HomeMy WebLinkAboutPermit Field Test & Inspection Report 2004-9-20
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SIP-20-2DD4 ~2:Slpm Frcm-K & A Enflneerlnl. Ine
+541-884-9350
T-795 P DD2/007 F-952
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K .. A Engineering, Inc.
P,O. 811128624, E....." OR 87402
521 MtrtreISL, Suite B. EDgell. OR 17402
(641) eu.Ia88 Voice
(141) 184-8361 FAX
8&ptember 21, 2fI04
Hayden Homes
2464 SW Glacier Piece, SUIte 110
Redmond, OR gn58
SUbject: Quality assurance - house foundation pad construotion
Jasper Meadows Subdivision - 2nd Addition
Springfield. Oregon
PrajeI:I: 74.04
PURPOSE AND SCOPE
As /'Bquested, K & A Engineer1ng, Inc, has completed monitoring the constructfon of 100000al foundation pads
at 1he SUbJect new residential 8UbdMSIon. 39 indMdual foundation pads were construct8d at the site and
prepared ready for fomdng new found8tlons.
Poor to COflstructiol1, a Geotechnlcallnvmlgation1 was made of the subdivision to develop specific
recommendatlons for developing ttI8 site for residential fou~atlonsr~' and utDltlas.
The purpose Of our alJVices was to provide monltOl' construction of foundation pacl8 to 8S5tlr81hat conrtruo1ion
ct1t8rla outlined In the gootschnlcallnvestlgation was addresaed. I
T1ll8 report documents foundatlan pad construction and makes recommendations far suitability for resldentl!l
foundation construction.
FOUNDATION PAD EXCAVAnGN
Genn
The foundltion pads devetoped for this proJect are to support conventionally framed residllntial atructurB8
suppotbld by conventfonal cast-ln-pI8ee conCRlte spraad footings. Due to the slope or lf18 Site most of the
foundation pads Wlrt constructed In two or morv benohos, separated In grade by approximately 1 to 2-feet.
FoundIUoa saill
l11e BeotechnJcaf lnvestklaUon (Bofre) had predlct8Cl that high plasticity silts or clays would underflB the sits.
Excavation for 1tI8 pat18 confirmed that ill most of the foundation pads, 1I1enJ was 1 to 3-feet of a gray, highly
plutlc, modllratBly atIff. and moist silt. In some locations the gray 81~ contained a s1gnlftcant amount of sub-
rounded igneous cobbles. 111Is silt was often covered by 0.&-10 to-feet of damp, very Iow..ftenslty peaty siltS.
Weathered YBfIOW-tan tuffaceous siltStone or sandstone was encounterud underneath the plastic sib.
1 BOInl As8OcIalBs. Inc., G80IuChnlcal MdgaIlon for tie Jasper Meadows S8GGI1d Addition, Sprfngfleld, Oraoon.
FtbrUary 16. 2005.
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$'P-~O-~004 02:31pm From-K & A En'lnBBrlng. Inc
+S41-GB4-S35e
T-735 P 009/007 F-952
K & A Engfneerlna, Inc.
The gray plastic sills and gray plastic ~1lt8 with oobbles were deepest through rhe westem porlion 01 the
subdivision. IsoIat8d zones of gmy plastic silt or plastic silt with cobbles wtll1 also encountered throughout the
central and eastern portions of the eubdlvlstcn.
faundllioD hd GonatruclloR
Because 1he depth and lIXlent of solis varied significantly across the llubcjlv~lQn, _ah pad was evaluated
IndMduallY to d8tlrmlne the proper depth of excavation and the amount 01 &elect fin to be placed in the
excavation.
For ITIMY CJf thl: foundatiOn pacl8, the depth to weathered slRstone or sandstone was less than 2.feet and, In
II1es9 cases, the foundation pads were excavated to bedrOCk, and graded smooth, level. and free from loose
materfals. In ~ casas the baSe or the excavation wu in two benches uparated in grade from 1 to 2-feet
select aranular fill \VIS placed In the ptlpared exoavatIon and brought 10 footing grade,
In those at!3S of deeper 0l'8Y plastic sUI, the silts were removed to a minimum depth of 1 &-inche8 below footing
grade. The bottoms of the excavattons were graded smooth, revel, and free from loose materials. In most
cases the base of tho mccavatfon was In two benches BeparatBclln grade from 1 to 2-f8et. Select granular no
was placed in the ~ axcavatton and brooght tD footing grade.
In aJJ ca5eS where peaty slits wenl encountered, the peaty-slits were completely removad fn)m the foundation
area.
SGltot Clrlmdar Fills
SeleCt granular fills consisted of a sub-base material and a baSe material. The SIbobue " ~~riaI was placed on
11\8 pf8Plf'd subgrade in the foundatton pads and con9fst8d of a S-Inch minus waU.grad8d quany ~ragat9.
'The bees material was placed over the stJb.i>ase rock ana cotl8l8t8d of a 11k1nch minus dense~raded quarry
&ggragate. 80th aggragate8 Wlnl produced at the Morse Bros. Quany In Sprlngftetd.
Tha sub-basG thiOICnUI generally ranged fiom 610 12-inches. Base rock ranged from 4 to 12-inches In
1hfo1cn8a8. In a few aues (Iot8 33 through 39) the sub-ba8e rock was elimInated and base rock was used
excklslv8ly fcr1he ;sIIct granular flU.
The select granular fiUS were well compacted in 12-inch maximum lifts (loose) using a steel-Whe8lsd vibratory
roller. Water was applied 88 necessary to maintain op!lmum water contlnt during compaction.
DenIIIy of 8c11c1......1ar fila
SUb-base
The density of the sub-base was evaIUatBd by InSpection of placement methods and fleld evaluation of water
contmt. 1lte density was considered adequate If passes by the large vibratory Btael-drum roller did not I8ave
VisIble markS In the sub-base 8gg~ at the edges of the drum BJ1d if the soil water conlBnt appeared to be
near optimum as d8t8rmIned In the ftakt.'
2 Squeezing a smaU amount of lie nner lO0J8aatll in the hand did not produce sillBificant free water and would f8R'laIn In a
,,~.Iy uniform ~ witKIut irnm8cIately failing apart.
Project 74.04 , Jasper Meadows Subdivision Phase II, Springfield, OR Page 2 of 3
Clfant Hayden Homes september 20, 2004
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