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Home My WebLink AboutBuilding Correspondence 2001-1-29 PAGE: p.2 02 Ja~ 30 01 07:52a l;' 01/29/2001 '12:09 R i v.va 11 e~ 5~158 Builders,Inc 541 367 K & II ENGINEERI~ 1638 'I .a f'nginppring K & A Engineering, Ine, P.O. Bo.105~4. Eugene, OR 97440 5~1 Ma/'l(eI 51., Suite 8. EUg~O~, 01197402 (541) 684-9399 Voice (541)684-9358 FAX Jaouary 29, ZO01 Greg L~rkin River Valley Builders P.O. Dox 2041 Corvailis, OR 97339 Subject: BUilding Pad Evaluation Ambleside. ~e.do~~, LO~I~S9 . _,_. 1~~.tJ5.aIGOnIS("ll~p~gfJe'd~~Y Springfiel~lPermlt # Of~OOI 0-01 Project 9.01 Dear Mr. Larllin: K & A Engineering, Inc. is pleased 10 have this opportunity to oroviae a~ evaluation of the suitabilitY of the 5ubjcc! building lot tor construction of a foundation lor a slngie-family resiaence, The s4e h~, been excavated and preparM for the construclion 01 standard cas1-in-place concrete slrip lootings, spread lootings, ana stem walls. Tnese recommendalions are made in accordance with "Excavalion and Foundation Requirements lor New Structures on Inaividu<ll Lots" eSlablished by the City 01 Springfield,' PURPOSE, SCOPE, AND LIMITATIONS The geotechnical engineering services summanzea herein "'" provided to assist River Valley Builders In properly preparinc the subjecl buildmg sites for foundation construclron, These ,ervic"" include engineering recommendations 10 avoid construction on unsuitable soils and quality control 01 compacted tills only. The scope 01 our services does nor include conslruction safety precautions, techniques, sequences, or procedures, except as specifically recommended in this report, Our services shOUld not be interpreled as an environmental assessmenf Of srte conditions. This geotechnical investigation, analysis, <lnd recommendations meet the stlnaards of care of competent geotechnicai engineelll providing sirnlla' services at the time these services were provided, We do not warranf or guarantee these recommendations, site surface, or subsurface COndlllons. GENERAL Lot 89 is located on the north side ot Falcon Drive near the center at tile subdivision, The existing ground surface slnpes slightly toward Ihe street Vegetation consists of native grasses, The ground surface (prior to excava~on) is even and unifnrm across lhe lot. with no evidence of sliding, springs, excessive erosion, or 'Ambleside Meadows Subdivision -,.. Mdition Ja~ 30 01 07:52a ~ 01/29/2001 12:09 RiV.Valle~ Builders,Ine 541 367 541GB B I< & A ENGINEERI. 1638 p.3 - PAGE 03 'r K & A Engineering, Inc. concentrated SurT3ce drainage, We observed excavation of lhis lot on January 16, 2001, Excavation and placemenl of compacted, engineered fill was completed and inspected on January 17, 200 r, LITHOLOGY Soils on this site consist of approximately 1 10 1S-feel of soil darl< brown organic silt over 110 .5-leet 01 gray, sliff, moist, highly-plastiC clay. At the base of the clay Is dense gray silly sand, The Clay and topsoil appear to have been imported lill and contain cUnslruclion debris inciuding broken concrete, GROUNDWATER There is little evidence 01 significant groundwater seepage In the cut lor the foundation paa. SURfACE WATER There is no evidence 01 surlace water concenlrated flows or surlace anomaiies that might COllect sur1ace water. EXCAVATION AND fOUNDATION SITE PREPARATION The son organic sill ana gray clays are unsuitable for foundation bearing malArial and were excavated and moved to the side (to be removed or utililed in landscaping), The depl~ of this excavalion ranged Irom one to 3.feer, and the depth and width were the foundation dimensions pius approximately 5-leet. A select slructural was place!! in the excavation on the stable, dense gray silty.sands, to bring the foundation are to required grade. The structUral fill consisled of one to three layers of compacted crushed aggregate, Oepending on the deptn 0' rill. The top 12-inches (ma><imum depth) is a Y.-inch minus crUShed aggregate. FiiI from 1-1001 to 2,Ieet consists ot , Y;,inch minus crushed aggregatc, FiU deeper lhan 2-'ee! consists 01 3-lnch cruSMd Dallast rock. A11lhe aggrecates were manufaclUred at tM Springfield quan)' and consist of hard, durable, angular basalt he density of the crushed aggregate was Tested and lound 10 average 103% of mQltimum relative dry dens~y as determined by ASTM 0698. RECOMMENDATIONS We recommend that the loundation excavation an!! preparation be approved by the local bUilding official for construction or conventional cast-in-prace concrete loundations, Unsuitable soils underneath the proposed loundation area nave been removed and repaced with stable structural fill. The touMalion area, as prepared, is suitable to support the proposed Single-family residence. In addition, we make the following recommendations: Subsurface Drainage Crawl space and perlmeler footing have been Instailed according to city requirements, The low point is at tile southwest comer of the excavation area and is routeo to the street curb (al the southwest lot corner). These drains will flow by gravily 10 the street. We recommend approval 01 these systems 3S constructed, Ambleside Meadows Lot 89, 3404 Falcon Dr. t'aQ€ 2 or 3 January 29, 2001 Ja~ 30 01 07:52a ~ 01/29/2001 12: 09 RiV.Val1e~ Bui1ders,Ine 541 367 5~IG8 8 k & A ENGINEERl. 1638 p.4 PAGE 0a ) " K & A Engineering, Inc. Roof Drainage Roof drains S~ould be collBC[ed in and piped to [he city storm drain system. We recommend that roof drainage be separated from the loollng/crawlspace drains by either a separate pipe system or a back,lIow prevention devi~e. Final Grading The organic topsoil excavated Irom the foundation area is suitable for IlIling around rhc pcrimetcr of l~e foundation and for tinal grading, The tinal grade shOuld direct surface drainage away lrom the structure, Thank you for t~is opportunity to be of service. Please cai if you Mve any q~estions. Respecllu"y, "'- Michael Remboldl, PE Principle Engineer, K & A Engineering, Inc, Am~lesido Meadows Lor 89, 3404 Falcon Dr. Page 3 of 3 January 29, 2001 Jar 30 01 07:53a , / 131/29/213131 12: 139 RivA Va lle~ SQH.e_e , . 'n.Place Denslly Inilial Reading, CI O,OU?'I 0.01401 Te.l No, 11 21 BUilders,Inc 541 367 K g A ENGINEERI. 1638 . In,Place DensilY Crushed Aggreaale Base Lot 89 Ambreside Mcadows Springfield final Re.~ln9. (I, Volume, cl 0,03261 0.0166 0,03421 0,02021 Moisturo Conlenl Sltl. Proclor Maximum Dry OensllY TaSI No, 1 fI Pan, q 12821 119.11 Project 9,01 Client: River Valley Builders Moisl D~ Samp!!. Sampl. + ran, R I'.n, g. 1597.51 1441.01 1522.31 1360.31 .- K & A Engienering, Inc. WeiO!'I..Q 1469.31 1403.21 Weight, Ill, 3.24 3,09 Wel DensilV, eel 174.2 153,1 139 pc! Moi.l"'. Dr, ' Conlent, De080y, I 'l\ pcl % COmD3eliO~ 11.9111 1531 ;11%i 131%1 1331 96%1 Average 103% p.5 PAGE 135 01129/2001