HomeMy WebLinkAboutCC - Drainage CalcsPROJECT NO. 10-18-016
DRAINAGE CALCULATIONS
FOR
Little Creek No. 2
City of Meridian
Ada County, Idaho
March 26, 2018
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J -U -B ENGINEERS, INC.
250 S. Beechwood Drive, #201
Boise, Idaho 83709
208-376-7330
PROJECT NO. 10-18-016
Little Creek No. 2
SITE OVERVIEW
Little Creek No. 2 Subdivision is located at the southwest corner of Wilson Lane and N. Locust Grove
Road in Meridian, Idaho. The proposed development consists of 23 townhome buildings and a
clubhouse on approximately 7.7 acres.
EXISTING DRAINAGE
The existing project site presently consists of a vacant agricultural field. The site is bounded by Little
Creeek Subdivision Phase 1 single family residential property to the east, commercial development
to the north and agricultural land to the south. The ground slopes gently from southwest to
northeast at grades generally less than 2%.
DRAINAGE DESIGN CONCEPT
The proposed stormwater improvements include the installation of roadways, pipe networks,
stormwater treatment systems, and storage facilities. The surface flow will be directed to and
contained within the road sections to designed low points where inlets will capture the stormwater
and convey it through a pipe network to a discharge location. A treatment system will be installed
for each pipe network prior to allowing the stormwater to be be discharged to the storage facility.
The site was divided into catchment areas based on the inlet locations. Each catchement area was
analyzed for the 25 -year flow rate for conveyance, the water quality event for treatment and the
100 -year runoff for storage.
CALCULATION METHODS
Calcualtions were prepared in accordance with the current edition of the Ada County Highway
District Stormwater Policy Manual using the rational method (Q=CIA). The catchment areas are
shown on the Drainage Catchment Plan. The average rainfall intensity is estimated from the
"Rainfall Intensity -Duration -Frequency Relationship" figure for each storm event noted. The time of
concentration is determined using the TR -55 method and combines the longest overland grass flow
time to gutter flow time. Calculations and spreadsheets are included with this report for all
catchment areas.
SOIL CONDITIONS
Based upon the preliminary soils and subsurface investigation provided in the soils report for this
subdivision, the existing soils will accept the runoff. However, in the event that during construction
the contractor encounters either groundwater or rock, a revised design will be done based upon
field conditions.
\\boisefiles\public\Projects\JUB\10-18-016 Little Creek Phase 2\Drainage\10_18_016_DrainageCalcs.xlsx
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Basin A
Contributing Catchment Areas: A
Required Water Quality Volume: 1,244 ft3
Required Water Quality Flow Rate: 0.61 cfs
Required Storage Volume: 3,053 ft3
Seepage Bed
Th
Sat
Volume Calculations
Storage Duration
Box Volume =
Depth =
5.5 ft
Interior Box Width =
48 in
Length =
93 ft
Infiltration Area =
1,395 ftz
Width =
15 ft
Infiltration Rate =
8 in./hr
Void Ratio =
40 %
Trench Infiltration =
930 ft3 /hr
Trench Volume =
3,069 ft3
Time for 90% Percolation =
1.20 hr
Id and Grease Trap Calculations
Box Volume =
1000 gallon
Interior Box Width =
48 in
QWQ = 0.61 ft3/sec
Baffle Separation =
20 in
Throat Velocity = 0.09 ft/sec
Number of Boxes =
1
Throat Area =
6.67 ftZ
Throat Velocity must be < 0.50 ft/sec
PROJECT NO. 10-18-016
Lithe Creek No. 2
\\boisefiles\public\Projects\JUB\10-18-016 Little Creek Phase 2\Drainage\10_18_016_DrainageCalcs.)dsx Page 4 of 9
Basin B
Contributing Catchment Areas:
Required Water Quality Volume:
Required Water Quality Flow Rate:
Required Storage Volume:
Seepage Bed
Th
(Volume
#4
1,070 ft'
0.52 cfs
2,627 ft'
Volume Calculations
Storage Duration
Box Volume =
Depth =
6 ft
Interior Box Width =
48 in
Length =
92 ft
Infiltration Area =
1,104 ft
Width =
12 It
Infiltration Rate =
8 in./hr
Void Ratio =
40 %
Trench Infiltration =
736 ft3/hr
Trench Volume =
2,650 ft3
Time for 90% Percolation =
1.31 hr
Sar
I and Grease Trap Calculations
Box Volume =
1000 gallon
Interior Box Width =
48 in
QWQ = 0.52 f3/sec
Baffle Separation =
20 in
Throat Velocity = 0.08 ft/sec
Number of Boxes =
1
Throat Area =
6.67 fe
Throat Velocity must be < 0.50 ft/se,
PROJECT NO. 10-18-016
Little Creek No. 2
\\boisefiles\public\Projects\JUB\10-18-016 Little Creek Phase 2\Drainage\10_18_ 016_DrainageCalcs.xlsx Page 5 of 9
Basin C
Contributing Catchment Areas: C
Required Water Quality Volume: 682 ft'
Required Water Quality Flow Rate: 0.33 cfs
Required Storage Volume: 1,674 ft'
Se(
Th(
s12 A
,F -U
Volume Calculations
Storage Duration
Box Volume =
Depth =
6 ft
Interior Box Width =
48 in
Length =
60 ft
Infiltration Area =
720 ft2
Width =
12 ft
Infiltration Rate =
8 in./hr
Void Ratio =
40 %
Trench Infiltration =
480 ft3/hr
Trench Volume =
1,728 ft3
Time for 90% Percolation =
1.28 hr
Sar
A and Grease Trap Calculations
Box Volume =
1000 gallon
Interior Box Width =
48 in
QWQ = 0.33 ft3/sec
Baffle Separation =
20 in
Throat Velocity = 0.05 ft/sec
Number of Boxes =
1
Throat Area =
6.67 ft2
Throat Velocity must be < 0.50 ft/sec
PROJECT NO. 10.18-016
Little Creek No. 2
\\boiseriles\public\Projects\fUB\10-18-016 Little Creek Phase 2\Drainage\10_18_016_1DrainageCalcs.x1sx Page 6 of 9
Basin D
Contributing Catchment Areas:
Required Water Quality Volume:
Required Water Quality Flow Rate:
Required Storage Volume:
Seepage Bed
Th
#h
D
227 ft'0.11 cfs
558 ft'
Volume Calculations
Storage Duration
Box Volume =
Depth =
6 ft
Interior Box Width =
48 in
Length =
30 ft
Infiltration Area =
240 ftz
Width =
8 ft
Infiltration Rate =
8 in./hr
Void Ratio =
40 %
Trench Infiltration =
160 ft3/hr
Trench Volume =
576 ft3
Time for 90% Percolation =
1.28 hr
Sat
PROJECT NO. 10-18-016
Little Creek No. 2
id and Grease Trap Calculations
Box Volume =
1000 gallon
Interior Box Width =
48 in
QWa = 0.11 ft3/sec
Baffle Separation =
20 in
Throat Velocity = 0.02 fUsec
Number of Boxes=
1
Throat Area =
6.67 ftz
Throat Velocity must be < 0.50 ft/sec
\\boisefiles\public\Projects\JUB\10-18-016 Little Creek Phase 2\Drainage\10_18_016_DrainageCalcs.xlsx Page 7 of 9
Basin E
Contributing Catchment Areas: E
Required Water Quality Volume: 334 ft'
Required Water Quality Flow Rate: 0.16 cfs
Required Storage Volume: 821 ft'
Seepage Bed
Th
#fa
Volume Calculations
Storage Duration
Box Volume =
Depth =
6 ft
Interior Box Width =
48 in
Length =
30 ft
Infiltration Area =
360 ft
Width =
12 ft
Infiltration Rate =
8 in./hr
Void Ratio =
40 %
Trench Infiltration =
240 ft3/hr
Trench Volume =
864 ft3
Time for 90% Percolation =
1.25 hr
Sal
PROJECT NO. 10-18-016
Little Creek No. 2
id and Grease Trap Calculations
Box Volume =
1000 gallon
Interior Box Width =
48 in
Qwo = 0.16 ft/sec
Baffle Separation =
Baffle
20 in
Throat Velocity = 0.02 ft/sec
Number of Boxes =
1
Throat Area =
6.67 ft2
Throat Velocity must be < 0.50 ft/sec
\\boisefiles\public\Projects\JUB\10-18-016 Little Creek Phase 2\Drainage\10_18_016_DrainageCalcs.xlsx Page 8 of 9
Boise Area Intensity -Duration -Frequency
NOAA Atlas 2
Intensity (inches per hour)
Design Storm
2
5
10
25
50
100
Tc
------- 2 year
3
0.17
10 min
0.69
1.15
1.45
1.85
2.20
2.58
0.25
15 min
0.59
0.97
1.22
1.56
1.86
2.18
0.33
20 min
0.49
0.81
1.01
1.30
1.54
1.81
0.42
25 min
0.43
0.71
0.89
1.14
1.35
1.58
0.50
30 min
0.41
0.67
0.85
1.08
1.29
1.51
0.58
35 min
0.34
0.56
0.70
0.90
1.07
1.25
0.67
40 min
0.31
0.51
0.64
0.82
0.98
1.15
0.75
45 min
0.29
0.48
0.60
0.77
0.91
1.07
0.83
50 min
0.27
0.45
0.56
0.72
0.85
1.00
0.92
55 min
0.26
0.43
0.54
0.69
0.82
0.96
1.00
1 hour
0.26
0.43
0.54
0.69
0.82
0.96
2.00
2 hours
0.16
0.25
0.31
0.39
0.46
0.54
3.00
3 hours
0.13
0.19
0.23
0.29
0.34
0.40
6.00
6 hours
0.09
0.12
0.14
0.18
0.21
0.25
12.00
12 hours
0.06
0.08
0.10
0.12
0.14
0.16
24.00
24 hours
0.04
0.06
0.06
0.08
0.09
0.10
NOAA Atlas 2
Intensity Duration Frequency
3.5
------- 2 year
3
-- - -
i
-x- 5 year
.-.
2.5
i
-x- 10 year
s
j-.........-
2
-- - --- -
\
-A 25 year
0 50
J
year
>4
�
j � �
-0- 100 year
I '
0.5
-
- --
-- -------------- ---------- ---
0
10 min 15 min
30 min 1 hour 2 hours 3 hours 6 hours
12 hours 24 hours
Duration in minutes and hours
0
0
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Ge oTe k, tne3.
320 Easy Cor race Dfiw Suite 300 Meridim, ID 83642-3511
f2081 889-1010 t208) 8884124 vwwwZeatekuj .com
January 28, 2016
Project No. 1780-ID3
)-U-B Engineers
250 S. Beachwood Ave, Suite 201
Boise, Idaho 83709
Attention: Mr. Scott Wonders
Subject: Geotechnical Evaluation for "Locust Grove Apartments" "Locust Grove
Apartments" - a 16+ Acre Multi -Family Residential Development Located on the South
East Corner of North Locust Grove Road and East Wilson Lane, Meridian, Idaho
In accordance with your request, GeoTek, Inc. (GTI) has completed a geotechnical evaluation of the
subject property for the construction of two- to three-story multi -family residential structures and
associated improvements. The purpose of our study was to evaluate the soils underlying the site and to
provide recommendations for project design and construction based on our findings. This report
outlines the geologic and geotechnical conditions of the site based on current data, and provides
earthwork and construction recommendations with respect to those conditions.
SCOPE OF SERVICES
The scope of our services has included the following:
I . Review of soils and geologic reports and maps for the site (Appendix A).
2. Site reconnaissance.
3. Review of aerial photographs.
4. Excavating and logging of six (6) exploratory test pits (Appendix B).
5. Obtaining samples of representative soils, as the exploratory test pits were advanced.
6. Performing laboratory testing on representative soil samples (Appendix D).
7. Assessment of potential geologic constraints.
8. Engineering analysis regarding foundation design/construction, foundation settlement, and site
preparation.
9. Preparation of this report.
GEOTECHNICAL I ENVIRONMENTAL I MATERIALS
LOCUST GROVE APARTMENTS
J -U -B ENGINEERS
PROJECT NO. 1779-ID3
SITE DESCRIPTION
JANUARY 28, 2016
PAGE 2
The project site consists of an irregularly shaped parcel totaling approximately 16+ acres that is
generally bound by E. Wilson Lane to the north, an existing apartment complex to the east, an existing
irrigation lateral and undeveloped land to the south, and existing N. Locust Grove Road to the west
(Figures I and 2). Currently, the majority of the property consists of farmland that has been
corrugated/irrigated and cultivated for crop farming purposes over many years. One residence with
existing outbuildings is located within the northern border of the site. From topographic maps, the
site's elevation is approximately 2,600± to 2,610± feet above mean sea level. Historically, topography
generally directs surface water to the northwest.
PROPOSED DEVELOPMENT
It is our understanding that site development would consist of performing typical cut and fill
earthwork to attain the desired graded configuration(s) for the construction of multiple two to three-
story multi -family residential structures with associated improvements.
FIELD STUDIES
Subsurface conditions at the site were explored by using a rubber -tired backhoe. Six (6) test pits
were advanced onsite. A log of each exploration is included with this report in Appendix B. Two (2)
percolation tests were also performed on the subject site (Appendix C). Field studies were
completed during January of 2015 by our field personnel who conducted field excavation location
mapping, logged the excavations, and obtained samples of representative soils for laboratory testing.
The approximate locations of the explorations are indicated on the enclosed Site Exploration Plan
(Figure 2). The Unified Soil Classification System (USCS) Classification was used to visually classify the
subgrade soils during the field evaluation.
REGIONAL GEOLOGY
The subject site is situated within the Boise River Valley, which comprises the northwestern portion
of the Snake River Plain physiographic province. The western portion of the Snake River Plain is
aligned in a northwest -southeast direction and generally divides the Owyhee mountains to the south
from the Central Idaho mountains toward the north (Wood and Clemens, 2004). The headwaters of
the Boise River are located in the Central Idaho mountains east of Boise, Idaho. The river leaves the
central mountains and enters the Snake River Plain near Barber and drains toward the west into the
Snake River near Parma. The Owyhee mountains and the Central Idaho Mountains are composed
predominantly of volcanic and igneous rocks. The western portion of the Snake River Plain is a
northwest trending complex graben formed by extension and regional uplift along the northern
boundary of the basin and range province (Wood and Clemens, 2004). The graben generally forms a
basin which has been partially filled with younger sedimentary and volcanic rocks (Malde, 1991).
The Boise River Valley is bounded on the northeast by the Boise Front, which is a northwest trending
-,—
LOCUST GROVE APARTMENTS
J -U -B ENGINEERS
PROJECT NO. 1779-1133
JANUARY 28, 2016
PAGE 3
topographic high extending generally from Boise to Emmett, Idaho. The Boise Front consists of
Cretaceous aged granitic and metamorphic rocks cut by Tertiary aged rhyolite and overlain with
Miocene aged lake sediments (Wood and Clemens, 2004). These units have been cut by northwest
trending faults which down drop these units toward the southwest. The faults also provide conduits
for Quaternary aged basalt intrusions and flows (Malde, 1991).
The depositional environment for the valley floor is dominantly lake laid deposits of sand, silt and clay.
These materials were deposited during two periods of lake activity, one during the Miocene and the
other during the Pleistocene. This valley infilling process has been subsequently truncated by down
faulting within the valley ranging in height from a few feet to over 50 feet. Younger alluvium has been,
and continues to be, transported dominantly by water and deposited on the basins gently sloping valley
floor and within low-level flood plains. Portions of the alluvial deposits are being down cut by
intermittent streams to the flood plain, and as a result stream terraces are being formed.
SITE SOILS
Artificial Fill
Based on our field studies, some spread fills were observed near the existing residence as well as along
perimeter of the site. This fill is generally associated with the construction of the adjacent roadways
and apartment complex as well as the onsite residence. This spread fill shall be considered artificial fill.
Much of the property has been cultivated for agricultural use, the upper 12 to 24 inches of material
has been disturbed and consists of a dark brown lean clay with a moderate amount of organics and
roots, this shall be considered artificial fill. Deeper fills may be encountered onsite. The "Artificial
Fills" are loose/soft and contain organics/roots and are not considered suitable for support of
foundations. All artificial fill material should be removed as described in the "Removals" section of this
report.
Native Alluvial Soils
Alluvial soils encountered generally consisted surficial layers of clays, silts, and sands underlain by
partially cemented sands and sands with varying amounts of gravel and cobbles. The moisture content
within the alluvial materials was generally slightly moist to moist near surface to wet to saturated at
depth. The consistency of these soils was soft near surface and ranged from firm/medium dense to
very dense at depth. We anticipate that the onsite soils can be excavated with conventional
earthwork equipment. Partially cemented layers of material were encountered in the majority of our
excavations; however, we anticipate that the onsite soils can be excavated with conventional
earthwork equipment equivalent to CAT D9R dozers and CAT 235 excavators. Special excavation
equipment and techniques may be necessary dependent upon if harder materials are encountered
during construction.
After artificial fill is removed, the upper 12 inches of the alluvium will require, at a minimum, some
removal and/or processing efforts to be considered suitable for the support of the proposed site
improvements. Locally deeper processing/removals may be necessary. Refer to the
"Recommendations Earthwork Construction" section of this report for specific site preparation
recommendations.
LOCUST GROVE APARTMENTS JANUARY 28, 2016
J -U -B ENGINEERS PAGE 4
PROJECT NO. 1779-1133
SURFACE & GROUND WATER
Irrigation ditches exist onsite and adjacent to the site and they transmit water on a periodic basis.
Generally, irrigation ditches and canals will locally influence ground water during the irrigation season
(i.e., May through October). Ground water was encountered in each of our excavations during our
field investigation with depths ranging between 9.5 to 11.5 feet below existing ground surface. Due to
existing ground water conditions, it should be expected that special excavation and fill placement
measures may be necessary. Wet materials should be spread out and air-dried or mixed with drier
soils to reduce their moisture content as appropriate for fill placement. Ground water is not
anticipated to adversely affect planned development, provided that earthwork construction methods
comply with recommendations contained in this report or those made subsequent to review of the
improvement plan(s). GTI assumes that the design civil engineer of record will evaluate the site for
potential flooding and set grades such that the improvements are adequately protected. These
observations reflect conditions at the time of this investigation and do not preclude changes in local
ground water conditions in the future from natural causes, damaged structures (lines, pipes etc.), or
heavy irrigation.
TECTONIC FAULTING AND REGIONAL SEISMICITY
The site is situated in an area of active as well as potentially active tectonic faults, however no faults
were observed during our field evaluation. There are a number of faults in the regional area, which
are considered active and would have an affect on the site in the form of ground shaking, should they
be the source of an earthquake. It is reasonable to assume that structures built in this area will be
subject to at least one seismic event during their life, therefore, it is recommended that all structures
be designed and constructed in accordance with the International Building Code (IBC). Based on our
experience in the general vicinity, references in our library, field evaluation of the site, a Seismic
Design Site Class Designation of `D' may be used for seismic design.
Secondary Seismic Constraints
The following list includes other potential seismic related hazards that have been evaluated with
respect to the site, but in our opinion, the potential for these seismically related constraints to affect
the site is considered negligible.
* Liquefaction
* Dynamic Settlements
* Surface Fault Rupture
* Ground Lurching or Shallow Ground Rupture
Summary
It is important to keep in perspective that if a seismic event were to occur on any major fault, intense
ground shaking could be induced to this general area. Potential damage to any settlement sensitive
structures would likely be greatest from the vibrations and impelling force caused by the inertia of the
structures mass than that created from secondary seismic constraints. Considering the subsurface
soil conditions and local seismicity, it is estimated that the site has a low risk associated with the
LOCUST GROVE APARTMENTS
J -U-13 ENGINEERS
PROJECT NO. 1779-1133
JANUARY 28, 2016
PAGE 5
potential for these phenomenon to occur and adversely affect surface improvements. These potential
risks are no greater at this site than they are for other structures and improvements developed on the
alluvial materials in this vicinity.
RESULTS OF LABORATORY TESTING
Laboratory tests were performed on representative samples of the onsite earth materials in order to
evaluate their physical and chemical characteristics. The tests performed and the results obtained are
presented in Appendix D.
CONCLUSIONS
Based on our field exploration, laboratory testing and engineering analyses, it is our opinion that the
subject site is suited for development from a geotechnical engineering viewpoint. The
recommendations presented herein should be incorporated into the final design, grading, and
construction phases of development. The engineering analyses performed concerning site preparation
and the recommendations presented below, have been completed using the information provided to
us regarding site development. In the event that the information concerning proposed development is
not correct, the conclusion and recommendations contained in this report shall not be considered
valid unless the changes are reviewed and conclusions of this report are modified or approved in
writing by this office.
RECOMMENDATIONS - EARTHWORK CONSTRUCTION
General
All grading should conform to the International Building Code (IBC) and the requirements of the City
of Meridian except where specifically superseded in the text of this report. During earthwork
construction all removals, drain systems, slopes, and the general grading procedures of the contractor
should be observed and the fill selectively tested.
If unusual or unexpected conditions are exposed in the field, they should be reviewed by this office
and if warranted, modified and/or additional recommendations will be offered. It is recommended that
the earthwork contractor(s) perform their own independent reconnaissance of the site to observe
field conditions first hand. If the contractor(s) should have any questions regarding site conditions, site
preparation, or the remedial recommendations provided, they should contact an engineer at GeoTek
for any necessary clarifications prior to submitting earthwork bids. All applicable requirements of local
and national construction and general industry safety orders, the Occupational Safety and Health Act,
and the Construction Safety Act should be met.
Demolition
The following recommendations are provided as guidelines in the event a structure is encountered
that are not intended to remain.
LOCUST GROVE APARTMENTS
J -U -B ENGINEERS
PROJECT NO. 1779-ID3
JANUARY 28, 2016
PAGE 6
1. All existing surface or subsurface structures (not intended to remain), within the area to be
developed, should be razed and moved off site.
2. If a septic tank (to be abandoned or below a proposed improvement) is located within the
project site, it is recommended that it be pumped out and with few exceptions likely removed.
Any leach lines, seepage pits, or other pipes associated with this structure should also be
removed or properly abandoned.
3. If any wells are encountered, an attempt should be made to identify the owner and purpose of
the well. Well abandonment should adhere to the recommendations provided by the Idaho
Department of Water Resources, the Public Health Department, or any other government
agencies. If the well is located in the area of a proposed structure, these recommendations
should be reviewed by GTI and if warranted, additional geotechnical recommendations will be
offered.
Removals/Processing - General
Presented below are removal/processing recommendations for the various earth materials
encountered on the project. Debris, vegetation, and other deleterious material should be
stripped/removed from areas proposed for structural improvements.
Based on a review of the exploratory logs and our site reconnaissance, after the artificial fill is
removed (upper 12 to 24 inches), a minimum removal/processing depth of 12 inches into alluvial
materials should be accomplished across the site. If the left in place soils can be scarified to encounter
a competent layer below; they may be processed in place; otherwise, they should be removed to
competent material. Locally deeper removals/processing may be necessary based on the field
conditions exposed
We recommend that all surficial lean and fat clays (if encountered) be removed from beneath the
foundations and replaced with a low expansive structural fill. The exposed ground surface should be
moisture conditioned and compacted a minimum of 12 inches to provide a more uniform foundation
support. A minimum relative compaction of 90 percent of the laboratory maximum modified density
(ASTM D 1557) at moisture content of optimum or above is necessary to generate any near surface
settlements. Locally deeper removals/processing may be necessary based on the conditions exposed.
Removal bottoms should be checked by a representative of GeoTek, Inc. to see if deeper removals
are necessary.
If very hard cemented materials are encountered during over -excavation, excavation may potentially
be terminated, but this will need to be determined on a case by case basis by a representative of GTI.
Foundations for the proposed structures may be founded on cemented material; however, in order to
avoid the potential for differential settlement, the entire foundation would need to be supported
entirely on the cemented material. If this is not possible, cemented materials should be removed to a
minimum depth of 12 inches below the bottom of the footing and replaced with compacted structural
fill. This can best be determined in the field based upon the conditions exposed. Termination of any
excavation on cemented soils will need to be reviewed by GTI and the owner.
LOCUST GROVE APARTMENTS
J -U -B ENGINEERS
PROJECT NO. 1779-1133
JANUARY 28, 2016
PAGE 7
If existing improvements or property line restrictions limit removals, condition specific
recommendations would be provided on a case-by-case basis. During earthwork construction, care
should be taken by the contractor so that adverse ground movements or settlements are not
generated affecting existing improvements.
Transitional Pads
Transitional pads are defined in this report as pads which are partially cut and partially fill. To mitigate
some of the differential settlement which will occur on transitional pads, the cut side should be over-
excavated/processed to a minimum depth equal to 2 feet below the bottom of the footings or to the
depth of the fill, which ever is less. On transitional pads with more than 7.5 feet of fill, plans need to
be reviewed by GTI and site-specific recommendations will be provided.
Excavation Difficulty
We anticipate that the onsite soils can be excavated with conventional earthwork. Seasonal
conditions could cause wet soil conditions to occur onsite. Depending on the depth of cuts, it should
be expected that special excavation and fill placement measures may be necessary. Wet materials
should be spread out and air-dried or mixed with drier soils to reduce their moisture content to the
appropriate level for fill placement. Frozen soils, if encountered, should be removed and allowed to
thaw prior to any fill placement or construction. Removal bottoms should be checked by a
representative of GTI to see if deeper removals are necessary.
Fill Placement
Subsequent to completing removals/processing and ground preparation, the excavated onsite and/or
imported soils may be placed in relatively thin lifts (less than 8 inches thick), cleaned of vegetation and
debris, brought to at least optimum moisture content, and compacted to a minimum relative
compaction of 95 percent of the laboratory standard (ASTM D 1557).
Import Material
Potentially, soils will be imported to the site for earthwork construction purposes. A sample of any
intended import material should first be submitted to GTI so that, if necessary, additional laboratory
or chemical testing can be performed to verify that the intended import material is compatible with
onsite soils. In general, import material should be within the following minimum guidelines:
* Free of organic matter and debris.
* Maintain less than 0.2 percent sulfate content.
* Maintain less than 3.0 percent soluble material.
* Maintain less than 0.02 percent soluble chlorides.
* Maintain less than 0.2 percent sodium sulfate content.
* Maintain a Plasticity Index less than 12 (i.e., low expansive).
* One hundred percent passing the six-inch screen.
* At least seventy-five percent passing a three-inch screen.
Observation and Testing
During earthwork construction all removal/processing and the general grading procedures should be
observed and the fill selectively tested by a representative(s) of GTI. If unusual or unexpected
conditions are exposed in the field, they should be reviewed by GTI and if warranted, modified and/or
additional recommendations will be offered.
LOCUST GROVE APARTMENTS
J -U -B ENGINEERS
PROJECT NO. 1779-1133
JANUARY 28, 2016
PAGE 8
Ground Water
Ground water was encountered during our field evaluation at depths of approximately 9.5 to 11.5+
feet, where observed, beneath the existing ground surface. Based on site conditions in the future, a
transient high ground water condition could develop over a clay or less permeable layer and this
condition could generate down gradient seepage. The possible effect these layers could have on this
and adjacent sites should be considered, and can best be evaluated in the field during grading. If
warranted by exposed field conditions, it may be recommended that a drainage system be established
to collect and convey any subsurface water to an appropriate location for drainage. Typically,
potential areas of seepage are difficult to identify prior to their occurrence; therefore, it is often best
to adopt a "wait and see" approach to determine if any seepage conditions do develop, at which time
specific recommendation to mitigate an identified condition can be provided.
Earthwork Settlements
Ground settlement should be anticipated due to primary consolidation and secondary compression.
The total amount of settlement and time over which it occurs is dependent upon various factors,
including material type, depth of fill, depth of removals, initial and final moisture content, and in-place
density of subsurface materials. Compacted fills, to the heights anticipated, are not generally prone to
excessive settlement. However, some settlement of the left in-place existing fill and alluvium is
expected and the majority of this settlement is anticipated to occur during grading.
Slope Stability
No significantly high (greater than ten feet) slopes are anticipated to be constructed onsite. All slopes
should be designed at gradients of 2 to I (Horizontal to Vertical) or flatter. All slopes should be
constructed in accordance with the minimum requirements of the City of Meridian and the
International Building Code. Cut and fill slopes are anticipated to perform adequately in the future
with respect to gross and surficial stability if the soil materials are maintained in a solid to semi-solid
state (as defined by the soils Atterberg Limits) and are limited to the heights prescribed herein.
The importance of proper compaction to the face of a slope cannot be overemphasized. In order to
achieve proper compaction, one or more of the three following methods should be employed by the
contractor following implementation of typical slope construction guidelines: 1) track walk the slopes
at grade, 2) use a combination of sheeps foot roller and track walking, or 3) overfill the slope 3 to 5
feet laterally and cut it back to grade.
Random testing will be performed to verify compaction to the face of the slope. If the tests do not
meet the minimum recommendation of 90 percent relative compaction, the contractor will be
informed and additional compactive efforts recommended. A final evaluation of cut slopes during
grading will be necessary in order to identify any areas of adverse conditions. The need for remedial
stabilization measures should be based on observations made during grading by a representative of this
office. Based on our observations, and if warranted, specific remedial recommendations will be
offered for stabilization.
LOCUST GROVE APARTMENTS JANUARY 28, 2016
J -U -B ENGINEERS PAGE 9
PROJECT NO. 1779-ID3
RECOMMENDATIONS — FOUNDATIONS
General
Foundation design and construction recommendations are based on preliminary laboratory testing and
engineering analysis performed on near surface soils. The proposed foundation systems should be
designed and constructed in accordance with the guidelines contained herein and in the International
Building Code.
Based on our experience in the area, the soils onsite should have a negligible corrosive potential to
concrete and metal, materials selected for construction purposes should be resistant to corrosion.
Where permitted by building code, PVC pipe should be utilized. All concrete should be designed,
mixed, placed, finished, and cured in accordance with the guidelines presented by the Portland
Cement Association (PCA) and the American Concrete Institute (ACI).
Based on our grading recommendations, the soils beneath the foundations are anticipated to have low
expansion potential. Therefore, foundation recommendations for low expansive soil conditions are
provided below. If more expansive soils are encountered, the pad(s) will either need to be regraded
and the more expansive soils removed by the contractor or increased foundation recommendations
will need to be provided.
Conventional Foundation Recommendations
Column loads are anticipated to be 50 kips or less while wall loads are expected to be 3 kips per lineal
foot or less. The conventional recommendations provided are from a geotechnical engineering
perspective (i.e., for expansive conditions) and are not meant to supersede the design by the project's
structural engineer.
Preliminary recommendations for foundation design and construction are presented below. The
specific criteria to be used should be verified on evaluation of the proposed buildings, structural loads,
and expansion and chemical testing performed after grading is complete.
The bearing values indicated are for the total dead plus frequently applied live loads and may be
increased by one third for short duration loading which includes the effects of wind or seismic forces.
When combining passive pressure and friction for lateral resistance, the passive component should be
reduced by one third. A grade beam, reinforced as below and at least 12 inches wide, should be
utilized across all large entrances. The base of the grade beam should be at the same elevation as the
bottom of the adjacent footings. Footings should be founded at a minimum depth of 24 inches below
lowest adjacent ground surface as required by local codes to extend below the frost line.
Reinforcement for spread footings should be designed by the project's structural engineer.
For foundations systems including a crawl space, it is recommended that it be designed so that water
is not allowed to penetrate the crawl space. Proper grading and backfill for the foundations is critical
and should adhere to the "fill placement" and "drainage" recommendations of this evaluation as well as
local building codes.
LOCUST GROVE APARTMENTS
J -U -B ENGINEERS
PROJECT NO. 1779-ID3
JANUARY 28, 2016
PAGE 10
The coefficient of friction and passive earth pressure values recommended are working values. Strip
footings should have a minimum width of one foot and spread footings should have a minimum soil to
concrete area of four square feet. Increases are allowed for the bearing capacity of the footings at a
rate of 250 pounds per square foot for each additional foot of width and 250 pounds per square foot
for each additional foot of depth into the recommended bearing material, up to a maximum outlined.
If the bearing value exceeds 3,000 psf, an additional review by GTI is recommended. As mentioned
earlier, the exposed ground surface should be moisture conditioned and compacted a minimum of 12
inches below bottom of footings. Prior to the placement of concrete, moisture should be added to
the subgrade soils to minimize water loss of the concrete during placement and curing.
Foundation Settlement
Provided that the recommendations contained in this report are incorporated into final design and
construction phase of development, total settlement is estimated to be less than one inch and
differential settlement is estimated to be less than 0.75 inches for a 25 -foot span. Two-way angular
distortions due to settlements are not estimated to exceed 1/400. The structures should be loaded
uniformly so as to avoid any localized settlements.
PAVEMENT SECTIONS
Pavement sections presented in the following table are based on an R -value of 12, assumed traffic
index(s) for residential construction and estimated traffic index(s) for commercial construction, and
the guidelines presented in the latest edition of the ACHD Development Policy Manual. These
pavement sections are presented for planning purposes only and should be verified based on specific
laboratory testing performed subsequent to rough grading of the site.
Pavement Construction and Maintenance
All section changes should be properly transitioned. If adverse conditions are encountered during the
preparation of subgrade materials, special construction methods may need to be employed. All
subgrade materials should be processed to a minimum depth of 12 inches and compacted to a
minimum relative compaction of 90 percent near optimum moisture content. All aggregate base
should be compacted to a minimum relative compaction of 95 percent at optimum moisture content.
The recommended pavement sections provided are meant as minimums. If thinner or highly variable
pavement sections are constructed, increased maintenance and repair should be expected. If the ADT
(average daily traffic) or ADTT (average daily truck traffic) increases beyond that intended, as reflected
by the traffic index(s) used for design, increased maintenance and repair could be required for the
pavement section.
Soil
Minimum
Allowable
Passive
Maximum
Footing
Expansion
Footing
Bearing
Coefficient
Earth
Earth
Type
Classification
Depth
Pressure
of Friction
Pressure
Pressure
(inches)
(psf)
(psf/ft)
(psf)
Strip/Spread
Low
j 24
2,000
j 0.35
j 250
3,000
The coefficient of friction and passive earth pressure values recommended are working values. Strip
footings should have a minimum width of one foot and spread footings should have a minimum soil to
concrete area of four square feet. Increases are allowed for the bearing capacity of the footings at a
rate of 250 pounds per square foot for each additional foot of width and 250 pounds per square foot
for each additional foot of depth into the recommended bearing material, up to a maximum outlined.
If the bearing value exceeds 3,000 psf, an additional review by GTI is recommended. As mentioned
earlier, the exposed ground surface should be moisture conditioned and compacted a minimum of 12
inches below bottom of footings. Prior to the placement of concrete, moisture should be added to
the subgrade soils to minimize water loss of the concrete during placement and curing.
Foundation Settlement
Provided that the recommendations contained in this report are incorporated into final design and
construction phase of development, total settlement is estimated to be less than one inch and
differential settlement is estimated to be less than 0.75 inches for a 25 -foot span. Two-way angular
distortions due to settlements are not estimated to exceed 1/400. The structures should be loaded
uniformly so as to avoid any localized settlements.
PAVEMENT SECTIONS
Pavement sections presented in the following table are based on an R -value of 12, assumed traffic
index(s) for residential construction and estimated traffic index(s) for commercial construction, and
the guidelines presented in the latest edition of the ACHD Development Policy Manual. These
pavement sections are presented for planning purposes only and should be verified based on specific
laboratory testing performed subsequent to rough grading of the site.
Pavement Construction and Maintenance
All section changes should be properly transitioned. If adverse conditions are encountered during the
preparation of subgrade materials, special construction methods may need to be employed. All
subgrade materials should be processed to a minimum depth of 12 inches and compacted to a
minimum relative compaction of 90 percent near optimum moisture content. All aggregate base
should be compacted to a minimum relative compaction of 95 percent at optimum moisture content.
The recommended pavement sections provided are meant as minimums. If thinner or highly variable
pavement sections are constructed, increased maintenance and repair should be expected. If the ADT
(average daily traffic) or ADTT (average daily truck traffic) increases beyond that intended, as reflected
by the traffic index(s) used for design, increased maintenance and repair could be required for the
pavement section.
LOCUST GROVE APARTMENTS
J -U -B ENGINEERS
PROJECT NO. 1779-ID3
JANUARY 28, 2016
PAGE 1 I
Positive site drainage should be maintained at all times. Water should not be allowed to pond or seep
into the ground. If planters or landscaping are adjacent to paved areas, measures should be taken to
minimize the potential for water to enter the pavement section.
OTHER RECOMMENDATIONS
Site Improvements
As is commonly known, expansive soils are problematic with respect to the design, construction and
long term performance of concrete flatwork. Due to the nature of concrete flatwork, it is essentially
impossible to totally mitigate the effects of soil expansion. Typical measures to control soil expansion
for structures include; low expansive soil caps, deepened foundation system, increased structural
design, and soil presaturation. As they are generally not cost effective, these measures are very
seldom utilized for flatwork because it's less costly to simply replace any damaged or distressed
sections than to "structurally" design them. Even if "structural" design parameters are applied to
flatwork construction, there would still be relative movements between adjoining types of structures
and other improvements (e.g., curb and sidewalk). This is particularly true as the level of care during
construction of flatwork is often not as meticulous as that for structures. Unfortunately, it is fairly
common practice for flatwork to be poured on subgrade soils, which have been allowed to dry out
since site grading. Generally after flatwork construction is completed, landscape irrigation begins,
utility lines are pressurized, and drainage systems are utilized; presenting the potential for water to
enter the dry subgrade soils, causing the soil to expand.
Recommendations for exterior concrete flatwork design and construction can be provided upon
request. If, in the future, any additional improvements are planned for the site, recommendations
concerning the geological or geotechnical aspects of design and construction of said improvements
could be provided upon request. This office should be notified in advance of any fill placement,
grading, or trench backfilling after rough grading has been completed. This includes any grading, utility
trench and retaining wall backfills.
MINIMUM
MINIMUM AGGREGATE
ASSUMED TRAFFIC
SUBGRADE
ASPHALT
THICKNESS (in.)
RIGHT -OF -AWAY
R -VALUE
CONCRETE
THICKNESS
Aggregate
Subbase
(in.)
Base (3/4"
(Pitrun)
minus)
Parking and Drives
No Truck Access
12
2.5
4.0
8.0
TI = 5.0
Truck Access
12
3.0
6.0
15.0
TI = 8.0
OTHER RECOMMENDATIONS
Site Improvements
As is commonly known, expansive soils are problematic with respect to the design, construction and
long term performance of concrete flatwork. Due to the nature of concrete flatwork, it is essentially
impossible to totally mitigate the effects of soil expansion. Typical measures to control soil expansion
for structures include; low expansive soil caps, deepened foundation system, increased structural
design, and soil presaturation. As they are generally not cost effective, these measures are very
seldom utilized for flatwork because it's less costly to simply replace any damaged or distressed
sections than to "structurally" design them. Even if "structural" design parameters are applied to
flatwork construction, there would still be relative movements between adjoining types of structures
and other improvements (e.g., curb and sidewalk). This is particularly true as the level of care during
construction of flatwork is often not as meticulous as that for structures. Unfortunately, it is fairly
common practice for flatwork to be poured on subgrade soils, which have been allowed to dry out
since site grading. Generally after flatwork construction is completed, landscape irrigation begins,
utility lines are pressurized, and drainage systems are utilized; presenting the potential for water to
enter the dry subgrade soils, causing the soil to expand.
Recommendations for exterior concrete flatwork design and construction can be provided upon
request. If, in the future, any additional improvements are planned for the site, recommendations
concerning the geological or geotechnical aspects of design and construction of said improvements
could be provided upon request. This office should be notified in advance of any fill placement,
grading, or trench backfilling after rough grading has been completed. This includes any grading, utility
trench and retaining wall backfills.
LOCUST GROVE APARTMENTS
J -U -B ENGINEERS
PROJECT NO. 1779-1133
JANUARY 28, 2016
PAGE 12
Landscape Maintenance and Planting
Water has been shown to weaken the inherent strength of all earth materials. Slope stability is
significantly reduced by overly wet conditions. Graded slopes constructed within and utilizing onsite
materials would be erosive. Eroded debris may be minimized and surficial slope stability enhanced by
establishing and maintaining a suitable vegetation cover as soon as possible after construction.
Compaction to the face of fill slopes would tend to minimize short-term erosion until vegetation is
established. Plants selected for landscaping should be lightweight, deep-rooted types, which require
little water and are capable of surviving the prevailing climate. From a geotechnical standpoint leaching
is not recommended for establishing landscaping. If the surface soils are processed for the purpose of
adding amendments, they should be recompacted to 90 percent compaction. Only the amount of
irrigation necessary to sustain plant life should be provided. Over watering the landscape areas could
adversely affect proposed site improvements. We recommend that any proposed open bottom
planter areas adjacent to proposed structures, be eliminated for a minimum distance of 5 feet and
desert landscape using xeriscape technology be used outside of this buffer zone. As an alternative,
closed bottom type planters could be utilized. An outlet, placed in the bottom of the planter, could be
installed to direct drainage away from structures or any exterior concrete flatwork. Irrigation timers
should be adjusted on a monthly basis.
Soil Corrosion
Based on our experience in the area, the soils onsite should have a negligible corrosive potential to
concrete and metal, materials selected for construction purposes should be resistant to corrosion.
Where permitted by building code PVC pipe should be utilized. All concrete should be designed,
mixed, placed, finished, and cured in accordance with the guidelines presented by the Portland
Cement Association (PCA) and the American Concrete Institute (ACI).
Trench Excavation
All footing trench excavations should be observed by a representative of this office prior to placing
reinforcement. Footing trench spoil and any excess soils generated from utility trench excavations
should be compacted to a minimum relative compaction of 90 percent if not removed from the site.
Considering the nature of the onsite soils, it should be anticipated that caving or sloughing could be a
factor in excavations. Shoring or excavating the trench walls and slopes to the angle of repose
(typically 25 to 45 degrees) may be necessary and should be anticipated in non-cemented soils. All
excavations should be observed by one of our representatives and conform to national and local safety
codes.
Onsite Utility Trench Backfill
Considering the overall nature of the soil encountered onsite, it should be anticipated that materials
will need to be imported to the site for use as pipe bedding and pipe zone material. All utility trench
backfill should be brought to near optimum moisture content and then compacted to obtain a
minimum relative compaction of 90 percent of the laboratory standard. Compaction testing and
observation, along with probing should be performed to verify the desired results. Sand backfill, unless
excavated from the trench, should not be used adjacent to perimeter footings or in trenches on
slopes. Compaction testing and observation, along with probing should be performed to verify the
desired results. Sand backfill, unless excavated from the trench, should not be used adjacent to
perimeter footings or in trenches on slopes. Compaction testing and observation, along with probing
should be performed to verify the desired results. Offsite utility trenches should be compacted to a
LOCUST GROVE APARTMENTS
)-U-B ENGINEERS
PROJECT NO. 1779-ID3
JANUARY 28, 2016
PAGE 13
minimum of 90 relative compaction. Compaction testing and observation, along with probing should
be performed to verify the desired results.
Drainage
Positive site drainage should be maintained at all times in accordance with the IBC. Drainage should
not flow uncontrolled down any descending slope. Water should be directed away from foundations
and not allowed to pond and/or seep into the ground. Pad drainage should be directed toward the
street or other approved area. The ground immediately adjacent to the foundation shall be sloped
away from the building at a minimum of 5 -percent for a minimum distance of 10 feet measured
perpendicularly to the face of the wall. If physical obstructions prohibit 10 feet of horizontal distance,
a 5 -percent slope shall be provided to an approved alternate method of diverting water away from the
foundation. Swales used for this purpose shall be sloped a minimum of 2 -percent where located
within 10 feet of the building foundation. Impervious surfaces within 10 feet of the building foundation
shall be sloped a minimum of 2 -percent away from the building. Roof gutters and down spouts should
be utilized to control roof drainage. Down spouts should outlet onto paved areas or a minimum of
five feet from proposed structures or into a subsurface drainage system. Areas of seepage may
develop due to irrigation or heavy rainfall. Minimizing irrigation will lessen this potential. If areas of
seepage develop, recommendations for minimizing this effect could be provided upon request.
PLAN REVIEW
Final grading, foundation, and improvement plans should be submitted to this office for review and
comment as they become available, to minimize any misunderstandings between the plans and
recommendations presented herein. In addition, foundation excavations and earthwork construction
performed on the site should be observed and tested by this office. If conditions are found to differ
substantially from those stated, appropriate recommendations would be offered at that time.
LIMITATIONS
The materials encountered on the project site and utilized in our laboratory study are believed
representative of the area; however, soil materials vary in character between excavations and
conditions exposed during mass grading. Site conditions may vary due to seasonal changes or other
factors. GeoTek, Inc. assumes no responsibility or liability for work, testing, or recommendations
performed or provided by others. Since our study is based upon the site materials observed, selective
laboratory testing and engineering analysis, the conclusions and recommendations are professional
opinions. These opinions have been derived in accordance with current standards of practice and no
warranty is expressed or implied. Standards of practice are subject to change with time.
LOCUST GROVE APARTMENTS
J -U -B ENGINEERS
PROJECT NO. 177'9 -IDD
JANUARY 28, 2016
PAGE 14
Thp- opportunity to be of service is greatly appreciated. If you have any questions concern!Rg this
report or if we may be of further assistance, please do not hesitate to contact the undersigned,
Respectfully submitted,
GeoTek, Inc.
David C. Waite, PE
Branch Manager
Senior Engineer
EMBEMM
E. Fairview Ave.
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* APPROXIMATE SITE LOCATION
Source: Google Maps 2016, GeoTek Field Observations, 2016.
Not to Scale
GEOTEK
GEOTECHNICAL I ENVIRONMENTAL I MATERIALS
320 E. Corporate Dr, Suite 300, Meridian, ID 83642
(208) 888-7010 (phone) / (208) 888-7924 (FAX)
FIGURE I
SITE VICINITY MAP
Locust Grove Apartments
Meridian, Idaho
Prepared for: J -U -B Engineers, Inc.
Project No.: Report Date: Drawn By:
1779-ID3 I January 2016 DCW
APPROXIMATE TEST PIT, PERCOLATION TEST, AND
GROUNDWATER MONITORING LOCATIONS
Source: Google Earth 2016, GeoTek Field Observations, 2016.
Not to Scale
FIGURE 2
SITE EXPLORATION PLAN
A21c-'. Locust Grove Apartments
Meridian, Idaho
G E O T E K Prepared for: J -U -B Engineers, Inc.
GEOTECHNICAL I ENVIRONMENTAL I MATERIALS
Project No.: Report Date: Drawn By:
320 E. Corporate Dr, Suite 300, Meridian, ID 83642 1779-ID3 January 2016 DCW
(208) 888-7010 (phone) / (208) 888-7924 (FAX)
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REFERENCES
Ada County Highway District Development Policy Manual, Revised by Resolution No. 690, October
2003
ASTM, 200, "Soil and Rock: American Society for Testing and Materials," vol. 4.08 for ASTM test
methods D-420 to D-4914, 153 standards, 1,026 pages; and vol. 4.09 for ASTM test method D-
4943 to highest number.
Breckinridge, R.M., Lewis, R.S., Adema, G.W., Weisz, D.W., 2003, Map of Miocene and Younger Faults
in Idaho, Idaho Geological Survey, University of Idaho
Day, Robert W., 1999, Geotechnical and Foundation Engineering — Design and Construction
Day, Robert W., 2002, Geotechnical Earthquake Engineering Handbook
GeoTek, Inc., In-house proprietary information.
Idaho Department of Water Resources, Treasure Valley Hydrology — Geology, January 2003
Idaho Department of Water Resources, Well Information, Well Driller Reports, 2015
Idaho Transportation Department CD-ROM Publications
Johnson, Bruce R. and Raines, Gary L., 1995, Digital representation of the Idaho state geologic map: a
contribution to the Interior Columbia Basin Ecosystem Management Project. USGS Open -File
Report 95-690
Malde, H.E., 1991. Quaternary geology and structural history of the Snake River Plain, Idaho and
Oregon. In: The Geology of North America, Quaternary Nonglacial Geology: Conterminous
U.S., Vol. K-2, 252-281 pp.
Othberg, K.L., 1994. Geology and geomorphology of the Boise Valley and adjoining areas, western
Snake River Plain, Idaho. Idaho Geological Survey Bulletin 29: 54 pp.
USGS, Cloverdale Quadrangle, 7.5 -Minute Series Topographic Map, 1979.
USGS, 2003, Seismic Hazard Map of Idaho, Peak Acceleration (%g) with 2% Probability of Exceedance
in 50 years.
F'A J 411AHAA
� I �-- M mlrT M-
LOG GENERAL NOTES
RELAT(1/E DENSITY OF COARSE�GRAINED SOILS
Standard Penetration (SPT) Relative Density
or N -Value (SS) Blows/Ft
0 - 3 Very Loose
4 - 9 Loose
10-29 Medium Dense
30-49 Dense
50+ Very Dense
SPT penetration test using 140 pound hammer, with 30 inch free fall on 2 inch outside diameter(1-3/8 ID) sampler
For ring sampler using 140 Ib hammer, with a 30 inch free fall on 3 inch outside diameter (2-1/2 ID) sample,
use N -value x 0.7 to get Standard N -value
For fine grained soil consistency, thumb penetration used per ASTM D-2488
r
F�ELATIV� �+RflPOR�'IONS OF SAND AND GRA�/�L;
CONSISTENCY OF FINE GRAINI=i�x StJILS
Descriptive Term of other
Unconfined
Standard
Weight
Compressive
Penetration or N-
With
15-29
Modifier
Consistency
Strength, Qu,
Value (SS)
Gravel
psf
Blows/Ft
#200 Sieve to #4 Sieve
< 500
<2
Very Soft
500-1,000
2 - 3
Soft
1,001 - 2,000
4 - 7
Firm
2,001 - 4,000
8-16
Stiff
4,001 - 8,000
17-32
Very Stiff
> 8,001
32+
Hard
RELAT(1/E DENSITY OF COARSE�GRAINED SOILS
Standard Penetration (SPT) Relative Density
or N -Value (SS) Blows/Ft
0 - 3 Very Loose
4 - 9 Loose
10-29 Medium Dense
30-49 Dense
50+ Very Dense
SPT penetration test using 140 pound hammer, with 30 inch free fall on 2 inch outside diameter(1-3/8 ID) sampler
For ring sampler using 140 Ib hammer, with a 30 inch free fall on 3 inch outside diameter (2-1/2 ID) sample,
use N -value x 0.7 to get Standard N -value
For fine grained soil consistency, thumb penetration used per ASTM D-2488
r
F�ELATIV� �+RflPOR�'IONS OF SAND AND GRA�/�L;
f
Descriptive Term of other
Percent of Dry
constituents
Weight
Trace
< 15
With
15-29
Modifier
> 30
Description General Characteristics
Very Dense to Moderately Hard Partially Cemented Granular Soil - Can be carved with a knife and broken
with force by hand.
Very Stiff to Moderately Hard Partially Cemented Fine -Grained Soil - Can be carved with a knife and
broken with force by hand.
Moderately Hard Moderate hammer blow required to break a sample
Hard Heavy hammer blow required to break a sample
Very Hard Repeated heavy hammer blow required to break a sample
�GRA1N
SIZE TERMINOLOGY
F
Major
Component of
Particle Size
Sample
Boulders
Over 12 inches
Cobbles
3 inches to 12 inches
Gravel
#4 Sieve to 3 inches
Sand
#200 Sieve to #4 Sieve
Silt or Clay
Passing #200 Sieve
Description General Characteristics
Very Dense to Moderately Hard Partially Cemented Granular Soil - Can be carved with a knife and broken
with force by hand.
Very Stiff to Moderately Hard Partially Cemented Fine -Grained Soil - Can be carved with a knife and
broken with force by hand.
Moderately Hard Moderate hammer blow required to break a sample
Hard Heavy hammer blow required to break a sample
Very Hard Repeated heavy hammer blow required to break a sample
LOG LEGEND
SAMPLING
MATERIAL
DESCRIPTION
Soil Pattern
USCS Symbol
USCS Classification
Very Loose
FILL
Artificial Fill
MH
GP or GW
Poorly/Well graded GRAVEL
Loose
GM
Silty GRAVEL
H
GC
Clayey GRAVEL
Medium Dense
GP -GM or GW -GM
Poorly/Well graded GRAVEL with Silt
VH
GP -GC or GW -GC
Poorly/Well graded GRAVEL with Clay
Dense
SP or SW
Poorly/Well graded SAND
SM
Silty SAND
Very Dense
SC
Clayey SAND
SP -SM or SW -SM
Poorly/Well graded SAND with Silt
x
SP -SC or SW -SC
Poorly/Well graded SAND with Clay
SC -SM
Silty Clayey SAND
ML
SILT
MH
Elastic SILT
CL -ML
Silty CLAY
CL
Lean CLAY
CH
Fat CLAY
PCEM
PARTIALLY CEMENTED
CEM
CEMENTED
BDR
BEDROCK
SAMPLING
Cohesionless
SPT.........
Ring Sample
No Recovery
Bulk Sample
Water Table
Cohesive Soils
NR
VL
Very Loose
CONSISTENCY
Cohesionless
Soils
Cohesive Soils
Cementation
VL
Very Loose
So
Soft
MH
Moderately Hard
L
IVD.
Loose
F
Firm
H
Hard
MD
Medium Dense
S
Stiff
VH
Very Hard
D
Dense
VS
Very Stiff
Very Dense
TEST PIT LOG
LOGGED BY: DCW
PROJECT #: 1779-ID3 METHOD: Backhoe
F,r
PROJECT: Locust Grove Apartments EXCAVATOR: Just Dig It
CLIENT: JUB Engineers DATE: 1/14/15
E C� T E K LOCATION: ELEVATION:
C
7SAMPLES
TEST PIT NUMBER: TP-1REMARKS
c
G
v
MATERIAL DESCRIPTION AND COMMENTS
FILL
Brown to Dk Brown Sandy SILT w/ organics; moist
So
1
SM
Lt Brown to Brown Silty SAND w/ some gravel; slightly
MD
moist
2
SP
Lt Brown Partially CEMENTED SANDS w/ silt and gravel;
VD -
3
slightly moist
H
4
5
SP
Tan to Lt Brown Fine-Med Coarse SAND; slightly moist
MD
6
7
SP
Tan to Lt Brown SAND w/ gravel & some cobbles; slightly
MD
8
moist
9
wet
Water measured at 9.5'
10—
......saturated
11
Bottom of Test Pit @ IV -0"
12-
2131415
13-
14-
15=
16-
6171819
17-
18—
"1
20
320 E. Corporate Drive, Suite 300, Meridian, Idaho 83642 (208) 888-7010 Fax: (208) 888-7924
TEST PIT LOG
LOGGED BY: DCW
PROJECT #: 1779-1 D3 METHOD: Backhoe
PROJECT: Locust Grove Apartments EXCAVATOR: Just Dig It
CLIENT: JUB Engineers DATE: 1/14/15
G E O T E K LOCATION: ELEVATION:
SAMPLES
C
v
QN
a
TEST PIT NUMBER: TP -2
REMARKS
o
M
Eco
m
y
D
o
v
MATERIAL DESCRIPTION AND COMMENTS
FILL
Brown to Dk Brown Sandy SILT w/ organics; moist
So
1
ML
Lt Brown to Brown Sandy SILT; slightly moist
S
2
CH
Lt Brown to Brown Sandy Fat CLAY; moist
F
3
4
SP
Lt Brown Partially CEMENTED SANDS w/ silt and gravel;
VD -
slightly moist
H
5
SP
Tan to Lt Brown SAND w/ gravel & some cobbles; slightly
MD
6
moist
7
8
9
moist to wet
10
saturated
Water encountered at
10.5'
11
Bottom of Test Pit @ 1 V-0"
12-
21314151617181920320
13-
14-
15-
16-
17-
18-
19-
20-
320E. Corporate Drive, Suite 300, Meridian, Idaho 83642 (208) 888-7010 Fax: (208) 888-7924
TEST PIT LOG
LOGGED BY: DCW
F'.0000
PROJECT #: 1779-ID3 METHOD: Backhoe
PROJECT: Locust Grove Apartments EXCAVATOR: Just Dig It
CLIENT: JUB Engineers DATE: 1/14/15
IG
E O T E K LOCATION: ELEVATION:
SAMPLES
a
=
C
y
dC
a
y
TEST PIT NUMBER: TP -3
LA
REMARKS
o
Ec
"o
o
co
m
co
CO)
D
v
MATERIAL DESCRIPTION AND COMMENTS
FILL
Brown to Dk Brown Sandy SILT w/ organics; moist
So
1CL
Lt Brown to Brown Sandy Lean CLAY; moist
F
2
SP
Lt Brown to Brown SAND w/ silt; slightly moist
MD
3
Sp
Lt Brown Partially CEMENTED SANDS w/ silt and gravel;
VD -
4
slightly moist
H
5
SP
Tan to Lt Brown SAND w/ gravel & some cobbles; slightly
MD
6
moist
-D
7
8
9
moist to wet
10
wet to saturated
Water encountered at
11
11.5'
—
Bottom of Test Pit @ 1 V-6"
12
13
14
15
16
17
18
19
L20
320 E. Corporate Drive, Suite 300, Meridian, Idaho 83642 (208) 888-7010 Fax: (208) 888-7924
TEST PIT LOG
LOGGED BY: DCW
PROJECT #: 1779-ID3 METHOD: Backhoe
PROJECT: Locust Grove Apartments EXCAVATOR: Just Dig It
CLIENT: JUB Engineers DATE: 1/14/15
G E O T E K LOCATION: ELEVATION:
SAMPLES
$
CL
w
E
TEST PIT NUMBER: TP -4
N
REMARKS
d
EC
_
a
N
v�
m
D
v
MATERIAL DESCRIPTION AND COMMENTS
FILL
Brown to Dk Brown Sandy SILT w/ organics; moist
So
1
CL
Lt Brown to Brown Sandy Lean CLAY; moist
F
2
SP
Lt Brown Partially CEMENTED SANDS w/ silt and gravel;
D-
slightly moist
VD
3
4
SP
Tan to Lt Brown SAND w/ gravel & some cobbles; slightly
MD
5
moist
-D
6
7
8
9
moist to wet
10
wet to saturated
Water encountered at
11
11.0'
.........
12 Bottom of Test Pit @ 1 V-6"
13-
14-
15-
16-
17-
18-
191
3141516171819
20
320 E. Corporate Drive, Suite 300, Meridian, Idaho 83642 (208) 888-7010 Fax: (208) 888-7924
TEST PIT LOG
320
LOGGED BY: DCW
PROJECT #: 1779-ID3 METHOD: Backhoe
PROJECT: Locust Grove Apartments EXCAVATOR: Just Dig It
CLIENT: JUB Engineers DATE: 1/14/15
G E O T E K LOCATION: ELEVATION:
SAMPLES
C
CL
)
c
d
�
TEST PIT NUMBER: TP -5
c
N
REMARKS
�,
E0
�
a
.N
0
0
N
:)MATERIAL
V
DESCRIPTION AND COMMENTS
FILL
Brown to Dk Brown Sandy SILT w/ organics; moist
So
1
ML
Tan Sandy SILT; slightly moist
S
2
CH
Brown to Dk Brown Sandy Fat CLAY; moist
F
3
Sp
Lt Brown Partially CEMENTED SANDS w/ silt and gravel;
VD -
4
slightly moist
H
5 mSP
Tan to Lt Brown SAND w/ gravel & some cobbles; slightly
MD
moist
6
7
8
moist to wet
9
wet to saturated
Water encountered at
10-
10.01
11
Bottom of Test Pit @ I V-0"
12-
21314151617181920
13-
14-
15-
16-
17-
18-
19-
20-
320 E. Corporate Drive, Suite 300, Meridian, Idaho 83642 (208) 888-7010 Fax: (208) 888-7924
TEST PIT LOG
LOGGED BY: DCW
F'.00a
PROJECT #: 1779-ID3 METHOD: Backhoe
PROJECT: Locust Grove Apartments EXCAVATOR: Just Dig It
CLIENT: JUB Engineers DATE: 1/14/15
G E O T E K LOCATION: ELEVATION:
SAMPLES
a
TEST PIT NUMBER: TP -6
REMARKS
CL
o
Ec
"o
o
iii
m
N
Cn
=)
v
MATERIAL DESCRIPTION AND COMMENTS
FILL
Brown to Dk Brown Sandy CLAY w/ organics; moist
So
1
2
CL
Tan Sandy Lean CLAY; moist
F
3
SM
Lt Tan to Tan Silty SAND; slightly moist
MD
4
5
SP
Tan to Lt Brown SAND w/ gravel & some cobbles; slightly
MD
moist
-D
6
7
8
9
moist to wet
10
wet to saturated
Water encountered at
11
11.0'
—
Bottom of Test Pit @ 1 V-6"
12
13-
314151617181920320
14-
15-
16-
17-
18-
19-
20-
320E. Corporate Drive, Suite 300, Meridian, Idaho 83642 (208) 888-7010 Fax: (208) 888-7924
��rllm
FIELD TESTS AND OBSERVATIONS (I 779-ID3)
PERCOLATION TESTS
The infiltration rate was determined by conducting percolation tests for onsite earth materials. The
infiltration rate was determined in inches per hour in general accordance with the City of Eagle
requirements. Infiltration rate results are presented below.
GROUND WATER MONITORING RESULTS
Ground water monitoring results are presented below. Ground water elevation results are recorded
in feet below existing grade.
LOCATION
INFILTRATION RATE
LOCATION
(Inches/Hour)
P- I (TP -2) @ 2'-6"
24.0+
P-2 (TP -4) @ 1'-8"
24.0+
GROUND WATER MONITORING RESULTS
Ground water monitoring results are presented below. Ground water elevation results are recorded
in feet below existing grade.
LOCATION
GROUNDWATER
ELEVATION
GW- I (TP -1)
9'-6"
GW -2 (TP -5)
9'-99p+
GW -3 (TP -6)
+ Indicates a dry reading to the bottom of piezometer
LABORATORY TESTS RESULTS (I 779-ID3)
ATTERBERG LIMITS
Atterberg limits were performed on representative samples in general accordance with ASTM D 4318.
The results are shown in the following plates.
PARTICLE SIZE ANALYSIS
Sieve analyses were performed in general accordance with ASTM test method C 136 and ASTM C 117.
Test results are presented in the following plates.