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Home My WebLink AboutPermit Building 2000-8-24 ~ Rug 25 00 07:03a 08/25/2000 66:34 River Valle~ Builders Inc 541 367 1638 5416849358 K & A ENGINEERING p.2 PAGE e!2 K & A Engineerlnu. Inc. P.O. 80x10524, Eagene. OR 97440 521 Markel St., Suite B. Eugene. OR 97402 (541) 684-9399 Voice (541) 684-9358 FAX August 24, 2000 Greg Landn River Valley Builders P.O. Box 2041 Corvams, OR 97339 SUbject Building Pad EvaluaUon Ambleside Meadows, Lots #154 and 113 Springfield, Oregqn ' Dear Mr.larkin: K & A Engineering, Inc. is pleased to have this opportunity 10 provide an evaluation of the suitability of the subject building lots for construction of foundations for single-family residences. Both of these lots have been excavated and preparad for the construction 01 standard cast-in-place concrete strip footings, spread footings. and stem walls. These recommendations are made In accordance with -Excavation and Foundation Requirements for New Strutures on Individual lots" establisned by the City of Springfield.' PURPOSE. SCOPE, AND LIMITATIONS The geotechnical engineering services summarized herein are provided 10 assIst River Valley Builders in properly preparing the subject building sites for foundation constnJction. These services include engineering recommendations to avoid construction on unsuitable sOils and qualltyconlro' of compacted fills only. The scope of ourselVices does not include constructiOn safety precautions, techniques, sequences, or procedures, BXceptas specifically recommended In this.report. Our services should not be interpreted as an environmental assessment of site conditions. This geotechnlca\ investlgation,analysis, and recommendations meet the standards Of care of competent geotechnical engineers providing slmilll' services al the tIme these services were provided. We do not warrantor guarantee these recommendations, site surface, or subsur1ace conditions. LOT 154 General lot 154 is located on the south side of Ambleslde Drive. The existing ground surface slopes to the street below at a grade or approximately 10%. Vegetation consls1s of native grasses. The ground suriace (prior to excavation) Is even and uniform across the lot. with no evidence of slidIng, spri(lJS, excessive erosion, or , Ambleside Meadows Subdivision _111 Addition " ....' Rug 25 00 07:03a 08/25/2000 0&:34 River Valle~ Builderslnc 541 367 1638 p.3 5416849358 K & A ENGINEERING PAGE 133 K & A Engineering, Inc. concentraled surface drainage. We observed excavation 01 this lot on August 11. 2000. Excavation and placement of compacted. engineered fill was completed and Inspected on August 24, 2000. lithDlogy Solis on this site consist of approximately 2 to Meet of dark brown, mOist, firm to stiff slits of medium plasticity (soli unit SU1). These soils are likely to have a moderately high liqUid limn and a moderate to high shrink/swell potential. Immediateiy underneath the soli is bedrock (ROCk Unit RU1) consisting of an undifferentiated tuffaceous, , sedimentary and volcanic conglomerate. lhIs rock unit Is an interesting conglomerate of mulU-colored manne siltstone fragments in a matrix of grayiSh.white volcanic tuff. sman marine fossils were observed in this unit. The rock unit appears have a relatively low degree Of weatterlng, a relative low shear strength. low permeability (i.e. few local discontinuities), and a moderate unit weight It was visually classified as 80BO.2 This rock unit appears stable and suitable for foundatiOn loads. Groundwater There is little evidence of significant groundwater seepage in the cut 10r the foundation pad. The rock Is not stained and appeared to have a low moisture content The overlying soil unit was slightly below the plastic limit. Sur1ac:e Water There is no evldence of surface water concentrated flows or surface anomalies that might collect surface water. Exeavatlon and Foundation Sile PreparatiOn The 5011 unit above the bedrock was excavated 800 wasted off.site. The pad was stepped with a lower level at the north side of the excavation. All loose soli and rock debriS were removed. ApproxImately 1 to 2-fe.et of angular 6-inch minlJs quany shot. rock was placed in the front (north side) of the excavation to bring the subgrade to a proper elevation. Finally, faurto 6-inches of a well-graded. angular, crushed aggregate (1'/e-inch minus) was placed on the entire building pad and compacted. The density of the crushed aggregate was tested and found to average 103%, Of maximum relative dry density as determined by ASTM D698. LOT 113 General LOllM Is located on the south end of the cul-de-sac at.36lll St. The eXIsting ground surface slopes to the street below at a grade ot approximately 5%. Vegetation consists of native grasses. 1M ground surface (prior to excavation) Is even and unWorm across the lot, with no evidence of sliding. springs, excessive erosion. or concentrated suJ1ace drainage. We observed excavatiOn of this lot on August 22. 2000. Excavation ana placement of compacted, engineered fill was completed and Inspected on August 24. 2000 Lithology Soils units on thiS site consist of: 1. Soil Unit 2 (SU2) . Approximately 2 to 4.feet of B hard tan siltV fill placed In the obliteration of an old roael. This material was located, on the east 113 of the lat. These soils are of an unknown origin and do not appear te be suitable for construction due 10 uncertain density non-uniformity. Z Unified Rock ClassificatiOn. See Attached. Ambleside Meadows , Meadows lots 154 an41,3 Page 2 of 3 August24,ZOOO '. ,'. .0,.,. ,- ~u~ 28 00 07:19a 08/25/2000 14:18 River Valle~ Builders.Inc 541 367 1638 541&849358 K & A ENGINEERING p.2 PAGE 02 K & A Englne~ring, Inc. 2. Soil Unit 3 (SU3) - 1 Vz to 2-feet of oray, damp. finn to stiff, moderately plastic slits. This soil unit was found near the south end of the excavation, midway between the east and wes1lines c1 excavation. 3. Soil Unit 1 (SU1) - 1 Yz to 2-feet of dark brown. mOist finn to stiff slits of medium plasticity. These solis are likely to have a moderately high liquid limil and a moderate to high shrink/sweU potential. This soil unit was in the areas not occupied by SU2 Dr SU3, and is identical to the soH unit found on lot 154. Immediately underneath the soil is bedrock (rock unit AU2) consisting of an Undifferentiated tuffaceous sedimentary rock. Unlike the rock unit at lot 154, this matenal appeared to be highly stained and decomposed. The rock has decomposed to an orange-brown, dense. silty-sand. This unit Is classified as EECD.' This material is stable, non-expansive. and suitable for placement of foundation loads. Groundwater There rs some eVidence of groundwater seepage In the cuttor the foundation pad because of the highly-stained state of the decomposed be<tock. ' However, the fesidual (decomposed rock) solIs have a moderate permeability. Sln1ac:e Water There is no evidence of surface water concentrated flows or surface anomalies that might collect SUrface water. Excavation and foundation SlIe Preparation The soli units above the bedrock were excavated and wasted off-site. AII/oose soil and rock debris were removed. As rrwch as 2 to 3-feet of angular 6-lnch minus quarty shot-rock was placed at the northeas1 comer Where a significant amount of SU2 was removed. and 1 to 1 ~ -feet of quarry rock was placed elsewhere on the north ~ Of the excavation to bring the subgrade to a proper elevation. Roally. four to 6-lnches of a wen- graded. angular, crushed aggregate (1 Yz..inch minus) was placed on the entire building pad and compacted. The density of the crushed aggregate was tested and found to average 102% of maximum relative dry density as determined by ASlM 0698. RECOARWfNDATIONS We recommend that the foundation excavation and preparation be approved by the local building official for construction of converrtional cast-in"place concrete foundatlons. In add Klan, we make the following recommendations: 1. Crawl spaces and footings should be drained to the storm water drain system as per standard City Specifications. . 2. final grading should direct surface drainage away from the structure to the street, and 3. ROOf draInage should be collected and piped to the storm drain system. Thank you for this opportunity to be of service. Please cal if you have any questions. ~ ~ ~-~ Michael Remboldt, P.E. PrinCIple Engineer, K & A Englneel1ng, Inc. 4 ... -- Respectfully. Ambleslde Meadows Meadows lots 154 and 113 Page 3 of 4 August 24, 2000 .. A~g 25 00 07:04a eS/25/2eee 66:34 5416849358 River Valle~ Builders Inc 541 367 1638 K & A ENG1NEERING In-Place Density Crushed Aggregate Base Lot 154 Ambleside Meadows Springfillld I PIle 0 n. e .,tv Infllll Ffna Reading. Readiag, Welgbt, wet Density, Teat No. cl cl. Volume, cl WeIIM,a lb. pcf 1 0,01070 0.02420 0,01350 814.9 1.93 142.9 2 0.01050 0.02350 0,01800 1150,0 2,64 140.9 3 0,01060 0.01750 0,00690 476,6 1.05 152,3 Std. Proc:tDr Maximum Dry Density 139 pc' MDiltUfe Content MDlI1 Moisture DrV Sample + Dry SlIIp! tGDtent, Ollllity, Tat No. Pa',G Pall., + Paa, a. % DCl % Com~fl 1 100.5 313.S 309.9 1,7% 140 101% 2 97.9 333 329.3 1.6% 139 100% 3 100.1 322.2 317.3 2.3% 149 107% Average 103% Protect: 7200 Cfient: RIVer Valley BuIlders " K & A Eagi8ner1ft9. Ine. \ PAGE p.5 05 08/24/2000 A~g 25 00 07:04a ~8/25/2eee 06:34 R i v e r', Valle~, B u i 1 de r sIn c 54 1 367 1 638 5<<116849358 K8 A ENGINEERING In-Place Oensity Crushed Aggregate Base Lot 113 Ambleslde Meadows Springfield In.P1ace DenlilY Initial Final Wet Readina. Reading, Deltslty, TIel No. eI cl. Volume, cl Weighl, a Wtlgbl, lb. pel 4 0.Ot070 0.02400 0.01330 89S.7 1.98 149.0 5 0.01070 0.02640 0.01570 1036.0 2.28 145.5 6 0.01070 0.02800 0:01730 1095.4 2.41 139.6 S1rJ. Proctor MaJdmum Dry Density 139 pcl MoIs'ure CDnlent' MOld Dry " Sample + Dry Sampl Maillore Deollty, Campactia Teat ND Paft, a Pan,a + Pal, I. CoQltnt,% pcl n 4 98.4 362.2 355.8 2.5% 145 105% 5 98.3 358.7 351.5 2.8% 141 ' 102% 6 100,1 432.6 424.4 2.5$ 136 98% Average 102% -., Client River Valley Builders Job: 7200 k & A Engineering, Int. p.6 PAGE ,ef> 08l24{2000 Rug 25 00 07:04a ~B/25/2~~~ 05:34 River Valle~ Builde~s Inc 541 367 1638 p.7 , 5416849358 , K & A ENGINEERING PAGE 131 UNIFIED ROCK CLASSIFICATION1 Tallie 1 - DEGREE OF WEATERING Micro Visually stained Partly Decomposed Completely Fresh ' Fresh State State Decomposed state Stale ($1$) (PDS) State (MFS) (VFS) (CDS) A 8 C D E Table 2 .. ESTIMATED STRENGTH =~'?'=~'''''j{JI] II\"IIfJ.",,~.. -", "I'" .'~ ' "tifjJ"--"'d""" ",,'" " "I "''''1''''),'' , ""1"'1- "-"} fZ;~~..n1(~; ""~-< ;' 0; ?j,;: r,'i,.,',1',th '~1".~;,;I:I~: ';:l:I,'i.q:'-I'\lIi:r.Y{':';',',~~:l:":;:;""-:~':""!:!,'L;r:ll'II'.ji;'11r:1'~' l'.....oI,J:,,~..~J"'_~f~ "J." ... .;...;J_"".fJJ.:J..1I:..::.='=IJ:1;L..~,~... ...... "....1"'.. ~.I.... ..~. 4-..I..__..__.:.~,~.,.~~.ljr"....... ~ "Rebounds" (Elastic) RQ > 15,000 psP >103 M a1 A "Dents" (Compression) Q , 3000-8000 pSI' , 21-55 M a1 C "Pits" {TensiOnal} PO 8000-15000 PSI' 55-103 M ' B Table 3 - DISCOKnNUlnES :" ~W;-:~-:(Wfi ;'J~".~\;. '; ,~li.r:'~~ 1_ J....WI 'llf':.-..'..f....-- ,,:""11 : .l" .'..'.. I .~ \I;"~, ,;.%~..~,;-:":"'tf.i;T':' .-.J;. :.r..I....~..:.t:=,.:: ,~.,"."~ 1~'W>.r-. r,!'411 ",,'J II!?' IJ}i.V ,Y'. t' "'II'4::''''':,-','.,I'Ii<II[.'''r11 ..,J.1f:i1':..~::...J i: ~ !s.:t ,,' . ... '~I'J.I.l_ ~..~....,\'...'" .,..'.. \,.- .. 1 . . ~l. . _.1. _...r .. ...., ,", f ~ . , k t,', "'.,.- '_ . ''-'' Solid Solid Solid Nonlntersecting Intersection (Random ' (Preferred (Latent Open Planes Open Planes Breakage) Breakage) Planes 01 (2-0) (3-D) (SRB) (Spa) Separation) '(LPS) , A B C D E , Table 4 - UNIT WEIGHT > 160 pcf 150-160 pet 140-150 per 130-140 pet <130 pcr > 2.55 !Vec 2.4-2.55 wee 2,25-2.40 glee 2.10-2.25 glee <:2.10 Oleo A B C D E I A-E" 'I Weathering ClasslfictUOIl NDmBIIClatul1I: I A-E! I A-E I Strength Discontinuity l A-E \ WeIght 1 Douglas A. Williamson. Bulletin of the Assoc. of Engineering Geologists, Vol. XXI No, 3, pp. 345-354. 1964. 2 Approximate Unconfined COrllpresslv8 Strength