HomeMy WebLinkAbout995400047 Geotech Assessment' FRON~: RUDiJEFFCO RHONE NO. : 3603855945 Jul. 19 2882 09:48AM R1
Public Utility District
Of Jefferson County
Board of Commissioners
FAX TRANSMITTAL Richa,d M, Shipman, District
Kenneth McMillen, District 2
TO:
COMPANY NAME:
. .....
F~O( NUMBER: ~~ '~ '7c~ cC ~--J
FROM:
NAME: ~-..L-/./~
NUMBER OF PAGES (including cove sheet):
The ~formation containedwith~n this facsimile message may be l)rivileged, confidential arid
exe. mjat from' dix¢los'ure under applicable laws. If you have received this communication in
error, please not~f'y v~, immediately at 360-385-5800
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' c~ON;: PUD1JEFFCO PHONE NO. : 3G03855945 Jul. 19 2002 09:48AM P2
L-~eotecnmcal Hepon mr
Proposed Water Tank
Snow Creek Development
Jefferson County, Washington
JuJy 2002
At S/[annor~ & Wilson. our mission is to be a progressive.
manab, ed professional con~t~lting fi*'m in the figlds of ~ngineering
and applied earth sclg~:c,s. Our goal is to perform our services
wlth the highest degree of profe.~$ionalism wi~h dug cor~ideration
to the best ~:nterest.~ of the public, our clieaZ$, and ot~r employee.~.
Submitted To:
Public Utility District #1 of Jefferson County
P.O. BOX 922
Port Hadiock, Washington 98339
By:
Shannon & Wilson, Inc.
400 N 34th Street, Suite 100
Seattle, Washington 98103
21.1 -09645-001
FRON]: PUD1JEFFCO PHONE NO. : 360S855945 Jul. 19 2002 09:49gM PS
July 17, 2002
Public Udlity Distdct #i of Jefferson County
P.O. Box 922.
Po~ Hadlock, WA 98339
Attn: Mr. Iirn Parker
RE: GEOTECHNICAL REPORT FOR PROPOSED WATER TANK~
~ SNOW CREEK DEVELOPMENT, JEFFERSON COUNTY, WASHINGTON
This letter report presents results of subsurface explorations and observations and provides our
geot¢ch~cal conclusions and recommendations for design and construction of a proposed
- concretz water tank in the Snow Creek Development near Discovery Bay. This work has been
performed in general accordance with our proposal dated December 18, 2001.
SITE AND PROJECT DESCRIPTION
The proposed water tank will be located in the Snow Crock Development on the east Side of the
hill between Snow Creek and Crocker Lake (see Figure 1) at approximately the same location as
thc existing steel water tank (see Figure 2). The tank site sl6pes gently down to the east at about
4 to 8 degrees. The e.xisting steel tank is a horizontal cylinder, approximately 38 feet long
(north-south) by about 11 feet in diameter. We understand that the existing tank is a converted
boiler and requires replacement. We also understand that the proposed replacement will be a
cylindrical concrete tank supported on a 9- to 12-inch4hick concrete mat foundation
ap~roxlmately 27 feet in diameter. Based on our conversation with the potential tank supplier,
Mark Gillis, the mat foundation design is based on an allowable soil bearing pressure of 1,700
pounds per square foot (psf) with a one-third increase under seismic loading conditions.
SIJBSURFACE EXPLORATIONS AND LABORATORY TESTING
In order to identify and characterize the subsurface conditions, two borings, designated B-1 and
B-2, were accomplished at the locations shown on Figure 2. The borings were located in the :
field by using tape measurements from existing site features.
400 NORTH 3,4TH STREET' SUITE 100
P.o. mox ~00~oa 21-1-09645-001
S~ATTL~, WASHINGTON 98103
206.832-8020 FAX 2O6.695.8777
T,DD; 1.800,833-f5388
~ FROMi: PUD1JEFFCO PHONE NO. : 3603855945 Jul. 19 2002 09:50AM P4
Public Utility District ~1 of lefferson County SHANNON ~WILSON, ~NC,
Attn: Mr. Jim Parker
July 17, 2002
Page 2
The borings were drilled and sampled using a track-mounted CM]E 45C drill fig operated by
Gregory Drilling under subcontract to Shannon & Wilson, Inc,, on January 28, 2002. The
borings were advanced using a hollow-stem auger. The borings ranged from about 19.2 to
19.8 feet d~¢p.
An experienced engineering geologist from Shannon & Wilson, Inc. observed drilling and
sampling operations a~d logged subsurface conditions encountered in each of the borings. A key
is provided on Figure 3 to assist in interpreting the subsurface conditions that were logged in
- each boring. The logs of the borings B-1 and B-2 are provided, on Figures 4 and 5, respectively.
Disturbed samples were generally retrieved from the borings in conjunction with the Standard
Penetration Test (SPT) in accordance with American Society for Testing and Materials (ASTM)
- Designation D 1586 at 2.5- to 4.5-foot depth intervals. The SPT consists of driving a 2-inch
outside-diameter (O.D.) split-spoon sampler 18 inches using a 140-pound hammer, free falling
30 inches. The number of blows required for the last 12 inches of penetration is termed the
. Standard Penetration Resistance. When 50 blows were required for 6 inches or less of
penetration, the test was stopped and the number of blows and the corresponding penetration
recorded. The Standard Penetration Resistance values are plotted on the respective boring logs,
Figures 4 and 5. These values provide a means for evaluating the relative density of granular
soils and the relative consistency (stiffness) of cohesive soils.
Soil samples were collected in each of the borings, seal6d in jars, and returned to our laboratory
for t~ting. Geotechrdcal laboratory tests were performed on selected samples for natural water
content determinations. The natural water contents are shown on the boring logs in Figures 4
" arlfl 5.
SUBSURFACE CONDITIONS
Geologic maps of the area indicate that the site is underlain by undifferentiated mudstone and
siltstone of the Tertiary age Twin River Formation that is overlain by a thin mantle of glacial
drift. Both Twin River Formation rock and overlying drift were observed in both of the borings.
The drift observed in the borings was typically a medium dense to dense, slightly gravelly to
gravelly, ~lighfly silty to silty sand. The relatively poor sorting and density of the drift suggest
Zi- 1-09645-O01-Ll/wpaka 21-1-09645-001
'~ FRON~: PUD1JEFFCO PHONE NO. : 3603855945 Jul. 19 2002 09:50AM P5
SHANNON ~Wl!~ON, INC.
Public Utility District ~1 of Jefferson County
Att-n: Mr. Jim Parker
July i7, 2002
Page 3
that it is likely a normally consolidated (i.e., not glacially overridden) ice contact deposit. The
drift was observed to a depth of 13 feet in boring B-I and 17 feet in boring B-2.
Based on the yep7 ~fficult ckdHing and SPT refusal; rock was present in borings B-! and B-2
below a depth of I3 and 17 feet, respectively. Only small pieces of broken gravel-size rock was
retrieved in conjunction with the SPT's, some of which appeared to "float" inside the hollow-
stem auger from thc overlying drift. However, based on the difficult drilling, limited samplest
and the geologic mapping J.n the area, this rock is likely siltstone and/or mudstone of moderate
strength.
Cn-oundwater Was observed in boring B-2 at a depth of about 6 feet but was not observed in
boring B-1. It is likely that the shallow groundwater observed in bo.ring B-2 is perched within
the drift, and similar zones of perched groundwater should be expected elsewhere within the
CONCLUSIONS AND RECOMMENDATIONS
Foundation Subgrade and Allowable Bearing Pressure
[ We recommend that mat foundation be located in the medium dense to dense drift or structural
fiQ placed directly over the medium dense to dense drift and at a depth of at least I8 inches
i , below the adjacent exterior grade. This drift was observed in the first samples (a depth of
! 2.5 feet) in each of the borings and may extend upward to the ground surface. Topsoil or fill that
r may be present above the drift should be completely removed. If topsoil or fill are present to
~ .' .... depths below the proposed elevation of the'bottom of the mat, the topsoil/fill should be removed
and the overexcavation backfilled with structural fill.
~ For the relatively large mat foundation, the allowable soil bearing pressure is controlled by
r--. allowable settlement. In our opinion, a maximum allowable soil bearing pressure of no more
than 2,500 psf should be considered for design of the 2%foot-diameter mat foundation to limit
total fbundation settlement to about 1 inch.' This bearing pressure may be increased by one-third
for earthquake loading conditions. For the expected bearing pressure of 1,700 psf, foundation
settlements may be on the order of ~/2 to sA inch, in our opinion. Differential settlement may be
on the order of one-half of the total settlement..
21-1-09645-001
,' FROMm: PUDIJEFFCO PHONE NO. : 3603855945 Jul. 19 2002 0~:51AM P6
SHANNON ~WiLSON~ INC.
Public Utility District #1 of Jefferson County
Attn: Mr. Jim Parker
July 17, 2002
Page 4
Structural Fill
If and where required, we recommend that fill placed beneath the'foundation mat be structural
fill and that it consist of a well-graded crushed rock, free of organic material, with no more than
$ percent passing the No. 200 sieve (based on the minus ~A-inch fraction), a maximum particle
size of 3 inches, and a moisture content at or slightly below its optimum value (plus or minus
2 percent) for compaction. Imported structural fill meeting these requirements would be suitable
for compaction, even under wet weather conditions, in our opinion. Additional
- recommendations for wet weather construction are provided subsequently in this letter.
The well-graded crushed rock should be thoroughly compacted to achieve a very dense and
unyielding surface as observed by'an experienced geotechnical engineer (or representative). The
-" rock should be placed in horizontal lifts not exceeding 4 inches for hand-operated compaction
equipment or 8 inches for heavy compaction equipment. Each lift should be thoroughly
compacted to a dense and unyielding condition as previously described before the next lift is
placed.
· -' Seismic Design
· ' We understand that the proposed water tank will be designed in accordance with the 1996
t American Water Works Association (AWWA) Standard for Welded Steel Tanks for Water
Storage. We note that the site is located in Seismic Zone 3, and the corresponding Zone
~ Coefficient, Z, is 0.30. Based on the results of subsurface explorations, it is our. opinion that the
site is best characterized as Soil Profile Type A, and the. corresponding Site Ampl~fication
.. Factor, S, is 1.0.
Wet Weather Earthwork
In western Washington, wet weather generally begins about mid-October and continues through
about May, although rainy periods may occur at any time of the year. Therefore, it would be
advantageous to schedule earthwork during the normally dry weather months of June through
md-October. Earthwork performed during the wet winter months will generally prove more
costly.
The on-site silty soils, including the recommended subgrade soils, are susceptible to changes in
moisture content, and could become muddy and unsuitable if wet shover subjected to
2 ~-3-0'~5-001-LY, q, akd 21-1-09645-001
FROM:: PUD1JEFFCO PHONE NO. : 3603855945 Jul. 19 2002 09:51AM P7
SHANNON ~WlLSON, lNG,
- Public Utility District #1 of :lcffcrson County
Attn: Mr. Jim Parker
luly 17, 2002
Page 5
construction traffic. The following recommendations are applicable if earthwork is to be
accomplished in wet weather or in wet conditions:
s .... Id co,,s,s, of clean, "'"'~'o~
,. ~;,, material ~' .... ~ + ........ rock .... not more ..... 5 pemen! passing
the No. 200 sieve, based on wet-sieving the minus 3A-inch fraction. Any fines should be
non-plastic.
, The ground surface in and surrounding thc construction area should be sloped and sealed
with a smooth-drum roller to promote runoff of precipitation away from work areas and
to prevent ponding of water.
,, ~work should be accomplished in small sections to reduce exposure to wet
conditions. If there is to be vehicular traffic over the exposed subgrade during
construction, the subgrade should be protected with a compacted layer (generally
inches or more) of clean crashed rock. The size or type of equipment may have to be
limited to prevent soil disturbance.
~ No soil should be left exposed to moisture or crush rock left uncompacted. A smooth
dram vibratory roller, or equivalent, should be used to seal the surface. Soils that become
too wet for compaction should be removed and replaced with clean crashed rock.
~ Excavation and placement of structural fill during wet weather should be observed on a
full-time basis by a geotechnicat engineer (or representative) experienced in wet weather
earthwork, to determine that all unsuitable materials are removed and suitable
compaction is achieved.
Coveting work area~, soil stockpiles, or slopes with plastic, sloping, ditching, installing sumps,
dewatering, and other measures should be..e.m.p.!0yed, as necess~y, to~ penuit proper completion
of the work. Straw bales and/or geotextile silt fences should be aptly located to control soil
movement and erosion. Final grades should be sloped away from the proposed water tank
foundation to reduce the possibility of water ponding adjacent to the facility.
We recommend that the above recommendations for wet weather earthwork be incorporated into
the contract specifications.
Construction Observation
We recommend that we be retained to observe the geotechnically-related construction, including
foundation subgrade preparation and compaction of structural fill. These observations would
21 -I .09645-001 -Lllwp/lkd. 21 - 1-09645-001
' FRDH~: PUDIJEFFCO PHONE NO. : 3603855g45 Jul. lg 2002 OS:52AM P8
SHANNON &WILSON, 1NC.
- Public Utility District #1 of Jefferson County
Att'a: Mx. Jim Parker
July 17, 2002
Page 6
allow us to confirm the subsurface conditions as they are exposed during construction and to
determine that the work is accomplished in accordance with our recommendaQons,
LIMITATIONS
The analy~s, conclusions, and recommendations presented in this report are based on the site
condition~ as they presently exist and assume that the explorations are representative of
subsurface conditions throughout the site; i.e., the subsurface conditions are not s. ignificanfly
different from those disclosed in the borings- If, during construction, subsurface conditions
different than those encountered in the explorations are observed or appear to be present, we
should be advisext at once so that we can review these conditions and reconsider our
-: recommendations where necessary. If there is a substantial lapse of time between the submission
of this report and the start of work at the site, or if cond/tions have changed due to naturat causes
' ' or construction operations at or adjacent to the site, it is recommended that this report be
reviewed to determine the applicability of the conclusions and recommendations considering the
changed conditions and time lapse.
Within the limitations of scope, schedule, and budget, the analyses, conclusions, and
recommendations presented in this letter report were prepared in accordance with generally
accepted professional geotechnical engineering principles and practices in this area at the time
this repoxt was prepared. We make no other warranty, either expressed or implied.
unanticipated soil conditions are commonly encountered and cannot be fully determined by
... merely taking soil samples or drilling borings. S.uch unexpected conditions frequently require
that additional expenditures be made to attain a properly constructed project. Therefore, some
:. contingency fund is recommended to accommodate such potential extra costs.
This report was prepared for the exclusive use of the Owner and/or. En~neer in the design of the
Water tank. It should be made available to prospective contractors and/or the Contractor for
information on factual data only, and not as a warranty of subsurface conditions, such as those
interpreted from the test borings and discussions of subsurface conditions included in this report.
Please note that the scope of our services did not include environmental assessments or
evaluations regarding the presence or absence of wetlands or hazardous or toxic substances in the
soil, surface water, groundwater, or air, on or below or around this site. We have experienced
2~4-09~-0o~-ru~ma 21-1-09645-001
,FROM ;' PUDiJEFFCO PHONE NO. : 3603855945 Jul. 19 2882 89:52AM P9
SHANNON ~WiLSON, INC.
Public Utility District $1 of Jefferson County
Atto: Mr. Jim Parker
July 17, 2002
Page 7
staff who c~n p~ovide these services and would be pleased to discuss these with you if the need
arises.
Shannon & Wilson, Inc. h~ prepared the attached, "Lmportant !nfonnation About Your
i Geoteehnical'Report," to assist you and others in understanding the use and limitations of our
t . report.
;
! ,
Sincerely,
~--.
, SIne,NON & W LSON,
,,
Willi:~m J. Perkinf/
,{ ~ Senior Principal ~fhgineer
1'
[,
FRU~': PUD1JEFFCO PHONE NO. : 3603S55945 Jul. 19 2002 10:~ORH P1
, ,, ~. [ , ~-' I Snow Creek Water Tank
Scale in Miles Discovery Bay, Washington
NOTE VICINITY MAP
Map adapted from t :24,000 USGS topographic map of
Uncas, WA quadrangle, dated t953, photore¥ised July 2002 21-1-09645-00'1
SHANNON & WILSON, INC. FIG, 1
{3eotec~nlr. al and Environmental G~,nsult~nts
FRO,~': PUD1JEFFCO PHONE NO. : 3603855945 Jul. 19 2002 10:32AM P2
0 '7,
~ .~ ~ 0
~ ,. .Z~
-.
FIG. 2
FROM': PUDIJEFFCO PHONE NO. : 3G03855945 Jul. 19 2002 10:32AM P3
Shannon & Wilson, Inc, (S&W), uses a soil ......... GRAIN SIZE DEFINITION
classification system modified from the Unified DESCRIPTION SIEVE NUMBER AND/OR SIZE
Sell Classification System (USCS). Elgments of
the USC.,S and other definitions are provided on FINES < #200 (0.8 mm)
this and the following page. Soil descriptions ......................................
are based on visual-manualprooedures (ASTM SAND*_ Fine #200 to #40 (0.8 to 0.4 mm)
D 2488-93) unless otherwise noted. - Medium #40 to #10 (0.4 to 2 mm)
- Coarse #10 to #4 (2 to 5 mm)
S&W CLASSIFICATION ' '
OF SOIL CONSTITUENTS GRAVEL*
- Fine ~4 to .3/4 inch (5 to 19 mm)
· MAJOR constituents compose more than 40 - Coarse 3/4 to ,3 inches (19 to 76 mm)
percent, by weight, of the soil. Major
oonsituents are capitalized (i.e., SAND). COBBLES 3 tO 12 inches (78 to 305
· Minor constituents compose 12 to 50 percent
-- of the soil and precede the major constituents BOULDERS > 12 inches (305 mm)
(i.e,, silty SAND). Minor constituents ' Unless o~herw~e noted sands end gravels, wher~
..' preceded by "slightly" compose 5 to 12 present, range from fine to coarse in grain size.
percent of the soil (i.e., slightly silty SAND).
,, Trace constituents compose 0 to 5 percent of RELATIVE DENSITY / CONSISTENCY
the soil (i.e., slightly silty SAND, trace of .........
,-- gravel). COARSE-GRAINED SOILS FINE-GRAINED
i N, SPT, RELATIVE N, SPT, RELATIVE
MOISTURE CONTENT DEFINITIONS BLOWS/FT. DENSITY BLOWS/F.T. ,CONS__I.~.~_E.N.(~¥
0 - 4 Very loose Under 2 Very soft
{ Dry Absence of moisture, dusty, dry 4 - 10 Loose 2 - 4 Soft
to the touch 10 - 30 Medium dense ~ 4 - 8 Medium
Moist Damp but no visible water 30 - 50 Dense 8 - 15 Stiff
~ Wet Visible free water, from below Over 50 Very dense 1,5 - 30 Ve~' stiff
' Over 30 Hard
i water table
~ ABBREVIATIONS WELL AND OTHER SYMBOLS
ATD At Time of Ddlring ~ Cement/Concrete Asphalt or Cap
Elev. Elevation
ft feet ~ Bentonite Grout ~ Slough
Fee Iron Oxide ~ Bentonite Seal ~ Ash
HSA Hollow Stem Auger
ID Inside Diameter t!~ Ti'il silica Sand
Bedrock
in inches
PVC
Screen
M~.n. Monument cover ........
Vibrating
W~re
N Blows for last two 6-inch increments
NA Not applicable or not available
NP Non plastic
OD Outside diameter
OVA Organic vapor analyzer
PIg Photo-ionization detector'
ppm parts per mil!ion
PVC Polyvinyl Chloride
, SS Split spoon sampler Snow. Creek Water Tank
SPT Standard penetration test Discovenj Bay, Washington
USC Unified sci/classification
WLI Water level indicator SOiL CLASSIFICATION
AND LOG KEY
July 2002 21-1-09645-00~:
SHANNON & WILSON, NC.I FIG, 3
Geotechnicel ancl ~.nvimnmentnl Consultants! Sheet 1 of 2
FRO, N': PUD1JEFFCO PHONE NO. · 3603855945 Jul. 1S 2002 iO:SSAM P4
GROUP/GRAPHIC~
MAJOR DIVISIONS SYMB~ [ TYPICAL DESCRIPTION
WelFgraded ~vels, g~vels,
~W gr~v~/s~n~xtures,~ttl~ or no fines
~ean Grovels ....
Gravels fines) GP Poorly graded grovels
: (~re ~an ~% ~ m ~um5, ~[me or no tines
or ~e ,,
fraction ~tained
~ Ne. 4 sieve) Gravels wi~ GM Silty gravels, g~ave[-sand-silt
Fi~
(mere ~an 1~ ~ C~y~ gravels.
[ COARSE- fines) GC
~.. GRNNED~ mi~ums
SOILS · ·
r~aln~ ~'~. SW .-..-.-.-. Well-graded ~ands, g~ave~ly aand~
[ 2~ sieve) Clean Sands +'.'.'.'+. l]ffie dr no fines
~ (less then 5% .....
~' ' ~nes) ~dy gta~ed sand gravel~ sa~s
Sands SP ~ ~le or no ~ nee
.... · (~% or more Of ..... '
~me f~cti~
~ pasts ~e No. 4 SM Silty sands, said-silt mixtures
' ~e~) Sands with
Fines ,.
(mo~ then 12% ........
~ = fines) SC Clayey s~nd~, ~nd-otey mi~ures
Iflorganlc silts ~ low to medium
pla~)ty, r~k rio?, san~ sil~. ,
ML g~ sil~, or aayey s~ wlt~ s~ig~t
~, p~ast~
~ '. Silts and Clays ~norganTc I~orgag~ clays ~ I~ to m~
(llqu/d II. it tess CL plasacEy, gravell~ clays, se~y
~an 5~) ~1~ clays, lean cmys
~ ' ~ Orga~ $ii~s ~nd organic si[~ ~ays of
= FINE~INED Organic OL~ ~w pla~ici~
~--' $Ol~
(~%~m .............
~ 2~ ~eve) MH e~a~m~OUSet~ic slit 6ne sands Ct
~ Inot~iO -
[ S~ a~ C~ Iqorg~ clay~ o~ m~dium to high
(l~uid li~ ~ or CH p~, saney ~at ~ay, or gravelly f~
; ~e) ..... c~aY ...........
~~ q~g~ni~ clays of m~lum m high
[ Organi~ OH p]~fi~y, o~anic silts
= HIGHLY- Primarily organ~ ma~er, dark In Peat, humuS, ~w~mp soils with high
[ ........ . ORGANIC PT
~ILS ~lor, and o~g~ni~ ~or o~an~ ~en~ [see A~M D 44~
Snow Creek Water Tank
Discovery Bay, Washington
1. Duel symbols (symbols separated by a hyphen, I.e., SP.SM, slightly
silty fine SAND)are used for soils w~h between 5% and 12% fines SOILCLASSIFICATION
or when the I~quld limit and plastlolty index values plot, in the CL-ML
area of the plasticity ~nart. AND LOG KEY
2. Borderline symbols (symbols separated by a slash. La., CL/MLo silty July 2002 21-1-09645-001
CLA Y/Clayey SIL'r; GW/E]W, sandy GRA VEL/gravelly SAND)
indicate mat the coil may fall into one of two possible basic groups. SHANNON & Wll-.SON, INC. ! FIG. 3
Ge~technlcal afl~l EnvffonmenteJ Consu~t~.nlsI shee'~ 2 of 2
FROMm: ~UD1J~FFCO PHON~ NO. : ~GOS055~5 Jul. 1~ 2002 10:3~AM ~5
sOIL DESCRIPTION ~ ~ -~ ,_ ~ Standard Penetration Resistance
(140 lb. weight~ 30-inch drop)
~ A Blows per foot
Surface Elevation: Approx. Ft.
Medium dense to dense, brown to gray, trace
to slightly grave[ly, slightly silty to silty SAND; .......... I ......... ~ ........
moist; scattered lenses of silty fine sand; SM,
-T-
SILTSTONEIMUDS-~I~IE (?);'little recovery. 13.0 sI ......... I .............. g014';
~=== 15
BOTTOM OF BORING lg.2 7'"~ .................. I 'S0/0:2~"
I
COMPLETED 1/28/2002 20 I
Note: Could not drill beyond 19.2 feet. .., .............................
0 20 40 60
LEGEND
~ % Water Content
- ~ample NOt Recovered ~ Ground Water Level ATD
-]- 2-inch O.D. Split SpOor~ SaMple Plasti~ Limit ~ ~ I Liquid Limit
'rr- 3~inch O,D, ~helby Tube ¢,~n~ple Natural Water Content
Snow Creek W~ter Tank
Discovery Bay, Washington
NOTES ..........
1. The .~b'etffication I~nes represent the approximate boundaries betwee~ soil tyt3es,
~r~l lhe transition may be gradual.
2. TEe diacuseion in ~he text of thia report iS necessary fot a pl'opet ut3dorSt~ndlng of LOG OF BORING B-1
the nature of the su~3sudaoe materials.
3. Groundwater level, if indicated above, is for the dele .,'.pecifie~ and may vary. July 2002 21-1-09645-001
4. riel'er to KEY for explanation of "Symbols" and defihiti0n~,,
5. USCS designation is based o~ visual-menu-',l c]nss[fication and selected SHANNON & WILSON, INC. I FIG. 4
.....I~bOral;OnJ }n~ex testing. Geotech~lcal eno Environtnen~el Oonsr;Itan~s
FR~': PUDiJEFFCD PHONE NO. : ~GOB855945 Jul. 19 2002 10:34AM P6
Geotechnical and Environmental Consultant~
Date:, J~y 17, 2~2
County
iMPORTANT INFORMATION ABOUT YOUR GEoTEOHNICAUENV RONMENTAL
REPORT
~N~UL~NG S~CES ~E.PERFORMED FOR SPECIFIC PURPO$ES AND FOR SPECIFIC CLIENTS.
~~ pr~e ~ to ~et ~e ~ific ~ of sp~ific individual~_ A repo~ p~par~ for a civil e~r.~y ~t be ad~te for
a co~cfion ~nffac~r or even ~o~ar ~vfl cn~. U~css indi~t~ o~wis~, your com~tant ~ yo~ r~expre~ly f~ you
~ e~r~ly for ~e pu~s you indica~ No one other than you ~ould apply ~s re~tt for i~s ~te~ p~s¢ wi~out first
~ng ~ ~e ~s~t, No party should apply ~is report for any purpose other ~an that ori~nally cont~plaed wi~out first
THB.~N~ULTA~ RE~RT IS BA~ED ON PROJECT, SPECIFIC FACTORS.
A ~c~~ m~ b bas~ on a subs~face c~]oration plan desired to consid~ a unJqne.~ of pmj~t-sp~c ~ctom.
~ on ~e pmj~ ~ may include: &e sepal antic of ~e s~ct~e and prop~ involve; i= size and confi~afion;
~ m~ and pracfi~; &e location of ~e sff~t~e on &e site and im orientation; o~ ~pmvmmU ~uch as access ro~s, ~king
~d und~o~d uffiifies; ~ &e addltion~ risk creat~ by scope-of-s~vice limitations impos~ by ~e client. To help avoid costly
~obl~, ~k ~ com~ to ev~t~ how any fact~ ~at c~ge subsequem to ~e date of ~e report may affect &e
U~s y~ mm~mt ~m~q O~e~j~, your re~ should not be us~: (1) when the mmre of ~, pro~s~ proj~t is ch~g~ (for
~s~l~, ff ~ offi~ b~l~ng ~I1 be ~ted ins~ of a p~ng garage, or if a reffig~a~ warehouse will b~ butt imt~ of an
~g~ one, ~ c~cals ar~ d~cove~ on or n~m ~v site); (2) when the size, elevation, or config~ation of the ~o~ ~oj~t
~mr~; (3) w~n &e'l~afion or orientation of ~e ~o~s~ proj~ is modified; (4) wh~n ~e is a change of o~ership; or (5) for
apportion to ~ adj~nt rite, ~m~m~ cmnot a~ept r~ns~ility for problems ~at may occur if they ae not comulted ~ factors
~h w~ comid~ in ~e devclop~t of ~e report ham changed.
~BSURFACE ~N~l~O CAN CH~GE.
b~ on co~ifio~ ~t exis~ at ~e fi~ of s~ace expl~sfion, cons~uction d~isiom ~ould not be. b~ on a ~po~
~y my have ~n ~ by time. ~k ~e consul~nt to advise if additional tesLq are desirable befo~ eons~ion st~s; ~r
~ction o~afiom at or adjacent to ~e ;ira and ~mml even[q s~ch as floods, ~qt~akes, ~ ~oundm~r fluc~atiom my also
$~s~ace ~fld~fio~ and, ~s, the cont~uing ad~uacy of a ;m~ch~caFonvko~n~ mpo~ The consultant s~ald ~ k~t ap~ of
any such cven~, ~ shoed ~ ~n~d ~ dete~ne if additio~ ~sm are n~ssa~.
MO~T ~ECOMME~D~TION~ ~E P~OFE0OlON~L JODGME~8,
Si~ v~lora~on a~ ~fing iden~ ac~l s~acc and subs~fa~ conditions only at those poinm wh~e s~ples m'e ~en. ~e dam
C~apoht~ by yo~ ~mtdt~t, who ~en applied judgment to reMer an opinion about overall subs~face renditions. The ~ml
~n materials may ~ f~ rare ~ad~I ~ abrup~ than your repo~ indicates, Actual condifiom in areas not ~mpl~ my diff~ ~om
th~ prCdict~ in yo~ r~. ~e no~ing can ~ done to prevent such sit~tions, you and yo~ consdtant can ~rk togeth~ m help
r~ ~ek impacm. ~ning yom' mns~mnt m observe subsurface construction operations can be pa~fieul~ly benefici~ in th~s
Page 1 of 2 1/2002
FROM~ : PUDiJEFFCO PHONE NO. : 3603855945 Jul. 19 2882 10:35AM P7
..,
· A REPORT'S CONCLUSIONS ARE PRELIMINARY. i"
The conclusions contained in your consultant's report arc preliminary because they mu,~t be based on the assumption tha! conditions revealed
through selective exploratory samphng are indicative of actual conditions throughout a site. Actual ,qubsurface co~tditio~s can be discerned ,,_
only during earthwork; therefore, you should retain yotlr consultant to observe actual conditions and to provide conclusions. Only the
consultant who prepared the report is fully familiar with the background information needed to determine whether or not the report's
recommendations based on those conclusions are valid and whether or not the contractor is abiding by applicable recommendations. The
consultant who developed your report, ca~not assume responsibility or liability for the adequacy of the report's recommendations if another ~' .
party is retained to observe construction.
THE CONSULTANT'S REPORT IS SUBJECT TO MISINTERPRETATION. [ .....
Costly problems cm occur when other design professionals develop their plans based on misintea-pretation of a geotechnical/env~o~mealtal '~:
report. To help avoid the,qe problems, the consultant should be retained to work with other project design professionals to ~xplain relevant
geotech~ical, geological, hydrogeological, and environmental findings, and to review the adequacy of their plans and specifications relative
tO these issues.
I3ORIN~ LOG;S AND/OR MONITORING WELL DATA SHOULD NOT BE SEPARATED FROM THE REPORT.
Final boring logs developed by the consultant are based upon interpretation of field logs (assembled by site personnel), field test results, and
laboratory and/or office evaluation of field samples a~d data. Only ileal boring logs and data am customarily included in
geo~hnical/en~konm~ntal reports. The~e final logs should not, under any circumstances, be redrawn for inclusion in architectural or other
design drawings, because drafters may COmmit errors o~ omissions in the transfer process.
To reduce ~he likelihood of boring log or monitoring well mislnteq~retation, contractors should be given ready access, to the complete ;,. ,
geotechnlcal ealgineeiil~envkonmental ~eport prepared or authorized for their use. If access is provided only to the report prepared for
you;'ym/should advise contractors of the report's limitations, assuming that a contractor was not one of the specific persons for whom the
~epoIt was prepped, and that developing construction cost estimates was not one of the sp~ific purposes for which it was prepared, While
a contractor may gain important knowledge fi'om a report prepared for another party, the contractor should discuss the report with your
c~nsultantandpe~~rmtheaddi~~nal~ra~mrnativew~rkbeIievedneeessaryt~~btainthedataspeci~ca11yappr~priate~or~~nstme~~nc~st ~-~.,
es~msting purposes, Some clients hold the mistaken impression that simply disclaiming responsibi!ity for the accuracy of subsurface
information always insulates them from attendant liability. Providing the best available informafioia to contractors helps prevent costly ~ ..
construction problems and the adversarial attitudes that aggravate them to a disproportionate scale. 'i ..
READ RESPONSIBILITY CLAUSES CLOSELY.
Because geoteelmieal/envi~onmental engineering is based extensively on judgment and opinion, it is far'less exact than other design ,.
discipline, s. This situation has ~ulted i~ Wholly tmwarran,~l claims being lodged against consultants. To help prevent fi_is problem,
co. nsnltants have developed a number of clauses for use in their contracts, reports and other documents,' These responsibility clauses am not
.... ~exc~l~ato~-elanses, de~igaed, to ~.ansfer the.consultant's liabilities to other parties; rather,, they'arc definitive clauses that identify where.the
eo,mltant~ r~po~sibilities begin and end. Their use helps all parties involved recognizethe'ir individual responsibilities and take '~'
appropriate action, Some of these definitive clauses are likely to appear in your report, and you are encouraged to read them closely. Your :,
consultant will be pleased to give full and frank answers to your questions.
The preceding paragraphs are based on information provided by the
A~FF_JAsaodafion of Engineering Fkras Practicing in the Oeoseienccs, Silver Spring, Maryland
Page 2 of 2 1/2002