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HomeMy WebLinkAboutPermit Field Test & Inspection Report 2004-9-20 "i \QQo~?etO\~ ~~- SIP-20-2004 a2:91pm Frgm-K & A Enflneerln., Ine +541-BU-83SQ T-795 P 002/007 F-952 a fngln'lHfng K I A Engineering, Inc. P.O. BOI28&24, Ea...... OR 87a 621 MIrtret St., Salite II. Eugene, OR 17402 (&41) 18..... Voice (141) 184-.. FAX September H, 2G04 Hayden Homes 2464 SW Glacter Place, Suite 110 Redmond, OR gn58 SUbject: Quality assurance - house foundation pad construotion Jasper Meadows Subdlvfsion - ~ Addition Springfield. Oregon Pmject: 74.04 PURPOSE AND SCOPE As mquested, K & A Engineering. Inc, has completacl mDnrtortng ttJe consbuctlon of Individual foundation pads at the subject new residantlBlsUMlVI8lon, 39 indMdual foundation pads were tgnslruct8d at the site and prepared ready for forming nllW foundaUontl. Prior to construction, a Geotechnlcallnvmlgatian1 was made of the subdivision to develop specific recommendatlons for developfng the site for I'Isldentlal fou~atIons,~. and UtIUtI8a. The purpose of our allVices was to provide monItOr construction of foundation padS to as&tlr8 that construotion criteria outlined In the geotschnlcallnvestlgation was addresaed. ' 11lfs report documents foundatfan pad consbUction and makes recommendatiOns tor suitability for resldentl!l foundation ~....,L JCtIon. FOUNDAl1ON PAD EXCAVAnGN GIIIII'Ii The foundlliOn pads developed for this project are to IiUpport conventionally framed residllntial structuI'88 supportlld by canventlonaf cast.fn-pf8Ce concrem spraad footings. Due to the slope or Ih8 Sb most of the foundation pads WIll con&tructed In two or moI1 benohas, separated In grade by approximately 1 to 2-feet. FouncllUoa hill l11e aeotectlnlcallnV88tlgaUon (BoIre) had predicted that high Plasticity silts or clays would underUe the site. Excavatlon for the pad8 conflnned that in most of the foundation Plds, 1here was 1 to 3-feet of a gray, highly . plastic, modllral8ly atIff. and moist sill In some locations the gray 81~ contained a slgnlftcant amount of sub- rounded Igneoua cobbles, ThIs silt was oftBn covered by 0.&.10 i.D-feet of damp, very Iow..(fenslty peaty siltS, Weathered )'BIlow-tin tuffaceous siltStone or sandstone was encounlenld ulldemeath the plastic sills. 1 BOIre AsaOcIatBs, Inc.. G8Otet:hnlcal MsIgaIlon for lie Jasper Meadows G8CGlld AddiliCll, Springfield, Oreoon, Ftbnary 16, 2003. 8 'd lSL9'oN S3~OH N30AVH ~dH:l 900l '9 'uBf $ep-ZO-2004 02:21pm Frum-K & A En,lnesrlnl. Inc. +S41-GB4-Q358 T-735 P 00S/007 F-BS2 K & A Engfneerlng, Inc:. The llray pJastic sIII8 and gray plutlc ~11t8 with oobbles were deepest through rhe western portion 01 the subdivision. Isolated zon98 of gray plastic silt or plastic silt with cobbles wtIl1 also encountered throughout the centJaI and eastern portions of the wbdMslon. falDldlliDl hd CORllrUcIIoR Because 1he depth and ant of solis varied significantly across the sub~IvI,lQn, ~oh pad was 8'laluated IndIVIdually to determfne the proper depth of excavation and the amount 01 select fin to be placed in the mmavatIon. For many of ~ foundatiOn pacJs, the depth to weathered slRstDne or sandstone was less than 2.feet and, In these cases, the foundation pads were excavated to bedrOCk, and gl'ldad smooth, level, and free from lOose materfals. In ~ casas the baSe of the excavation wa:s in two benches separated in grade from 1 to 2.feet. Select aranular fill was placed In the pl1pared l))CCavation and brought to footing grade, In those .,. of deeper gray plastic sOl, the sifts were removed to a minimum depth of 1 &-inche8 below footing grade. The battoltl$ of the excavations were graded smoottl, level, and me from loose matB~als. In most cases the base of thO mcoavatIon was In two benches separated In grade from 1 to 2-f8et. Select granular no was placed in the pt6parQd axcavatlon and brD\lght to footing grade. In aD cases where peaty slits well encountered, the peaty-slits were completely removed frOm the foundation area. hIeeI Gr8nUI8r Fills SeleCt granular fills consisted of a sub-base mater1aI amJ a baSe matet1aI. The ~bue material was pJaoecl on 1M prepared subgrade in the foundatton pads and con9llltDd 01 a S-1nch ITIInUs weu.grad8d quarry aool'8Oata. The baes material was placed over the stJb.i>ase rock and consl8tBd of a 1 *Inch minus dense~l'8ded quarry aggregate. Bo1h aggregates ware produced at the Morse Bros. Quany In Spr1nofle1d. l11a aub-baSG ttiOkness generallY ranged from 6 to 12-jnches. Base rock ranged from 4 to 12-inches In 1hIc1cn88a. In a fvw aases (loti 33 thJVuOh 39) the sub-ba8e rock was elimInated and base rock was used exckJslV8Iy for1he uIect granular flU. The &elect granular fiUS were well compacted in 12-inch maximum lifts (loose) using a st:eel-Wheeled VIbratory roller. Water was applied 88 necessary to maintain op!lmUm water content during compaction. Denllty of Select.... filla SIJb.;base The density of the su~base was evaluated by InSpection Of placcmenl: methods and fleld evaluation of water content. The denslly was considered adequate If passes by the large vibratory stseI-drum roJIer did not rave VlsJbIe markS In the BUb-base agg~ at ttl8 edges of the drum lUId if the 80~ water col1t8nt appeared to be near optimum 88 determined In the field. II 2 SquHzIng a small amount of 118 liner aaGnlUalu in the hand did not produce significantfree water and WOUld remain In a relllMly unIfonn bat wttKwt irnrn8CIateIy faOlng apart. Project 74.04 Jasper Meadows Subdivision Phase II, Springfield, OR Page 2 of S ClIant Hayden Homes september 20, 2004 t 'd lU9'oN S3~OH N30AVH ~d9t:l 900l 'g 'uBf