2005-9474 CN/G c Sect & TESTING, rNc.
a PHONE P.O. Box 600627
(619)280-4321
j San Diego, CA 92160-0627
T O L L F R E E 6280 Riverdale Street
(877)215-4321
W F A X San Diego, CA 92120
- (619) 280-4717 www.scst.com
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REPORT OF
SOIL INVESTIGATION
PROPOSED OLSTAD RESIDENCE
942 STRATFORD DRIVE
ENCINITAS, CALIFORNIA
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PREPARED FOR:
DAVE AND LISA OLSTAD
942 STRATFORD DRIVE
ENCINITAS, CALIFORNIA 92024
PREPARED BY:
SOUTHERN CALIFORNIA SOIL & TESTING, INC.
6280 RIVERDALE STREET
SAN DIEGO, CALIFORNIA 92120
Providing Professional Engineering Services Since 1959
< Sol, & TiSTING, INC.
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� PHONE p.0. Box 600627
® (619) 280-4321
San Diego, CA 92160-0627
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(877) 215-4321 6280 Riverdale Street
= San Diego, CA 92120
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December 12, 2005 SCS&T No. 0511060
Report No. 1 R
Dave and Lisa Olstad
942 Stratford Drive
Encinitas, California 92024
Subject: REPORT OF SOIL INVESTIGATION
PROPOSED OLSTAD RESIDENCE
942 STRATFORD DRIVE
ENCINITAS, CALIFORNIA
Dear Mr. and Mrs. Olstad:
In accordance with your request, we have completed a soil investigation for the subject project.
The findings and recommendations of our study are presented herewith.
In general, the findings of this study indicate that the site is suitable for the proposed
development. The main geotechnical condition affecting construction is the presence of
potentially compressible fill underlying the site to a depth of about 3'/4 feet. This condition will
require special site preparation and foundation considerations as described herein.
If you have any questions after reviewing the findings and recommendations contained in the
attached report, please do not hesitate to contact this office. This opportunity to be of
professional service is sincerely appreciated.
Respectfully submitted,
SOUTHERN CALIFORNI��-.--44ZZSTING, INC.
Daniel dler C 6 �3
Vice Pre dent
DBA:sd
(1) Addressee
(5) A2 Studios
TABLE OF CONTENTS
SECTION PAGE
1. INTRODUCTION AND PROTECT DESCRIPTION.....................................................................1
2. PROJECT SCOPE............. ....................................................................... ................................1
3. FINDINGS...........................................................................................................................................2
3.1. SITE DESCRIPTION..........................................................................................................................2
3.2. SOIL DESCRIPTION..........................................................................................................................2
3.3. GROUNDWATER.............................................................................................................................2
4. CONCLUSIONS..................................................................................................................................2
5. PRELIMINARY RECOMMENDATIONS......................................................................................3
5.1. GRADING........................................................................................................................................3
5.1.1. Site Preparation....................................................................................................................3
5.1.2. Surface Drainage..................................................................................................................3
5.1.3. Earthwork..............................................................................................................................4
5.2. FOUNDATIONS................................................................................................................................4
5.2.1. General..................................................................................................................................4
5.2.2. 'Rein rcement........................................................................................................................4
5.2.3. Seismic Design Factors.........................................................................................................4
5.2.4. Settlement Characteristics.....................................................................................................5
5.2.5. E yansion Choracteristics....................................................................................................5
5.2.6. Foundation Plan Review.......................................................................................................5
5.2.7. Foundation E.rcavation Observation.....................................................................................5
5.3. INTERIOR CONCRETE SLABS-ON-GRADE........................................................................................5
5.4. EXTERIOR CONCRETE SLABS-ON-GRADE.......................................................................................6
5.5. SOLUBLE SULFATE.........................................................................................................................7
5.6. EARTH RETAINING WALLS .............................................................................................................7
5.6.1. Foundations...........................................................................................................................7
5.6.2. Passive Pressure...................................................................................................................7
5.6.3. Active Pressure..................................................:...................................................................7
5.6.4. Retaining Wall.Subdrains and Waterproofing......................................................................8
5.6.5. Backfill..................................................................................................................................8
5.6.6. Factor of Sofetv.....................................................................................................................8
6. LIMITATIONS...................................................................................................................................8
6.1. REVIEW, OBSERVATION AND TESTING ..........................................................................................8
6.2. UNIFORMITY OF CONDITIONS.........................................................................................................8
6.3. CHANGE IN SCOPE..........................................................................................................................9
6.4. TIME LIMITATIONS.........................................................................................................................9
6.5. PROFESSIONAL STANDARD............................................................................................................9
7. FIELD EXPL ORATION..................................................................................................................10
8. LABORATORY TESTING..............................................................................................................10
M Y
TABLE OF CONTENTS (Continued)
SECTION PAGE
ATTACHMENTS
FIGURES
Figure 1 Site Location Map
' T
PLATES
Plate 1 Site Plan
Plate 2 Soil Classification Chart
Plates 3-5 Test Pit Logs
Plate 6 Direct Shear
Plate 7 Single Point Consolidation
Plate 8 Subdrain Detail
Plate 9 Retaining Wall Subdrain
APPENDICES
Appendix A Technical Bulletin
ST
4 SOIL & TI STING, INC.
! P H O N E P.O. Box 600627
0 (619) 280-4321 San Diego, CA 92160-0627
i T O L L F R E E
U (877) 215-4321
6280 Riverdale Street
= F A X San Diego, CA 92120
(619) 280-4717 www.scst.com
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SOIL INVESTIGATION
z PROPOSED OLSTAD RESIDENCE
942 STRATFORD DRIVE
ENCINITAS, CALIFORNIA
1. INTRODUCTION AND PROJECT DESCRIPTION
This report presents the results of our soil investigation for a proposed residential project to be
constructed at 942 Stratford Drive in the city of Encinitas, California. The site location is shown
on Figure No. 1 on the following page.
We understand that the project will consist of the construction of a two-story structure of wood-
frame construction. Shallow foundations and conventional concrete slab-on-grade floor
systems are anticipated. Grading is expected to be relatively minor and for drainage purposes.
To assist in the preparation of this report, we were provided with a site plan prepared by A2
Studios, dated January 7, 2005. The site configuration and the approximate locations of our
exploratory trenches are shown on Plate No. 1.
2. PROJECT SCOPE
The investigation consisted of: surface reconnaissance, subsurface exploration, obtaining
representative disturbed and undisturbed samples, laboratory testing, analysis of field and
laboratory data, and preparation of this report. More specifically, the intent of this investigation
was to:
a) Explore the subsurface conditions to the depths influenced by the proposed
construction.
b) Evaluate the pertinent engineering properties of the various strata that can influence the
proposed construction, including bearing capacities, expansion characteristics, and
settlement potentials.
c) Address potential construction considerations that may be encountered due to
subsurface conditions and provide recommendations concerning these conditions.
d) Develop geotechnical engineering criteria for site grading.
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Dave and Lisa Olstad December 12,2005
Proposed Olstad Residence SCS&T No. 0511060-1 R
Page 2
e) Recommend an appropriate foundation system for the type of structure anticipated and
develop preliminary soil engineering design criteria for the recommended foundation
system.
3. FINDINGS
3.1. SITE DESCRIPTION
The project site is a rectangular-shaped parcel located at 942 Stratford Drive in the city of
Encinitas, California. The site is bordered by Stratford Drive on the east and developed
residential property on all other sides. The property slopes gently to the east and west and is
occupied by a single-family residential structure, concrete patio, asphaltic concrete driveway
and minor walls. Vegetation consists of typical residential grasses and landscape.
3.2. SOIL DESCRIPTION
Based upon the findings of our investigation, the site is underlain by artificially-placed fill soils
and terrace deposits.
Fill Soils: As exposed in the test pits, the site is underlain by about 6 inches of landscape
topsoil. This material is underlain by fill soils. Fill was encountered in all the test pits,
extending to a maximum depth of about 3'/4 feet below existing grade. These deposits
consist of brown to red brown, moist, loose, slightly silty sand. The fill in Test Pit No. 2
contains roots.
Terrace Deposits: Terrace deposits underlie the fill. This material consists of brown
grayish-tan, moist, dense, silty sand.
3.3. GROUNDWATER
No groundwater was noted during our investigation. However, changes in groundwater levels
can occur after development of a site, as a result of alteration of the permeability characteristics
of the soil, alteration in drainage patterns, or increases in irrigation water. It is our opinion that
seepage can be most effectively addressed on an individual basis if and when it develops.
4. CONCLUSIONS
In general, no geotechnical conditions were encountered which would preclude the construction
of the residence as currently proposed provided the recommendations presented herein are
implemented.
The subject site is underlain by about 3'/4 feet of potentially compressible fill. These materials
are considered unsuitable, in their present condition, for the support of settlement sensitive
S i_T,
Dave and Lisa Olstad December 12, 2005
Proposed Olstad Residence SCS&T No. 0511060-1 R
Page 3
improvements. It is therefore recommended that the fill be removed. It can be replaced as
compacted fill where needed to meet final grades.
5. PRELIMINARY RECOMMENDATIONS
5.1. GRADING
5.1.1. Site Preparation
Site preparation should begin with the demolition of existing improvements and the removal
of the resulting debris, as well as any vegetation and deleterious matter from the areas of
the site to receive the proposed structure and any associated improvements. It is
recommended that the existing fill be removed. The soils removed should be moisture
conditioned, and replaced as uniformly compacted fill where needed to meet proposed
grades. As encountered in the test pits, maximum removal depth will be about 3 feet.
However, deeper removals may be necessary in areas of the site not investigated.
Minimum lateral removal limits should be 5 feet beyond the perimeter of the improvements
or property line, whichever is less. The soils exposed at the bottom of the excavation should
be scarified to a depth of 12 inches, moisture-conditioned and compacted to at least 90%
relative compaction prior to the placement of fill soils. All fill should be placed in 6- to 8-thick
loose lifts and compacted to at least 90% relative compaction. The maximum dry density
and optimum moisture content for the evaluation of relative compaction should be
determined in accordance with ASTM D 1557-00, Method A or C.
5.1.2. Surface Drainage
Proper drainage is imperative. Drainage around the improvements should be designed to
collect and direct surface water away from the improvements and toward appropriate
drainage devices. Rain gutters with downspouts that discharge runoff away from the
structure into controlled drainage devices are recommended.
The ground around the proposed improvements should be graded so that surface water
flows rapidly away from the improvements without ponding. In general, we recommend that
the ground adjacent to structures be sloped away at a gradient of at least 2 percent.
Densely vegetated areas where runoff can be impaired should have a minimum gradient of
at least 5 percent within the first 5 feet from the structure.
Drainage patterns provided at the time of fine grading should be maintained throughout the
life of the proposed improvements. Site irrigation should be limited to the, minimum
necessary to sustain landscape growth, and over-watering should be avoided. Should
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Dave and Lisa Olstad December 12,2005
Proposed Olstad Residence SCS&T No. 0511060-1 R
Page 4
excessive irrigation or impaired drainage occurs, zones of wet or saturated soil may
develop.
5.1.3. Earthwork
All earthwork should be accomplished in accordance with the attached Recommended
Grading Specifications and Special Provisions. All special site preparation
r recommendations presented in the sections above will supersede those, in the standard
Recommended Grading Specifications. Fill should be compacted to at least 90% relative
compaction at or slightly over optimum moisture content. Utility trench backfill within 5 feet
of the proposed structures and beneath pavements should be compacted to a minimum of
90% relative compaction. The upper 12 inches of subgrade beneath paved areas should be
compacted to 95% relative compaction. This compaction should be obtained by the paving
contractor just prior to placing the aggregate base material and should not be part of the
mass grading requirements.
5.2. FOUNDATIONS
5.2.1. General
Shallow foundations may be utilized for the support of the proposed improvements. The
footings should have a minimum depth of 18 inches below lowest adjacent finish pad grade
(below interior slab-on-grade and sand blanket). A minimum width of 12 and 24 inches is
recommended for continuous and isolated footings, respectively. , A bearing capacity of
2000 pounds per square foot (psf) may be assumed for said footings. For property line
footings, a bearing capacity of 1000 psf is recommended. The bearing capacity may be
increased by 1/3 when considering wind or seismic forces.
5.2.2. Reinforcement
Both exterior and interior continuous footings should be reinforced with at least two No. 5
bars positioned near the bottom of the footing and at least two No. 5 bars positioned near
the top of the footing. This reinforcement is based on soil characteristics and is not intended
to be in lieu of reinforcement necessary to satisfy structural considerations.
5.2.3. Seismic Design Factors
Provided below are seismic design factors applicable to the subject project. The seismic
design factors were determined in accordance with the California Building Code.
ACT
Dave and Lisa 01stad December 12,2005
Proposed Otstad Residence SCS&T No. 0511060-1 R
Page 5
Seismic Zone 4: Z=0.40
Source Fault: Rose Canyon
Seismic Source Type: B
Soil Profile Type: So
Distance to Seismic Source: 4.0 kilometers
Near-Source Factor Na=1.1
Near-Source Factor.N,=1.3
It is likely that the site will experience the effects of at least one moderate to large
earthquake during the life of the proposed improvements.
5.2.4. Settlement Characteristics
The anticipated total and/or differential settlements for the proposed structure may be
considered to be within tolerable limits provided the recommendations presented in this
report are followed. It should be recognized that minor cracks normally occur in concrete
slabs and foundations due to shrinkage during curing or redistribution of stresses and some
cracks may be anticipated. Such cracks are not necessarily an indication of excessive
vertical movements.
5.2.5. Expansion Characteristics
The prevailing foundation soils were found to be nondetrimentally expansive. The
recommendations in this report reflect this condition.
5.2.6. Foundation Plan Review
The foundation plans should be submitted to SCS&T for review to ascertain that the
recommendations contained in this report have been implemented, and no revised
recommendations are necessary due to change in the development scheme.
5.2.7. Foundation Excavation Observation
It is recommended that all foundation excavations be approved by a representative from this
office prior to forming or placement of reinforcing steel.
5.3. INTERIOR CONCRETE SLABS-ON-GRADE
Interior concrete slab-on-grade floors should have a thickness of at least 4 inches and be
reinforced with at least No. 3 reinforcing bars placed at 18 inches on center each way. Slab
reinforcement should be placed approximately at mid-height of the slab and extend at least 6
inches down into the footings. Slab reinforcement should be placed approximately at mid-height
of the slab and should extend at least 6 inches into the footings. Slabs-on-grade should be
underlain by a 4-inch thick blanket of clean, poorly graded, coarse sand (sand equivalent = 30
or greater) or crushed rock. This blanket should consist of no more than 20 percent and 10
I
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Dave and Lisa Olstad December 12, 2005
Proposed Oistad Residence SCS&T No. 0511060-1 R
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percent passing the #100 and #200 sieves, respectively. Where moisture sensitive floor
coverings are planned, vapor retardant should be placed over the sand layer. An additional 2
inches of sand should be placed over the vapor retardant. Typically, visqueen is used as a
vapor retardant. If visqueen is used, a minimum 10-mil is recommended.
It is our understanding that the moisture protection layer described above will allow the
transmission of 6 to 12 pounds of moisture per 1000 square feet per day through the slab under
normal conditions. Moisture emissions may vary widely depending upon factors such as
concrete type and subgrade moisture conditions. If this amount of moisture is excessive,
additional recommendations will be provided by this office. It is recommended that moisture
emission tests be performed prior to the placement of floor coverings to ascertain whether
moisture emission values are within the manufacturer's specifications. In addition, over-watering
should be avoided, and good site drainage should be established and maintained to prevent the
build-up of excess sub-slab moisture.
5.4. EXTERIOR CONCRETE SLABS-ON-GRADE
Exterior slabs and driveway slabs should have a minimum thickness of 4 inches and should be
reinforced with at least No. 3 bars at 18 inches on center each way. All slabs should be
provided with weakened plane joints. Exterior slabs adjacent to landscape areas should be
provided with cut off walls designed following the minimum recommendations for dimension and
reinforcement provided for continuous footings.
Joints should be placed in accordance with the American Concrete Institute (ACI) guidelines
Section 3.13. Joints should be placed where cracks are anticipated to develop naturally.
Alternative patterns consistent with ACI guidelines also can be used. The landscape architect
can be consulted in selecting the final joint patterns to improve the aesthetics of the concrete
slabs-on-grade.
A 1-inch maximum size aggregate concrete mix is recommended for exterior slabs. A
water/cement ratio of less than 0.6 is recommended. A lower water content will decrease the
potential for shrinkage cracks. It is strongly suggested that the driveway concrete mix have a
minimum compressive strength of 3,000 pounds per square inch (psi). This suggestion is
meant to address early driveway use prior to full concrete curing. Both coarse and fine
aggregate should conform to the "Greenbook" Standard Specifications for Public Works
Construction.
Special attention should be paid to the method of curing the concrete to reduce the potential for
excessive shrinkage and resultant random cracking. It should be recognized that minor cracks
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Dave and Lisa Olstad December 12, 2005
Proposed Olstad Residence SCS&T No. 0511060-1 R
Page 7
occur normally in concrete slabs and foundations due to shrinkage during curing redistribution of
stresses. Some shrinkage cracks may be expected. Such cracks are not necessarily an
indication of vertical movements or structural distress.
Factors that contribute to the amount of shrinkage that takes place in a slab-on-grade include
joint spacing, depth, and design; concrete mix components; water/cement ratio and surface
finishing techniques. According to the attached undated "Technical Bulletin" (see Appendix A)
published by the Southern California Rock Products Association and Southern California Ready
Mixed Concrete Association, flatwork formed of high-slump concrete (high water/cement ratio)
utilizing 3/8-inch maximum size aggregate ("Pea Gravel Grout' mix) is likely to exhibit extensive
shrinkage and cracking. Cracks most often occur in random patterns between construction
R joints.
5.5. SOLUBLE SULFATE \
It is recommended that water soluble sulfate tests be performed after grading is completed.
Furthermore, it should be recognized that post-construction factors such as fertilizer and/or
soluble sulfate in the water supply may increase water soluble sulfate contents to detrimental
levels. This potential should be evaluated by the project structural engineer.
5.6. EARTH RETAINING WALLS
5.6.1. Foundations
The recommendations presented in the foundation section of this report are also applicable
to earth retaining structures.
5.6.2. Passive Pressure
The passive pressure for the portions of the walls and foundations extending into compacted
fill or formational soils may be considered to be 350 psf per foot of depth up to a maximum
of 1500 psf. This pressure may be increased 1/3 for seismic loading. The coefficient of
friction for concrete to soil may be assumed to be 0.35 for the resistance to lateral
movement. When combining frictional and passive resistance, the friction should be
reduced by 1/3. The upper 12 inches of soil should not be considered when calculating
passive pressures for exterior walls.
5.6.3. Active Pressure
The active soil pressure for the design of unrestrained earth retaining structures with level
backfills may be assumed to be equivalent to the pressure of a fluid weighing 34 pounds per
cubic foot (pcf). This pressure does not consider any other surcharge loads. If any are
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Proposed Olstad Residence SCS&T No. 0511060-1 R
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anticipated, this office should be contacted for the necessary increase in soil pressure.
P These values also assume a granular and drained backfill condition. Waterproofing
specifications and details should be provided by the project architect. A subdrain detail is
r provided on the attached Plate No. 8.
5.6.4. Retaining Wall Subdrains and Waterproofing
Retaining wall subdrains should be installed in accordance with the detail presented on
Plate No. 9. Waterproofing specifications and details should be provided by the project
architect. The geotechnical engineer should be requested to verify that retaining wall
subdrains and waterproofing have been properly installed.
5.6.5. Backfill
All backfill soils should be compacted to at least 90% relative compaction. Expansive or
clayey soils should not be used for backfill material. Therefore, it is anticipated that
imported soil will be used for wall backfill. Imported fill should be approved by this office prior
to delivery to the site. The wall should not be backfilled until the grout has reached an
adequate strength.
5.6.6. Factor of Safety
The above values, with the exception of the allowable soil bearing pressure, do not include a
factor of safety. Appropriate factors of safety should be incorporated into the design to
prevent the walls from overturning and sliding.
6. LIMITATIONS
6.1. REVIEW, OBSERVATION AND TESTING
The recommendations presented in this report are contingent upon our review of final plans and
specifications. Such plans and specifications should be made available to the geotechnical
engineer and engineering geologist so that they may review and verify their compliance with this
report and with Appendix Chapter 33 of the Uniform Building Code.
It is recommended that SCS&T be retained to provide continuous soil engineering services
during the earthwork operations. This is to verify compliance with the design concepts,
specifications or recommendations and to allow design changes in the event that subsurface
conditions differ from those anticipated prior to start of construction.
6.2. UNIFORMITY OF CONDITIONS
The recommendations and opinions expressed in this report reflect our best estimate of the
project requirements based on an evaluation of the subsurface soil conditions encountered at
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Dave and Lisa O/stad December 12, 2005
Proposed Olstad Residence SCS&T No. 0511060-1 R
f Page 9
the subsurface exploration locations and on the assumption that the soil conditions do not
deviate appreciably from those encountered. It should be recognized that the performance of
the foundations and/or cut and fill slopes may be influenced by undisclosed or unforeseen
variations in the soil conditions that may occur in the intermediate and unexplored areas. Any
unusual conditions not covered in this report that may be encountered during site development
should be brought to the attention of the geotechnical engineer so that he may make
modifications if necessary.
6.3. CHANGE IN SCOPE
This office should be advised of any changes in the project scope or proposed site grading so
that we may determine if the recommendations contained herein are appropriate. This should
be verified in writing or modified by a written addendum.
6.4. TIME LIMITATIONS
The findings of this report are valid as of this date. Changes in the condition of a property can,
however, occur with the passage of time, whether they are due to natural processes or the work
of man on this or adjacent properties. In addition, changes in the standards-of-practice and/or
government codes may occur. Due to such changes, the findings of this report may be
invalidated wholly or in part by changes beyond our control. Therefore, this report should not be
relied upon after a period of two years without a review by us verifying the suitability of the
conclusions and recommendations.
6.5. PROFESSIONAL STANDARD
In the performance of our professional services, we comply with that level of care and skill
ordinarily exercised by members of our profession currently practicing under similar conditions
and in the same locality. The client recognizes that subsurface conditions may vary from those
encountered at the locations where our borings, surveys, and explorations are made, and that
our data, interpretations, and recommendations be based solely on the information obtained by
us. We will be responsible for those data, interpretations, and recommendations, but shall not
be responsible for the interpretations by others of the information developed. Our services
consist of professional consultation and observation only, and no warranty of any kind
whatsoever, express or implied, is made or intended in connection with the work performed or to
be performed by us, or by our proposal for consulting or other services, or by our furnishing of
oral or written reports or findings.
S c
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Dave and Lisa Olstad December 12, 2005
Proposed Olstad Residence SCS&T No. 0514060-1R
Page 10
7. FIELD EXPLORATION
- F
Three hand dug test pits were excavated on February 23, 2005 at the locations indicated on the
attached Plate No. 1. The field work was conducted under the observation of our-engineering
personnel.
The pits were carefully logged when made. These logs are presented on the following Plate
Nos. 3 through 5. The soils are described in accordance with the Unified Soil Classification
System as illustrated on the attached simplified chart on Plate No. 2. In addition, a verbal
textural description, the wet color, the apparent moisture and the density or consistency are
provided. The density of granular soils is given as very loose, loose, medium dense, dense or
very dense. The consistency of silts or clays is given as very soft, soft, medium stiff, stiff, very
stiff, or hard.
Disturbed and "undisturbed" samples of typical and representative soils were obtained and
returned to the laboratory for testing.
8. LABORATORY TESTING
Laboratory tests were performed in accordance with the generally accepted American Society
for Testing and Materials (ASTM) test methods or suggested procedures. A brief description of
the tests performed is presented below:
a) CLASSIFICATION: Field classifications were verified in the laboratory by visual
examination. The final soil classifications are in accordance with the Unified Soil
Classification System.
b) MOISTURE-DENSITY: In-place moisture contents and dry densities were determined
for representative soil samples. This information was an aid to classification and
permitted recognition of variations in material consistency with depth. The dry unit
weight is determined in pounds per cubic foot, and the in-place moisture content is
determined as a percentage of the soil's dry weight. The results are summarized in the
pit logs.
c) COMPACTION TEST: The maximum dry density and optimum moisture content of
typical soils were determined in the laboratory in accordance with ASTM Standard Test
D 1557-91, Method A. The results of these tests are presented herein.
Sample Description Maximum Optimum
Density Moisture
P2 @ 1'-3' Brown, Silty Sand 125.0 9.4
i_CT
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Proposed Olstad Residence SCS&T No. 0511060-1 R
Page 11
e) DIRECT SHEAR TEST: A direct shear test was performed in accordance with ASTM D
3080. The shear stress was applied at a constant rate of strain of approximately 0.02
inch per minute. The results of these tests are presented on Plate No. 6.
f) SINGLE POINT CONSOLIDATION TESTS: Single point consolidation tests were
performed on selected "undisturbed" samples. The consolidation apparatus was
designed to accommodate a 1-inch high by 2.375-inch or 2.500-inch diameter soil
sample laterally confined by a brass ring. Porous stones were placed in contact with the
top and bottom of the sample to ,permit the addition or release of pore fluid during
j testing. Selected loads were applied to the samples and the resulting deformations were
recorded. The percent consolidation is reported as the ratio of the amount of vertical
compression to the original sample height. The test samples were inundated to
determine their behavior under the anticipated loads as soil moisture increases. The
results of these tests are presented on Plate No. 7.
S
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SUBSURFACE EXPLORATION LEGEND
UNIFIED SOIL CLASSIFICATION CHART
SOIL DESCRIPTION GROUP TYPICAL NAMES
SYMBOL
1. COARSE GRAINED,more than half of material is larger than No.200 sieve size.
GRAVELS CLEAN GRAVELS GW Well graded gravels,gravel-sand mixtures, little or no fines.
More than half of
coarse fraction is GP Poorly graded gravels,gravel sand mixtures,little or no fines.
larger than No.4
sieve size but GRAVELS WITH FINES GM Silty gravels,poorly graded gravel-sand-sift mixtures.
smaller than 3*. (Appreciable amount of fines)
SANDS CLEAN SANDS SW Well graded sand,gravelly sands, little or no fines.
More than half of
coarse fraction is SP Poorly graded sands,gravelly sands,little or no fines.
smaller than No.4
sieve size. SANDS WITH FINES SM Silty sands,poorly graded sand and silty mixtures.
(Appreciable amount of fines)
SC Clayey sands,poorly graded sand and day mixtures.
[I. FINE GRAINED, more than half of material is smaller than No.200 sieve size.
SILTS AND CLAYS ML Inorganic sifts and very fine sands, rock flour,sandy sift
Liquid Limit less than 50 or clayey-sift-sand mixtures with slight plasticity.
CL Inorganic clays of low to medium plasticity,
gravelly clays,sandy clays,silty clays, lean days.
OL Organic sifts and organic silty clays or low plasticity.
SILTS AND CLAYS MH Inorganic sifts,micaceous or diatomaceous fine
Liquid Limit greater than 50 sandy or silty soils,elastic sifts.
CH Inorganic clays of high plasticity,fat clays.
OH Organic clays of medium to high plasticity.
111. HIGHLY ORGANIC SOILS PT Peat and other highly organic soils.
V - Water level at time of excavation or as indicated CK Undisturbed chunk sample
US - Undisturbed,driven ring sample or tube sample M Bulk Sample
SC - Sand Cone SP - Standard penetration sample
CON - Consolidation DS - Direct Shear
El - Expansion Index SA Sieve Analysis
MS - Maximum Size of Particle PI Plastic Index
MAX - Maximum Density RC Relative Compaction
ST Shelby Tube UC Unconfined Compression
SPT Standard Penetration Sample TX Triaxial Compression
pH pH&Resistivity RS Ring Shear
SF/CL Suff ate&Chloride AL Atterberg Limits
SOUTHERN CALIFORNIA PROPOSED OLSTAD RESIDENCE
S T SOIL & TESTING, INC. BY: DBA JDATE: 4/4/2005
JOB NUMBER: 0511060-1 1 PLATE NO.: 2
GC Clayey gravels,poorly graded gravel-sand,clay mixtures.
LOG OF TEST PIT NUMBER P-1
Date Excavated: 02-23-05 Logged by: DAS
Equipment: Hand tools Project Manager: DBA
Surface Elevation (ft): N/A Depth to Water(ft): N/A
SAMPLES
w
W o d a:
= U C Y W 0 U)
SUMMARY OF SUBSURFACE CONDITIONS Q v~i
0 o m ci ? m P
0 g
0
LANDSCAPE TOPSOIL
SNV FILL: Brown to reddish-brown, moist, loose, SLIGHTLY SILTY
SP SAND
1
2
3
TERRACE DEPOSITS: Brown greenish-tan, moist, dense,
sM SILTY SAND
4
CK
5
Pit ended at 5 feet
S C SOUTHERN CALIFORNIA PROPOSED OLSTAD RESIDENCE
S T SOIL & TESTING, INC. BY: DBA DATE: 04-04-05
JOB NUMBER: 0511060-1 PLATE NO.: 3
LOG OF TEST PIT NUMBER P-2
Date Excavated: 02-23-05 Logged by: DAS
Equipment: Hand tools Project Manager: DBA
Surface Elevation (ft): N/A Depth to Water(ft): N/A
SAMPLES
W 0 d }
ca cr
Ir a SUMMARY OF SUBSURFACE CONDITIONS o U)
D m j m Cr ~
> g
0
LANDSCAPE TOPSOIL
SM/ FILL: Brown to reddish-brown, moist, loose, SLIGHTLY SILTY
SP SAND, roots
1
3 TERRACE DEPOSITS: Brown greenish-tan, moist, dense,
SM SILTY SAND
5
CK
6
Pit ended at 6.5 feet
7
S C SOUTHERN CALIFORNIA PROPOSED OLSTAD RESIDENCE
ST SOIL & TESTING, INC. BY: DBA DATE: 04-04-05
JOB NUMBER: 0511060-1 PLATE NO.: 4
LOG OF TEST PIT NUMBER P-3
Date Excavated: 02-23-05 Logged by: DAS
Equipment: Hand tools Project Manager: DBA
Surface Elevation (ft): N/A Depth to Water(ft): N/A
SAMPLES
0 U
W o a CE
= U CC Y W
w (n SUMMARY OF SUBSURFACE CONDITIONS � � Q c~n CC
� o m m ~LU
J
C
LANDSCAPE TOPSOIL
SW FILL: Brown to reddish-brown, moist, loose, SLIGHTLY SILTY
sP SAND
1
2
3
TERRACE DEPOSITS: Brown greenish-tan, moist, dense,
snn SILTY SAND
4
CK 10.4 114.3
5
Pit ended at 5 feet
S C SOUTHERN CALIFORNIA PROPOSED OLSTAD RESIDENCE
S T SOIL & TESTING, INC. BY: DBA I DATE: 04-04-05
JOB NUMBER: 0511060-1 1 PLATE NO.: 5
DIRECT SHEAR SUMMARY
a
5000 -- - -- ----- ---- - -
4500 ------- ,- - --
I
4000
3500
L 3000 ------- — - - - -- ------- - —�'
u i
W
H2500 i ---- -= - - - --- -
a:
Lu 2000 -- - - - --- - = ----
i
1500 --- -- --
i
1000 ---- ---- —
500 ' -- -- ----- - ---- -
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
NORMAL STRESS [PSF] (2 3/8" SAMPLE)
ANGLE OF COHESION
INTERNAL INTERCEPT
SAMPLE DESCRIPTION FRICTION (0) (PSF)
P2 @ 1'-3' Remolded to 90% 34 200
$C
SOUTHERN CALIFORNIA PROPOSED OLSTAD RESIDENCE
$T SOIL & TESTING, INC. BY: DBA/SD DATE: 4/12/2005
JOB NUMBER: 0511060-1 PLATE NO.: 6
SINGLE POINT CONSOLIDATION TEST RESULT
SAMPLE NO. P3 @ 4'
INITIAL MOISTURE (%) 10.4
INITIAL DENSITY(PCF) 114.3
CONSOLIDATION BEFORE WATER ADDED (%) 1.5
CONSOLIDATION AFTER WATER ADDED (%) 1.8
FINAL MOISTURE (%) 12.2
AXIAL LOAD (KSF) 2.86
S C SOUTHERN CALIFORNIA PROPOSED OLSTAD RESIDENCE
S T SOIL & TESTING, INC. BY: DBA I DATE: 4/12/2005
JOB NUMBER: 0511060-1 IPLATE NO: 7
GRADING .'GNU► t."NDE:RE:t."I'
St'BDIUVIN DET.'!iL
Not to Scale
Vii' minimum
Flrusty Grade
Native
Sol/
Mir ifi 1.10
or equivalent
",ilinimum 1 ft- ft -- -_
/ Native 2°,(S 2'o
d" perforated ;Mastic pipe. S;al
DR35 or equivalent, hol#�s ,'own_
Minimum 1% to drain.
Concrete plug at
sofid pipe connection
SC
SOUTHERN CALIFORNIA PROPOSED OLSTAD RESIDENCE
$T SOIL &TESTING, INC. BY: DBA DATE: 04-12-05
JOB NUMBER: 0511060-1 IPLATE NO.: 8
—' 8" min.
Compacted
Gr- _Fill
'—"'""——�'"" Typical Retaining Wall
t. (D Subdrain Detail
crushed Not to Scale
2 rock. !
2I3 wall
height
5 _
1`
min.
Miradrain 6000
Compacted or equivalent.
p� 2:3 wall height
Fill
4
Q
1
f
0 Floor Slab Cr
Q Filter Fabric between rock and soil
Q Backcut Li
0 Waterproof back of wall following architect s specifications
Q 4 minimum perforated pipe. SDR35 or equivalent. holes down. 1 `all to outlet,
top of p;pe below top of slab. encased in 3,'4' crushed rock- Provhje 3 cubic feet
per :.near foot crushed rocK minimum. Crushed rock to be surroinded by filter
f.jbrie ,Mirafi 140N or equivalent). with 6" minimum overlap-
Provide sad OL,tlet pipe at Suitable location.
SC
SOUTHERN CALIFORNIA PROPOSED OLSTAD RESIDENCE
S SOIL & TESTING, INC. BY: DBA DATE: 04-04-05
JOB NUMBER: 0511060-1 1 PLATE NO.: 9
APPENDIX A
IT
A F
s �
s }
t
6
^� t
F
t
Southern Southern TECHNICAL
California California
Rock Ready Mixed
Products Concrete BULLETIN
Association Association
3/8" AGGREGATE "PEA GRAVEL GROUT"
MIX FOR USE IN FLATWORK
"Pea Gravel" pump mixes are being used in many locations in Southern California for slabs on
grade. Many complaints of`poor' concrete, mainly cracking, are due to the use of these mixes.
The ease of placing this "concrete" at long distances from the ready-mix truck with minimum
manpower has been the primary reason for the increased use of small line grout pumps.
Slabs made of high slump concrete improperly cured in any environment, with or without
reinforcement, will shrink excessively and crack extensively. These mixes tend to shrink more
than conventional 1" aggregate concrete mixes because of the need for more sand or fines and
water to make the mix more fluid or pumpable. This increased shrinkage will cause more
cracking. Minimum cement contents are usually ordered for economy. This makes for a higher
water/cement ratio that also leads to lower strengths and more cracking.
Freedom from random cracking is desired for all concrete floors. The degree to which random
shrinkage cracking can be reduced is improved by using concrete with a minimum shrinkage
potential that contains the maximum size of coarse aggregate and the maximum amount of
coarse aggregate consistent with placing and finishing methods. A larger aggregate size permits
a lower water content in the concrete which results in less shrinkage of the cement paste.
Suggested Spacing of Control Joints
Slab Less than Larger than Slump less Control Joint
thickness '/,-in.aggregate '/,-in.aggregate than 4-in. Min.depth
inches spacing,ft. spacing,ft. spacing,ft. Inches
3 6 8 9 0.75
4 8 10 12 1.00
5 10 13 15 1.25
6 12 15 18 1.50
7 14 18 21 1.75
Crack control of concrete slabs on grade is dependent upon slab thickness, shrinkage potential of
the concrete, curing environment and suggested joint spacing as demonstrated by the above
table.
Building Residential Driveways, Sidewalks
' F
and California
Concrete is an excellent building material for residential LAYOUT - JOINTS
construction. In addition to its superior overall appearance,it can The first task of the planning process is to determine the
be molded to many shapes and finished with many textures. location and slope of the concrete. The concrete should be sloped
Concrete may be colored or combined with stone,brick, or file so that water drains away from buildings and does not accumulate
paving in many interesting patterns. Concrete is a good material in low spots. A slope of 1 to 2%(or 1/8 tol/4 inch per linear foot)
to use for ground cover. Concrete slabs are low-maintenance, is generally recommended.
long-lasting home additions,especially when compared to other Concrete shrinks as it dries out and therefore will crack. In
materials. order to control cracks into straight lines and to minimize the
With carefull planning the average homeowner can construct occurrence of cracks,"contraction"and"isolation"joints are cut
his own patio or sidewalk, or he may choose to employ an or tool grooved into concrete slabs. "Joints" are simply
experienced contractor. In either case the homeowner should weakened cross sections in slabs resulting in good looking
familiarize himself with these guidelines so that the end result preplanned cracks.(figure 2)
will be consistent with the homeowner's desires.
Patio n� e
a b Service Stoop d Q
walk p
PQ
9
a � 3
D
a
0�9
0 • '
- Hours
a
Porch
Isolation
joints Steps
p P 9
a
Vb
L�V � a Front walk Er Double-car o/�p a �Q driveway p�lr: a
Control
joints
Isolation joints Sidewalk
Flare Curb
Fig. 1 Concrete walks,driveways,and patios should be provided with properly-
placed joints.
Control joints
SAWED TOOLED SLAB THICKNESS - REINFORCING
Most walks and driveways are constructed approximately 4"
SLAB •�I -? v.: ^ �� ;n, �,.a SLAB thick unless vehicles heavier than cats frequently pass over the
�� concrete. If the slab is subjected to heavier loads,a thickness of
=pit
SOIL ►1 -111 'lU llll so,l 5" is usually recommended It is important that the slabs are
CONCRETE CRACKS BELOW JOINTS uniformly thick. They should be as thick in the middle as they are
Fig. 2 at the edges.
Wire fabric or other types of steel reinforcing are generally not
needed or recommended for walks,patios,and driveways.
A) "Contraction Joints"are grooves built into slabs which
allow the concrete to break in a straight line. The maximum
distance between contraction joints should generally be held
down to about 10 feet. Slab sections should be approximately
square and should not be L-shaped. The length of a slab should
not exceed 1.5 times the width. Driveways which are two cars FORMWORK AND SUBGRADE PREPARATION
wide should be provided with a joint down the middle of the It is important that the soil beneath the slab is cut to a uniform
driveway (figure 1). Joints should be cut to a depth equal to at depth,is firm and compacted,and is moist but not wet. This soil
least 1/4 of the thickness of the slab (e.g. 1"deep in a 4" thick must be stable or the concrete will crack. It is usually not
slab). If the joint is to be created by saw-cutting rather than by necessary to place plastic sheeting under exterior concrete slabs
grooving with a tool before the concrete has hardened, the saw and it is never recommended that the concrete is placed directly
cutting should be done no later than the day after the concrete is onto plastic sheeting. If plastic sheeting is to be used,place a 2"
placed(especially during hot weather),the same day,if possible. layer of damp, not wet, sand on top of the plastic so that the
concrete can dry out uniformly throughout its depth.
Formwork must be sturdy and adequately braced 2 x 4-inch
B) "Isolation Joints"which separate the slab from adjacent boards are generally used and should be staked no more than 4
fixed structures such as house footings and plumbing fixtures feet apart. All "butt joints"in the lumber should be backed up
will allow the concrete to shrink back from those structures with a stake (figure 4). Remember, you will not have time to
instead of cracking out in the middle of the slab. In order to construct or reconstruct the formwork when the concrete arrives
prevent the new slab from bonding to existing structures and so do the necessary work now!
pipes, the slab should be isolated by placing premolded joint
material or building paper between the new slab and those
structures (figure 3). Either avoid installing drains cast into the
new slab,or allow for slab movement around the drain. A wide
joint space may be filled with caulking later.
Put stake at all butt joints. After nailing,cut
off stake for
easier finishing.
�- 2X4—.5 •
Isolation joints
HOUSE
1 Isolation joint �`� soil
Off Fig,4
When the slab shrinks,it is free to move, thus preventing a crack.
SLAE
SOIL
TOOL UP FIRST!
ndation settles, the slab Now is the time to line up the necessary tools, or to make sure
s not affected, the contractor has the tools he needs.
Fig. 3 A)Sturdy wheelbarrows or buggies are needed if the concrete
Use isolation joints between concrete sections that need to move relative can not be placed directly from the truck chute,and if the concrete
to each other. is not going to be pumped. A sturdy "wheelbarrow operator"or
two would be a nice addition to the labor crew.
B)Short-handed,square-ended shovels are used to spread out H)A semi-stiff bristled push-broom may be used to create a
the concrete in the forms, and to tamp down the concrete along roughened non-slip surface. In addition to providing an excellent
the edges of the slab. non-slip surface, the use of a "broom finish" reduces or
C)A straightedge(usually a 2 x 4 board) is used to strike off eliminates the need for trowelin fi
and level the concrete using a sawing style motion. g( 8��)•
` n D)A wood or metal float is used to further level the concrete A heavy spray application of liquid curing compound is the
without sealing the surface(figure 5). most practical method to prevent rapid drying and cracking of the
slab. Water may be used istead but the concrete must be kepi
continually wet for three to seven days. The use of plastic
sheeting may cause strong discoloration of the concrete surface.
ORDERING YOUR CONCRETE
If you order your own concrete,consult with your local ready.
mixed concrete producer to select the correct concrete mixturc
for your needs. Unless your house is located at high elevation,
Fig. 5 where freezing and thawing occurs regularly,there is no need tc
use air-entraining admixtures.
Bull floats may be either wood or magnesium. For non-air-entrained Be sure to tell the supplier if the concrete is to be pumped intc
concrete,.wood bull floats may be best but for air-entrained concrete, place. Be sure that the truck has access to the point at which yot
metal bull floats are better. Bull floats are used to get rid of the high and
ft want him to discharge his load. Check the width of driveways an(
low spots after staightedging. the height of overhead power and telephone lines. Be advise(
that concrete trucks are heavy and may crack existing walks an(
driveways.
The use of pea gravel (3/8')pump mix is not recommended fo
E)Edger tools should be used all the way around the exposed residential use. This type of concrete shrinks more when it drie
edges so that a rounded edge is formed. In addition to making the than concrete made with 1" gravel. Because it shrinks more i
concrete look good,rounded edges are safer is case of trips and also cracks more. If the homeowner must use a 3/8"
falls. pump mix please refer to the technical bulletin,3/8"A
_..fig rLegate"Pea Grave
F) Jointing tools are used to cut straight grooves into the Grout" Mix foE-U5e in Flatwork, published by the Technica
concrete. The jointing tool should have a blade depth of at least Committee of the Southern California Ready Mixed Concret
one-fourth the depth of the slab(figure 6). A contractor may elect Association.
to saw-cut joints the next day or may use premolded plastic strips. Concrete is sold in units of cubic yards (I cubic yard
G)A trowel is used to seal and compact the top surface of the cubic feet). Order quantities small enough so that you can equals
concrete. Repeated troweling will create a hard smooth slippery and finish the concrete before it hardens. An experience,
surface which usually is not desirable for exterior concrete homeowner should order no more than 3 cubic yards at one tim
exposed to rain or other water. and should have at least one other person to help. Avoid placin
Fig. 6
Fig.7
A straightedge such as a board, 1 inch thick and at least 6 inches wide, Broomed finish can be obtained by pulling damp brooms across freshl
is recommended as a guide when scoring with a groover.
floated or troweled surfaces.
concrete during very hot and windy weather,or at least get more
help. Concrete placed during hot weather will dry sooner and has REFERENCES
a tendency to crack. 1. "Concrete in Practice" (CIP) Series. Available from National
When placing your order remember to include an allowance Ready Mixed Concrete Association, 900 Spring Street, Silver
for an additional 10%. This should prevent you from coming up Springs,Maryland 20910.
just short of what you need due to waste,spillage,and variations 2. "Cement Mason's Guide," Publication No. PA122.02H, Portland
? in measurements. Cement Association, 5420 Old Orchard Road, Skokie, Illinois
60077
3. "Residential Concrete," National Association of Home Builders,
SAFETY 15th&"M"Streets,N.W.,Washington,D.C.20005.
Exercise crowd control over children,dogs,neighbors and the 4 Institute, P.O. Box 19150 Redford Station, Detroit, Michigan
like. Beware of trucks as they back into position. Wear protective 48219.
clothing like rubber gloves to keep the wet concrete off of your
skin. People with sensitive skin can have their skin irritated by
5 "Finishing Concrete Slabs, Exposed Aggregate, Patterns, and
wet concrete. Colors" Publication No. IS206.01T, Portland Cement Association,
5420 Old Orchard Road,Skokie,Illinois 60077.
The Portland Cement Association and the soudtern califonda Ready Mixed Concrete Association disclaim
w
than that responsibility for the application of the stated principles or for the accuracy of the sources oLbes
SUMMARY Fcde toed or information developed by tite Assmiatiom
Further information including advice on special finishes is
contained in the list of references in this publication. Building Phone (818) 441-3107 for a list of our preferred ready mixed
residential driveways,sidewalks and patios of concrete is a good concrete providers.
outdoor project for the homeowner. Hopefully these guidelines
will assist you in completing a successful and satisfying job.
(Illustrations in this publication courtesy of the National Association of
Home Builders, the American Concrete Institute, and Portland Cement
Association.)
L C NIA
PROMO
COUNCI
Southern California
Ready Mixed
Concrete Asso6adun
Drainage Study
Olstad Residence
Portion of Lot 2, Block "E", Map No, 2141
942 Stratford Drive
Encinitas, California
Prepared for:
� David and Lisa Olstad ��� , �� i` '� 3 [ ��
942 Stratford j.
o d Drive
Encinitas, CA 92024 5
� i AUG 15
Prepared by:
Christensen Engineering & Surveying
g
7888 Silverton Avenue, Suite "J"
San Diego, CA 92126
(858) 271-9901
August 07, 2005
Introduction
This project involves the demolition the existing single family residences and
existing appurtenances located at 942 Stratford Drive in Encinitas, followed by the
construction of the new Olstad Residence. The project also includes landscaping,
the construction of site walls and the addition of a new driveway and gravel ditch
in front of the site as well as a new infiltration trench located at the westerly
boundary of the site. The existing driveway and asphalt in the area fronting the site
will be removed and a new driveway and gravel drainage structure will be
constructed
The attached drainage area map is from San Diego County 200 scale topographic
map 318-1677 dated 10-25-1985. The areas of offsite runoff tributary to this site,
prior to construction are shown on the attached large scale Drainage Area Map.
The current improvements drain westerly onto the lot westerly of the site.
Following construction of the proposed improvements this drainage pattern will
persist but with former offsite drainage being diverted away from the Olstad
property.
The Rational Method was used to calculate the anticipated flow for the 100-year
storm return frequency event. The 4" & 6" PVC drain system was tested and
found adequate to convey anticipated runoff..
i
I�
Antony K. Christensen 08.07.05 Date
RCE 54021
Exp. 12-31-05
JN A2005-109
Calculations
1. Intensity Calculation
(From the City of San Diego Drainage Design Manual, page 86, San
Diego County Hydrology Manual, Table 3-3)
Tc = Time of concentration
= 1.8(1.1-C Dist. u2
( S 1/3 )
Since the slope over the area with the greatest elevation change is
(30'/580') 5.2% over the site and the distance traveled is 580 feet and
the runoff coefficient is 0.60.
Tc = 4.17 minutes
Since use of this value results in an unreasonable Intensity value Table
3-2 of the County Hydrology Manual is utilized using MDR-3 Element
and the ultimate slope.
TC = 5.7 minutes
Ix = 7.44 P6 Duration -0.645
Since D = 5.7
Ix= 2.42 P6
from: San Diego County Hydrology Manual Rainfall Isopluvial
Map for 100 year Rainfall Event—6 Hour
P6(loo)= 2.7
The six-hour storm is selected over the 24-hour storm due to its closer
approximation to the site's time of concentration.
So:
I100= 2.42 (P6)
I1oo= 2.42 (2.7)
- I1oo= 6.53 inches
2. Coefficient Determination
For residential area
From Table 2
C= 0.60
3. Volume calculations
Q = CIA
Areas of Drainage
Area Pre-Construction = 0.413 Acres
Area Post-Construction TOTAL= 0.219 Acres
Area Post-Construction A= 0.087 Acres
Area Post-Construction B= 0.058 Acres
Area Post-Construction C= 0.074 Acres
Q100 Pre-Construction = (0.60) (6.53) (0.486)
Q100 Post-Construction TOTAL = (0.60) (6.53) (0.219)
Q100 Post-Construction A = (0.60) (6.53) (0.087)
Q100 Post-Construction B = (0.60) (6.53) (0.058)
Q100 Post-Construction C = (0.60) (6.53) (0.074)
Q100 Pre-Construction = 1.90 CfS
Q100 Post-Construction TOTAL = 0.86 cfs
Q100 Post-Construction A = 0.34 cfs
Q100 Post-Construction B = 0.23 cfs
Q100 Post-Construction C = 0.29 cfs
Prior to construction a portion of offsite drainage, as shown on the
attached drainage area map, contributes runoff to the site. Following
construction the former offsite drainage will be conveyed along
Stratford Drive and away from the site. All site drainage will flow over
landscaping before being conveyed to the rear of the lot (westerly) as
has been the route of runoff before construction. Post-construction this
lessened quantity of runoff will flow over an infiltration trench before
being conveyed to the property westerly of the site and from there onto
Arden Road and into the public drains system located therein.
4. Discussion
The Olstad residence, pre-construction, gathers onsite and offsite
drainage and conveys it to the property westerly of the site. Following
construction all of the offsite runoff will be conveyed to Stratford Drive
and the resultant lessened quantity of runoff will flow over landscaping
onsite before flowing over an infiltration trench and then to the property
located westerly of the site. This plan will lessen the quantity of runoff
reaching the property westerly of the Olstad site. Therefore the
downstream property should be positively affected by this project since
runoff quality will decrease due to runoff previously from offsite areas
flowing over that property now flowing within Stratford Drive.
S. Test for Adequacy
The attached program was used to test for adequacy of the PVC drains. The
drain was found to be adequate to convey the runoff.
APPENDIX
IN ails
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San Diego County Hydrology Manual Section: 3
Date: June 2003 Page: 12 of 26
Note that the Initial Time of Concentration should be reflective of the general land-use at the
upstream end of a drainage basin. A single lot with an area of two or less acres does not have
a significant effect where the drainage basin area is 20 to 600 acres.
Table 3-2 provides limits of the length (Maximum Length (LM)) of sheet flow to be used in
hydrology studies. Initial T; values based on average C values for the Land Use Element are
also included. These values can be used in planning and design applications as described
below. Exceptions may be approved by the "Regulating Agency" when submitted with a
detailed study.
Table 3-2
MAXIMUM OVERLAND FLOW LENGTH (LM)
& INITIAL TIME OF CONCENTRATION Ti
-- Element* DU/ .5% 1% 2% 3% 5% 10%
Acre LM FT, LM T; LM T; LM T; LM T; LM I T;
Natural 50 13.2 70 12.5 85 10.9 100 10.3 100 8.7 100 6.9
LDR 1 50 12.2 70 11.5 85 10.0 100 9.5 100 8.0 100 6.4
LDR 2 50 11.3 70 10.5 85 9.2 100 8.8 100 7.4 100 5.8
LDR 2.9 50 10.7 70 10.0 85 8.8 95 8.1 100 7.0 100 5.6
MDR 4.3 50 10.2 70 ' 9.6 80 8.1 95 7.8 100 6.7 100 5.3
MDR 7.3 50 9.2 65 8.4 80 7.4 95 7.0 100 6.0 100 4.8
MDR 10.9 50 8.7 65 7.9 80 6.9 90 6.4 100 5.7 100 4.5
MDR 14.5 50 8.2 65 7.4 80 6.5 90 6.0 100 5.4 100 4.3
HDR 24 50 6.7 65 6.1 75 5.1 90 4.9 95 4.3 100 3.5
HDR 43 50 5.3 65 4.7 75 4.0 85 3.8 95 3.4 100 2.7
N. Com 50 5.3 60 4.5 75 4.0 85 3.8 95 3.4 100 2.7
G. Com 50 4.7 60 4.1 75 3.6 85 3.4 90 2.9 100 2.4
O.P./Com 50 4.2 60 3.7 70 3.1 80 2.9 90 2.6 100 2.2
Limited I. 50 4.2 60 3.7 70 3.1 80 2.9 90 2.6 100 2.2
General 1. 50 3.7 60 3.2 70 2.7 80 2.6 90 2.3 100 1.9
*See Table 3-1 for more detailed description
3-12
AE EQUATION
Tc s (11.91-3)0.38S
Feet AE
5000 Tc = Time of concentration(hours)
L - Watercourse Distance(mlles)
4000 AE = Change in elevation along
effective slope line(See Figure 3-5)(west)
x000 Tc
Hours Minutes
2000 4 240
3 180
1000
900
800 2 180 120
0
100
♦ 90
S00\
♦ e0
♦♦�+ TO
d 1 60
300 ♦foie
♦ 50
200
♦ 40
♦ L
♦ Miles FM
♦ 30
100 ♦1
4000 20
\ 18
3000 16
SO O.S \
\ 14
40 2000 ♦\ 12
1800
30 1600 ♦ 10
1400 ♦ g
1200 8
20 1000
900 7
E00 6
T00
5
10 500
4
400
300 3
S
1200
E L Tc
SOURCE:California Division of Highways(1941)and Kirpich(1940)
F I G U R E
Nomograph for Determination of
Time of Concentration (Tc)or Travel Time(Tt)for Natural Wtrtersheds 3-4
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Type of conveyance is a : Area "A" 4" PVC Drain
Diameter of conveyance equals . 3333333 Feet
Slope of conveyance equals 2 %
Roughness equals . 01
Flow quantity equals . 3400229 CFS
Area equals 8 . 003839E-02 Square Feet
Velocity equals 4 . 247962 FPS
Depth of flow equals . 3286658 Feet
Type of conveyance is a : Area "B" 4" PVC Drain
Diameter of conveyance equals . 333333 Feet
Slope of conveyance equals 2 %
Roughness equals . 01
Flow quantity equals . 2300608 CFS
Area equals . 0520681 Square Feet
Velocity equals 4 . 417293 FPS
Depth of flow equals . 2166666 Feet
SCREEN 7
COLOR 4 , 3
CLS
LINE INPUT "Enter the type of Conveyance" ; tg$
PRINT "Type of Conveyance is" ; tg$
10 INPUT "Enter the flow quantity" ; Q
20 INPUT "Enter the Slope" ; s
25 INPUT "Enter the Diameter" ; D
30 INPUT "Enter the Roughness Coefficient " ; n
35 theta = . 001
40 A = ( 1 / 8 ) * ( theta - sine ( theta) ) * D ^ 2
50 R = ( 1 / 4 ) * ( 1 - ( ( SIN( theta) ) / theta) ) * D
60 Qt = ( 1 . 49 / n) * A * (R - ( 2 / 3 ) ) * s " ( 1 / 2)
70 IF Qt < Q THEN theta = theta + . 001 ELSE PRINT "Q equals" ; Qt ; "theta equals"
; theta
80 IF theta > 6 . 28318 THEN PRINT "Pipe Diameter Too Small "
82 IF theta > 6 . 28318 THEN END
85 IF Qt < Q GOTO 40 ELSE GOTO 90
90 V = Q / A
95 PRINT "Velocity equals" ; V
100 IF theta < 3 . 14159 THEN Y = . 001 ELSE GOTO 141
110 X = Y * (D - Y)
120 Z = ((SIN( . 5 * theta) ) * D / 2 ) " 2
130 IF Z > X THEN Y = Y + . 001 ELSE PRINT "Depth Equals" ; Y
140 IF Z > X GOTO 110 ELSE 150
141 Y = D / 2
142 X = Y * (D - Y)
143 Z = ( ( SIN( . 5 * theta) ) * D / 2) " 2
144 IF Z < X THEN Y = Y + . 001 ELSE PRINT "Depth Equals" ; Y
145 IF Z < X GOTO 142 ELSE 150
150 INPUT "Do you want a hardcopy of Data? Enter 1 if Yes" ; C
160 IF C = 1 GOTO 165 ELSE END
165 LPRINT "Type of conveyance is a: " ; tg$
170 LPRINT "Diameter of conveyance equals" ; D; "Feet "
180 LPRINT "Slope of conveyance equals" ; s * 100 ;
190 LPRINT "Roughness equals" ; n
200 LPRINT "Flow quantity equals" ; Qt ; "CFS"
210 LPRINT "Area equals" ; A; "Square Feet "
220 LPRINT "Velocity equals" ; V; "FPS"
230 LPRINT "Depth of flow equals" ; Y; "Feet "