i ii10 1111 002 ons 1019 D19 437 071 ISO 304 6L11 1 11 2.36 4 78 9512519 : 37.rf 76 2 17113 OiAmETER CF PI II1CLES IN MILLIMETERS J _ 1 241 rayl ■OEff GRAVEL 25 Si. SAND 42 % $FLT RIND CLAY 33 % I LIaLJI D LIMIT % PLASTICITY INDEX SAIPIPLJaF I i1 end with Gravel FROM. Put 2 al 3 to 4 Feet - I •. .. 115 347A H OHADATION TEST R E L , Figure 3 .. 1. tarlh-Po.1 4ealtdrr114g1 r—ra7F- 511-1-71-27-11 t'7 W I i I r II a. l w . I , 6I ' G C � c ` r • li 8 c 1 , ..,. , H 1- i • WZ› = i �'rj- 4 LTJ 44 F EC i iii E 1,-,i, iii - - -I- 1. iCI # 3 j Ze 4 J Er j i �`� - # _ —1C13 to 0 Wg ci 1.—‹ o.5 ci.*1 47 ." ' ---r7p 1 - t 1 0. < 0 la, 2 �� _. --1 . f ILL 2 of y�n i ' Y 1--- '-i--k-h---:i.-1- _,":1 ithi _ 7.;, :c a ---p--1-1---.1-1-6-1- • 5 Q i i drie 1 rt .._. ' I