HomeMy WebLinkAboutPE 2.11.37; PARK DRIVE BELLAVISTA; REPORT OF SOIL INVESTIGATION; 1980-03-24S WILLIAM 5: MIOUSHOS & ASSOCIATE'S
W. S. KROOSKOS, CIVIL ENGINEER OUNDATION ENGINEERING
AL VENTON. ENGINEERING GEOLOGIST . ENGINEERING GEOLOGY
4320 VANDEVER AVENUE SAN DIEGO. CALIFORNIA 92120 PHONE 283.6506
I. p ;JI.3
March 24, 1980 . Mr Allan K. MacDougall Job No. 80-6269
5005 Tierra Del Oro
Carlsbad, California 92008
SUBJECT: Report of Soil Investigation
R. Dickerson Residence
4600 Park Drive .
Carlsbad, California
Dear Mr. MacDougall:
In accordance with your request, we have conducted an investigation
of the surface and subsurface soils at the above subject residential
•site. . . . ••
The enclosed report summarizes the results of the subsurface
explorations, test results of the typical bearing soi's, and
the recommendations made by our firm for the proper design of the
S . structure, and the development of the site to receive the proposed
improvements.
Our investigation reveals that the site contains sandy soils with
a trace of clay. These natural ground soils extend to an
undetermined depth below the top of existing ground. It is our
opinion, that if the foundations and footings of the proposed
structure are properly reinforced as recommended in this report,
they will be suitable for the support of the proposed structure
and the other improvements. . . •
This opportunity to be of service is sincerely apprecated. .
Very truly yours, •
WILLIAM S. KROOSKOS & ASSOCIATES
S . William S. Kro skos, President
WSK:skm RICE 11318 •
) S •
REPORT OF SOIL INVESTIGATION
R. DICKERSON RESIDENCE
4600 PARK DRIVE
CARLSBAD, CALIFORNIA
SCOPE:
This report presents the findings and results of our invest-
igation at the site of the proposed residence and other contemplated
improvements. It is our understanding that the proposed structure
is tobe. constructed' of conventional type foundations, footings,
and of standard type building materials, not exceeding one story
in height. '
The plans available for our.use in preparing this report consisted
of a site plan with, the contours showing the approximate plan
dimensions of the proposed structure, prepared by Vonn Designs.
'This plan indicates that an approximate cut of 4 feet will be
'' performed along the northern portion of the residence, and the
'fill soils generated will be compacted along'thesouthern portion
of the 'site to make way for a flat pad. • • S
With the above in mind, this soil investigation was undertaken' in
' order to: . S
Classify the natural ground bearing soils' to an approximate
depth of 3 feet below the top of existing ground and determine
the' presence and effect of any expansive soils that could
cause detrimental damage to the proposed structure and the
other improvements. S
Determine the approximate depth and extent of any uncompacted
fill soils that exist on the site and'recornmend treatment of
these soils to support the proposed improvements.
Determine the safe soil bearing value of the firm natural
S ground soils and the compacted fill soils (compacted to at
least 90 percent of maximum dry density).
4. Determine any construction problems that may develop at the
building site as a result of the soil characteristics
encountered.
•
SITE:
The site of the proposed structure is located on the north side
of Park Drive, on a southerly trending slope. Elevations range
from a high of 32 in the north, to a low of 18 in the south.
The residence is to be located on a parcel approximately 200 feet
long by 149 feet wide.
Page
Report of Soil Investigation Job No. 80-6269
R. Dickerson Residence
4600 Park Drive
Carlsbad, California
The site is presently covered with light grasses.
FIELD INVESTIGATIONS:
One hand boring was performed in the proposed cut area and in the
proposed building area. The boring was located in the field by
our engineering geologist referring to site plan.
The boring was advanced by hand tools. The encountered soils
from the boring excavation were visually identified during the
field operation by our engineering geologist. Disturbd samples -
of soils were transported to the laboratory for testing.
A boring log was prepared on the basis of an inspection of the
excavation, and the results are summarized on the enclosed
Figure No. II.
LABORATORY TESTS:
The following tests were performed on the sampled soils in order
to properly classify them, and to determine their physical and
mechanical characteristics.
Mechanical Analysis: This test is conducted on each soil type' in
order to determine the percentage of grain size. The analysis is,
' made in conformance with A.S.T.M. 422-54T. The potential expansivity
of clay soils can be determined from this test, since expansivity
is a function of percentage of colloids (fines less than .001mm).
Compaction Test: The laboratory ôornpaction test is performed on the
typical natural ground bearing soils in accordance with A.S.T.N. Test
Method D 1557 (four inch diameter mold, five layers, 25 blows each
layer, 10. pound hammer, 18 inch drop, using all material passing a
No. 4 sieve) . This test is conducted on the soils n order to
determine the optimum moisture and the maximum dry density. The'
maximum density represents the value to which it is possible to
compact the the soil in the field with the proper compactive effort.
Expansion Test: An expansion test was conducted on the potentially
expansive soils. This test was performed in accordance with the
requirements set forth in-Chapter 6 of the County of San Diego
Ordinance No. 2925, Test for Expansive Soils. Expansive soils are
classified as follows:
Swell , Expansivity
0 to 3 Percent --------------Low
3 to 6 Percent --------------Medium
6 to 12 Percent -------------'High
Above 12 Percent ------------Very High
Page 3
Report of Soil Investigation Job No. 80-6269
R. Dickerson Residence
4600 Park Drive
Carlsbad, California
CONCLUSIONS AND RECOMMENDATIONS:
The following summarized conclusions and recommendations are based
on the analysis of all the data and information obtained from the
soil investigation. This includes our visual inspection of the
building site; field investigations and laboratory tests on the
typical bearing soils; and our general knowledge and experience
with these natural ground soils.
The natural ground soils on this site to 'a depth of 3 feet
have been classified as follows: These soils consist of
tan sands with ,a clay trace, which occur to an undetermined
depth. They possess low expansive characteristics with a
swell varying from 2 to 4 percent.
Since it is the intention of constructing the proposed structure
and other improvements on the existing low expansive natural
ground soils, then it is recommended that the following work
be performed.
The continuous foundations shall be founded a minimum depth
of 12 inches into the firm, natural ground soils. These
foundations -shall be reinforced with at least two No. 5
steel bars; one bar shall be located near the top of the.
foundation and the other bar shall be located near the
- bottom.
The concrete floor slabs of the structure shall be founded
on at least 2 inches thick of non-expansive soils; such
as silts and sands, decomposed granite, crusher run base,
etc., and shall be reinforced with either 6x6 -10x10 steel
wire mesh or No. 3 steel bars placed 48 inches on centers
both ways.
Non-structural.concrete slabs such as patios and sidewalks
shall be founded on at least 2 inches thick of non-expansive
soils.
.3. Natural ground cut slopes of maximum inclinations of 1.5 horizontal
to 1.0 vertical, and compacted fill slopes of maximum inclinations.
. . of 1.5 horizontal to 1.0 vertical will be stable for the soil
native to this site and expected to be utilized in the compacted
fills.
4. It is our opinion, based on test results and our experience,.
that these natural ground soils and the compacted fill soils
. (compacted to at least 90 percent of maximum dry density)
possess a safe soil bearing value of 2,000 pounds per square
foot. This soil bearing value may be utilized for the design
f
1/
Page 4.
Report of Soil Investigation Job No. 80-6269
B. Dickerson-Residence
4.600 Park Drive
Carlsbad, California
of continuous foundations, and spread footings when founded .
a minimum depth of 12 inches into the compacted non-expansive
fill soils and compacted non-expansive natural ground soils.
This soil bearing value may be increased one-third for design
loads that include wind or seismic analysis.
5. Planter areas adjacent to the structure shall be constructed to
slope away from the foundations and floor slabs (minimum of one
percent) . Planter boxes adjacent to the structure shall be
constructed with drain tile in gravel directing the subsurface
waters away from the structure towards the lower level,of the
site.
6., Future swimming pools or other subsurface structures shall be
properly designed and reinforced with steel to reflect the
expansive clay soils that underlie this site. The design of
these subsurface structures shall follow the recommendations
of a structural engineer and soils engineer.
Backfill 'soils behind retaining walls and in utility trenches
which support structures, patios, sidewalks, driveways, asphalt•
pavement, etc., (other than landscaping) shall be placed and
compacted, to at least 90 percent of maximum dry density. - '
The compacted fill soils that will occur within five feet. of the
proposed fill slope will possess poor latèra] stability, even
though they will be certified to a relative compaction of 90
percent .of maximum dry density or better. Proposed structures 0
and other improvements such as walls, fences, patios, sidewalks,
swimming pool, driveways,- asphalt pavement, etc., that are located
within five feet of the face of compacted fill slope could suffer
differential 'movement as a result of the poor lateral stability
of these soils. ' 0
Foundations and footings of the proposed structure, walls, etc.,
when founded five feet and further away from the top of compacted
fill slope may be of standard design meeting 'the requirements of
the governing agency and designed in conformance with the
recommended soil bearing value. If proposed foundations and
footings are located closer than five feet inside the top of
O compacted fill slope, they shall be deepened one foot below
a 1.5 horizontal to 1.0 vertical line projected outward' and
downward from a point five feet horizontally inside the top of
compacted fill slope. (Refer to Figure No.IV
Adequate measures shall be undertaken to properly.finish grade
S ..the site after the structure and the other improvements are in
place, such that the drairiage waters from this improved site and
the adjacent properties are directed away from the foundations,
footings, floor slabs and topsof slopes, via surface swales and
I ..' Page
Report of Soil Investigation ' Job No. 80-6269
R. Dickerson Residence '
4600 Park Drive
Carlsbad, California'
subsurface drains towards the lower level of the site or to the
natural drainage direction for this area. Proper surface and
subsurface drainage will insure that no waters will seek the
'level of the bearing soils under the foundations, footings and . ' floor slabs which could result in undermining and differential
settlement of the structure and the other improvements.
11. All compacted fill slopes and natural ground cut slopes (that do
not consist of dense soils or rocks') shall be planted with an
erosion resistant plant following the general requirements of
the County of San Diego.
GRADING SPECIFICATIONS:'
The grading operation shall be performed in accordance with 'the
enclosed "Grading Specifications", Attachment 1; the recommendations . summarized herein; and the general grading requirements of the
City of Carlsbad.
The fill soils will be inspected and tested by members from our
firm to insure that they were compacted to at. least 90 percent
of maximum dry density. 'Upon the completion of the grading . ' operation, a Report of Certification of Compacted Fill will be
prepared by our firm, summarizing the soil test results, our
findings and recommendations.
LIMITATIONS:
'
The recommendations summarized in this report are based on the
evidence obtained from the boring excavation; laboratory test
results of the encountered natural ground soils; examination of
the site by our engineering geologist and soils engineer;' and
experience 'with the soils native to this site.
During the grading operation, qualified personnel from our firm will
perform an inspection of the underlying soils to substantiate the
conclusions and recommendations as summarized in our report. If
any irregularities are observed, specific action will be undertaken
by our firm to provide 'an adequate remedy.
It is the responsibility of the owner or developer to insure that
the recommendations summarized in this report are carried out
in the field.
This report and all subsequent reports and addendums automatically
become a part of the,building specifications.
Respectfully submitted, '
WILLIAM S. KROOSKOS & ASSOCIATES 0
William S. Kroosko , President
7 I WSK:skm RCE 1,1318
(4) Addressee '
LIM
••
. - -
BORING SUMMARY SHEET
-. O> V
Boring No ± Elevation cc
CL
o Cri 0 Ln cc
0
1 - Medium dense moist .brorn sand :
• with clay trace (SM-SC) 10 2.1
2-® •
.3 - ____ • ____------------ ------------.-- -- --•--- ____
0 20 30
LABORATORY COMPACTION TEST
DIRECT SHEAR TEST DATA 1 2 3
APPARENT COHESION (pet)
APPARENT FRICTION ANGLE
SOIL SOIL CLASSIFICATION BORING
NO.
TRENCH
NO.
DEPTH
TYPE
Brown Sand With Clay Trace ____ 2
11
Eli
I
-
--
i I I , I
SWELL TEST DATA I 2 3
INITIAL DRY DENSITY (pcf) 105
INITIAL WATER CONTENT (%) 10
LOAD (pit) 144
PERCENT SWELL 2 .1
FILL SUI1BIUTY TESTS]
JOB NO.80-62691 FIGURE NO. III
e
Proposed Structure
Concrete Floor Slab
F
S I-oil
S
___ ___
- •i. -•
j Top of Cbmpacted S
ill Slope
Compacted Fill Slope
Maximum Inclination S -
- 15 10
Reinforcementof S ••1.-' - - - S S * S
Foundations and Floor Slab4_
following the recommendations
of theArchitect or Structural-, 1 Minimum
Engineer L--&
daton Concrete Foun ion
Compacted Fill - -
- ,5'-
S S
/
TYPICAL SECTION
Showing Proposed Foundation Located Within Five Feet of Top of
S Compacted Fill Slope) S S
Job No 83-6269
S S • S S
S
• Figure No. 1v.
Attachment 1
,
Pagel.
GRADING SPECIFICATIONS
0
GENERAL: The intent of this item is to properly establish, procedures
for:, clearing, compacting natural ground, preparing areas to be filled;' . and placing and compacting fill material to the grades and slopes as
shown on the approved plans.
CLEARING: All vegetation, brush, and debris shall be removed, piled,
and burned or otherwise disposed of to give the surface a neat and
finished appearance.
COMPACTING NATURAL GROUND: After clearing, the natural ground shall
be scarified to a depth of' at least 12 inches, watered to optimum
requirements, and compacted to not less than 90 percent of maximum dry
density, according to A.S.T.M. Test Method D 1557 in a 4 inch dia-
meter cylindrical mold of 1/30th cubic foot volume. Field density . ' tests shall be taken in the natural ground in accordance with A.S.T.M.
Test Method D 1556.
FILL MATERIALS: Materials for the fill shall be approved by the soils
engineer and shall be free from vegetable matter and other deleterious
substances. In the event that expansive materials are encountered
within 2 feet of finish grade, they should either be entirely removed
or thoroughly mixed with good granular material before incorporating
them in fills. No footing shall be allowed to bear on soils which in
the opinion of the soils engineer are 'detrimentally expansive, unless
designed for this clayey"condition.
PLACING AND COMPACTING FILL MATERIAL: After preparing the areas to
be filled, the fill materials shall be placed in layers not to exceed
6 inches in compacted thickness. Each layer shall be watered to
optimum requirements and compacted to not less than 90 percent of
maximum dry density in accordance with A.S.T.M. Test Method D 1557.
Compaction of the fill shall then proceed in the specified manner
to the grades as shthm on the approved plans.
When the slope ratio of the original ground is steeper than 5.0 hor-
izontal to 1.0 vertical, the original ground shall be steepened or
benched. Ground slopes flatter than 5.0 horizontal to 1.0 vertical
shall be benched when considered necessary by the Soils Engineer.
.. Fill slopes shall be compacted by means of sheepsfoot roller or other
suitable equipment. Slope compaction shall be continued until the
slopes are stable, but not too dense for planting.
Field density tests shall be taken when considered necessary by the
soils engineer in accordance with A.S.T.M. Test Method D 1556 and . shall be made not exceeding 2 feet in vertical height, providing
each layer is. tested.
SUPERVISION: Continuous supervision of the fill shall be made by
the representative, of William S. Krooskos & Associates during the
grading operation so that he can certify that the fill was placed
in accordance with these specifications.
SEASON LIMITS: No 'fill material shall be placed, spread or rolled
during unfavorable weather conditions. When the work is interrupted
by heavy rain, the filling operation shall not be resumed until field
tests' indicate that the moisture content and density of the fill are
as previously specified.
S S UNIFIED 'SOIL CLASSIFICATION CHART
• ' SOIL DESCRIPTION GROUP SYMBOL TYPICAL NAMES
'S . : COARSE GRAINED: More than '
half of material is larger
than a No. 200 sieve.
GRAVELS - CLEAN GRAVELS GW Well-graded' gravels, gravel-
More than half of Coarse and sand mixtures, little
fraction is larger than or no fines.
No. 4-sieve size but GP Poorly graded gravels, S
smaller than 3'. gravel and sand mixtures,
little or no fines.
GRAVELS WITH FINES , ' GM Silty gravels, poorly
V , '(Appreciable amount) graded gravel-sand-silt •• . .V V
mixtures. ' V
GC Clayey gravels, poorly
• graded gravel-'sand-clay.
V mixtures. V
V SANDS - CLEAN SANDS SW Well graded sand, gravelly'
More than half of coarse ' sands, little or no fines. . fraction is smaller than SP Poorly graded sands, gravelly'
V V a'1,16. 4 sieve sands, little or no fines.
V SANDS WITH FINES SM Silty sands, poorly graded
V (Appreciable amount) sand and silty mixtures. V
V V V sc Clayey sands, poorly graded
• sand and clay mixtures.
V
V FINE GRAINED: More than -
V
V V
half of material '-is smaller •
than a No. 200 sieve. V
V
V SILTS AND CLAYS V ML Inorganic silts and very
fine sands, rock flour,
V sandy silt or clayey-silt
V
V V sand mixtures with slight
V
V V plasticity. V
'. ,Liquid Limit * CL Inorganic clays of low to
S less than 50 medium plasticity, gravelly . V
V V V
V V V
clays, sandy dlays, silty
clays, lean clays. V
V
V OL Organic silts and organic V
V V silty clays of low
V
V plasticity.
SILTS AND CLAYS MH V Inorganic silts, micaceous . or diatomaceous fine sandy
V V or silty soils, elastic
V V silts. V
V • Liquid Limit •
V V
V greater than 50 CH Inorganic clays of high
V ' plasticity, fat clays. V
V OH V Organic clays of medium to
V high plasticity.
V HIGHLY ORGANIC SOILS PT Peat and other highly
V V organic soils. V
• V V WILLIAMS. KROOSKOS & ASSOCIATES V
V V V Soil & Foundation Engineels V V