HomeMy WebLinkAboutLANDMARK APARTMENTS EXPANSION - PDP - PDP120031 - SUBMITTAL DOCUMENTS - ROUND 1 - RECOMMENDATION/REPORTf*,I,in g,'!u'l
EARTH ENGINEERING
CONSULTANTS, lNc.
January 3l,20Az
Grace Custom Homes
2836 Links Drive
Boulder, Colorado 80301
Attn: Mr. Ron Grace
Re: Grace Housing Complex
South Shields and Prospect
Fort Collins, Colorado
EEC ProjectNo. i982026
Mr. Grace:
Our geotechnicai subsurface exploration report for the referenced project was submitted
to your attention on March 12, 1998. We have recently been asked to comment on
possible revised recommendations given the four-year time span since the original
exploration was completed. Those comments are enclosed with this letter.
ln general, we expect the soils at this site would be consistent with those observed in our
i998 exploration. We are not aware of any site gading completed since the time of our
1998 report. However, srvell potential is a function of the moisture content of the
subgrade soils and the moisture content of soils commonly fluctuates over time. The
soils observed in a portion of the borings were moderately plastic and showed low to
moderate swell potential at the moisture and density conditions observed in the test
borings. Care should be taken at the time of construction to verify that in-sifu soils would
not be expected to show appreciable swell in the subgrade and bearing materials. As a
worst case, overexcavation aird backfili procedures might be required to increase the
moisture content of the subgrade soils used for support of roadways, exterior flatwork,
floor slabs or footines.
CENTRE FoR ADVANCED TEcHNoLoGy
Z30 | RESEARcH BoulrveRD, Sur.rE l04
Fonr CoturNs, CoLoRADo 8O526
(97O) ?24- | 522 (FAlyJ
??4-4564 CDN#2594A-004
SUBSURFACE EXPLORATION REP ORT
PROPOSED GRACE HOUSING COMPLEX
SOUTH SHIELDS STREET AND PROSPECT
FORT COLLINS, COLORADO
EEC PROJECT NO. 1982026
EARTH ENGINEERING
CONSULTANTS, lNc.
CDN#2594A-004
SUBSURT'ACE EXPLORATION REPORT
PROPOSED GRACE HOUSNG COMPLEX
SOUTH SHIELDS STREET AND PROSPECT
FORT COLLINS, COLORADO
EEC PROJECT NO. 1982026
CDN#2594A-004
Re:
March 12,1998
Grace Custom Homes
2836 Links Drive
Boulder, Colorado 8030 I
Attn: iMr. Ron Grace
Subsurface Exploration Report
Proposed Grace Housing Complex
South Shields Street and Prospect
Fort Coliins, Colorado
EEC ProiectNo. 1982026
Mr. Grace:
Enclosed, herewith, are the results of the geotechnical subsurface exploration you requested lbr the
referenced project. In summary, the subsurface soils at this site consisted of low plasticity lean clay
soils overlying higher plasticity claystone bedrock. Groundwater was encountered at depths ranging
from approximately 5 to greater than 15 feet below present site grades.
Based on results of the field borings and laboratory testing completed for this project, it is our
opinion tire proposed lightiy loaded residential buildings could be supporled on conventional tboting
foundations bearing in the near surface cohesive soils. Those soils could also be used for direct
support of floor slabs for the proposed lesidential structures. Care will be necessary to establish t-loor
elevations above seasonal high groundrvater levels, particularly in the south portion of the site. Tire
near surface soils can also be used for direct support of the site pavements.
EARTH ENGINEERING
CONSULTANTS, lNc.
CENTRE FoR ADVANCED TEcHNoLoGY
230 | RESEARcH BouLEVARD, SutrE l04
FoRT coLLlNS, CoLoRADo 4O526
(97O) 2?4-l5?2 {lFAx, ??4-4564
tErY4t
CDN#2594A-004
Farth Fnoine"'ing COnSUi-rants. InC.
EEC ProjectNo. 1982026
March 12, 1998
Page 2
Geotechnical recomrnendations concening design and construction of the foundations and suppofi
of the floor siabs and pavements ar'e presented in the text of rhe attached report. If you have any
questions conceming the enclosed report, or if we can be of fuither service to you in any other way.
please do not hesitate to contact us.
Lester L. Litton, P.E.
Principal Engineer
LLLldmf
cc: Jim Sell Design
Very truiy yours,
Consultants, Inc.
CDN#2594A-004
SUBSURFACE EXPLORATION REPORT
PROPOSED GRACE HOUSING COMPLEX
SOUTH SHIELDS STREET AND PROSPECT ROAD
FORT COLLTNIS, COLORADO
EEC PROJECT I.IO. 1982026
March 12, 1998
INTRODUCTION
The subsurface exploration for the proposed Grace residential complex to be constructed to the
east of South Shields Street and south of Prospect Road in Fort Coliins, Colorado, has been
completed. Six soii borings extending to depths of approximateiy 15 feet below present site grades
were advanced in the proposed development area to evaluate existing subsurface conditions.
Piezometers were installed at selected boring locations to allol for longer term observations of
site groundwater. Individual boring logs and a diagram indicating the approximate boring
locations are included with this report.
We understand the proposed project involves construction of three i2-plexes and eight patio homes
with associated drive and parking areas. We expect the residential structures rvill be lightly
loaded, wood frame buildings with foundation loads less than 3 kips per lineal foot for continuous
wall loads and 50 kips for individual column loads. Floor loads will be light. We understand the
12-plexes will be non-basement and the patio units will contain basements or garden levels where
possible. Cuts and fills less than 3 feet will be required to develop site grades. Traffrc on the sire
pavement should be limited to low volumes of automobiles and light trucks.
The purpose of this report is to describe the subsurface conditions encountered in the borings.
analyze and evaiuate the test data and provide geotechnical recommendations concernin,u design
and construction of the foundations and support of floor slabs and pavements.
CDN#2594A-004
EEC project No. 19g2026
Earth Ensineerlne consultaats' Inc'
March 12, 1998
Page 2
EXPLORATION AND TESTING PROCED{JRES
The boring locations were established in the field by representatives of Eanh Engineering
Consultants, Inc. (EEC) by pacing and estimating angles frorn identifiable site features. Those
approximate boring iocations are indicated on the attached boring location diagram. The locations
of the borings should be considered aecurate only to the degree implied by the methods used to
make the field measurements.
The borings were performed using a truck-mounted, CME-45 drill rig equipped rvith a hydraulic
head empioyed in drilling and sampling operations. The boreholes were advanced using 4-inch
nominal diameter continuous flight augers and samples of the subsurface materials encountered
were obtained using split-barrel and California barrel sampling procedures in general accordance
with ASTM Specification D-1586. In those sampling procedures, standard sampling spoons are
driven in the ground by means of a 140-pound hammer falling a distance of 30 inches. The
number of blows required to advance the samplers is recorded and is usgd to estimate the in-situ
relative density of cohesionless soils and, to a iesser degree of accuracy, the consistency of
cohesive soils and hardness of weathered bedrock. In the Califomia sampling procedure, relatively
undisturbed soil samples are obtained in removable brass liners. Ail samples obtained il the field
were sealed and returned to the laboratory for further examination, classification and testing.
Moisture content tests were completed on each of the recovered samples. Appropriare samples
were tested for unconfined strength using a calibrated hand penetrometer with dry density tesrs
completed on the samples recovered by the California sampling method. Washed sieve analysis
and Atterberg limits tests were completed on selected samples to evaluate rhe quantity and
piasticity of the fines inthe subgrades. Swell/consoiidation tests were performed to evaluate the
tendency of the subgrade soils to change volume with variation in moisture content. Results of
the outlined tests are indicated onthe attached boring logs and summary sheets.
As a part of the testing program, ail samples were examined in the laboratory by an engineer and
classified in accordance with the attached General Notes and the Unified Soil Classification System
CDN#2594A-004
EEC project No. 19g2026
Ferth Fnoinc";ng consultants' Inc'
March 12, 1998
Page 3
based on the soil's texture and plasticity. The estimated group symbol for the Unified Soil
Classification System is shown in the appropriate column on the boriag logs and a brief description
of that classification system is included withthis report. Classification of the bedrock was based
on visual and acrual observation of disturbed samples and auger cuttings. Coring and/or
petrographic analysis may reveal other rock types.
SITE AND SI.IBSURF'ACE CONDITIONS
The Grace complex wili be constructed immediately east of the existing Landmark Apartments
southeast of the corner of South Shields Street and Prospect Road in Fort Collins. The
development parcel is presently used as corral and pasture for horses. Other than small
outbuiidings, no evidence of prior building construction was observed on the site by EEC site
personnel. Site drainage is to the south with maximum difference in ground surface elevations
across the site on the order of 10 to 15 feet. Small drainage swale mns generally northwest to
southeast across the southwest corner of the property.
An EEC field geologist was on site during drilling to evaluate the subzurface conditions
encountered and direct the drilling activities. Fieid logs prepared by EEC sire personnel were
based on visual and tactual observation of disturbed samples and auger cuttings. The final boring
lo-es included with this report rnay contain modifications to those field logs based on results of
laboratory testing and engineering evaluation. Based on results of the field borings and laboratory
testing, subsurface conditions can be generalized as fbllows.
Three to six inches of vegetation and/or topsoil was encolrntered at the suriace at the boring
locations. The topsoil/vegetation was underlain by brown lean clay with varying amounts of silt
and sand. The cohesive soiis were very stiff to stiff above observed groundwater and softer below
those depths. The site cohesive soils showed low potential for swell with increases in moisfure
content. The low plasticity cohesive soils extended to the bottom of borings B-1, B-5 and 8-6
and to depths of approximately 13 to 14 feet ar the other boring locations.
CDN#2594A-004
EEC project No. 19g2026
Earth Eneineerine consuitants' Inc'
March 12, i998
Page 4
Highly weathered claystone bedrock was encountered beneath the lean clay soils at boring
locations B-2, B-3 and B-4. The ciaystone bedrock was soft to moderately hard and could be
drilled with conventional soil augers, The claystone has higher plasticity than the overburden soils
rvith higher potential for volume change with variation in moisture content. Borings B-2, B-3 and
B-4 were terminated at depths of approximately 15 feet in highly weathered claystone.
The stratification boundaries indicated on the boring logs represent the approximate location of
changes in soil and rock types; in-situ, the transition of materials may be gradual and indistinct.
WATER LEVEL OBSERVATIONS
Observations were made while drilling and after completion of the borings to detect the presence
and depth to hydrostatic groundwater. In addition, 2-inch nominai diameter field-slotted PVC
piezometers were installed at selected boring locations to prevent caving of the boreholes and
allow for longer term monitoring of groundwater level. Water level readings completed to date
are indicated in the upper right hand corner of the boring logs. Those indicated water levels are
srated as depth below existing ground surface at each of the boring locations. In general, the water
levels varied from a depth of approximately 6 feet to depths greater than rhe boring depth of
approximately 15 feet.
Fiuctuations in groundwater levels can occur over time depending on variations in hydroiogic
conditions and other conditions not apparent at the time of this report. Zones of perched and/or
uapped water can be encountered in the more permeable zones in the subgrade soils and perched
water is commonly encountered in soils overlying less permeable highly wearhered bedrock. The
location and amount of perched/trapped water can also vary over time depending on variarions in
hydrologic conditions and other conditions not apparent at the time of this report.
CDN#2594A-004
Earth Engineering Consultants, Inc.
EEC Project No. 1982026
March 12, 1998
Paop 5
ANALYSIS AND RECOVTMENDATIONS
Foundations
Based on the matedals observed at the test boring locations, it is our opinion the near surface soils
could be used to support the proposed lightly loaded residential structures on conventional footing
foundations. We recommend those foundations extend through all existing vegetation and/or
topsoil and bear in the natural, stiff to very stiff lean clay with varying amounts of silt and sand.
For design of footing foundations bearing in the natural, stiff to very stiff cohesive soils, we
recommend using a net allowable total load soil bearing pressure not to exceed 3,000 psf. The
net bearing pressure refers to the pressure at foundation bearing level in excess of the minimum
surrounding overburden pressure. Total load should include full dead and live loads. A minimum
dead load pressure of 1,000 psf should be used for design of the foundations.
Exterior foundations and foundations in unheated areas should be located a minirnum of 30 inches
below adjacent exterior grade to provide frost protection. We recommend formed continuous
footings or trenched foundations have a minimum width of 12 inches. Formed grade beam
foundations should have a minimum rvidth of 8 inches. Individual column foundations should have
a minimum dimension of 24 inches. If it is necessary to void portions of the foundations to
develop the recommended dead load pressure, we recommend those voids be formed with
minimum 4 inch thick void forms designed to prevent an influx of soil and debris into the voided
area.
No unusual problems are anticipated in completing the excavations required for construction of
the footin-e foundations. Occasional soft and loose zones were observed in the overburden soils
and care should be taken to see thar the footin-q foundations are supported on suitable strength
natural soiis. As a minimum, hand auger borings should be completed at each column location
and along continuous footing iine5 ro see that the bearing soils are suitable for support of the
design bearing pressure. Care should also be taken during construction to avoid disturbing the
foundation bearing materials. This will be particuiarly important in the sourh areas of the site
CDN#2594A-004
Earth En-gineerhg Consultants, Inc.
EEC Project No. 1982026
lvlarclr 12, 1998
Page 6
where those foundations may extend closer to hydrostatic groundwater table. Materials which are
loosened or disrurbed by the construction activities or materials which become dry and desiccated
or wet and softened should be removed and replaced or footing foundations extended to bearing
on suitable strength natural materials.
We estimate the long{enn settlement of footing foundations designed and constructed as outlined
above would be less than 1 inch.
Below Grade Areas
Care wiil be necessary in establishing appropriate bearing elevations for below grade areas to see
that suitable separation is maintained between the seasonal high groundwater level and the
basement/garden level floor elevations. It has been out experience that low groundwater levels
occur during the mid-rvinter months and high groundwater levels occur during late summer and
early fall. Continued monitoring in the site piezometers should be completed to evaluate
groundwater level fluctuations into the fall of this year. That information can be used to provide
a better estimate of maximum hieh groundwater leveis in the area. We can assist in this area at
your request.
We recommend a perimeter drain system be instailed around the exterior of belorv grade areas to
reduce the potential for developnent of hydrostatic loads on below grade walls and/or infiltration
of surface water into the below *qrade areas. In
general, the perimeter drain system should consist
of perforated metal or plastic pipe piaced at approximate foundation bearing level around the
exterior perimeter of the struch-lre. The drainline should be sloped to drain to a sump area rvhere
water can be removed without reverse flow into the system. The perimeter drain should be
surrounded by a minimum of 6 inches of appropriately sized granular filter soil and either the
drainline or filter soil shouid be surrounded by a filter fabric to help prevent an influx of fines into
rhe system. Depending on the final finished floor elevations relative to anticipated high
groundwater levels, installation of an underslab floor drain system may also be recommended.
CDN#2594A-004
Ferth Fnoineering ConSultants, Inc.
EEC Project No. 1982026
March 12, 1998
Page 7
The decision to install an underdrain slab system can be made concurrent with establishing the
floor elevations for the structures.
Backfill placed adjacent to below grade walls should consist of approved, low-volume change
materials which are free from organic and debris. The on-site silry sandy iean clay can be used
for backfill in these areas, If off-site materials are used, we recommend those materials have a
liquid iimit of 40 or less and plasticity index of 18 or less. The top 2 feet of backfill around the
structure should contain sufficient fines to prevent rapid inflow of infritration water adjacent to the
structure. The site cohesive soils could be used in this area.
The backfill materials should be placed in loose lifts not to exceed 9 inches thick, adjusted in
moisture content and compacted to at least 90% of the material's maximum dry densiry as
determined in accordance with ASTM Specification D-698, the standard Proctor procedure. The
moisture content of the backfrll materials should be adjusted to be within the range of +2% of
standard Proctor optimum moisture at the time of compaction. In areas where the backfill
materials will support sidewalks, steps, patios, driveways or similar improvements, those backfill
materials should be compacted to at ieast 95% of standard Proctor maximum dry density' Care
should be taken during placement of the backfill to avoid placing excessive lateral stresses on the
below grade walls. Hand or light mechanical equipment should be used for placement of backfill
in these areas.
For design of below grade walis where appropriate steps have been taken to eliminate hydrostatic
loads, we recornmend using an equivaient fluid pressure of 35 pounds per cubic foot. The
equivalent fluid pressure is based on an "at rest" stress distribution analysis which includes an
assumption of slight wall rotarion. The wall rotation is estimated to result in a deflection equal
to 0.5 % ttmes the height of the wall. The equivalent fluid pressure provided is based on
horizontal backfill with no allowance provided for surcharge loading or point loads within the
backfill. The equivalent fluid pressure also does not include a factor of safety.
CDN#2594A-004
Earth Engineering Consultants, Inc.
EEC Project No. 1982026
March i2, 1998
Page 8
Floor Slab and Pavement Subgrades
All existing vegetation and/or topsoii should be removed from beneath the pavement and building
areas. After stripping and completing all cuts and prior to placement of any fill, floor slabs or
pavements, we recommend the in-place soils be scarified to a minimum depth of 9 inches, adjusted
in moisture content and compacted to at least 95% of the material's maximum dry density as
determined in accordance with ASTM Specification D-698, the standard Proctor procedure. The
moisture content of the scarified materials should be adjusted to be within the range of *.2% of
standard Proctor optimum moisture at the time of compaction.
Fill materials required to develop the floor slab or pavement subgrades should consist of approved,
low-voiume change materials which are free from organi.c matter and debris. The on-site silty
sandy clays could be used for fill in these areas. If off-site materials are used, we recommend they
have a maximum liquid limit of 40 and maximum plasticity index of 18. The fiI1 materials should
contain sufficient fines to prevent ponding of water below the floor slabs or pavements. The fill
materials should be placed in loose lifts not to exceed 9 inches, adjusted in moisture content as
recommended for the scarified materials and comoacted to at least 95% of the material's standard
Proctor maximum dry density.
After preparation of the subgrades, care should be taken to avoid wetting or drying of those
subgrades prior to placement of the floor slabs or pavements. Although the on-site lean clay soils
show low expansion potenrial at moderate moisture content, expansion potential can be increased
significantly by densifying the subgrade materials and allowing them to dry appreciabiy prior to
placementof the overlying improvements. Care should also be nkento avoiddisturbing the in-
place subgrades prior to placement of the overlying floor slabs or pavements. Materials which are
loosened or disturbed by the construction activities or materials which become dry and desiccated
or wet and softened should be removed and replaced or reworked in place prior to placement of
the floor slabs and pavemenrs.
CDN#2594A-004
Earth Engineering Consultants, Inc.
EEC Project No. 1982026
March 12, 1998
P,oP q
Pavement Structure
We anticipate the on-site pavements will be used by low volumes of automobiies and light trucks.
We believe the on-site pavements are private streets and, therefore, not subject to City of Fort
Collins design methodology and criteria.
Based on previous experience with similar subgrade and traffic conditions, we recornmend the site
pavements consist of 3 inches of hot bituminous pavement overlying 6 inches of aggregate base.
The hot bituminous pavement should be consistent with City of Fort Collins or Colorado
Department of Transportation (CDOT) requirements for grading C or CX materials. The
aggregate base should be consistent with CDOT requirements for Ciass 5 or Class 6 base.
An alternative fulI depth asphaltic concrete pavement section could be considered. The fulI depth
asphaltic section should consist of 2 inches of surface course asphalt and 3 7z inches of asphaltic
concrete base. The surface course asphalt should be consistent with City of Fort Collins or CDOT
criteria for grading C or CX materials and the aggregate base should be consistent with similar
recommendations for grading G.
Positive drainage should be developed across the pavements and away from the pavement edges
to avoid wetting of the subgrade materials. Subgrade materials which become wetted subsequent
to construction can result in loss of subgrade support and premature failure of the pavement
section.
Other Considerations
Positive drainage should be deveioped away from the new structures to avoid wetting the bearing
or subgrade materials. We recommend a minimum slope of 1 inch per foot for the first l0 feet
away fromthe strucfures. Dorvnspouts or roof drains shouidbe designed to discharge at least 5
feet away from the structures and landscaping immediately adjacent to the building should be
limited to plants with lo.,v water requirements.
CDN#2594A-004
Earth Engineering Consuitants, Inc.
EEC Project No. 1982026
March 12. 1998
Page 10
GENERAL CO1VIMENTS
The preliminary analysis and recommendations presented in this report are based upon the data
obtained from the soil borings performed at the indicated locations and from any other information
discussed in this report. This report does not reflect any variations which may occur between
borings or across the site. The nature and extent of such variations may not become evident until
further exploration or construction. If variations appear evident, it will be necessary to re-evaluate
the recommendations of this report.
It is recommended that the geotechnical engineer be retained to review the plans and specifications
so that comments can be made regarding the interpretation and implementation of our geotechnical
recommendations in the design and specifications. It is further recommended that the geotechnical
engineer be retained for testing and observations during earthrvork and foundation construction
phases to help determine that the design requirements are fulfilled.
This report has been prepared for the exclusive use of Grace Custom Homes for specific
application to the project discussed and has been prepared in accordance with generally accepted
geotechnical engineering practices. No warranty, express or implied, is made. In the event that
any changes in the naure, design or location of the project as outlined in this report are planned,
the conclusions and recommendations contained in this report shall not be considered valid unless
the changes are reviewed and the conclusions of this report modified or verified in writing by the
geotechnical engineer.
CDN#2594A-004
DRILLING AND DCPLORATION
DRILLING & SAMPLING SYMBOLS:
SS: Split Spoon - 13/8" I.D., 2" O.D., uuless otherwise noted PS:
Piston Sample
ST: Thin-Walled Tube - 2" O.D., unless otherwise noted WS: Wash
Sample
R: Ring Bane I Sampl er - 2.42" I.D., 3" O.D. unless otherwise noted
PA: Power Auger FT: Fish Taii Bit
HA: Hand Auger RB: Rock Bit
DB: DiamondBit:4",N,B BS: BulkSamPle
AS: Auger Sample PM: Pressure Meter
HS: Hollow Stem Auger WB: Wash Bore
Standard "N" Penetration: Blows per foot of a 140 pound hammer falling 30 hches on a 2-inch O.D. spiit spoor! excqcr where noted.
WATER LEVEL MEASI]REMENT SYMBOLS :
wL : Water Level WS : While SamPling
WCI: wet Cave in WD : While Driiiing
DCI: Dry Cave in BCR: Before Casing Removal
AB : After Boring ACR: After Casting Removal
Water levels indicated on the boring logs are the levels measured in the borings at the time indicated. In pervious soiis, the indj
levels may reflect the location of ground water. In low permeability soils, the accurate determination of ground water levels is
possible with only short term observations.
DES6RIPTIVE SOIL CLASSIFICATI9N PTIYSICAL PROPERTIES OF BEDROCK
Soil Classification is based on the Unified Soii Classification DEGREE OF WEATT{ERING:
system and the ASTM Designations D-2488. Coarse Grained Sfieht Slight -d-e-composition of parent material
Soils have move than 50o/o of their dry weight retained on a Jomts' May oe color
soils have move cnange'
than )u7o oI theu ClIy welght.retalnec on a
#200 sieve; they are described as: boulders, cobbies, gravel or Moderate
$ome - decomposition and color chang
sand. Fine Grained Soils have less than 50% of their dry weight tbrougnour'
retailed on a #200 sieve; they are described as : clays, if they High
Rock highly decomposed, may be extremel
are plasdc, and silts if they are slightly plastic or non-plastic. broken.
Major constih.rents may be added as modifiers and minor
HARDNESS AND DEGREE OF CEMENTATION:
constituents may be added according to the relative proportions Limestone and
Dolomite:
basedongrainsize.Inadditiontogradation,coarsegrainedffiittoscratchwithknife.
soils are defined on the basis of their relative in-place density
Moderately Can be scratched easily with knife.
and fine grained soils on the basis of their consistency.
.
Example: Lean clay with sand, trace gravel, stiff (CL); silty Hard
Canaot be scratched with fingernail'
sand, trace gravel, medium dense (SM). Soft Can be scratched
with fiagernail.
CONSISTENCY OF FINE-GRAINED SOILS @
Hura Canbe sElatched easily with knife, camot
scratched with fingernail'
Unconfined Compressive
Strensth. v\r ! ^\D !9, C)u- nsf Consistencv Moderately Can be scratched with filgeroail.
Hard
< 500 Very Soft Snft Can be easilv dented but nor molded u
Soft Qan be easily dented but nor molded wi
5oo - 1,ooo Soft fingers.
hngers'
i,00 1 - 2,000 Medium
Sandstone and Conqlomerate:
i;331 -i;333 i,l[r,o, ffiscratchingaknirebiade
8,001 - i6,000 Very Hard Cemented
IJNNFUED SOM- CILASSMTC.AIITON SYSlIlE}d
Soil Clossificotion
Group Grcup Nome
Criterio for Assigning Group Symbols ond Group nomes Using Loboroiory Tests Symbol
Scnis 50% or
more coorse
frccrion posses
No. 4 sieve
Coorse-Croined
Soils more lhon
50% retoined on
No. 200 sieve
Crovels more thon
50% o( coorse
iroc:!on retoined
on ),1o. 4 sieve
Cleon Grovels Less
thon 5% fines
Grovels wiih Fines
more lhon 12%
fin es
Cleon Sonds Less
tnon )zo nnes
S*d. t"ith Fi.*
more thon 12%
fines
Cu>_a ond <0ci3E
.- ^ -i
Uu<4 crldlor l>Lc>J
t',*.
".*rt "-ta
- --
Fines clossify os CL or CF
Cu)6 ond
'1 <Qc<J'
Cu<6 ondlor 1)Cc>J-
Fines closslfy os ML or MH
Fines clossify os CL or CH
Well-Ercded grovel'
D ,"aarl,",,.- ' ar :. nAaA nra,,ali
",t
--.'"t *
Cloyey Grovel t'"''
Well-grcded sond'
' Daatlv-rraAad cnndr
"""t :'
Slliy sc.d "*
Cloyey scndq'
GW
GP
SW
SP
SM
SC
Fin e-Groined
Soils 50% or
mara nnccp< lhc
No. 200 sieve
Silis ond Cloys
Liquid Limii. less
Prospecl Rood
I
F ---- .-\
12-plex
N
NOI TO SCALE
r)
/Londmork
Aportmenis
\.'
l2-plex
I
i
I
Ii
l,\ J\
.ll\ \\ ,*\-
l)) lv
,V ;* ,/
./i -e- ,//-
/r) ,Y/ ;*
5pfln9 LreeK Suoorvrsron \
\
BORING LOCATION DIAGRAM
GRACT APARTMINTS, FORT COLLINS, COLCRADO
PROJICT NO: 1 982026 DAT[: FTBRU ARY 1 998
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EARTH ENGINEERING CDN#2594A-CO\004 ISULTANTS
GRACE APARTMENTS
FORT COLLINS. COLORADO
PROJECT NO: 1982026 DATE: FEBRUARY 199E
LOG OF BORING g-1
RIG TYPE: CME45 SHEET 1 OF WATER DEPTH
FOREMAN: SK JIAKI UAIE AJIIILE DRILLING
qn'
AUGER TYPE: 4" CFA FINISH DAT \FTER DRILLING
qt
SPT HAM[4ER: MANUAL UKFAUtr ELEV N/A I DAYS AB 7
SOIL OESCRIPTlON m N
IBLOWS/FT)
QU
{PSR
MC
l%) (PcF)
A.LIMITS .200
t%l
SWELL
LL PI PRESSURE % @ 500 PsF
SANDY LEAN CLAY (cL)
lrt
brown L
stifi to very stiff
?
25 9000+ 1 1.1
19.4 '19
1 500 psf
6
d
9
id
SILTY SANDY LEAN CLAY (CL)
brown
soft to stiff
30.4
11
13
SANDY LEAN CLAY (CL)
brown E
I
siiff to very stiff I
14
to
17
18
'19
20
28 13.4
BOTTOI,,OF I BORING 15.5'
21
22
23
24
Earth En gineering Consultants
CDN#2594A-004
GRACE APARTMENTS
FORT COLLINS, COLORADO
PROJECT NO: 1982026 I DATE: FEBRUARY 1998
LOG OF BORING B-2
RIG TYPE: cME45 SHEET 1 OF WATER DEPTH
FOREMAN: SK START DATE I/HILE DRILLING 8.0'
AUGER TYPE: 4" CFA :INISH
OATE <.40-la AFTER ORILLING
SPT HAMMER: MANUAL SURFACE EL NIA DAYS AB
SOIL DESCRIPTION m 0 N
tSLOWS/FT)
OU
(PSFI
MC
t%) tPC F)
A-Ll['llTS -200
i..|)
SWELL
PI @ 500 PsF
SANDY LEAN oLAY (cL)
iat
orown L
sriff to very stiff
mineral deposits
2
3
7
13 9000+ lc I
20.0
SANDY LEAN CLAY (CL)
brown/orange brown
sofl.to stiff lss
8
9
1l
14
lt
7 1000
HIGHLYWEATHERED SHALE
oiive i;
I
s€n I
2000
BOTTOIlI OF BORING 15,5' 16
17
-t;
l,I t
-,;
i--
i_"
t,,
Ilzs
24
25
EarthEngineering Consultants
CDN#2594A-004
GRACE APARTMENTS
FORT COLLINS, COLORADO
PROJECT NO: 1962026 DATE: FaBRUARY 1998
LOG OF BORING B-3
START DATE I Z.ZS.gA
AUGER TYPE: 4'' CFA
SPT HAMMER: MANUAL 2 DAYS AB
SANDY LEAN CLAY (CL)
brown/orange brown
stiif lo very stiff
HIGI.'1LY \r'.€ATHERED SHALE
olive
sofl
BOTTOM OF BORING 15.5' to
17
18
20
21
?2
23
24
It
nq Consultants
CDN#2594A-004
GRACE APARTMENTS
FORT COLLINS, COLORADO
AUGER TYPE: 4'. CFA
SANDY LEAN CLAY (CL)
Drown
stifi to very stiff
SANDY LEAN CLAY (CL)
reddish brown
stiff to very stiff
HIGHLY IA/EATHEREO SHALE
olive
son lo moderately hard
BOTTOM OF BORING 15.5'
CDN#2594A-004
START OATE
SPT HAMMER: MANUAL
SANDY SILTY LEAN CLAY (CL)
orown
stiff to very stiff
BOTTOM OF BORING 15.5'
GRACE APARTMENTS
FORT COLLINS, COLORADO
CDN#Consultants 2594A-004
GRACE APARTMENTS
FORT COLLINS. COLORADO
SHEET 1 OF 1
SANDY LEAN CLAY (CL)
Drown
stiff to very stiff
mineEl deposiis
SILTY LEAN CLAY (CL)
Drown
stifito very stiff
BOTTOM OF BORING 15.5'
CDN#2594A-004
12
t0
swtLL/cONSOL|DATION TIST RTSULTS
0.5
Lood (TSF)
6
c,
=-
ao
ID
E
Q'
o
c,
o
0,
Moteriol Description: Brown Sondy Leon Cloy
Somple Locotion: tt- t s-2 4'
Liquid Limit: 37 | Plostic Limit: 18
| Plosticity Index: 19 |
% Possing f200: 62.5
Beginning Moisture: lz.s I Dry Densitf 1n.4
| Ending Moisture: 20.7
Swell Pressure: 1300 psf % Swell @ 500 psf
: 1.J7"
I
I
I
I
I
-{
I
I I
Project: Groce Aportments
Fort Collins, Colorodo
Project No: 1982026
Doie: Februorv 1998 ]B]B@
CDN#2594A-004
thcn 50
lnor9on rc
orgon rc
Pl>7 ond plots on or obove
Pl(4 or plots below "A"LineJ
Liquid L:mit -
oven dried
Liquid Limit - not
dried
Leon cloy (L'
silt (*"
Orgonic cloy x.uu.u
6raenir eill (l-!'o
A Lrne"
<0.75 0L
CL
ML
inorgon ic Pl plots on or obove "A'Line
Pl plois below "A"Line
Liquid Limit -
oven dried
Silts ond Cloys CH
lvlH
<0.75 0H
Liquid Limit -
n6l lried
Highly orgonic soils Primorily orgonic motter, dork in color, ond orgonic odor PT Peci
LIQUID LIMIT (LL)
^9osed on the moteriol poss;ng
lhe J-in, (75-
nf,) siew
3ll field somDle conloined cobeies or boulders,
.r bath, odd "with
cobbles or aculders, or both"
:Gr6vels with 5 to 127 fines re.uired duol
symoolS:
GW-GM well groded grovel wiii! silt
6W-GC well-groded g.ovel wiii :ldy
5?-GM poorly-groded grqvel wiih silt
3P-GC poorly-grqded grovel wirr cloy
)Sonds wilh 5 lo 122 lines reauire duol
strn b ol s:
SW-SM well-groded sqnd with srlt
Sw-SC well-groded sond wiih::cy
SP-SM pcorly groded sond wiir silt
S?-SC poorly groded sond sil,i c!oy
eCu=Dso,/D'Cc=
eI**
Flf soil ccnioins
>152 sond, occ-wi[h sond"to
group nome.
clf fines clossify os CL-ML, use cuol sYmbol
GC-CM, or SC-SM.
Flf fines ore orgonic, odd"with orgonic fines"lo
group nome
ilf soil conIoins >15%qrovei, ooc'with grovel"
lo gaoup nome.
rlf Attetberg limits plots shoded
oreo, soil is o
CL-ML, cilty cloy.
(lf
soil cootoins 15 to 29Zolus No' 200, odd
"with scnd' or
'with grcvei",
wnichever is
predomindn t.
Llf soil contoins > J0'orus lic.200
preaominontly scnd, odd
'so::y
to grouP
Mlf soil contoins >
30% cius l''a' 200
predominontly grovel, odc'grrcly- to grouP
NPI>4 ond plots
on or ooore'A" line.
oPl34 or.
plots )elow "A- line.
Pn: plots on or ooove'A'iire.
oPt olots
be{ow'A' line.
x
z
=
a
I For Clossilicotiod ot un.-9r
I ond fine-groined lroclion ol
--l
groin.d soils
)ul- lororio.
ot "A"-1ine
I Ho.izontol or PI-4 to LL=21
I rnen
Pr-0.7J (Lr--20)
I €quot;on ot "LJ'-1ine
rincd soils
r.5. / ,/ ntt'
l'w)' nYt
'l tn- \J' ;9
I
.oL I
""1
Pr=0.9 (Ll_-6) ^\^
gw 1i
I os
V-./
ilvlH
I
OHI
j"vl- i- cr
I
CDN#2594A-004
Can be scratched with krife.
RELATIVE DENSITv oF coARSE-cRANED soILS:
i:f:t,"u
can be broken apart easilv nith furgers
N-Blorvs/ft Relative Density
0-3 Very Loose
4-9 Loose
10-29 Medium Dense
30-49 Dense
50-80 Very Dense
80 + Extremely Dense
CDN#2594A-004