896 w/MOD, Major modification to above (t, Studies & Reports•
•
•
•
•
NorCaL Err&leerk g
Soils and Geotechnical Consultants
10641 Humbolt Street Los Alamitos, CA 90720
(562) 799-9469 Fax (562) 799-9459
December 20, 2016 Project Number 18559-15
Gregory and Adriana Popovich
1 Middleridge Lane South
Rolling Hills, California 90274
RE: Report of Geotechnical Observation and Testing of Rough Grading
Operations - Proposed Equestrian Dressage and Lunging Ring for Single
Family Residence - Located at 1 Middleridge Lane South, in the City of
Rolling Hills, California
• Dear Mr. and Mrs. Popovich:
Pursuant to your request, this firm has provided this geotechnical report to summarize
the observation and testing performed during rough grading operations at the above
referenced project. The geotechnical aspects were conducted in accordance with our
• report titled "Geotechnical Engineering Investigation", dated January 5, 2016, Project
Number 18559-15. Our geotechnical services pertaining to the grading of the project
development are summarized in the subsequent sections of this report.
•
•
Site Grading
The purpose of the grading operations was for the placement of fill to provide structural
support of the proposed development. All vegetation and demolition debris was stripped
and removed from the fill area prior to the placement of any fill soils. The upper low
density surface soils area were removed to competent native material, the exposed
surface scarified, moisture conditioned and then recompacted to a minimum of 90%
relative compaction. Soils within the lower slope area were properly benched and
compacted during grading operations.
•
• December 20, 2016 Project Number 18559-15
Page 2
A drain line was installed adjacent to the bench vertical cut located approximately
• halfway up the slope. The drain consisted of 4-inch diameter perforated PVC pipe and
3/ inch diameter gravel wrapped with filter fabric. Solid PVC pipe was connected to the
drain and extended out to the face of the slope. The approximate location of the drain is
shown on the attached plan.
•
•
Fill soils placed were compacted to a minimum 90% of the laboratory standard in lifts
not in excess of eight inches in thickness. The maximum depth of fill soils placed was
approximately 10 feet. A track mounted loader was utilized for compaction control. A
water hose provided moisture control. Our services did not include any surveying of
excavation bottoms, building corners, or subgrade elevations during grading operations.
• Laboratory/Field Testing
The relative compaction was determined by Sand Cone Method (ASTM: D1556-07) and
by the Drive Tube Method (ASTM: D 2937-10). The maximum density of the on -site
soils was obtained by the laboratory standard (ASTM: D1557-12) and results are shown
• on Table I. Tests were performed a minimum of every 500 cubic yards placed and
every two feet in depth of fill placed. A summary of the compaction tests of the rough
grading operations are described in Appendix B with locations shown on the
accompanying plan.
•
•
•
A. Expansion index tests in accordance with ASTM D 4829-11 were performed on
remolded samples of the upper soils to determine the expansive characteristics
and to provide any necessary recommendations for reinforcement of the slabs -
on -grade and the foundations. Results of these tests are provided on Table II in
Appendix A.
B. Soluble sulfate tests in accordance with California Test Method 417 were
performed on representative soils samples to estimate the potential for corrosion
of concrete in contact with theon-site soils. Results are provided on Table III in
Appendix A.
NorCal Engineering
•
• December 20, 2016 Project Number 18559-15
Page 3
•
•
•
•
•
Foundation Design
Any proposed foundations may be designed utilizing an allowable bearing capacity of
1,500 psf for a minimum depth of 24 inches below lowest adjacent grade. A one-third
increase may be used when considering short term loading from wind and seismic
forces. All foundations located near adjacent slopes shall meet all setback criteria per
the latest California Building Code (CBC) standards. All foundations shall have a
minimum 12 inch width for any one story structure. All continuous foundations shall be
reinforced with a minimum of two, No. 4 bars,top and bottom. A representative of this
firm shall inspect all foundation excavations prior to pouring concrete.
Slab Design
All concrete slabs shall be at least four inches in thickness reinforced a minimum of No.
3 bars spaced sixteen inches apart in each direction, positioned in the center of the slab,
and placed on approved subgrade soils. Prior to placement of slabs, the subgrade soils
shall be moisture conditioned to 3% above optimum moisture content to a depth of
eighteen inches.
A vapor barrier (6-mil minimum thickness) should be covered with one inch of approved
sand and underlain by six inches of sand beneath all floor slabs sensitive to the
infiltration of moisture. All concrete slab areas to receive floor coverings should be
• moisture tested to meet all manufacturer requirements prior to placement.
•
•
•
Expansive Soil
Due to the expansive nature of the subsurface soils, special attention should be given to
the project design and maintenance. The attached Expansive Soil Guidelines should be
reviewed by the engineers, architects, owner, maintenance personnel and other
interested parties and considered during the design of the project and future property
maintenance.
NorCal Engineering
•
•
•
•
•
December 20, 2016 Project Number 18559-15
Page 4
Corrosion Design Criteria
Representative samples of the surficial soils revealed negligible sulfate concentrations.
Therefore, all concrete in contact with on site soils shall be designed in accordance with
Table 4.3.1 of ACI 318 Building Code and Commentary. Sulfate test results may be
found on the attached Table III.
Limitations
It should be noted that our work does not warrant or guarantee that the contractor
responsible for each phase of the project has performed his work in accordance with the
project specifications.
We appreciate this opportunity to be of service to you. If you have any further
• questions, please do not hesitate to contact the undersigned.
Respectfully submitted,
NORCAL ENGINEERI
•
Keith D. Tucker
Project Engineer
R.G.E. 841
•
•
•
•
•
NorCal Engineering
Walter K. Mott
Project Manager
• December 20, 2016 Project Number 18559-15
Page 5
E zi ansive Soil Guidelines
•
The following expansive soil guidelines are provided for your project. The intent of
these guidelines is to inform you, the client, of the importance of proper\ design and
maintenance of projects supported on expansive soils. You, as the owner or other
interested party, should be warned that you have a duty to provide the
• information contained in the soil report including these guidelines to your design
engineers, architects, landscapers and other design parties in order to enable
them to provide a design that takes into consideration expansive soils.
In addition, you should provide the soil report with these guidelines to any property
manager, lessee, property purchaser or other interested party that will have or assume
the responsibility of maintaining the development in the future.
Expansive soils are fine-grained silts and clays which are subject to swelling and
contracting. The amount of this swelling and contracting is subject to the amount of
fine-grained clay materials present in the soils and the amount of moisture either
• introduced or extracted from the soils. Expansive soils are divided into five categories
ranging from "very low" to "very high". Expansion indices are assigned to each
classification. If the expansion index of the soils on your site, is 21 or higher, you have
expansive soils. The classifications of expansive soils are as follows:
•
•
•
Classification of Expansive Soil*
Expansion Index Potential Expansion
0-20 Very Low
21-50 Low
51-90 Medium
91-130 High
Above 130 Very High
*From Table 18A-I-B of California Building Code (1988)
When expansive soils are compacted during site grading operations, care is taken to
• place the materials at or slightly above optimum moisture levels and perform proper
compaction operations. Any subsequent excessive wetting and/or drying of expansive
soils will cause the soil materials to expand and/or contract. These actions are likely to
cause distress of foundations, structures, slabs -on -grade, sidewalks and pavement over
the life of the structure. It is therefore imperative that even after construction of
improvements, the moisture contents are maintained at relatively constant levels,
• allowing neither excessive wetting or drying of soils.
•
NorCal Engineering
•
• December 20, 2016 Project Number 18559-15
Page 6
Evidence of excessive wetting of expansive soils may be seen in concrete slabs, both
interior and exterior. Slabs may lift at construction joints producing a trip hazard or may
• crack from the pressure of soil expansion. Wet clays in foundation areas may result in
lifting of the structure causing difficulty in the opening and closing of doors and windows,
as well as cracking in exterior and interior wall surfaces. In extreme wetting of soils to
depth, settlement of the structure may eventually result. Excessive wetting of soils in
landscape areas adjacent to concrete or asphaltic pavement areas may also result in
• expansion of soils beneath pavement and resultant distress to the pavement surface.
Excessive drying of expansive soils is initially evidenced by cracking in the surface of
the soils due to contraction. Settlement of structures and on -grade slabs may also
eventually result along with problems in the operation of doors and windows.
• Projects located in areas of expansive clay soils will be subject to more movement and
"hairline" cracking of walls and slabs than similar projects situated on non -expansive
sandy soils. There are, however, measures that developers and property owners may
take to reduce the amount of movement over the life the development. The following
guidelines are provided to assist you in both design and maintenance of projects on
expansive soils:
•
•
•
t
•
• Drainage away from structures and pavement is essential to prevent
excessive wetting of expansive soils. Grades of at least 3% should be
designed and maintained to allow flow of irrigation and rain water to
approved drainage devices or to the street. Any "ponding" of water adjacent
to buildings, slabs and pavement after rains is evidence of poor drainage; the
installation of drainage devices or regrading of the area may be required to
assure proper drainage. Installation of rain gutters is also recommended to
control the introduction of moisture next to buildings. Gutters should
discharge into a drainage device or onto pavement which drains to roadways.
• Irrigation should be strictly controlled around building foundations, slabs and
pavement and may need to be adjusted depending upon season. This
control is essential to maintain a relatively uniform moisture content in the
expansive soils and to prevent swelling and contracting. Over -watering
adjacent to improvements may result in damage to those improvements.
NorCal Engineering makes no specific recommendations regarding
landscape irrigation schedules.
• Planting schemes for landscaping around structures and pavement should
be analyzed carefully. Plants (including sod) requiring high amounts of water
may result in excessive wetting of soils. Trees and large shrubs may actually
extract moisture from the expansive soils, thus causing contraction of the
fine-grained soils.
NorCal Engineering
•
• December 20, 2016 Project Number 18559-15
Page 7
•
0
•
•
•
•
•
•
o Thickened edges on exterior slabs will assist in keeping excessive moisture
from entering directly beneath the concrete. A six-inch thick or greater
deepened edge on slabs may be considered. Underlying interior and exterior
slabs with 6 to 12 inches or more of non -expansive soils and providing
presaturation of the underlying clayey soils as recommended in the soil
report will improve the overall performance of on -grade slabs.
o Increase the amount of steel reinforcing in concrete slabs, foundations and
other structures to resist the forces of expansive soils. The precise amount
of reinforcing should be determined by the appropriate design engineers
and/or architects.
o Recommendations of the soil report should always be followed in the
development of the project. Any recommendations regarding presaturation
of the upper subgrade soils in slab areas should be performed in the field
and verified by the Soil Engineer.
NorCal Engineering
•
•
•
•
•
•
APPENDICES
(In order of appearance)
Appendix A — Laboratory Tests
Table I — Maximum Density Tests
Table II — Expansion Index
Table III - Sulfate Tests
Appendix B — Summary of Compaction Tests
Site Plan
• Summary of Compaction Tests
•
•
•
NorCal Engineering
•
•
•
•
•
Appendix A
•
•
NorCal Engineering
•
• December 20, 2016 Project Number 18559-15
Page 8
•
•
•
•
•
TABLE I
MAY.IMUM DENSITY TESTS
(ASTII1I: D1557-12)
Optimum Maximum Dry
Sample Classification Moisture Density (Ibs./cu.ft.)
I Clayey SILTSTONE 17.0 97.0
II Silty CLAY 16.5 105.0
III Silty CLAY 19.0 94.0
TABLE II
EXPANSION INDEX TESTS
(U.B.C. STD. 4829-11)
Expansion
Sample Classification Index
Pad Subgrade Silty CLAY 83
TABLE III
SULFATE TESTS
Sample Sulfate (% by Weight)
Pad Subgrade 0.010
NorC al Engineering
•
•
•
•
•
•
•
•
•
•
•
Appendix B
NorCal Engineering
•
1 "-50'
,(5
•
•
•
•
•
D.G.
DIRT
77
,RUSH'
l
f X593.9
\`-
ASPHALT ----`--- t
X599.6
x593.7
x 599.9
GONG
'-� 599.4 t t
599.7
11
X 598
EXISTING EASEMENT FOR
ROAD PURPOSES
535.6
,43.3
-
.t 60'
PROPOSED !
LUNGING .^
RING
1 1
______ ___
EXISTING
RESIDENCE
rim
J=APPROXIMATE LIMITS OF GRADING
5.3
I PROJECT 18559-15
•
/ '&34 j F , a
...ti...+.�^^ fW[r.,r •+".,'� _ ,; yIF�`1. CCNC Ai 5.7 \ 171
q --yy\;` \ t\t,
GONG
�1'!..`•?t`..\
•
I l I
L=349.95'
ma - /
/555
NoTCal Engineering
SOILS AND GEOTECHNICAL CONSULTANTS
POPOVICH
I DATE DECEMBER 2016
. ////
:EXISTING TRAVELED ROADWAY
•
i
/i
_oh
EXISTING TRAVELED ROAD
LOCATION CF COMPACTION TESTS
• December 20, 2016 Project Number 18559-15
Page 9
SUMMARY OF COMPACTION TEST RESULTS
• Date of Test Percent Unit Wt. Relative Soil Test
Test No. Location Depth Moisture lbs./cu.ft. Compaction Type S/D
•
•
7/21/16 101 Site Grading 8.0-8.5 19.0 89.4 92 I D
7/21/16 102 Site Grading 4.0-4.5 18.1 90.2 93 I D
7/21/16 103 Site Grading 4.0-4.5 19.8 92.6 95 I D
7/21/16 104 Site Grading 4.0-4.5 17.7 82.3 95 I S
7/21/16 105 Site Grading 6.0-6.5 18.6 87.6 90 I D
7/21/16 106 Site Grading 3.0-3.5 16.9 89.1 92 I D
7/22/16 107 Site Grading 2.0-2.5 18.7 98.6 94 II D
7/22/16 108 Site Grading 2.0-2.5 18.4 95.2 91 II S
7/25/16 109 Site Grading 0.0-0.5 14.9 97.5 93 II D
7/25/16 110 Site Grading 0.0-0.5 16.4 97.8 93 II S
7/26/16 111 Site Grading 10.0-10.5 18.4 91.2 94 I D
7/26/16 112 Site Grading 10.0-10.5 18.1 91.5 93 I S
7/26/16 113 Site Grading 10.0-10.5 18.7 89.3 92 I D
• 7/27/16 114 Site Grading 8.0-8.5 21.4 86.1 92 III D
7/27/16 115 Site Grading 8.0-8.5 20.6 88.3 94 III D
7/28/16 116 Site Grading 8.0-8.5 19.5 87.8 93 III S
7/28/16 117 Site Grading 8.0-8.5 21.0 88.0 94 III D
7/28/16 118 Site Grading 6.0-6.5 19.3 87.6 93 III S
• 7/29/16 119 Site Grading 4.0-4.5 20.8 86.4 92 III D
7/29/16 120 Site Grading 8.0-8.5 20.6 86.7 92 III S
•
7/29/16 121 Site Grading 10.0-10.5 17.7 91.3 94 I D
7/29/16 122 Site Grading 8.0-8.5 18.5 89.5 92 I D
8/1/16 123 Site Grading 2.0-2.5 19.0 87.6 90 I D
8/1/16 124 Site Grading 2.0-2.5 18.9 88.4 91 I S
8/2/16 125 Site Grading 9.0-9.5 20.1 86.9 92 III D
8/2/16 126 Site Grading 6.0-6.5 20.9 87.9 94 III D
8/2/16 127 Site Grading 0.0-0.5 20.3 86.6 92 III D
8/2/16 128 Site Grading 0.0-0.5 21.0 88.7 94 III S
• 8/4/16 129 Site Grading 6.0-6.5 21.7 85.5 91 III D
8/4/16 130 Site Grading 3.0-3.5 20.5 86.4 92 III D
8/5/16 131 Site Grading 8.0-8.5 18.9 91.6 94 I D
8/5/16 132 Site Grading 8.0-8.5 18.7 89.7 92 I S
**Retest of failing tests after area reworked
S= Sand Cone Method
D= Drive Tube Method
NorCal Engineering
• December 20, 2016 Project Number 18559-15
Page 10
SUMMARY OF COMPACTION TEST RESULTS
• Date of Test Percent Unit Wt. Relative Soil Test
Test No. Location Depth Moisture lbs./cu.ft. Compaction Type S/D
•
•
8/5/16 133 Site Grading 8.0-8.5 18.8 90.0 93 I D
8/5/16 134 Site Grading 8.0-8.5 18.6 90.5 93 I S
8/8/16 135 Site Grading 6.0-6.5 21.6 88.8 94 III D
8/8/16 136 Site Grading 4.5-5.0 22.0 86.7 96 III S
8/9/16 137 Site Grading 4.0-4.5 23.5 87.4 93 III D
8/9/16 138 Site Grading 3.5-4.0 20.9 82.7 88 III D
8/9/16 138A** Site Grading 3.5-4.0 19.1 86.8 92 III D
8/11/16 139 Site Grading 2.0-2.5 21.2 88.4 94 III S
8/11/16 140 Site Grading 2.0-2.5 21.4 89.1 95 III D
8/11/16 141 Site Grading 2.0-2.5 20.5 87.8 93 III S
8/15/16 142 Site Grading 0.0-0.5 16.1 87.5 90 I D
8/15/16 143 Site Grading 0.0-0.5 17.8 91.6 94 I S
8/15/16 144 Site Grading 0.0-0.5 16.9 92.4 95 I D
• 8/15/16 145 Site Grading 0.0-0.5 17.4 87.7 90 I D
8/15/16 146 Site Grading 0.0-0.5 17.6 95.2 91 II D
8/15/16 147 Site Grading 0.0-0.5 17.6 96.2 92 II S
•
•
•
•
**Retest of failing tests after area reworked
S= Sand Cone Method
D= Drive Tube Method
NorCal Engineering
•