HomeMy WebLinkAboutIsland Vista Lot 4 - Soils Information for Foundation Design - 2005.11.22NOR r nWESTERN TERRITORIES, lNC.
A JLS GROUP COMPANY
717 SOUTH PEABODY STREET, PORTANGELES, WA 98362' Engineers Land Surveyors - Geo/ogisfs
. Constructian lnspection ' Materials Testing
(360) 452-S491 fnX +SZ-a+Se www.nti4u.com E-Miil: info@nti4u.com-
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JLS GROUP,INC.
November 22,2005
Linda Hsdson
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Fort Townsend, WA 98368
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With regards to the deep foundation, we recommend drilled reinforced concrete piers
with a minimum diameter: of .16". The bottom of the piers must bear on firm, undisturbed
soi!. We recommend an allowable pier capacily of 2,700 pounds for 16" diameter piers.
, We'recommend thatthe depth of the:piers be at least one foot below the angled
setbaek,line shown on Figure 5 (enclosed) of the geotechnical report. Jhus, at 28 feet
back from.the edge of the bluff, the pier depth should be a rninimqqgf 9'. For spread
footings we reeommend an allowable bearing pressure of 2000psf. Footings should also
be located behind/below the setback line, thus at 35' back from the bluff, footings should
be at least 3'deep.
Subject: Soils lnformation for"Fcundation Design cf l-louee for Tax # 9637C0004,
City of Port Townsend
Dear Mrs. Hodson
We pecommend an allowable passive, pressure in terms of equivalent fluid pressure of
230pcf and'an allowable coefficient of friction of 0.35. These values include a factor of
safetv of 1.5.-1
At your request, we have performed additional work regarding the foundation design of
your new house as requested by your structural engineer
The tra'nsition from piers to footings should be based upon the contractor's ability to
provide a foundalion at the required depth, or orl e,conomic considerations. For
bxample, if the contractor can install a:91 'deep,footing at28' back fi:om the bluff, then
piers are not required. ',
lf you have any question regarding this matter or need further assistance, please give
us a call.
Sincerely,
NORTHWESTERN TERRITORIES, INC.
bert A. Leach, P.E., MBA //l2rJos
Principal Engineer
EXPIRES 12t30t2006
Bill Payton, L.E.G.
Engineering Geologist
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Exoires 11/06/06