HomeMy WebLinkAboutPD 2019-0032; GOERTZEN RESIDENCE; FINAL SOILS REPORT; 2022-06-10 (3)June 10, 2022
Greg Goertzen
3466 Camino Michelle
Carlsbad, California 92009
Subject:
Dear Mr. Goertzen:
File No. 1127H6-19
FINAL REPORT
Proposed Residential Building Site
2651 Acuna Court
City of Carlsbad
P.O. Box 1195
Lakeside, California
92040
(619) 443-0060
In accordance with your request, this is the Final As-Built Geotechnical Report. The following
items apply:
A. Soils encountered during grading were substantially the same as those encountered in
our Site Inspection Report June 7, 2019, revised February 25, 2020.
B. Compacted soil placement has been observed and tested. Test results are presented in
our Report of Compacted Filled Ground dated January 12, 2021.
C. Foundation soils have been tested for expansive characteristics. The expansion index is
<50. The footing recommendations have been incorporated into the Site Inspection.
D. The footing excavations we inspected extend to the proper depth and bearing strata
as recommended in our reports.
E. Site preparation is in substantial conformance with the recommendations contained in
the above referenced soil reports.
If you have any questions, please do not hesitate to contact our office.
Respectfully submitted,
Chin C. Chen, RPE C 34442
CCC/mlj
lttH, TEITEltl
January 12, 2021
Greg Goertzen
3466 Camino Michelle
Carlsbad, California 92009
SUBJECT:
Dear Mr. Goertzen:
File No. 1127H6-19
Report of Compacted Filled Ground
Proposed Residential Building Site
El Fuerte Street and Acuna Court
City of Carlsbad
P.O. Box 1195
Lakeside, California
92040
(619) 443-0060
In accordance with your request, our firm has inspected the grading operation and tested the fill
soils that were placed and compacted during the preparation of the subject side. This is to report
the results of our soil tests. The work was performed between September 14, 2020 and January
6, 2021. The site is located at Lot 84 El Fuerte Street at the corner of Acuna Court, City of
Carlsbad.
To briefly summarize the work, we found the compaction of the fill soils to conform to the
recommended and approved grading specifications and current standard practices.
SECTION No. 1. SCOPE
Our function consisted of providing the engineering services involved with determining the
degree of compaction of fill placed on the site in accordance with the recommendations set forth
in our Site Inspection dated February 25, 2020 and our Site Inspection -Response to Third Party
Geotechnical Reviews dated December 19, 2019, February 26, 2020 and March 25, 2020.
The results of the field density tests are presented on Page T-1 under "Table of Test Results".
The laboratory determinations of the maximum dry densities and optimum moisture contents of
the fill soils are set forth on Page L-1 under "Laboratory Test Results". The approximate
locations of the filled ground and the field density tests are presented on Plate No. 1 entitled
"Location of Field Density Tests".
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Greg Goertzen File No. 1127H6-19 January 12, 2021
The grading was performed for the purpose of creating a level building pad for the construction
of the proposed residential structure.
SECTION No. 2. SOIL CONDITIONS
Soils used in the fill were those generated from the on-site grading operation and imported from
off site.
EARTHWORK
Preparation: Prior to placement of fill, the areas to receive fill were scarified, watered and
compacted to 90 percent. Natural ground to receive fill was tested to determine its relative
compaction. Native soils having a relative compaction ofless than 85 percent were removed,
replaced and compacted to 90 percent.
Placing and compacting fill: Fill soil was placed, watered and mechanically densified in the
areas indicated on attached Plate No. 1. During grading, any fill found to have a relative
compaction of less than 90 percent was reworked until the proper density of 90 percent had been
achieved.
Field density test results: To verify compaction, field density tests were performed in
accordance with applicable American Society of Testing and Materials (ASTM) test methods.
Test method ASTM D1556-82 was used at the indicated locations.
SECTION No. 3. SUMMARY AND RECOMMENDATIONS
Based on the work and tests described hereinbefore and work description set forth in Section 1,
'Scope', we conclude:
1. The filled ground has been compacted to 90%.
2. The placement of fill has been accomplished in accordance with the grading
specifications and with current standard practices.
3. Spread footings will have a minimum allowable bearing value of at least 2000
pounds per square foot. The allowable bearing value will be considerably more
for footings larger than 12 inches wide and/or 12 inches deep. If loads heavier
than 2000 pounds per square foot for continuous footings are anticipated, we
should be contacted for an increased bearing value.
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Greg Goertzen File No. l 127H6-l 9 January 12, 2021
4. Detrimentally expansive soils were not encountered. Conventional spread footings
founded a minimum of 18 inches below lowest adjacent grade and having a width
determined by the allowable soil bearing value as detailed above are recommended
for foundation support. Footing widths should be at least 15 and 24 inches for
continuous and square footings respectively due to practical considerations as well
as Building Code requirements. Reinforcing in footings should consist of one #4
steel bar placed continuously in the top and bottom of continuous footings regardless
of structural requirements. Reinforcing for isolated footings are dictated by the
structural requirements.
5. Concrete Slab-On-Grade, SOG, should be designed by the project's structural
engineer based on anticipated loading conditions. We recommend that
conventional reinforced concrete SOG for this project be founded on 4 inches of
Class II Virgin Aggregate Base (with approximately 2% +/-over optimum
moisture content and 90% compaction, relative to the lab maximum dry density,
ASTM D 1557), overlying a 12 inch thick zone of adequately placed and
compacted structural fill. We recommend that a moisture barrier be provided by a
membrane, visqueen 10 mils in minimum thickness or equivalent, be placed at top
of well compacted Class II Aggregate Base, then covered with 2 inches of moist
clean sand having a minimum sand equivalent of 30 when tested in accordance
with the American Society of Testing and Materials test method 'ASTM Dl555.
Floor slabs, as a minimum, should be 5 inches thick with #4 reinforcing steel at
16" on-center each way. Reinforcement should be placed at mid-height of the
slab. The final slab thickness and reinforcement should be determined by the
structural design engineer. Control joints should be provided in accordance with
the recommendations of the structural design engineer.
SITE EROSION CONTROL
During the construction, surface water should be controlled via berms, gravel bags and/or
sandbags, silt fence, straw wattles, siltation basins, while maintaining positive surface grades or
other methods to avoid damage to the finish work or adjoining properties. All site entrances and
exits must have coarse gravel or steel shaker plates to minimize offsite sediment tracking. Best
management Practices (BMP's) must be used to protect storm drains and minimize pollution.
The contractor should take measures to prevent erosion of graded areas until such time as
permanent drainage and erosion control measures have been installed. After completion of
grading, all excavated surfaces should exhibit positive drainage and eliminate areas where water
might pond.
SITE AND SURFACE DRAINAGE
Drainage at the site should be directed away from foundations, collected and tight lined to
appropriate discharge points. Consideration may be given to collecting roof drainage by eave
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Greg Goertzen File No. l 127H6-19 January 12, 2021
gutters and directing it away from foundations via non-erosive devices. Water, either natural or
from irrigation, should not be permitted to pond, saturate the surface soils or flow towards the
foundation. Landscaping requiring a heavy irrigation schedule should not be planted adjacent to
foundations or paved areas. The type of drainage issues found within the project and materials
specified and used should be determined by the Engineer of Record.
GROUNDWATER AND SURF ACE WATERS
There was no indication of a near-surface groundwater table within our exploratory trench or
perched groundwater. Although groundwater is not expected to be a significant constraint to the
proposed development, our experience indicates that near-surface groundwater conditions can
develop in areas where no such groundwater conditions previously existed, especially in areas
where a substantial increase in surface water infiltration results from landscape irrigation or
unusually heavy precipitation. It is anticipated that site development will include appropriate
drainage provisions for control and discharge of surface water runoff. The type of drainage
issues found within the project and materials specified and used should be determined by the
Civil Engineer. The type of plants and soil specified along with proper irrigation used should be
determined by the Landscape Architect.
SECTION No. 4. LIMITATIONS
UNIFORMITY OF SOIL CONDITIONS:
The values presented in this report are based on our evaluation of the observed, exposed soil
conditions. We have assumed that the soil conditions in the remaining portions of the site can be
interpolated without significant deviation in physical properties. We have made a conscientious
effort to select representative test locations and to provide enough tests for a statistically
adequate population in excess of current standard practices. However, parameter values may be
substantially different in other areas due to unforeseeable variations in the soils. Also, the
parameters are affected in time by the moisture-expansion (volume)-pressure changes that
seriously affect the tested values.
ENGINEERING INTERPRETATION:
We are available for consultation and should be made aware of any pertinent condition or
problem. Our conclusions will be re-evaluated and any problem or potential problem solved
with a minimum effort and cost before it gets out-of-hand.
TIME LIMITS:
This report presents conclusions and findings that are valid as of this date. Changes on this site
and adjacent property including grading, improvements, drainage, erosion, etc. may directly
affect the findings, conclusions and recommendations presented herein. Subsequent alterations
or conditions may invalidate these recommendations and values. The values in this report will
probably remain applicable for one year provided the site conditions remain unaltered. After this
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Greg Goertzen File No. 1127H6-l 9 January 12, 2021
period, we should be contacted to inspect the site and review this report so that we may verify its
validity.
WARRANTY:
Certain risks are involved with geotechnical and soil engineering work, which should be
recognized by those involved. We have performed our services in accordance with current
standard practices and procedures. These practices and procedures are those presently utilized
by members of our profession in this region. We do not express or imply a warranty or
guarantee regarding these services.
OUTSIDE RESPONSIBILITY:
It is the responsibility of the client (firm or person to whom this report is submitted) to insure
that the information presented herein is made available to the concerned parties. In addition, it is
the client's responsibility to make certain that any construction reflects any applicable
requirements and conforms with the current codes of jurisdictive governmental agencies.
PROJECT CONCEPT:
We should be notified of any changes in the proposed structures, construction, or site grading, or
project concept so that any addendum or modifications to this report may be provided as
necessary.
SOIL TEST METHODS:
Summary of the
GRADING SPECIFICATIONS USED
for
Proposed Residential Building Site
El Fuerte Street and Acuna Court
City of Carlsbad
Maximum Density & Opt Moisture
Density of Soil In-Place
ASTM D1557-78
ASTM D1556-82
Soil Expansion
Shear Strength
Gradation & Grain Size
Capillary Moisture Tension
LIMITING SOIL CONDITIONS:
Minimum Compaction
UBC STANDARD 29-2
ASTM D3080-72
ASTM Dl 140-71
ASTM D2325-68
90% for "disturbed" soils. (Existing
fill, newly placed fill, plowed ground, etc.)
85% for natural, undisturbed soils.
95% for pavement subgrade within 2' of finish grade and
pavement base course.
5
Greg Goertzen
Expansive Soils
Insufficient Fines
Oversized Particles
PREPARATION FOR FILL:
File No. 1127H6-19
Expansion index exceeding 20
Less than 40% passing the #4 sieve.
Rocks over 1 O" in diameter.
January 12, 2021
Brush, trash, debris and detrimental soils were cleared from the area to receive fill. Detrimental
soil was removed to competent soil. Slopes exceeding 20% were stepped with benches 1 O' or
greater in width. The area to be filled was scarified to a 6" depth and compacted.
FILL MATERIAL:
Contained sufficient fines and did not contain oversized particles or excessive organics. Special
attention was given to the disposition of any oversized rock, organic soils and expansive soils.
Please read this report carefully. If you have any questions, please contact our office. This
opportunity to be of service is sincerely appreciated.
Page L-1, Page T -1 and Plate I are parts of this report.
Respectfully submitted,
Chin C. Chen, RPE C 034442
CCC/mlj
cc: (3) submitted
6
Greg Goertzen
Page L-1
File No. 1127H6-19 January 12, 2021
LABORATORY TEST RESULTS
The maximum dry densities and optimum moisture contents of the fill materials as determined by the
A.S.T.M., Dl557-78, Method A, which uses 25 blows of a 10 pound rammer falling from a height of 18
inches on each of 5 layers in a 4 inch diameter 1/30 cubic foot compaction cylinder, are presented as
follows:
Maximum Optimum
Dry Density Moisture
Soil Type lb./cu.ft. Content dry wt.
1 Tan to red brown, silty sands with
light clay, gravel, rock 121.5 12.1
2 Yellow-brown, silty, clayey, fine
to coarse sand with gravel 127.5 10.2
3 Yell ow-brown, silty, clayey, fine to
coarse sand with gravel and concrete 126.4 10.1
Greg Goertzen
Page T-1
TEST SOIL
NO. TYPE
1 1
2 1
3 1
4 1
5 1
6 1
7 1
8 1
9 1
10 1
11 2
12 2
13 2
14 3
f.g. = finish grade
DEPTH
OF FILL
ATTEST
IN FEET
+2
+4
+6
+8
+10
+12
+14
6
8
+20
f.g.
f.g.
f.g.
+2*
* Retaining Wall Backfill
File No. 1127H6-19 January 12, 2021
TABLE OF TEST RESULTS
A.S.T.M., Dl556-82
MAXIMUM
FIELD DRY DRY
MOISTURE DENSITY DENSITY PERCENT
% P.C.F. P.C.F. COMPACTION
16.8 109.9 121.5 90.4
9.7 111.4 121.5 91.7
13.1 112.8 121.5 92.8
11.6 112.2 121.5 92.3
10.1 113.9 121.5 93.7
15.5 111.3 121.5 91.6
14.2 112.5 121.5 92.6
11.6 115.2 121.5 94.8
12.1 115.6 121.5 95.1
12.6 114.8 121.5 94.5
8.7 118.9 127.5 93.3
9.7 120.1 127.5 94.2
10.1 120.9 127.5 94.8
9.2 114.8 126.5 90.7
-------~ ✓ ----------EL FUl2RiE ST
LOCATION OF
FIELD DENSITY TESTS
PtATl r
JOB NO.
BY
DATE
FIELD DENSITY TEST
COMPACTED FILL
TOP OF SLOPE
TOE OF SLOPE
/l 2 71{ (, -I '1
'°"" NO SC AL€..,_,