HomeMy WebLinkAboutCUP 02-23; LARWIN PARK; FINAL REPORT OF TESTING AND OBSERVATION SERVICES; 1984-06-16-
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- GEOCON
I N C 0 R P 0 B A T E D ENGINEERS AND GEOLOGISTS • CONSULTANTS IN THE APPLIED EARTH SCIENCES
Pile No. D-0684-M03
- June 19, 1984
-
RECEIVED.
Standard Pacific of San Diego
.7290 Clairemont Mesa Boulevard
San Diego, California 92111 SEP 1? 1001
Attention: Mr. Sam Thompson CITY OF CARLSBAD
- .
PLANNING DEPT. Subject: CARLSBAD TRACT NO. 74-4
(SPINNAKER POINT, PRASE II)
- ELM AVENUE, CARLSBAD, CALIFORNIA
FINAL REPORT OF TESTING AND OBSERVATION
SERVICES DURING MASS GRADING OPERATIONS
Gentlemen:
In accordance with your request and our proposal dated March 2, 1984, we
- have provided testing and observation services during the mass grading of
the subject subdivision. Our services were performed during the period of
January 23 through April 26, 1984. The scope of . our services Included the
-
following: .
Observing the grading operation, including the installation
of subdrains and the removal and/or processing of loose
-
. topsoil, existing uncontrolled fill soils and alluvial soil.
Providing geologic Inspections and recommendations relative
- to the construction of -'bu-t.t-ress—f4d-is and periodic observa-
tions of out slopes.
Performing in-place density tests in the placed and compacted
fill.
Performing laboratory tests on samples of the prevailing soil
- conditions used for fill.
Preparing an As-Graded Geologic Map.
Providing professional opinions as to. the grading contrac-
tor's general adherence to the geotechnical aspects of the
-
plans and specifications.
- 9530 DOWDY DRIVE • SAN DIEGO, CALIFORNIA 92126 • PHONE (619) 695-2880
- File No. D-0684-M03
June 19, 1984
. Preparing this final report of grading.
General
The grading contractor for the project was Templeton Engineering
- Corporation. The project plans were prepared by Rick Engineering Company
of San .Marcos, California and are entitled "Grading Plans for Carlsbad
Tract No. 74-4 (Quail Ridge).
The project soils reports are entitled "Soil and Geologic Investigation for
Quail Ridge" dated November 6, 1976 and "Soil and Geologic Investigation
(Addendum) for Spinnaker Point, Phase II" dated January 10, 19846 Both
- reports were prepared by Geocon, Incorporated
References to elevations and locations hereifl were based on surveyor's or
- grade checker's stakes in. the field and/or interpolation, from the
referenced Grading Plans.
Grading
Grading began with the removal of brush and vegetation from the area to be
graded and the material was then exported from the site. Loose topsoils,
- existing uncontrolled fill soils and loose alluvial soils in areas to
receive fill were removed to firm natural ground.
-- Prior to placing fill, the exposed natural ground surface was scarified,
moisture conditioned and compacted. Fill soils derived from onsite cutting
operations were then placed and compacted in layers until the design
-
elevations were attained.
During the grading operation, compaction procedures were observed and in-
place density tests (ASTM D1556) were performed to evaluate the relative
- compaction of the placed fill. Field observations and the results of the
In-place density tests indicate that the fill has generally been compacted
to at least 90 percent relative compaction. The results of the in-place
density tests are summarized in Table II. The approximate locations of the
In-place density tests are shown on the Site Plans (Figures 1 through 6).
Laboratory tests were performed on samples of material used for fill to
- evaluate moisture-density relationships, optimum moisture content, maximum
dry density (ASTM D1557-70, Method C), and expansion characteristics. The
results of the laboratory tests are summarized in Tables I and III.
-2-
GE000N
INCORPORAT E D
File No. D-0684-M03
June 19, 1984
Slopes
Major cut and fill slopes have inclinations of 2.0 horizontal to 1.0
vertical with maximum heights' on the order of 20 feet and 60 feet,
respectively. Minor interior slopes have Inclinations of 1.5 horizontal to
- 1.0 vertical. The fill slopes were periodically backrolled with a sheeps-
foot compactor during construction and were track-walked with a bulldozer
upon completion. All slopes should be planted, drained and maintained to
reduce erosion. Slope planting should consist of a drought-tolerant mixture
of native plants and trees having a variable root depth. Slope watering
should be kept to a minimum to just support the vegetative cover.
- Finish Grade Soil Conditions
During the grading operation, building pads which encountered clayey soils
-. at grade were undercut at least 3 feet and capped with granular soils.
Similarly, our observations and test results indicate that granular soils
were placed within at least the upper 3 feet of finish grade on fill lots.
-- The laboratory test results indicate that the prevailing soil conditions
within 3 feet of finished grade on each building pad have an Expansion
Index of 4 or less and are classified as having a "very low" expansion
potential as defined by Standard Table 29-C. Table III presents a summary
-. of •the Indicated Expansion Index of the prevailing soil condition of each
lot.
Subdralns
Subdrains were installed beneath canyon fills and behind buttress fills at
the general locations shown on Figures 1 through 6. The construction and
-- design of drains generally conforms to the recommendations contained in the
project soil reports.
Buttress Fill
A buttress fill was constructed En the area shown on Figures 4 and 6 in
- - accordance with the recommendations contained in the project soil report
dated January 10, 1984. The as-built dimensions are shown approximately on
the 'above referenced site plans along with the location of the subdraln
Installation.
Soil and Geologic Conditions
The soil and geologic conditions encountered during grading were found to
be similar to those described in the project geotechnical reports. The
site Is underlain primarily by a Pleistocene Terrace deposit which consists
-• of red to orange-brown, silty sands. Underlying this unit is the Eocene-
aged Santiago Formation which consists of interbedded sandstone and
-3-
GEOCCN
INCORPORATED
- File No. D-0684-M03
June 19, 1984
clays tone exposed only in a few places on the project such as along Elm
Avenue and parts of Pontiac and Lakewood Streets. Bedding attitudes -- observed within this unit varied from horizontal to as much as 11 degrees
locally In easterly and southerly directions. Aras containing dips adverse
to slope stability were located in the area designated for buttressing and,
-- hence, were stabilized during construction. The enclosed reductions of the
approved Grading Plans depict the as-graded geologic conditions observed.
No soil or geologic conditions were observed during the grading which, in
our opinion, would preclude the continued development of the property as
planned.
Based upon laboratory test results and field observations, it is our - opinion that the prevailing soil conditions within 3 feet of finish pad
grade. consist of "very low" expansive soils as classified by UBC Table 29C
and 'slow" expansive as defined by PHA/HUD criteria.
- CONCLUSIONS AND RECOMMENDATIONS
-
Foundations and Concrete Slabs-on Grade
1. Conventional spread and/or continuous footings founded at least 12
inches below lowest adjacent grade in properly compacted or dense
-- undisturbed "low" expansive soil may be designed for an allowable soil
bearing pressure of 2,000 psf (dead plus live loads). Footings should have
a minimum width of 12 inches. This bearing pressure may be increased by up
- to one-third for transient loads such as wind or seismic forces.
Pr-
All continuous footings should be reinforced with at
einforcing bars, one placed near the top of the footing and one near the
In areas where the depth of fill varies significantly from one side of
- ( the structure to another (Lots 84 through 91), it Is recommended that 044
footings be reinforced with four No. 4 steel bars; two top and two bottom.
Foundations for these lots shouliLalso be 18 lnahain dnrh -
- 4. Concrete slabs-on-grade should have a nominal thickness of 4 inches
and, where part of the living area, should be reinforced with 6x6-10/10
welded wire mesh. The slabs should be underlain with 4 inches of clean
sand or onsite soils. (Onsite, fine-grained soils meet FHA/}WD criteria
for use as base materials). Where moisture sensitive floor coverings are
planned, a vlsqueen moisture barrier protected by a 2-Inch sand cushion
should be provided. Great care should be taken during the placement and
nringof concrete flatwork to reduce the potential for shrinkage cracking.
( 5. Concrete slabs (including garages) for Lots 84 through 91 Auld be
reinforced with No. 3 steel bars placed 18 inches center to center, to
\ reduce cracking that may be caused by minor differential settlement.
-4-
GEOCON
INCORPORATED
- File No. D-0684-M03
June 19, 1984
6. Footings placed within 7 •feet of the top of slopes should be extended
In depth such that the outer bottom edge of the footing is at least 7 feet
- horizontally from the face of the slope.
7 No special subgrade presaturation Is deemed necessary prior to placing
- concrete, however, the exposed foundation and slab subgrade soils should be
sprinkled as necessary to maintain a moist condition as would be expected
in any such concrete placement.
- Lateral Loads
V 8. The pressure exerted by an equivalent fluid weight of 300 pcf should be
- used to provide resistance to design lateral loads.. This design value
assumes that footings or shear keys are poured neat against properly
compacted granular fill soils or undisturbed formational soils and that the
- . soil mass extends at least 5 feet horizontally from the face of the footing
or three times the height of the surface generating passive pressure,
whichever Is greater. The upper 12 inches of material not protected by
floor slabs or pavement should not be included In design for passive
resistance.
9. If friction is to be used to resist lateral loads, a coefficient of
- friction between soil and concrete of 0.4 may be utilized.
Retaining Walls
-
. 10. Unrestrained retaining walls should be designed to resist the pressure
exerted by an equivalent fluid weight of 35 pcf. This value assumes that
granular onsite material will be used for backfill, that the backfill
surface will be level, and that no surcharge loads will be acting on the
wall. For walls with backfill surfaces inclined at no steeper than 2.0 to
1.0, an active pressure exerted by an equivalent fluid weight of 45 pcf
- should be used.
11. For walls restrained from movement at the top, such as basement walls,
- an additional uniform horizontal pressure of (7H) psf (u equals the height
of the wall in feet) should be applied in addition to the active lateral
pressures given above.
- 12. All retaining walls should be provided with a backfill drainage system
adequate to prevent the buildup of hydrostatic forces.
- . 13. Adequate drainage provisions are imperative. Under no circumstances
should water be allowed to pond adjacent to footings. The lots and
building pads should be properly finish graded after buildings and other
improvements are in place so that drainage water is directed away from
-- foundations, concrete slabs and slope tops to controlled drainage devices.
-5-
GEOCCN
I NCORPORATED
- File No. D-0684-M03
June 19, 1984
Any additional grading performed at the site should be done under our
observation and testing. All trench backfill material In excess of 12
Inches In depth within lot areas depth should be compacted to at least 90
percent relative compaction. This office should be notified at least 48
hours prior to commencing additional grading or backfill testing.
14. ItIs recommended that foundation excavations be observed by the soil
engineer or his representative to confirm that finish grade soil conditions
are as anticipated by this report.
LIMITATIONS
- The conclusions and recommendations contained herein apply only to our work
with respect to grading, and represent conditions at the date of our final
Inspection, April 26, 1984. Any subsequent grading should be done under
our observation and testing. As used herein, the term "observation" implies
only that we observed the progress of the work with which we agreed to be
Involved. Our conclusions and opinions as to whether the work essentially
complies with the job specifications are based on our observations,
experience and testing. Subsurface conditions, and the accuracy of tests
used to measure such conditions, can vary greatly at any time. We make no
warranty, expressed or Implied, except that our services were performed In
- accordance with engineering principles generally accepted at this time and
location.
- We will accept no responsibility for any subsequent changes made to the
site by others, by the uncontrolled action of water, or by the failure of
others to properly repair damages caused by the uncontrolled action • of
water.
If there are any questions regarding our recommendations or if we may be of
further service, please contact the undersigned.
Very truly yours, CO
4
INCORPORATED
aelWart Thomas Ve La ap
CEG 706 RCE 20427
- MWH:lm
(6) addressee
-6-
GE000N
EN Co B P0 BATED
File No. D-0684-M03
June 1.9, 1-984
-- TABLE I
Summary of Laboratory Compaction Test Results
-- ASTM D1557-70
- Maximum Dry Optimum
Sample Density Moisture
No. Description pcf - %Dry Wt.
- 1 Brown, Silty Clayey SAND, 126.6 9.1
poorly graded, fine to
medium (Topsoil)
2 Greenish-gray, Silty Clayey 123.0 11.2
SAND, poorly graded, fine
to medium
3 Red-brown, Clayey Silty SAND, .124.4 10.8
poorly graded, fine to medium
(found with cobble)
4 Red, Silty SAND, poorly 128.4 8.7
graded, medium
5 Orange, Clayey Silty SAND, 120.1 12.1
poorly graded, medium
6 Brown, Silty SAND, poorly 126.2 11.3
graded, medium (Topsoil)
7 Light tan, Clayey Silty 120.9 12.4
SAND, poorly graded, fine
8 Green CLAYSTONE 111.2 17.3
.9 Light brown to gray, 118.9 14.0
slightly Sandy Clayey SILT
10 Yellow-gold, Clayey Silty 119.9 13.2
• SAND, well graded to coarse
11 Orange, Clayey Silty SAND 124.7 10.7
• poorly graded, medium to
coarse ,
I
. GE000N
INCORPORATED
FINAL REPORT OF TESTING AND OBSERVATION
SERVICES DURING MASS GRADING OPERATIONS
FOR.
CARLSBAD TRACT NO. 74-4
(SPINNAKER POINT)
e!kst r
For
STANDARD PACIFIC OF SAN DIEGO
San Diego, California
By
GEOCON, INCORPORATED
San Diego, California
September, 1983
- GEOCON
- I N C 0 R P 0 R A T B D ENGINEERS AND GEOLOGISTS • CONSULTANTS IN THE APPLIED EARTH SCIENCES
File No. D-0684-M02
September 13, 1983
- Standard Pacific of San Diego
7920 Clairemont Mesa Boulevard
San Diego,' California 92111
Attention: Mr. Sam Thompson
-- Subject: CARLSBAD TRACT NO. 74-4
(SPINNAKER POINT)
CARLSBAD, CALIFORNIA
LOTS 1-68, 155-193 and 207-224
- FINAL REPORT OF TESTING AND OBSERVATION
SERVICES DURING MASS GRADING OPERATIONS
Gentlemen:
In accordance with your request, we have provided testing and observation
- services during the mass grading of the subject subdivision. Our services
were performed during the period of January 21, 1983 through July 19, 1983.
The scope of our services included the following:
. Observing the grading operations including the installation
of subdrains, buttress fills and the removal and/or process-
ing of loose topsoils, uncompacted fill and alluvium.
Performing in-place density tests in the placed and compacted
fill.
Performing laboratory tests to aid in evaluating the
compaction, shear strength, expansion and grain size
characteristics of various soil conditions encountered.
Preparation of an as-graded geologic map.
Preparation of this report.
General
The grading contractor, for the project was the Templeton Grading
Corporation. Grading was to be accomplished in accordance with the Grading
Plans prepared by Rick Engineering Company and dated January 18, 1983. The
- geotechnical report dated November 6, 1976 for the project was prepared by
Geocon, Incorporated.
- 9530 DOWDY DRIVE • SAN DIEGO, CALIFORNIA 92126 . PHONE (619) 695-2880
File No. D-0684-M02
September 13, 1983
References to elevations and locations, herein, are based on surveyor's
stakes in the field and extrapolation from the referenced Grading Plans.
Grading
- Prior to the commencement of grading for a particular cut or fill areaj the
surface was cleared of brush and major vegetation which was then exported
from the property. Loose topsoils, existing uncontrolled fill soils and
alluvial soils in areas to receive fill were removed to firm natural
ground. The exposed ground surface was then scarified and moisture
conditioned in preparation to receive fill. Fill soils derived from onsite
cutting operations were then placed and compacted in layers until the
desired final grade elevations were attained. In-place density tests, in
accordance with ASTM D1556 were, performed during the fl-lung process. The
results of these tests are summarized on Table II and indicate that a
- relative compaction of at least 90 percent was being obtained. Table I
presents a summary of the laboratory tests to determine the maximum dry
density and optimum moisture content of the various fill soils encountered.
These tests were performed in accordance with ASTM D1557-70, Method C.
Finish Grade Soil Conditions
- During grading, building pads which encountered clayey soils at grade were
undercut 2 feet and capped with granular soils. Fill pads were also capped
with at least 2 feet of granular soils. The degree of expansion of the
prevailing finish grade soil condition for each lot in each subdivision is
- discussed in the Conclusions and Recommendations of the report, page 4.
In addition to the capping of building pads described above, the cut
portion - of those pads which contained a cut-fill transition within the
building area was undercut at least 2 feet and replaced with compacted fill
soil.
Subdrains
Subdrains were installed at the general locations shown on the enclosed
- site plans.
Buttress Fill
A stability fill was constructed during the site grading in the area of the
cut slope.located south of Lots 39 through 43. A subdrain was provided for
this fill which exits the fill slope behind Lot 44.
Soil and Geologic Conditions The soil and geologic conditions encountered
during grading were found to be similar to those described in the project
- geotechnical reports. Medium dense to dense, silty, very fine sands and
-2-
GEOON
I N (. (1 R P U £ P V TI
File No. D-0684--MO2
September 13, 1983
clays tones of the Santiago Formation were exposed generally below elevation
305. Medium-grained sandstone of a Pleistocene terrace deposit was
-
encountered above elevation 305 feet.
Several minor faults were observed within the area that received a
-. stability fill adjacent to Lots. 39 through 43. The enclosed reduced copies
of the project grading plans depict the as-graded soil, and geologic
conditions observed. In addition, the approximate location of subdrains
are shown. Bedding within the geologic formations was observed to be
massive and near horizontal. No Soil or geologic conditions were observed
during grading which, in our opinion,- would preclude the continued
development of the property as planned.
It should be noted that the enclosed reduced grading plans may not present
the actual as-graded elevations and contours.
-3-
GE000N
I NCO I1Pfl R A? n
File No. D-06844102
September 139 1983
CONCLUSIONS AND RECOMMENDATIONS
- Based upon laboratory test results and field observation, it is Our opinion
that the prevailing soil conditions within 2 feet of finish grade consists
of low to moderately expansive soils as defined by HUD/FHA expansive soil
- criteria.
Low expansive conditions, Lots 1-20, 22-56, 62, 63, 155, 158-161,
-
1639 164, 1660 1679 170-172, 214-224,
180, 181
Moderate expansive soil conditions, 21, 57-61, 156, 157, 649 65,
162, 1659 168-169, 173-179, 182-193,
207-213
Based on our observations, it is our opinion that the subject lots have
been satisfactorily graded in accordance with the recommendations contained
in our "Soil and. Geologic Investigation, Quail Ridge, Carlsbad, California"
dated November 5, 1976 and our addendum letters dated December 15, 1982 and
- January 6, 1983.
We recommend that footings founded in low expansive to moderately
- expansive soils with potential swells of less than 6 percent be designed
for an allowable soil bearing pressure of 2000 psf at at depth of 12 inches
below lowest adjacent grade. Footings should have minimum widths of 12
- inches. This pressure may be increased by up to one-third for transient
loads such as wind or seismic forces.
Continuous footings placed in moderately expansive soils should be
reinforced with two No. 4 reinforcing bars, one placed near the top of the
footing and one placed near the bottom.
Reinforcement of foundations placed in low expansive soils-possessing a
potential swell of less than 2 percent is optional. Previous experience
with similar soil conditions indicates that minimal reinforcement of
foundations and slabs located where low expansive soil conditions are
- present is effective in minimizing minor distress caused by soil volume
changes related to moisture changes and minor settlement.
- 5. Concrete slabs-on-grade should have a nominal thickness of 4 inches and
should be reinforced with 6x6-6/6 welded wire mesh over moderately
expansive soils and 6x6-10/10 welded wire mesh over low expansive soil.
- The slabs should be underlain by 4 inches of sand. Where moisture sensitive
floor coverings are planned, a visqueen moisture barrier with a 1-inch sand
covering should also be employed. It is our opinion that materials within
2 feet of finish grade on Lots 1-20, 22-56, 62, 639 155, 158-161, 163, 164,
1679 170-1729 180, 181, and 214-224 may be classified asd silty sands
-4-
GE000N
'I INCORPORATED
File No. D-0684-NO2
September 13, 1983
(SM) or gravelly sands (SW) and, therefore, meet the FHA/HUD specifications
for base course materials outlined in the Minimum Property Standards.
6. The recommended reinforcement presented above is based on soil condi-
tions only and is not intended to be in lieu of reinforcement necessary to
-
satisfy structural loadiügs.
Footings located within 5 feet of the top of slopes should be extended
in depth until the outside bottom edge of the footing is at least 5 feet
- from the face of the slope.
It is recommended that all canyon drain outlets be inspected after
completion of landscaping to verify that they have not been blocked or
buried during fine grading operations. Our office should be notified to
perform this inspection.
- 9. It is recommended that the soil engineer observe all footing excavations
to verify that the soil conditions exposed in these excavations are the
same as those exposed at finish grade.
Any additional grading performed at the site should be done under our
observation and testing. All trench backfill material in excess of 12
inches deep should be compacted to at least 90 percent relative compaction.
- This office should be contacted at least 48 hours prior to commencing
additional grading or needing backfill testing.
- LIMITATIONS
The conclusions and recommendations contained herein apply only to our work
with respect to grading, and represent conditions at the date of our final
observations on July 19, 1983. Any subsequent grading should be done under
our observation and testing. As used herein, the term "observation' implies
only that we observed the progress of the work we agreed to be involved
-- with. Our conclusions and opinions aá to whether the work essentially
complies with the job specifications are based on our observation
experience and test results. Subsurface conditions, and the accuracy of
- tests used to measure such conditions, can vary greatly at any time. We
make no warranty, expressed or implied, except that our services were
performed in accordance with engineering principles generally accepted at
this time and location.
We will accept no responsibility for any subsequent changes made to the
site by others, by the uncontrolled action of water, or by the failure of
others to properly repair damages caused by the uncontrolled action of
water.
-5-
GEOCON
INCORPORATED
- File No. D-0684-M02
September 13, 1983
If you have any questions regarding our recommendations or if we may be of
further service, please contact the undersigned.
Very truly yours, •
GEOCON, INCORPORATED
Zomas V. Lan p Qla r4t
RCE 20427 • • CEG 706
MWR:lm
(6) addressee
LIN -6-
GE000N
INCORPORATED
- File No. D-0684-M02
September 13, 1983
-- TABLE!
Summary of Laboratory Compaction Test Results
ASTM D1557-70
Maximum Dry Optimum
Sample Density Moisture
- No. Description pef % Dry Wt.
1-1 Red-brown, medium-grained, 129.3 10.0
Silty SAND
4-1 Orange-brown, Silty SAND and 137.3 7.3
GRAVEL
10-1 Light brown, Silty, medium- 128.0 8.5
grained SAND
17-3 Light brown, fine Clayey SAND 113.0 16.3
1 White/gray, poorly graded, 125.0 9.8
- - medium SAND
2 Green, Sandy CLAY 109.9 19.7
3 Gray/brown.-well graded Silty 131.2 7.3
SAND
- 4 Dark brown, Silty, well graded 125.7 8.6
SAND
5 Gray/brown, well graded, Clayey 119,2 12.2
• Silty SAND
- 6 Dark brown, carbonized, fine, 128.8 10.6
Silty SAND with glass, gravelly
concrete and other debris
7 Very fine to fine, light brown, 119.1 13.4
Silty CLAY
8 Brown, Silty, fine to medium 120.0 8.8
SAND
9 Dark brown/black SILT, fine to 124.0 11.5
medium coarse SAND, broken
glass, some debris
GE000N
INCORPORATED
File No. D-0684-M02
September 139 1983
-. TABLE t (Continued)
Summary of Laboratory Compaction Test Results
ASTM D1557-70
Maximum Dry
Sample Density
No. Description pcf.
10 Tan-beige, Clayey, fine to 127.9
• medium SAND
ii Red-brown, Clayey, well 126.0
graded SAND with gravel,
rounded cobbles
12 Reddish-brown, well graded 128.2
SAND with rounded gravel
13 Light green, well graded, 116.3
fine to coarse SAND
14 Check Point, light green,
Silty CLAY
15 Light green, fine and medium, 120.2
Silty Clayey SAND
16 Light tan, very fine to 121.2
medium, slightly Silty SAND.
17 Reddish-brown, well graded 131.2
SILT to coarse SAND with
rounded gravel & small cobbles
18 Light brown, gray with green 125.0
tint, fine to medium SAND
19 • Greenish, Silty, medium to
• 121.1
coarse SAND
20 Green., well sorted SILT to 120.6
coarse SAND
21 Black, Silty CLAY organics 110.2
22 Light yellow, fine to medium, 114.3
Silty Clayey SAND
GE000N
INCORPORATED
Optimum
Moisture
Z Dry Wt.
9.4
10.2
10.0
14.3
13.2
11.0
8.7
11.2
12.5
13.1
16.0
15.6
File No. D-0684-M02
September 13, 1983
TABLE I (Continued)
Summary of Laboratory Conmaction Test Results
ASTM D1557-70
Maximum Dry Optimum
Sample Density Moisture
No. Description pcf % Dry Vt.
23 Gray, slightly Sandy Silty 115.6 13.3
CLAY
24 Light olive green, very fine 103.1 22.1
to fine SILT
25 Reddish-brown, slightly Clayey, 128.4 10.2
fine to medium SAND
26. Medium tan, very fine, Sandy 117.0 13.7
Silty CLAY
27 Red-orange, poorly graded, low 128.3 9.9
cohesion, dry, loose, Silty
SAND
28 Gray-brown decomposed GRANITE 131.0 . 5.5
29 Gray-brown decomposed GRANITE 134.6 7.2
GE000N
114 CO K P0 RATED
CARLSBAD TRACT' NO. 744
(SPINNAKER POINT)
LEGEND
Qa._....COMPACTEO FILL
LIT LOT (COMPACTED FILL)
Qt---------TERRACE DEPOSITS
is------..SANTIAGO FORMATION
,PI ___APPROX. LOCATION OF SUBDRAIN
AS-BUILT GEOLOGIC MAP
G1000N.
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GE-O-CON "
I N C 0 R P 0 R A T E D ENGINEERS AND GEOLOGISTS • CONSULTANTS IN THE APPLIED EARTH SCIENCES
File No. D-0684-M02
March 8, 1983
Standard Pacific of San Diego
7290 Clairemont Mesa Boulevard
San Diego, California 92111
Attention: Mr. Sam Thompson
Subject: QUAIL RIDGE
LOTS 215 THROUGH 219 (MODEL LOTS)
CARLSBAD, CALIFORNIA
TESTING AND OBSERVATION SERVICES DURING GRADING
-. OPERATIONS; PARTIAL FINAL REPORT OF GRADING
Gentlemen:
In accordance with your request and our proposal dated November 24, 1982,
we have provided engineering observation and testing services during
grading of the subject lots as part of our engineering services during
- grading of the Quail Ridge subdivision.
Our services included:
observing the grading operation including the removal and/or•
processing of loose topsoil and uncompacted fill soils;
performing in-place density tests in the placed and compacted
fill;
performing laboratory. tests on representative samples of the
material used for fill; and
providing professional opinions in regard to the contractor's
general adherence to the plans and specifications.
Locations and elevations presented herein are based on the "Grading Plan
for Carlsbad Tract No. 74-4, Quail Ridge' prepared by Rick Engineering
Company and dated June 8, 1981 and stakes set by the contractor's grade
checker.
9530 DOWDY DRIVE • SAN DIEGO, CALIFORNIA 92126 • PHONE (714) 695-2880
File -No. D-0684-M02
March 8, 1983
- As part of the grading, the site was cleared of organics and other surface
debris. Grading of the lots consisted of excavating loose topsoils,
preparing the areas to be filled and making cuts and fills to design grade.
- The subject lots are design cut-fill transition lots. During grading, the
cut portion of the lots were undercut 2 feet and the material was moisture
conditioned and then properly recompacted.. In-place density tests were
performed during grading to help evaluate the relative compaction of the
- placed fill. Field observations and the results of the in-place field
density tests indicate that the fill has generally been compacted to at
least 90 percent of maximum laboratory density as determined-in accordance . ..-.
- with ASTM D1557-70.
Laboratory tests were made on representative samples of the material used
for fill. Tests were performed to evaluate moisture-density relationships
and maximum dry density and optimum moisture content. The results of the
laboratory tests are shown on Table I. The results of the in-place density
tests are shown on Table II. The in-place density test results have been
extracted from the tests from the ongoing site grading and no attempt has
been made to renumber these tests. The approximate locations of the in-
place density tests have been recorded on a copy of the grading plans for
reference. Our visual inspection indicates that the material within 2 feet
of rough lot grade can be classified as nonexpansive to slightly expansive.
CONCLUSIONS AND RECOMMENDATIONS
1. Based on our observations, it is our opinion that the subject lots have
been satisfactorily graded in accordance with the recommendations contained
- in our "Soil and Geologic Investigation, Quail Ridge, Carlsbad, California"
dated November 5, 1976 and our addendum letters dated December 15, 1982 and
January 6, 1983.
- 2. We recommend that footings founded in nonexpanaive to slightly
expansive, properly compacted fill soils be designed for an allowable soil
bearing pressure of 2000 psf when founded at 12 inches below lowest
- adjacent grade. Footings should have minimum widths of 12 inches. This
pressure may be increased by up to one-third for transient loads such as
wind or seismic forces.
3. Continuous footings should be reinforced vith.two No. 4 reinforcing
bars, one placed near the top of the footing and one placed near the
bottom.
-2-
GEOCCN
TVI'flD a a •WII
Pile No. D-0684-M02
March 8, 1983
- 4. Concrete slabs-on-grade should have a nominal thickness of 4 inches and
should be reinforced with 6x6-10/10 welded wire mesh placed at the slab
midpoint. The slabs should be underlain by 4 inches of clean concrete
--
sand. Where moisture sensitive floor coverings are planned, a visqueen
moisture barrier with a 2-inch sand covering should also be employed.
5. 'The recommended reinforcement presented above is based on soil condi-
tions only and is not intended to be in lieu of reinforcement necessary to
satisfy structural loadings.
- 6. Footings should not be located within 8 feet of the top of slopes.
FootingS that must be located in this zone should be extended in depth
until the outside bottom edge of the footing is at least 8 feet from the
face of the slope.
LIMITATIONS
Each lot . should be finish graded after the structures and other improve-
ments are in place so that drainage waters from the lots and adjacent
properties are directed off the lots and away from building foundations,
- floor slabs, and slope tops. Even when such drainage is provided, a
shallow or near-surface ground-water 'condition can, and may, develop in
areas where no such ground-water condition existed prior to site develop-
ment. This is particularly true in residential developments where a
substantial increase in surface water infiltration results from landscape
irrigation. We will accept no responsibility for any subsequent changes
made to the site by others or by the uncontrolled action of water or. by the
- failure of others to properly repair damages caused by the uncontrolled
action of water.
- The conclusions and recommendations contained herein apply only to our work
with respect to grading, and are based on conditions at the conclusion of
our fulitime observation. Any subsequent . grading should be done under our
observation and testing.
Subsurface conditions and the accuracy of tests used to. measure such
conditions can vary greatly at any time. Therefore, our opinion means only
- that we performed our services in such a manner as to have reasonable
certainty that the work essentially complies with the job specifications.
We make no warranty, expressed or implied, except that our services were
performed in accordance with engineering principles generally accepted at
this time and location.
/51
- -3-
GE000N.
I NCORPORATK P
File No. D-0684-M02
-
March 8 1983
- If you have any questions, please contact the undersigned.
Very truly yours,
- GEOCON, INCORPORATED
Pt*Chael WM.IHLa-r
-
/Michael R.Mh1llY
- CEG 706 RCE 28188
NRR: MWR: im
- (4) addressee
- - -4-
GE000N
NCOPORATD
I
File No. D-0684-M02
March 89 1983
TABLE
Summary of Laboratory Compaction Test Results
Soil Max. Dry Density Optimum Moisture
Type Source & Description pcf Z dry wt.
10 Tan, Clayey SAND . 127.9 9.4 -
11 Red-brown, Clayey SAND 126.0 10.2
TABLE II
Sutmnary of Field Density Test Results
Date Irest Dry Dens. Moisture Rel Comp. Soil Type
- 1983 No. Location & Elevation pcf Z dry wt. % of max. & Remarks
3/4 91 Lots 217/218 293 122.4 10.4 96 10
- 92 Lots 215/216 298 123.2 8.5 96 10
93. Lots 218/219 293 123.0 9.4 96 10
- 3/5 94 Lots 216/217 300 119.0 12.4 93 10
95 Lots 215/216 301 122.2 12.7 95 10
-
96 Lot 218 297 122.6 12.2 97 11
97 Lot 217 301 119.7 10.4. 95 II
98 Lot 216 303 124.0 10.7 97 10
-
. . 99 Lot 215 304 120.8 10.0 95 11
100 Lot 215 FG 306 117.1 12.1 91 10
- 3/7. 101 Lot 216 Slope 301 118.4 11.7 . 94 U
102 Lot 216 FO 308.8 120.9 . 12.4 95 11
103 Lot 217 PG 302.5 121.6 .11.3 95 . 10
104 Lot 218 PG 299.4 120.5 13.3 94 10
105 Lot 219 PG 296 119.5 11.7 93 10
3/8 106 Lot 215 305 120.1 . 11.7 94 . 10
107 Lot 216 304 117.6 10.5 92 10
108 Lot 217 302 118.9 10.5 94 11
109 Lot 218 299 120.5 9.4 94 10
- 110 Lot 219 295 119.3 10.7 93 10
GE000N
I N CORPORATE D
File No. D-0684-M03
June 19, 1984
TABLE III
Expansion Index
Lots 69-153, 194-2069 225-230
Fill and Cut/Fill Lots Cut Lots
Lot No. El Lot No. El Lot No. EL
77 1.4 115-119. 4 69-70 4.2
78-80 4 125 0 71 4.2
- 81-84 1.4 126-138 4 72-76 0
85-86 0 140-151 4 98-106 1.4
87 1.4 153 4 113 4
88 0 194-204 0 114 4
- 89 1.8 205 1.4 • 120-124 1.4
- 90 1.8 225-230 0 139 4
91 1.4 152 4
- •92 4 206 • 4
93 4
94-97 3.2
- • 107 6
108 6 •
- 109-112 0
GE000N
INCORPORATED