HomeMy WebLinkAboutPermit Field Test & Inspection Report 1996-7-17
SpIT :Iliio.: GR/,IICH ENGINEERING; .7-18-96 8: 31 AMi 541 746 0389 .
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503 726 3689 i
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Branch Engineering
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310 Nor'ul 5r.h Scr".,r.
Springfield, Or'egon 97477
(541) 746-0637
FAX (541) 748-0389
SOilS INSPECTION REPORT
/,ODRESS:
P~lOJECT NO.
F:-lEPARED BY:
q I.tD1VfO
X61363:lvyzStreet;::SurinafieJd::-Or",fQon
96.-. ~05
Steve Keating
I,,, inspection was made at the above listed site for the purpose of assessing 1l1e suitability l'(
Ihe .existing soils for superimposed loads, These loads are identified as foundation footings
;'>lId stemwalls with interior strip footings and isolated piers, together with an overlying
residential structure of generally regular shape, with a maximum load of 1000 PSF.
There are three soil units (SU) exposed by the excavation. SU #1 consists ot dtJrk brown Silty
clay loam, approximately 12 to 24 inches in depth. Which will be above the base of excavation
in rnost areas. SU 1/2 consists of a light brown colored plastic Clay with little granular content.
approximately ~o to 48 inches thick. It has become wetted to a depth of 1/2 to 1 inch where
exposed to recent rains, and is uniformly moist through the thickness at the unit where
e"pos.~d on the sides of the excavated area. SU tt3 consists of a cobbly silty clay of
indeterminate depth, and is exposed only on a smiill portion of the rear ot the excavation.
Tlie exposed areiiS appear to be uniformly moist. There is no evidence of plastic cracking in
any of Ihe soil units, and no evidence of water seepage from uphill snllrces..
Wllile clay soils can provide competent bearing for building strJctures, this/i~ highly dependent
on soil mnisture conditions, both present and future, Saturated soils have vinually no sllear
strength and (;armot provide useful bearing. Since most local clay soils are expansive, they
will also shrink when drying, and cause senlements. We recommend that the site be overlaid
with a light geotextile (Typar 3401 or equal) and a 12 inch compacted crushed rock fill be
plaCed to distribute building loads and protect the clay soils from variations in moisture
content.
For placing the structural fill, please refer to the following instructions:.
I, Install a geotextile barrier (Typar 3-101 or equal) a barrier to prevent intermixing of the
rock topping and the subgrade soils. Without a barrier the base will "pump". and
adequtJl<J compaction will not be achieved.
2, Import 1-1/2" - (0) crushed quarry rock fill (or an approved substitute). Place till
material in two 6 inch lifts compacting at each lift with at least a 6.ton rated roller
compactor.
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/II/hen the ti"haS-~~-~onwleJed;-d'ld'-IY,~ for, a, den.sitVtes(ff~Er;U;a certifie~testin-g'
laEora"tory'(BraOn~l?teE!1~h'9~~r'PSI~a,!~~81:.~~~~~c};~~~@I~ ,
fompl~tJon o,f the~ te,sl: tfie~ngl,~~!3r ~}I!,,~~,s~e a rcpo~ IO~he owner c_ertltyrng <~e .fl~,~as
/dequate'fo( re"s~dentlal foundahon loads of 1000 pounUs-per-square-foOl Ofib..~?JAf19!l
TAIl,NSPORTATION
SUI-lVI=YING
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CIVIL
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sEj!:r ~~ BHANCH E~JGINEERING; -18~96 8:32AM; 541 746 0389
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It is aiso important that all concrete foundations and flatwork be reinforced, as they are
otherwise unable to resist soil and temperature related stress without cracking, We have
included a typical foundation reinforcing detail. Special consideralion must be given 10 Slr"ps
in the foundation, to ensure that the reinforcing is continuous through the step, so that a
weakened area is not created. It is much simpler and far less expensive to prevent structural
damage than it is to repair it.
Once the foundation has been installed. the building's owners should observe the lollowing
steps, which will reduce shrink-swell in the underlying soils, and further reduce the potential of
rlamage to the building structure:
1. Never permit the soils to completely dry out in the summer. When the average
monthly fainfall varies excessively. it invites shrinking or swelling. An irrigation system
can be used to provide water during drier periods, and evaporation rates can be
retarded by landscaping materials Which cover the soils, and\or bark-mulching, which
will require periodic replacement,
Other sources of water should be kept away from the foundations If an off-site water
SOllrce develops (a natural drainage way, or run-off from a neighboring property) or tlle
downspouts or 9utter begin to leak, it is important to intervene, and direct this water
away from the foundation area.
After the excavation of saturated clay soils and compaclion of fills as specified, the site Will
be suirable for the intended use, subject (0 the following provisions:
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1. The foundation areas are backfilleo to a minimum depth of 18" below finisherl grarle
2, The building fo01ings are to be provided with perforated PVC drain lines bedded in a
minimum 12" depth of 1 -1/2" open graded drain rock. with piping draining to the lower
portion of the site The building underfloor drain may be connected to this pipe at an
elevation at least 12" below the lowest point of the subfloor grade. The owner will
have to make provisions for stormwater discharge on site as storm sewers are not
available.
J. The rainwater piping will be installed parallel. but not connected to, the foundation am1
sublloor area drains.
The above provisions will ensure that subsurface moisture levels will remain (:()"'ii~teTJ!
tltruughout the year, and the piping will not conduct air currents which may tend to dry the
footing area soils during periOdS of warm dry weather.
If you have any questions concerning the above report, or require further intorm<ltion. please
lee I free to call. .
Soils report: 6863 Ivy Street, Springfield
Branch Engineering - 310 North Fifth Street, Springfield, OR - 9
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