HomeMy WebLinkAboutWESTFIELD PARK POOL - PDP - 27-94B - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTUNIFIED SOIL CLASSIFICATION SYSTEM
Soil Classification
Criteria for Assigning Group Symbols and Group Names Using Laboratory Test;' Group c.,...�,.1 Group Names
Coarse -Grained
Soils more than
50% retained on
No. 200 sieve
Gravels more than
509'q of coarse-
fraction retained on
No. 4 sieve
Clean G�a:'els Less
than 5i !Ines`
Gravels ':rich Fines
more than 12% fines:
Cu > 4 and 1 < Cc <3'
Cu < 4 and/or 1 > Cc > 3:
Fines classify as ML or MH
Fines classify as CL or CH
GW
GP
GM
GC
Well-gra'ded - " ''
',r_:e:
Poorly graded gravel`
Silty gravel,G,H
Clayey gravel'G"
Sands 50% or more
Clean Sands Less
Cu > 6 and 1 < Cc < 3'
SW
Well -graded sand'
of coarse fraction
passes No. 4 sieve
than 50% fines'
Cu < 6 and/or 1 > Cc > 3'
SP
Poorly graded sand'
Sands with Fines
Fines classify as ML or MH
SM
Silty sand"'
more than 12% fines'
Fines Classify as CL or CH
SC
Clayey sand"'
Fine -Grained Soils
Silts and Clays
inorganic
PI > 7 and plots on or above "A line'
CL
Lean clay'-'-'
50% or more
Liquid limit less
PI < 4 or plots below "A" line
ML
K
SiItL "
passes the
than 50
No. 200 sieve
organic
Liquid limit - oven dried
Organic clay`•L•"L"
< 0.75
OL
Liquid limit - not dried
Organic silt""
Silts and Clays
inorganic
PI plots on or above "A" line
CH
Fat clay'•L-"'
Liquid limit 50
P1 lots below "A" line
MH
Elastic Silt"""
or more
organic
Liquid limit - oven dried
Organic clay&LAP
< 0.75
OH
I — —
Liquid limit - not dried
Organic slit`-"L'
I Primarily organic matter dark in color, and organic odor PT Peat
Highly organic so l s
ABased on the material passing the 3-in.
lDgo1 q
(75-mm) sieve
.eCu=Dqq/DLq Cc = D x D
'if field sample contained cobbles or
�q °"
boulders, or both, add "with cobbles or
boulders, or both" to group name.
`Gravels with 5 to 12% fines require dual
'If soil contains > 15% sand, add "with
symbols:
GW-GM well -graded gravel with silt
sand" to group name.
Glf fines classify as CL ML, use dual symbol
GW-GC well -graded gravel with clay
GP -GM poorly graded gravel with silt
GC -GM, or SC-SM.
"If fines are organic, add "with organic fines"
GP -GC poorly graded gravel with clay
'Sands with 5 to 12% fines require dual
to group name.
'If soil contains > 15% gravel, add "with
symbols:
SW-SM well -graded sand with silt
gravel" to group name.
'If Atterberg limits plot in shaded area, soil is
SW -SC well -graded sand with clay
a CL-ML, silty clay.
SP-SM poorly graded sand with silt
SP-SC poorly graded sand with clay
f], cl]f f�licallan fl !gin"-9,einrc fe�f I �
and lint-q,]Infe '."::pan el ce"rff-
q,"Inf" fa,lf i
F]��.]M1lil ]f •]I • �L • I
c�:e• ];S
Z I
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v
�MH OR OH
. -- LITID LIMIT (L-)
"If soil contains 15 to 29% plus No. 200, add
.with sand" or "with gravel", whichever is
predominant.
`If soil contains > 30% plus No. 200
predominantly sand, add "sandy" to group
name.
mit soil contains > 30% plus No. 200,
predominantly gravel, add "gravelly" to group
name.
"PI > 4 and plots on or above "A" line.
GPI < 4 or plots below "A" line.
'PI plots on or above "A" line.
'PI plots below "A" line.
Irerracon
REPORT TERMINOLOGY
(Based on ASTM 0653)
Expansive Potential The potential of a soil to expand (increase in volume) due to absorption of
moisture.
Finished Grade The final grade created as a part of the project.
Footing A portion of the foundation of a structure that transmits loads directly to the
soil.
Foundation The lower part of a structure that transmits the loads to the soil or bedrock.
Frost Depth The depth of which the ground becomes frozen during the winter season.
Grade Beam A foundation element or wall, typically constructed of reinforced concrete,
used to span between other foundation elements such as drilled piers.
Groundwater Subsurface water found in the zone of saturation of soils, or within fractures in
bedrock.
Heave
Upward movement.
Lfthologic
The characteristics which describe the composition and texture of soil and
rock by observation.
Native Grade
The naturally occuring ground surface.
Native Soil
Naturally occurring on -site soil, sometimes referred to as natural soil.
Optimum Moisture
The water content at which a soil can be compacted to a maximum dry unit
Content
weight by a given compactive effort.
Perched Water
Groundwater, usually of limited area maintained above a normal water
of an intervening relatively impervious continuing
elevation by the presence
stratum.
Scarify
To mechanically loosen soil or break down existing soil structure.
Settlement
Downward movement.
Skin Friction (Side
The frictional resistance developed between soil and an element of structure
Shear)
such as a drilled pier or shaft.
Soil (earth)
of rocks, anns of d which particlesproduced
Sedimentsormay
tand chemical disintegration her unconsolidated l
byphysical
not contain organic matter.
Strain
The change in length per unit of length in a given direction.
Stress
The force per unit area acting within a soil mass.
Strip
To remove from present location.
Subbase
A layer of specified material in a pavement system between the subgrade and
Subgrade
base course.
The soil prepared and compacted to support a structure, slab or pavement
system.
Irerracon
REPORT TERMINOLOGY
(Based on ASTM D653)
Allowable Soil
The recommended maximum contact stress developed at the interface of tl�je
Bearing Capacity
foundation element and the supporting material.
Alluvium
Soil, the constituents of which have been transported in suspension by flowing
water and subsequently deposited by sedimentation.
Aggregate Base
A laver of specified material placed on a subgrade or subbase usually beneath
Course
slabs or pavements.
Backfill
A specified material placed and compacted in a confined area.
Bedrock
A natural aggregate of mineral grains connected by strong and permanent
cohesive forces. Usually requires drilling, wedging, blasting or other methods of
extraordinary force for excavation.
Bench
A horizontal surface in a sloped deposit.
Caisson (Drilled pier
A concrete foundation element cast in a circular excavation which may have an
Sometimes referred to as a cast -in -place pier or drilled shaft.
or Shaft)
enlarged base.
Coefficient of
A constant proportionality factor relating normal stress and the corresponding
Friction
shear stress at which sliding starts between the two surfaces.
Colluvium
Soil, the constituents of which have been deposited chiefly by gravity such as
at the foot of a slope or cliff.
Compaction
The densification of a soil by means of mechanical manipulation.
Concrete Slab -on-
A concrete surface layer cast directly upon a base, subbase or subgrade, and
Grade
typically used as a floor system.
Differential
Unequal settlement or heave between, or within foundation elements of a
Movement
structure.
Earth Pressure
The pressure or force exerted by soil on any boundary such as a foundation
wall.
ESAL
Equivalent Single Axle Load, a criteria used to convert traffic to a uniform
standard, (18,000 pound axle loads).
Engineered Fill
Specified material placed and compacted to specified density and/or moisture
conditions under observations of a representative of a geotechnical engineer.
Equivalent Fluid
A hypothetical fluid having a unit weight such that it will produce a pressure
a lateral support presumed to be equivalent to that produced by the,
against
actual soil. This simplified approach is valid only when deformation conditions
are such that the pressure increases linearly with depth and the wall friction is
Existing Fill (or
neglected.
Materials deposited through the action of man prior to exploration of the site.
man-made fill)
Existing Grade
The ground surface at the time of field exploration.
Irerracon
LABORATORY TESTS
SIGNIFICANCE AND PURPOSE
TEST I SIGNIFICANCE - I PURPOSE
;alifomia Used to evaluate the potential strength of subgrade soil,
Bearing subbase, and base course material, including recycled
Ratio I materials for use in road and airfield pavements.
G�nsolidation Used to develop an estimate of both the rate and amount of
both differential and total settlement of a structure.
Direct Used to determine the consolidated drained shear strength o
Shear soil or rock.
Dry
5rpansion
3radation
Liquid &
astic Limit,
Plasticity
Index
ermeability
pH
Resistivity
R-Value
Soluble
Used to determine the in -place density of natural, inorganic,
fine-grained soils.
Used to measure the expansive potential of fine-grained soil
and to provide a basis for swell potential classification.
Used for the quantitative determination of the distribution of
particle sizes in soil.
Used as an integral part of engineering classification systems
to characterize the fine-grained fraction of soils, and to
specify the fine-grained fraction of construction materials.
Used to determine the capacity of soil or rock to conduct a
liquid or gas.
Used to determine the degree of acidity or alkalinity of a soil.
Used to indicate the relative ability of a soil medium to carry
electrical currents.
Used to evaluate the potential strength of subgrade soil,
subbase, and base course material, including recycled
materials for use in road and airfield pavements.
Used to determine the quantitative amount of soluble
sulfates within a soil mass.
Unconfined To obtain the approximate compressive strength of soils that
^ompression possess sufficient cohesion to permit testing in the
unconfined state.
Water Used to determine the quantitative amount of water in a soil
Content mass
Pavement
Thickness
Foundation
Bearing Capacity,
Foundation Design &
Index Property
Soil Behavior
Foundation & Slab
Soil
Classification
Soil
Classification
Groundwater
Flow Analysis
Corrosion
Potential
Contusion
Potential
Pavement
Thickness
Corrosion
Potential
Bearing Capacity
Analysis
for
Foundations
Index Property
Soil Behavior
lferracon
DRILLING AND EXPLORATION
DRILLING & SAMPLING SYMBOLS:
R : Rina Barrell - 2.42" I.D., 3" O.D., unless othamvise need
SS : Split Spoon - 1 " I.D., 2" O.D., unless otha^.vise noted PS : Piston Sample
ST : Thin -Walled Tube - 2" O.D., unless otherv:ise noted WS : Wash Sample
PA : Power Auger FT : Fish Tail Bit
HA : Hand Auger RB :Rock Bit
DB : Diamond Bit = ^", N, B BS : Bulk Sample
AS : Auger Sample PM : Pressure Meter
HS : Hollow Stem Auger DC : Dutch Cone
WB : Wash Bore
Penetration Test: Blows per foot of a 140 pond hammer falling 30 inches on a 2-inch O.D. split spoon, except where
noted.
WATER LEVEL MEASUREMENT SYMBOLS:
WL : Water Level WS :While Sampling
WC] : Wet Cave in WD :While Drilling
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 soils,
the indicated levels may reflect the location of groundwater. In low permeability soils, the accurate determination of
groundwater levels is not possible with only short term observations.
DESCRIPTIVE SOIL CLASSIFICATION:
Soil Classification is based on the Unified Soil Classification system and the ASTM Designations D-2487 and D-2488.
Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; they are described as: boulders,
cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are
described as: clays, if they are plastic, and silts if they are slightly plastic or non -plastic. Major constituents may be
added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In
addition to gradation, coarse grained soils are defined on the basis of their relative in -place density and fine grained soils
on the basis of their consistency. Example: Lean clay with sand, trace gravel, stiff (CL); silty sand, trace gravel, medium
dense ISM).
CONSISTENCY OF FINE-GRAINED SOILS:
Unconfined Compressive
Strength, O.u, psf
Consistency
< 500
Very Soft
500 - 1,000
Soft
1,001 - 2,000
Medium
2,001 - 4,000
Stiff
4,001 - 8,000
Very Stiff
8,001-16,000
Very Hard
RELATIVE PROPORTIONS OF
SAND AND GRAVEL
Descriptive Term(s)
(of Components Also Percent of
Present in Sample) Dry Weight
Trace < 15
With 15 - 29
Modifier > 30
RELATIVE PROPORTIONS OF FINES
Descriptive Term(s)
(of Components Also
Percent of
Present in Sample)
Dry Weight
Trace
< 5
With
5 - 12
Modifier
> 12
RELATIVE DENSITY OF
COARSE -GRAINED SOILS:
N-Blows/ft. Relative Density
0-3 Very Loose
4-g Loose
10-29 Medium Dense
30-49 Dense
50-80 Very Dense
80+ Extremely Dense
GRAIN SIZE TERMINOLOGY
Major Component
of Sample
Size Range
Boulders
Over 12 in. (300mm)
Cobbles
12 in. to 3 in.
(300mm to 75mm)
Gravel
3 in. to #4 sieve
(75mm to 4.75mm)
Sand
#4 to #200 sieve
(4.75mmto 0.075mm)
Silt or Clay
Passing #200 Sieve
(0.075mm)
Irerr con
No Text
1 4 � 141
V
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0.50
0.48
0.46
0.44
0.42
0.40
0.38
0.36
0.34
0.32
0.30 1 10
0.1
APPLIED PRESSURE, TSF
Boring and depth (ft.) Classification DD MC%
101 1 3.0 SANDY LEAN CLAY CL 116 10
PROJECT }3'"r
•Feld Park Pool of dreams _ Seneca JOB NO. ZUUUZA04
c.___. r_:..,. DATE 6/12/01_
CONSOLIDATION TEST
TERRACON
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APPLIED PRESSURE, TSF
Boring and depth (ft.) Classification DD I MC
7-
101 1 3.0 SANDY LEAN CLAY CL 116.1 10
PROJECT Westfield Perk Pool of dreams . SPnera JOB NO. 2000N54
Street/Westfield Drive DATE 6/12/01
CONSOLIDATION TEST
TERRACON
APPLIED PRESSURE, TSF
Boring and depth (ft.) Classification DD I MC
7-
101 1 3.0 SANDY LEAN CLAY CL 116.1 10
PROJECT Westfield Perk Pool of dreams . SPnera JOB NO. 2000N54
Street/Westfield Drive DATE 6/12/01
CONSOLIDATION TEST
TERRACON
,
LOG OF TEST BORING NO. 2
Page 1 of 1
CLIENT
ARCHITECT / ENGINEER
Wickham Gustafson Architects
SITE Seneca Street/Westfield Drive
PROJECT
Fort Collins, Colorado
Westfield Park Pool of Dreams
SAMPLES
TESTS
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CLAY
SANDY LEAN
Brown, calcareous, moist, stiff
760
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120
4.5 96.7
SO4=
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SM
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SS
12"
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STT.TY CLAYEY SAND
5
Red, brown, moist, medium dense
6.5 to loose 94.7
SI TY AND Red, brown, moist,
medium dense to loose
1
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BOTTOM OF BORING
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THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS
Irerracon
BORING STARTED 5-22-01
wL
U DRY WD
BORING COMPLETED 5.22-01
-
WL
RIG C1b1E-55
FOREb1AN DAR
WL
Initial Water Level Reading
APPROVED 1
JOB s 20005254
LOG OF TEST BORING NO. 1 Page 1 of 1
CLIENT ARCHITECT / ENGINEER
Wickham Gustafson Architects
SITE Seneca Street/Westfield Drive PROJECT
— - - kP 1 fD
DESCRIPTION
Approx. Surface Elev.: 100.8 ft.
0.5 6" TOPSOIL
CANNY LEAN C' .AY
Brown, moist, calcareous, stiff
CT7 TV AYEY SAND
6.5 Red, brown, calcareous, moist,
medium dense
CTT.TY SAND
Red, brown, moist, medium dense
15.0,
J
Westfield
SAMPLES
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TESTS
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CL 1 SS 12" 13 14
2 ST 12" 10
SM 3 SS 12" 11 9
95.8 5
94.3
10
15
4 1 SS 1 12" 1 15
5 1 SS 1 12" 1 10 1 3
25/10/52 1
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS BORING STARTED $-22-01
EwL a DRY WD BORING COMPLETED $-22-01
WL 1 Derr acon RIG C -55 FOREMAN DAR
wL Initial Water Level ReadingAPPROVED DAR IOB # 20005254
WE571ELD DRIVE (PROPOSED)
F__---
t LAWN
I
I POOL
DECK
I POO
I `
NO.I
I
l
POOL
t DECK
LAWN
l
I LAWN
LEGEND
* TEST BORINGS
DIAGRAM IS FOR GENERAL LOCATION ONLY,
AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES.
r POOL HOUSE
FUTURE
ADDITION
L- — — — — —
NO.2
POOL
HOUSE
LAWN
PASKING
LOT
I
I
I
1
I
I
6
FIGURE I: 51TE PLAN
POOL OF DREAMS
LLESTFIELD PARK
FORT COLLINS. COLORADO
Project hhgn DAR
r
Irerracon
Project "o0005254
Defilgrod N, DAR
scale' 1' . 40'
ctia`yed �' DAR
Date.
5RI/01
301 N. Nolues 6vest
Approved Bq' DAR
D.Aon Bye SDC
Fort C lillm, Colorado 80521
Flle Nam: 5254FIGI
Flgvc No. I
Geotechnical Engineering Exploration
Westfield Park Pool of Dreams
Terracon Project No. 20005254
Fill, backfill, and surface drainage in the pool area should be placed in accordance
with`the recommendations in the Earthwork section of this report. Grading should be
provided for diversion of deck surface runoff away from the pool area. In no case
should water be allowed to pond around the slab perimeter.
GENERAL COMMENTS
Terracon should be retained to review the final design plans and specifications so comments
can be made regarding interpretation and implementation of our geotechnical
recommendations in the design and specifications. Terracon also should be retained to
provide testing and observation during excavation, grading, foundation and construction
phases of the project.
The analysis and recommendations presented in this report are based upon the data
obtained from the borings performed at the indicated locations and from other information
discussed in this report. This report does not reflect variations, which may occur between
borings or across the site. The nature and extent of such variations may not become
evident until construction. If variations appear, it will be necessary to reevaluate the
recommendations of this report.
The scope of services for this project does not include either specifically or by implication
any environmental assessment of the site or identification of contaminated or hazardous
materials or conditions. If the owner is concerned about the potential for such
contamination, other studies should be undertaken.
This report has been prepared for the exclusive use of our client for specific application to
the project discussed and has been prepared in accordance with generally accepted
geotechnical engineering practices. No warranties, either express or implied, are intended
or made. In the event that changes in the nature, 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 Terracon reviews the changes, and either verifies
or modifies the conclusions of this report in writing.
12
Geotechnical Engineering Exploration
Westfield Park Pool of Dreams
Terracon Project No. 20005254
soft soils, groundwater and/or severe pumping, it may be necessary to excavate the
deep portion of the pool with a backhoe or power shovel. `
Consideration should be given to the use of reinforced gunnite concrete for pool
construction. This material can normally withstand relatively large soil movements
without cracking. Care should be taken during construction to waterproof the pool so
that leakage will not occur. As a precaution, pressure relieve values should be
provided in the base of the pool to prevent flotation should groundwater rise when
the pool is empty.
A drainage system should be provided around and beneath the pool. The drain
should consist of a minimum six-inch layer of clean gravel (minimum 3/4-inch size)
beneath, and along the sides of the pool. The top of the drain layer should be sealed
with 18 inches of relatively impermeable soil at the surface. The gravel layer beneath
the pool should be sloped so that it will drain into tiles or perforated drain pipe. The
layout of the perforated pipe should include at least one pipe running down the
center of the pool lengthwise. Cross -connecting pipes, spanning with the pool,
should be placed at six-foot centers. The cross -connecting pipes should be joined to
the center pipe with solid "tees" or "cross" connections. The center pipes should be
sloped to a suitable positive gravity outlet or sloped to a sump located in the
equipment room, permitting pump discharge.
The bottom of the excavation beneath the gravel layer and the pipe should be lined
with an impervious membrane (polyethylene film or equal) in order to reduce potential
moisture fluctuations in the subgrade soils. Pressure relieve values should be
provided in the base of the pool to prevent excessive uplift pressures from
developing in the event of failure of the drain system.
The soils that will support pool deck slabs around the pool could expand with
increasing moisture content. To reduce possible damage that could be caused by
expansive soils, we recommend:
• deck slabs be supported on moisture -controlled fill material with no, or very
low expansion potential
• strict moisture -density control during placement of subgrade fills
• placement of effective control joints on relatively close centers and isolation
joints between slabs and other structural elements
• provision for adequate drainage in areas adjoining the slabs
• use of designs which allow vertical movement between the deck slabs and
adjoining structural elements
11
r
Geotechnical Engineering Exploration
Westfield Park Pool of Dreams
Terracon Project No. 20005254
• Underground Utility Systems
All piping should be adequately bedded for proper load distribution. It is suggested
that clean, graded gravel compacted to 75 percent of Relative Density ASTM D4253
be used as bedding. Where utilities are excavated below groundwater, temporary
dewatering will be required during excavation, pipe placement and backfilling
operations for proper construction. Utility trenches should be excavated on safe and
stable slopes in accordance with OSHA regulations as discussed above. Backfill
should consist of the on -site soils or imported material approved by the geotechnical
engineer. The pipe backfill should be compacted to a minimum of 95 percent of
Standard Proctor Density ASTM D698.
Corrosion Protection
Results of soluble sulfate testing indicate that ASTM Type I Portland cement is
suitable for all concrete on and below grade. However, if there is no, or minimal cost
differential, use of ASTM Type II Portland cement is recommended for additional
sulfate resistance of construction concrete. Foundation concrete should be designed
in accordance with the provisions of the ACI Design Manual, Section 318, Chapter 4.
Surface Drainage
Positive drainage should be provided during construction and maintained throughout
the life of the proposed project. In areas where sidewalks or paving do not
immediately adjoin the structure, we recommend that protective slopes be provided
with a minimum grade of approximately 5 percent for at least 10 feet from perimeter
walls. Backfill against footings, exterior walls, and in utility and sprinkler line trenches
should be well compacted and free of all construction debris to reduce the possibility
of moisture infiltration.
Downspouts, roof drains or scuppers should discharge into splash blocks or
extensions when the ground surface beneath such features is not protected by
exterior slabs or paving. Sprinkler systems should not be installed within 5 feet of
foundation walls. Landscaped irrigation adjacent to the foundation system should be
minimized or eliminated.
Swimming Pool Design and Construction
It is our understanding that the pool will be multi -family public capacity -sized ranging
in depth from 3 to 5 feet in the shallow end and approximately 10 to 14 feet in the
deep end. It is anticipated that excavations for the proposed construction can be
accomplished with conventional rubber -tired equipment. If excavations encounter
10
Geotechnical Engineering Exploration
Westfield Park Pool of Dreams
Terracon Project No. 20006254
On -site clay for backfill or grading purposes should be Compacted within a moisture
content range of 2 percent below, to 2 percent above optimum. Imported or on -site
granular soils should be compacted within a moisture range of 3 percent below to 3
percent above optimum unless modified by the project geotechnical engineer.
Excavation and Trench Construction
Excavations into the on -site soils may encounter caving soils and groundwater,
depending upon the final depth of excavation. The individual contractor(s) should be
made responsible for designing and constructing stable, temporary excavations as
required to maintain stability of both the excavation sides and bottom. All
excavations should be sloped or shored in the interest of safety following local, and
federal regulations, including current OSHA excavation and trench safety standards.
The soils to be penetrated by the proposed excavations may vary significantly across
the site. The preliminary soil classifications are based solely on the materials
encountered in widely spaced exploratory test borings. The contractor should verify
that similar conditions exist throughout the proposed area of excavation. If different
subsurface conditions are encountered at the time of construction, the actual
conditions should be evaluated to determine any excavation modifications necessary
to maintain safe conditions.
As a safety measure, it is recommended that all vehicles and soil piles be kept to a
minimum lateral distance from the crest of the slope equal to no less than the slope
height. The exposed slope face should be protected against the elements.
Additional Design and Construction Considerations
Exterior Slab Design and Construction
Exterior slabs -on -grade, exterior architectural features and utilities founded on or in
backfill may experience some movement due to the volume change of the backfill.
Potential movement could be reduced by:
• minimizing moisture increases in the backfill
• controlling moisture -density during placement of backfill
• using designs which allow vertical movement between the exterior features
and adjoining structural elements
placing effective control joints on relatively close centers
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Geotechnical Engineering Exploration
Westfield Park Pool of Dreams
Terracon Project No. 20005254
Subgrade Preparation
Subgrade soils beneath interior and exterior slabs, and beneath pavements should
be scarified, moisture conditioned and compacted to a minimum depth of 8 inches.
The moisture content and compaction of subgrade soils should be maintained until
slab or pavement construction.
Fill Materials and Placement
Clean on -site soils or approved imported materials may be used as fill material and
are suitable for use as compacted fill beneath interior or exterior floor slabs.
Imported soils (if required) should conform to the following:
Percent finer by weight
Gradation (ASTM C136)
6".........................................................................................................100
3"....................................................................................................70-100
No. 4 Sieve.....................................................................................50-100
No. 200 Sieve..............................................................................50 (max)
LiquidLimit.......................................................................30 (max)
Plasticity Index.................................................................15 (max)
Engineered fill should be placed and compacted in horizontal lifts, using equipment
and procedures that will produce recommended moisture contents and densities
throughout the lift. Recommended compaction criteria for engineered fill materials are
as follows:
Material
Minimum Percent
(ASTM D698)
Scarified subgrade soils.........................................................................95
On -site and imported fill soils:
Beneath foundations..................................................................95
Beneathslabs............................................................................95
Beneathpavements...................................................................95
Aggregate base (beneath slabs)............................................................95
Miscellaneous backfill (non-structural areas).........................................90
8
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Geotechnical Engineering Exploration
Westfield Park Pool of Dreams
Terracon Project No. 20006254
If moisture sensitive floor coverings are used on interior slabs, consideration
should be given to the use of barriers to minimize potential vapor rise through
the slab.
Floor slabs should not be constructed on frozen subgrade.
• Other design and construction considerations, as outlined in the ACI Design
Manual, Section 302AR are recommended.
Earthwork
General Considerations
The following presents recommendations for site preparation, excavation, subgrade
preparation and placement of engineered fills on the project.
All earthwork on the project should be observed and evaluated by Terracon. The
evaluation of earthwork should include observation and testing of engineered fill,
subgrade preparation, foundation bearing soils, and other geotechnical conditions
exposed during the construction of the project.
Site Preparation
Strip and remove existing fill, debris, and other deleterious materials from proposed
building and pavement areas. All exposed surfaces should be free of mounds and
depressions that could prevent uniform compaction.
The site should be initially graded to create a relatively level surface to receive fill,
and to provide for a relatively uniform thickness of fill beneath proposed building
structures.
All exposed areas which will receive fill, once properly cleared and benched where
necessary, should be scarified to a minimum depth of eight inches, conditioned to
near optimum moisture content, and compacted.
It is anticipated that excavations for the proposed construction can be accomplished
with conventional earthmoving equipment.
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Geotechnical Engineering Exploration
Westfield Park Pool of Dreams
Terracon Project No. 20005264
At -Rest: Submerged Soils/Hydrostatic Loading
Cohesive soil backfill (on -site clays).......................................90 psf/ft
Cohesionless soil backfill (on -site sands)...............................85 psf/ft
Fill against grade beams and retaining walls should be compacted to densities specified in
Earthwork. Compaction of each lift adjacent to walls should be accomplished with hand -
operated tampers or other lightweight compactors. Overcompaction may cause excessive
lateral earth pressures, which could result in wall movement.
Seismic Considerations
The project site is located in Seismic Risk Zone 1 of the Seismic Zone Map of the United
States as indicated by the 1997 Uniform Building Code. Based upon., the nature of the
subsurface materials, a soil profile type S, should be used for the design of structures for the
proposed project (1997 Uniform Building Code, Table No. 16-J).
Floor Slab Design and Construction
Some differential movement of a slab -on -grade floor system is possible should the subgrade
soils become elevated in moisture content. To reduce potential slab movements, the
subgrade soils should be prepared as outlined in the earthwork section of this report.
For structural design of concrete slabs -on -grade, a modulus of subgrade reaction of 100
pounds per cubic inch (pci) may be used for floors supported on existing on -site soils. A
modulus of 200 pci may be used for floors supported on at least 2 feet granular structural fill
or on -site granular soils meeting the specifications outlined below.
Additional floor slab design and construction recommendations are as follows:
Positive separations and/or isolation joints should be provided between slabs
and all foundations, columns or utility lines to allow independent movement.
Control joints should be provided in slabs to control the location and extent of
cracking.
Interior trench backfill placed beneath slabs should be compacted in
accordance with recommended specifications outlined below.
In areas subjected to normal loading, a minimum 6-inch layer of sand, clean -
graded gravel or aggregate base course should be placed beneath interior
slabs.
6
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Geotechnical Engineering Exploration
Westfield Park Pool of Dreams
Terracon Project No. 20005254
Foundation excavations should be observed by the geotechnical engineer. If the soil
conditions encountered differ sigrfificantly from those presented in this report, supplemental
recommendations will be required.
Lateral Earth Pressures
For soils above any free water surface, recommended equivalent fluid pressures for
unrestrained foundation elements are:
• Active:
Cohesive soil backfill (on -site clay)........................................50 psf/ft
Cohesionless soils (on -site sand or imported material) .......... 35 psf/ft
• Passive:
Cohesive soil backfill (on -site clay)......................................250 psf/ft
Cohesionless soils (on -site sand or imported material) ........ 350 psf/ft
Coefficient of Base Friction..........................................................0.35
• Adhesion at base of footing .................................................... 500 psf
Where the design includes restrained elements, the following equivalent fluid pressures are
recommended:
• At rest:
Cohesive soil backfill (on -site clay)........................................65 psf/ft
Cohesionless soils (on -site sand or imported material) .......... 50 psf/ft
The above -referenced lateral earth pressures do not include any factor of safety and are not
applicable for submerged soils/hydrostatic loading. The following values are for lateral earth
pressures for the potential submerged soils/hydrostatic loading conditions for various
structures, which may be constructed beneath the groundwater level.
Active: Submerged Soils/Hydrostatic Loading
Cohesive soil backfill (on -site clays).......................................85 psf/ft
Cohesionless soil backfill (on -site sands)...............................80 psf/ft
• Passive: Submerged Soils/Hydrostatic Loading
Cohesive soil backfill (on -site clays).....................................125 psf/ft
Cohesionless soil backfill (on -site sands).............................175 psf/ft
5
Geotechnical Engineering Exploration
Westfield Park Pool of Dreams
Terracon Project No. 20005254
not be indicative of other times, or at other locations. Groundwater levels can be expected
to fluctuate with varying seasonal and weather conditions. `
ENGINEERING ANALYSES AND RECOMMENDATIONS
Geotechnical Considerations
The site appears suitable for the proposed construction based on a geotechnical
engineering viewpoint. The following foundation system was evaluated for use on the site:
spread footings bearing on undisturbed natural soils and/or structural fill
Slab -on -grade construction is considered acceptable for use, provided that design and
construction recommendations are followed.
Foundation Systems
Due to the presence of low swelling soils on the site, spread footing foundations bearing
upon undisturbed, native subsoils and/or engineered fill are recommended for support for
the proposed structure. The footings may be designed for a maximum bearing pressure of
1500 psf. In addition, the footings should be sized to maintain a minimum dead -load
pressure of 500 psf. The design bearing pressure applies to dead loads plus design live
load conditions.
Exterior footings should be placed a minimum of 30 inches below finished grade for frost
protection and to provide confinement for the bearing soils. Finished grade is the lowest
adjacent grade for perimeter footings.
Footings should be proportioned to reduce differential foundation movement. Proportioning
on the basis of equal total movement is recommended; however, proportioning to relative
constant dead -load pressure will also reduce differential movement between adjacent
footings. Total movement resulting from the assumed structural loads is estimated to be on
the order of 3/4 inch or less. Differential movement should be on the order of 1/2 to 3/4 of
the estimated total settlement. Additional foundation movements could occur if water from
any source infiltrates the foundation soils; therefore, proper drainage should be provided in
the final design and during construction.
Footing foundations and masonry walls should be reinforced as necessary to reduce the
potential for distress caused by differential foundation movement. The use of joints at
openings or other discontinuities in masonry walls is recommended.
4
Geotechnical Engineering Exploration
Westfield Park Pool of Dreams
Terracon Project No. 20005254
program was formulated to determine engineering properties of the subsurface materials.
Boring logs were prepared and are presented in Appendix A.
Laboratory tests were conducted on selected soil samples and are presented in Appendix B.
The test results were used for the geotechnical engineering analyses, and the development
of foundation and earthwork recommendations. All laboratory tests were performed in
general accordance with the applicable ASTM, local or other accepted standards.
Selected soil samples were tested for the following engineering properties:
• Water Content • Expansion
• Dry Density • Plasticity Index
• Consolidation • Water Soluble Sulfate Content
• Grain Size Distribution
SITE CONDITIONS
The site is west of Seneca Street and south of the proposed Westfield Drive. The area for
the proposed constructions is relatively flat, currently vegetated with grass and weeds and
exhibits slight surface drainage in the east to southeast direction.
SUBURFACE CONDITIONS
Soil Conditions
The subsurface soils at the site consisted of sandy lean clay to approximate depths of 4-1/2
to 5 feet. Underlying the sandy lean clay was silty clayey sand which extended to silty sand.
Silty sand was encountered at an approximate depth of 6-1/2 feet below existing site grades
and extended to depths explored, 15 feet.
Field and Laboratory Test Results
Field and laboratory test results indicate the native clay layer to be stiff in consistency,
exhibit low to moderate swell potential and moderate bearing capabilities. The granular
sand stratum is loose to medium dense in relative density, exhibits a low to non -swell
potential and low to moderate bearing characteristics.
Groundwater Conditions
Groundwater was not encountered to depths explored during initial site exploration. These
observations represent groundwater conditions at the time of the field exploration, and may
3
Geotechnical Engineering Exploration
Westfield Park Pool of Dreams
Terracon Project No. 20005264
grading plans were not provided prior to the subsurface exploration activities, however, it is
anticipated the finished floor elevations will be at or slightly above existing site grades. `
SITE EXPLORATION
The scope of the services performed for this project included a site reconnaissance by an
engineering geologist, a subsurface exploration program, laboratory testing and engineering
analyses.
Field Exploration
A total of 2 test borings were drilled on May 22, 2001 to an approximate depth of 15 feet
below existing site grades at the locations shown on the Site Plan, Figure 1. One test boring
was located and drilled within the proposed swimming pool area, and one test boring was
located and drilled between the proposed pool house and the proposed parking area. All
borings were advanced with a truck -mounted drilling rig, utilizing 4-inch diameter solid stem
augers.
The borings were located in the field the client. Ground surface elevations at each boring
location were obtained by measurements with an engineer's level from a temporary bench
mark. The accuracy of boring locations and elevations should only be assumed to the level
implied by the methods used.
Continuous lithologic logs of each boring were recorded by the engineering geologist during
the drilling operations. At selected intervals, samples of the subsurface materials were taken
by means of pushing thin -walled Shelby tubes, or by driving split -spoon samplers.
Penetration resistance measurements were obtained by driving the split -spoon into the
subsurface materials with a 140-pound hammer failing 30 inches. The penetration
resistance value is a useful index in estimating the consistency, relative density or hardness
of the materials encountered.
Groundwater conditions were evaluated in each boring at the time of site exploration
Laboratory Testing
All samples retrieved during the field exploration were returned to the laboratory for
observation by the project geotechnical engineer and were classified in accordance with the
Unified Soil Classification System described in Appendix C. At that time, the field
descriptions were confirmed or modified as necessary and an applicable laboratory -testing
E
GEOTECHNICAL ENGINEERING REPORT
WESTFIELD PARK POOL OF DREAMS
SOUTHWEST CORNER OF SENECA STREET AND
PROPOSED WESTFIELD DRIVE
FORT COLLINS, COLORADO
TERRACON PROJECT NO. 20005254
JUNE 21, 2001
INTRODUCTION
This report contains the results of our geotechnical engineering exploration for the proposed
multi -family public capacity -size swimming pool ranging in depth from 3 to 14 feet with a
diving area as well as an associated pump/maintenance house and parking areas to be
located at the southwest corner of Seneca Street and the proposed Westfield Drive. The
site is located in the Northeast 1/4 of Section 34, Township 7 North, Range 69 West of the
6th Principal Meridian, Larimer County, Colorado.
The purpose of these services is to provide information and geotechnical engineering
recommendations relative to:
• subsurface soil conditions
• groundwater conditions
• foundation design and construction
• lateral earth pressures
• floor slab design and construction
• swimming pool design and construction
• earthwork
• drainage
The recommendations contained in this report are based upon the results of field and
laboratory testing, engineering analyses, and experience with similar soil conditions,
structures and our understanding of the proposed project.
PROPOSED CONSTRUCTION
Based on information provided, we understand the proposed construction will consist of a
multi -family public capacity -size swimming pool ranging in depth from 3 to 14 feet with a
diving area as well as an associated pump/maintenance house and parking areas. Final
1
Geotechnical Engineering Exploration
Westfield Park Pool of Dreams
Terracon Project No. 20005254
APPENDIX A `
Site Plan and Boring Location Diagram
Logs of Borings
APPENDIX B
Laboratory Test Results
APPENDIX C
General Notes
iv
TABLE OF CONTENTS
Page No.
Letterof Transmittal........................................................................................................... i
INTRODUCTION.................................................................................................................1
PROPOSEDCONSTRUCTION.......................................................................:..................1
SITEEXPLORATION..........................................................................................................2
FieldExploration......................................................................................................2
LaboratoryTesting..................................................................................................2
SITECONDITIONS.............................................................................................................3
SoilConditions........................................................................................................ 3
Field and Laboratory Test Results........................................................................... 3
GroundwaterConditions.......................................................................................... 3
ENGINEERING ANALYSES AND RECOMMENDATIONS.................................................4
Geotechnical Considerations...................................................................................4
FoundationSystems................................................................................................4
LateralEarth Pressures...........................................................................................5
SeismicConsiderations......................................................................:....................6
Floor Slab Design and Construction........................................................................6
Earthwork................................................................................................................ 7
GeneralConsiderations............................................................................... 7
SitePreparation........................................................................................... 7
SubgradePreparation..................................................................................8
Fill Materials and Placement........................................................................8
Excavation and Trench Construction........................................................... 9
Additional Design and Construction Considerations................................................ 9
Exterior Slab Design and Construction........................................................ 9
Underground Utility Systems........................................................................10
CorrosionProtection....................................................................................10
SurfaceDrainage.........................................................................................10
Swimming Pool Design and Construction....................................................10
GENERALCOMMENTS.....................................................................................................12
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Geotechnical Engineering Exploration
Westfield Park Pool of Dreams
Terracon Project No. 20006254
We appreciate the opportunity to be of service to you on this phase of your project. If you
have any questions concerning this report, or if we may be of further service to you, please
do not hesitate to contact us.
Sincerely,
TERRACON
Daniel R. Lambert, E.I.T.
Geotechnical Engineer.
Copies to: (3) Addressee
(1) Mr. Bob Gustafson - Wickham Gustafson Architects
Manager
r
June 21, 2001
Pool of Dreams Limited
4455 Seneca Drive
Fort Collins, CO 80526
Attn: Ms. Judy Shaw
Irerracon
:01 N. Howes • P.O Sox 503
FCrt Dooms. roic.,x1r, 30521 .;)507.1
3; O143»0359 Ft,R i9i01 .rY..t-r,c;.:
Re: Geotechnical Engineering Report
Westfield Park Pool of Dreams
Southwest Corner of Seneca Street and Proposed Westfield Drive
Fort Collins, Colorado
Terracon Project No. 20005254
Terracon has completed a geotechnical engineering exploration for the proposed multi-
family public capacity -size swimming pool ranging in depth from 3 to 14 feet with a diving
area as well as an associated pump/maintenance house and parking areas. This study was
performed in general accordance with our Proposal No. D2000067 dated December 7, 2000.
The results of our engineering study, including the boring location diagram, laboratory test
results, test boring records, and the geotechnical recommendations needed to aid in the
design and construction of the proposed pool, foundations, and other earth connected
phases of this project are attached.
The subsurface soils at the site consisted of sandy lean clay to approximate depths of 4-1/2
to 5 feet. Underlying the sandy lean clay was silty clayey sand which extended to silty sand.
Silty sand was encountered at an approximate depth of 6-1/2 feet below existing site grades
and extended to depths explored, 15 feet. Groundwater was not encountered in either
boring during initial drilling operations. The results of field exploration and laboratory testing
completed for this study indicate that the soils at the site have low expansive potential and
low to moderate load bearing characteristics.
Based on the subsurface conditions encountered and the type of construction proposed, it is
recommended the mechanical, locker room and maintenance facility structure be supported
by conventional -type spread footings. Slab -on -grade construction is considered feasible at
the site provided the recommendations set forth in the report are followed.
Arvrma ■ Arkansas ■ Colorado ■ Ooonga ■ Idaho ■ Ilhr,;u ■ Iowa ■ Kansas ■ Kontucky ■ %Nlnesota ■ Missouri ■ Montana
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Ouality Engineering Since 1965
GEOTECHNICAL ENGINEERING REPORT
WESTFIELD PARK POOL OF DREAMS
SOUTHWEST CORNER OF SENECA STREET AND
PROPOSED WESTFIELD DRIVE
FORT COLLINS, COLORADO
TERRACON PROJECT NO. 20005254
JUNE 21, 2001
Prepared for:
POOL OF DREAMS LIMITED
4455 SENECA DRIVE
FORT COLLINS, COLORADO 80526
ATTN: MS. JUDY SHAW
Prepared by:
Terracon
301 North Howes Street
Fort Collins, Colorado 80521
Irerraco