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Home My WebLink About1987-12-01 Soil Investigation ReportiMsm Companies SUBIERRANEAII EMBINEERINe CORP. professional solutions to your soil engineering needs JOB NO. X-87289 SOIL INVESTIGATION PROPOSED HOUSE ADDITION LOT 12, BLOCK 1, BALDUR PARK ADDITION 1412 BALDUR PARK ROAD ORONO, MINNESOTA A report prepared for MR. CURTIS HAGFORS December, 1987 6875 Highway 65 N.E. P.O. Box 32308 Minneapolis. MN 55432 (612) 574-1242 12203 Nicollet Ave. So. Burnsville. MN 55337 (612) 890-6510 REPORT ON SOILS INVESTIGATION PROPOSED HOUSE ADDITION 1412 BALDUR PARK ROAD ORONO, MINNESOTA We were retained by Mr. Curtis Hagfors to perform a soil investigation for this project. The purposes of our work were to determine the general soil and groundwater conditions near the area of the proposed addition, and to prepare a report of our findings, including recommendations for the design and installations of foundations. ERaCED.URE__ By agreement with the Client one (1) test hole was drilled near the proposed building addition area. The field work was performed on December 1, 1907 using a truck-mounted CME-55 drill unit. The test hole was advanced with 3-1/4"i.d. x 7"o.d. continuous flight, hollow stem augers which act as a temporary casing to prevent collapse of the sides of the hole. r;j SVOTUUMMCAJV pa Box 32308 hUrmtopois, MN 55^2 laia PniutjLatji>-I » n-P 4-Vw It 1 ASt^i*^ Aip at 2 to 5 foot intervals of depth, in accordance with procedures designated in ASTM D-1586. Periodic observations for groundwater levels in the borehole were made while .drilling and upon completion. All soil samples obtained were brought to our laboratory for examination, classification and testing. Laboratory te..its Included determinations of natural moisture content. The samples will be retained for a period of at least 90 days from date of issue of this report, after which they will be discarded unless we are otherwise notified. Drawing No.l is a site plan showing the test hole location. Detailed soil descriptions together with the standard penetration test blows per foot and natural moisture contents are given on the appended Borehole Log. The capital letters in parentheses represent the appropriate group symbols of the Unified Soil Classification System. A chart explaining this system is appended. Elevations in this report are to geodetic datum, and were obtained using the bench mark noted on the site plan. ^ ammmAmMM PO Be* 32308 MS SH32 / The site is located on a small peninsula extending into the North Arm of Lake Minnetonka, and is a lake shore lot. The proposed building area is flat, and is only slightly higher than lake water level. This was formerly a swamp area, but was filled over to raise it above lake level. The major natural inorganic soil type in this area is clayey glacial till related to the Des Moines ice lobe of the Wisconsin glaciation. The upper portions of the clayey glacial till was later modified by stream action, which left a covering deposit of sandy and silty material. Lake Minnetonka has receded to its present size, leaving deposits of peat and organic clay formed at its former margin. Some fill has been placed over the property during previous development of the lot. SOI L_C.0NJ).m.011S__ Four basic soil types were encountered in our Investigation. These are: fill; lake margin organic soils; stream deposited silt and sand; and Des Moines clayey glacial till. The area of our test hole may have been lake bottom land reclaimed by filling. There appears to be about a 7* thick surface layer of fill at our test hole location. This fill is a mixture of silty and clayey fine sand with variable organic content. The sand fill is damp to saturated, and loose. The fill is unsuitable for foundation or floor slab support due to the compressible organic material buried below it. f.akw Margins Orflanic_Soil.a_ Underlying the sandy fill is a majcr deposit of peat and organic silty clay with mollusk shell fragments. This stratum extends from 7 to 20 foot depths below grade. Standard penetration test resistances within this soil formation are consistently 2 blows per foot, indicative of a very soft condition. The peat and organic clay are weak, highly compressible, and unsuitable for foundation or floor slab support. 6^5 Hmt 6S N£. PO 6 m1Z3M s^iSBwn_DBPXS5iiificLJiand_flnd_fiiI.t ( Underlying the post-glacial lake toargln soils is a 9 foot layer of stream or alluvially deposited silt and sand, of later glacial age. The upper portions of the deposit consists of fine sandy silt, which grades to a fine to medium sand with silt traces. The silt component of this formation is stiff in consistency, and the sand component is medium dense. The sandy silt and sand layer has moderate load bearing capacity and low compressibility, and is a suitable subsoil. Hes Jloinea-Clayey Glaclal..Tm— The major underlying soil typo at this site commences at 29 foot depth below present fill surface, and extends beyond the terminal depth of the boring. This is Des Moines clayey glacial till, which consists of sandy clay with traces of gravel throughout. The sandy clay has slight plasticity. A standard penetration test in the glacial till was 10 blows per foot, indicative of a tough consistency. Natural moisture content of the sandy clay is 23%. The Dos Moines clayey till has moderate load bearing capacity and very low compressibility, and is a suitable foundation subsoil. JMnEiUI4NE«J« 6 qal^NnWATRR nONDlTIOMS_ f Free groundwater was encountered in the boring at a depth of 3' below existing grade, corresponding to elevation 928.1*. The water elevation in the North Arm of Lake Minnetonka, approximately 110' northeast of the test hole location was 928.2* Had our period of observation boon longer, the water level in the boring would have risen to match or slightly exceed the lake water level. The observed groundwater level at the site represents a permanent groundwater table, coinciding with the level of Lake Minnetonka. (The design 100-year floor flood level of Lake Minnetonka is 931.5*}. Excavation extending below elevation 829* to 828* will likely encounter major groundwater intrusion, and provisions will have to be made to control the groundwater. SIRU-CTHRAL INFORMATION— The existing building is an old, 1-story wood frame house, with a shallow crawl space under. We understand that an addition to the original building was constructed in about 1954. The floor level of the house is about 1-1/2 feet higher than the adjacent outside grade. ■ smuuukMuui 687S Hmv 65 SC PO Bom32J08 HiwecpoU. HN SS432 >^The existing structure appears to have performed well, with Ao obvious settlement or cracking. Nevertheless it is very likely that settlement occurred in the past, probably within the first 5 to 10 years after original construction. We were informed by the owner, Mr. Hagfors, that the house is supported on shallow footings which extend to only 2 to 3 feet below grade. It is now proposed to construct a 1 or 2-story wood frame addition with crawl space under. Structural loads on the footings or the subsoil will bo relatively light. Our single soil boring, which is actually further from the lake than the addition, indicates 7* of old fill over a 13 thickness of very soft lake margin organic soils including 2' of peat. It is our considered opinion that support of the new addition on conventional continuous strip footings under the bearing walls would result in excessive differential settlement between the new addition and the existing structure. Furthermore the influence of the new loading associated with the new construction will extend under adjacent portions of the existing house, and could cause some settlement of the affected portion of the old structure. Thus some form of special foundations is recommended. 8 f Two types of foundations should be considered for the new addition. A. Shallow RaftJype-Eoundatioj- - If some small settlements of the addition and possibly the existing structure can be tolerated a shallow raft-type foundation could bo used. The raft-type foundation should consist of a thickened-edgo slab with intermediate stiffener ribs in both directions. This reinforced concrete slab could be used as the floor of the addition, but then would not match the existing floor level. Alternatively a built-up wood floor could be constructed above the foundation slab, with shallow air space under, to create matching floor elevations. All obviously organic surface topsoil fill should be removed from the proposed building pad area. We strongly recommend that no now fill should be added, so that new loading on the subsoil is minimized. The exposed sandy subsoil should then be thoroughly surface compacted with a small, self-propelled drum roller operated in its non-vlbratory mode, so as to minimize distress to the existing building. A total of 50 complete coverages of the roller is recommended. O 6975H«v65N£ rO MowiMpoAt. HVS5412 I The foundation should then be cast, as detaiiea on ’attached drauing, F-1. Perimeter insulation has been included, to minimize frost heave potential. The addition should be founded totally on the raft-type foundation, without transmitting new loads to the existing house. At the match line between the new addition and the existing house a complete, vertical control joint system should be Incorporated, capable of tolerating up to 5/16" of potential differential settlement. Roof flashings at this match lino should be fabricated with wider than usual flashing material. Altwrnattva B. Deep Foundation System_ _ If no new settlements can be tolerated, then a deep foundation system should bo used to transmit the building loads down into the competent Inorganic soils at depth. Duo to the close proximity to the existing house, the use of driven piles is not recommended. Vibrations developed during driving may damage the existing structure and cause additional settlement duo to possible compaction of underlying loose sands during vibration. The pile-driving hammer also emits a fine spray of diesel fuel which can ruin the paint on the house. therefore recommended as a suitable means of support of the proposed addition. Auger cast concrete piles should be Installed to achieve at least 10' of embedment into the natural sand and tough clayey glacial till below the organic soils. At our single test hole location the piles would extend about 32 feet below existing grade, but piles closer to the lake would potentially be longer. Recommended design capacity of this type of pile is: PILE DIAMETER RECOMMENDED ALLOWABLE PILE NET WORKING LOAD * lincheaJL_ _ _ _ _ _ _lismaj—- - - - - - - - - - - - - - - - - - - 12 17 * After allowance for potential negative skin friction caused by settlement of the lake margin soils. G^K£L - - - - - --- - - -—— / The soil conditions have been established at our specific test hole locations only. Conditions elsewhere on the site may vary, and extrapolation of the results is not warranted. The installation of auger cast piles should be monitored by a qualified Geotechnical Engineer, as soil conditions are expected to vary, and field changes in design pile length may be warranted. The excavation, surface compaction, and raft foundation installation should be monitored and tested by a qualified Soil Engineer. We would be pleased to provide the necessary field engineering observation and testing services. The recommendations contained in this report are Intended solely for a project of the type described herein. In the event that any changes in the nature, design or location of the building is planned, the conclusions and recommendations contained in this report shall not be considered valid unless these changes are reviewed, and the conclusions of this report are modified or verified in writing. 1=. ■ « snnmmAMEAM 697SHmv 65 HE This report has been prepar^d^ortneeiccTusIveuse^rTirT^ Curtis Hagfors and his agents, for specific application to the proposed house addition at 1412 Baldur Park Road, Orono, Minnesota in accordance with generally accepted soil and foundation engineering practices. The soil testing services performed by Subterranean Engineering Corp. for this project have been conducted in a manner consistent with that level of skill and care ordinarily exercised by other member** cf the profession currently practicing in this area, under similar budgetary and time constraints. No other warranty, expressed or implied, is made. Submitted December 17, 1987 SUBTERRANEAN ENGINEERING CORP. mn4%t IP# ft«t IP# SUtt ot MiaMtttP. /Z-/7-^7 . Nt Rodney H. Ambrosle Registered Professional Engineer Mervyn Mindess Registered Professional Engineer RWA:MM/pg Distribution: 4 cc Mr. Curtis Hagfors 1 cc File = '1 ^ 4 ^. =p. 6S7iHwv65NC MN550? BOReMoi-E: 1-00 <rr DESCRIPTION !• forsoil-t tUcI sn.iv fine ‘-o/j^Cj i\ evdiua BAUD, trace roots. Daep. ,____________;___________________ \FllLi Dart brown CLAVfV line BAUD, / OL STANDARD ELEVATION PENETRATION RLOH8 PER <FT.> IM.0M8/FT.I SIX IN. O lO 20 30 90-I- 2.5 ji\ trace roots. Deep to eel. Loose.; . * *. FILL! Prey organic 8ILIY fine SANDi h trace roots. Pet to saturated. ; loose. \ Dart broHO fibrous FEAf. 20.0 o- 2Y.0 31.0 \Spongy. Saturated. Soft. Dart grey organic SILtV CLAV, trace flcllust' shells, iledioa plastic. Soft. Grey SAIIPV SILT. Non-plastic. Stiff. MIL Grey fine to «ediu« SAIlDf trace to a little silt. Saturated. Nediua dense. Srey SANDY CLAV, trace gravel. .^Silgtitly plastic. Tough.___________ IfOLE liRniliAliF^ Ho'refusal. NOTE: Free ground water at 3' depth utiile drillingi at 3.5' depth after drilling. H.C. % i Viw 0 •} 0 i 0 0 "Pl o! i i PROJECT NAME AND IIDUBE ADniTIOM - I'M2 triLDLITr PARK RU. LOCATION Lot 12, Bloch 1 - Bjldcr Fisrh Mdd. tlr UMO, liinocsoLa JOO NUMBER BORINS NUMBER DATE DRIIXEO BY X-B72B9 1 DEC- I, 1937 H.M, 1 R.B. SI_IB~TE:F%ff^AIME#^IM EIMI3 INEIBIIR 1 MO COMf=»- IMPORTANT INFORMATION ABOUTYOUR GEOTECHNICAL ENGINEERING REPORT ^ ! Mof e constiuctlon problems are caused by site subsurface conditions than any other factor, ^ troublesome as sub- surface problems can be. their frequerKy and extent have been lessened considerably In recent years, thanks to the Association of Soil and Foundation Ensineers (ASFE), When A5FE was founded In 1969. subsurface problems were frequently being resolved through lawsuits. In fact, the situation had grown to such alarming proportions that consulting geotechnical engineers had the worst profes sional liabllily record of all design professionals, fly I960. ASFE-mrmfvr roaiiifliag uil aarf fcmndatlcn rn^rlnmi had the tot nt/rttfonuf fidWfy rrcflnf This dramatic turn-about can be atliibuted directly to client acceptance of problem-solving programs and materials developed by ASF E for Its mem bers’ application. IMi autplanu w ^infd haattst ckrrrrf fmdirJ Ifir ASF E drrmflif* I*) ht fn Ifrdr run ^r Inlrmfi. Disputes benefit only those who earn their living from olhets’ disagreements. The following suggestions and observations arc offered to help you reduce the geotcchnlcal-ielalcd delays, cost-over runs and other costly headaches that can occur during a construction pru|cct. A GEOTECHNICAL ENGINEERING REPORT IS BASED ON A UNIQUE SET OF PROIECT-SPEanC FAaORS A gcotcctinkal englnectlne repott Is based on a subsuilace exploiailon plan designed In Incorporate a unique set ol prolecl-spccillc factors Ihcsc typically Include the general nature of the structure Involved. Its site and conligurallon; the location of the structure on the site and Us oricnlnllon; physical toncornllaiUs such as access roads, parking lots, and underground utilities, and the level ol additional risk which the client assumed by virtue ol limilallons Impmed upon the exploratory program To help avoid costly prob lems. consult the geotechnical engineer lo determine how any factors which change subscf|ucnl lo the date of his icpoil may alicci his recommendations Unless yourconsultlrrggcolec'.nical engineer indicates otherwise (rout im’IrdiiilailrttgintvHn() rrrorl shouU not bt iisnl • Wlicn the nature of the proposed structure Is clianged. for example, if an office building will be eteclcd Instead of a parking garage, or il a lefilgct- ated warehouse will be built Instead of an unrcfrlg- crated one, • wlien the she or conliguralion of the proposed sliuclurelsalteied; • when the location or orientation of the proposed sliuctuic Is modilied; • when there Is a change of ownership, or • lorappIlcaliontoanadlaccnlsUc. A (rmtnfirtiral rn^riivv hinnel atari trspontililily /or gruf’Irrni ufmh m.iji cfmfiy if fir it not tcntullfJ a/tniadns lomUarJ In hit npotls tfrvrky'mml fimr dianjrnf MOST GEOTECHNICAL "RNDINGS" ARE PROFESSIONAL ESTIMATES Site exploration Identifies actual subsutlace conditions only at those points where samples are taken, when they are taken Data derived through sampling and subsecfuent laboratory testing are extrapolated by the geotechnical engineer who then renders an opinion aberut overall sub* surface conditions, their likely reaction lo proposed con* struction activity, and appropriate foundation design. Even under optimal circumstances actual conditions may differ horn those o|ilned lo exist, because no geotechnical en* ginccr. no matlei how qualified, and no subsurface explo ration program, no matter how comprehensive, can reveal what Is hidden by earth, texk and time, for example, the actual Interface between materials may be far more gtadir.il or abrupt than the report Indicatirs. and actual conditions In areas not sampled may dlllet from predic* lions Nolkliiir can bt dent lo pwml Ikr unanlirtfwirri. ^1 slrys tan bt labfn la hrlr fninitnht IkHr Imfad. For this reason, moil nmirnitii im-nrrr rrldin Ikdr gratnkiiiul ((imultonl Ikrouafi Ikr iiNniruclion to Identify variances, conduct ailditlonal tests which may be necdcri. and lo recommend solutions lo prolitems encountered on site SUBSURFACE CONDITIONS CAN CHANGE Subsurface conditions may be modified by constantly- changing natural forces because a geotechnical engineer* Ing icpoil Is Isised on c> mditlons which existed at the lime of siibsuihice exploration, loiulriidion dnisions skouM net bt batfJ OM a (inilormiuil ntgiMrrriitii nporl tthou adtamy may havt bem allaifil f'u lime Speak with the geotechnical consultant lo learn If addilional tests are advisable before construe* lion starts Conslrucllon operations at or adjacent to the site and natural events such as llocxls earthquakes or groundwater lluctuatlons may also allect subsurface conditions and. thus, the continuing adcqu-icy of a geotechnical report, lire gcotccfinical engineer should be kept apprised of any such events, and should be consulted lo determine If additional tests are necessary A GEOTECHNICAL ENGINEERING REPORT IS SUBIECT TO MISINTERPRETATION Costly problems can occur when other design profession als develop their plans based on misinterpretations of a geotechnical engineering report 1b help avoid these prob lems. the geotechnical engineer should be retained lo work with other appropriate design professionals lo explain relevant geotechnical findings and lo review the adequacy pLASSiFiCATiON QF SOILS FOH ENGINEERING PURPOSES ASTM Dtflfnatlon: D 2487 - 68 T AND D 2468 - 66 T tyUnIflotton Svittn^ Mi|of #«llionf I 1 I *8 I >i I |1 I -5 llli jlllll jll ll II Ty^leai W«tt fir id#d 0* P fnlaturtt. tltllfl or no f1n«t Poorly ffrtdod gtivtlf, grtvtl* Mr>d rntatufM.UllU or no llrMl Silty If* mlMufM •t Mnd tilt CliViyra mliturtt «li«1 Wollfifidfd tindi.ortvflly Mndt JlttU Of no IlnM Poorly tanrfi, 0tovtlly Modi, Unit Of no fintt L«l»of«tory ciMilfleotlon crliotlt Silty Mndt, land-atlt mlMluiH Cltyay tar>dt« und clay mti- tuftt 0,0 —ftMm lhart 4; Ce*jj^^Qjjb#n^raar» 1 and 3 Not maatlng alt r•(Nation taquiramania for GPf Aiiatbarg llmliabalow**A** llrw or PJ. laaa then 4 Abova **A** tint wlih P.I. batwaan 4 and 7 art Ar//na caaaa taqulrlng u« of dual tymbolaAtlarbarg llmlta abova *'A"* tlna with P.1, giaatar than 7 O«o fOjof* Not maatlng all gradation raquiramanta for SW Aitaibarg llmtta halow **A** llna or PJ. laaa than 4 Llmlta plotting In hitchad torra with P.l. batwaan 4 •nd 7 ara hord^fUtw oaaaa taqulrlng u« of tfuaf tym* boll.Atlatbarg timita abova **A** llna with P.I. graatar than 7 i ll tj ll Inof0an)e ilila and vary llna unda, rock flour* illly or clay* ay floa unda or elayay allta vrilh »lt0hl plaiilcity 'S «• j i^ i a s| *11 IP InotQank dayi of low to ma* dlum plaulclty* elava, undy clayi* attiy ctaya* laan daya Organtc allta and organic illty daya of low plattlclty MH Inorganic allta, mtcacaoua or diatomKaoua flna undy or alliy aolla, alaatlc allta Inorganic daya of high plu* ticliy, fat daya Organic daya of madlum lo high plattlclty. organic allta 1 1 1 1 1 For dautflcatlon of finagran aolla and flna fraciton of coai __ gratnad aolla. Attarbarg Llmlta plotting hatchad araa art bordirlfna di ficatlona taqulrlng u« of d tymboli. wd raa*// In aal* hjil CM / / Eqiiitllon ri-o.T ol A-llt 3(LL '30) / / ./ OHar IMH CL / / ......:LmI / MLa<dOL Paat and othar highly organic •Oita 40 60 60 Liquid Limit Ptaaildty Cfiad Bubtorranean onoinaerino corp. GENERAL NOTES Datcrlpllva Terminology CONSISTENCY tiWM Soil Still Tough Vory Tough Hard N VAIUE 0-4 5-» ?-l5 16*30 Over 30 APPKOX UNCONriNtD COMPRESSION STRENGTH 0 1300 3000 4000 Over 1300 p<f 3000 pti 4000 ptf BOOO p«l eooo pif DENSITY um V«ry Loot# loot* Medium Dtnt« 0 tns« Vtry D«ni« N VAlUt 0-4 S-IO 11-30 31-30 Ovtr 50 WEIATIVE PBOPO>TION5 TERM Trace A llllU Soma With RANGE 0 - 5«/o 6 - 15®/o 16 - 30«»/o 31 - 50"/o MATERlAi CLASSIFICATION TERM Boulder Cobble Med Courie Gravel Fine Gravel Sand Sill and Clay SUE Over B Inchei B — 4 Inchei 4-3/B Inchei 3/8 ln-N« 10 ileve N® 10 Ileve-N® 300 ileve Finer lhan 300 ileve MOISTURE DESCRIPTION DEGREE .OF SATURATION % Dry 0 Humid 1-25 Domp 23-50 Mofsl 50-73 W«l 75-99 Solurotfd 100 Dorlnp Log Symbols Immodlalo Water Level 24 Hour V/eler Level Loss 01 Drilling Fluid Undisturbed Sample Wst«r lev«tt ihmvn on the boring tops aro Umi lavals maaaured In ttm boringa at tha lima and undar tfia corKlIllona Indicated. In sand, the Indicated lavali can bo conaldtrad rallabla gfourvi wotar lavala. In clay toll. It Is not possible to datarmlna tha ground water lovot within tlio normal acopa of a test boring Invasllgatlon. aecopt whara laniaa or layers of more parvloua watarbaarlng ooll are prasani and lhan a tong period of time may ba nacaatary to laach aqultibrlun. Tlioiafora. tha poalilon of lha watar lavat ayrreol for cohealva or mined taictuia aolla nwy not Indicate the true level of tha ground watar tiblOe lira avaltabte water level Inlomwtlon U given at the bottom of the log ahaat. SUBTERRANEAN ENGINEERING CORP.