1996-4782 G
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Category
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Name
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Street Address
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Serial #
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Description
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IENG G
I DESIGN GROUP
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ENGINEERING DESIGN & PlANNING CONSULTANTS FOR RESIDENTIAL AND COMMERCIAL CONSTRUCTION
Date:
October 31, 1996
To:
Sidney and Harriett Howard
c/o Steven Borrow
175 Jupiter Street
Encinitas, CA. 92024
Re:
Proposed Residence to be located at 120 Neptune Avenue, Encinitas, CA.
Subject:
Compaction Report for Building Pad Undercuts.
~
In accordance with your request, we have provided geotechnical observation and
compaction testing services during pad undercuts for the proposed improvements. These
proposed improvements include a split level, partial single and two story residence.
Grading operations were conducted on-site during the period of October 24, 1996 through
October 30, 1996. Prior to the start of grading, areas to be graded where stripped of
vegetation and existing improvements, which were removed from the site. Site grading
generally consisted of removal of any loose surficial topsoil/fill material to undisturbed
formational sandstone (five feet outside building footprint where possible). Pad undercuts
generally consisted of removals extending to a depth of five feet and three fèet for the
upper pad and lower pads, respectively. Compaction to finish subgrade was accomplished
utilizing a 04 Bulldozer and water hose. The bottom of removals were scarified to a depth
of approximately 12 inches and moisture conditioned. Undercuts were observed by a
representative from our firm prior to the placement of compacted fill.
Soils placed during grading were derived from pad undercuts, and based on experience
with similar soil types, are non-expansive in nature. Formational sandstone materials were
visually classified, and have a low expansive nature. During grading, fill soils were
generally mixed, moisture conditioned, and compacted to a minimum of 90 percent of the
Page No.1
Job No. 961318-4
475 CARMEL STREET. SAN MARCOS, CA . 92069 . (619) 752-7010 . FAX (619) 752-7092
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maximum dry density (ASTM D1557-78). Fill soils were placed under the part time
observation and testing of our personnel.
The subsoil conditions encountered within the subject area during site grading, are
generally similar to those anticipated for the site.
FI
The approximate locations of our field density tests are presented in Figure No.1, "Field
Density Test Location Map". The results of the laboratory and field tests for the referenced
site are presented in Table No.1, "Laboratory and Field Test Results".
Field density tests were performed in accordance with ASTM 01556-82 (Sand Cone
Method). Our test results indicate that the fill placed, under our observation and testing,
in the areas indicated in Figure No.1, "Field Density Test Location Map", have been
compacted to at least 90 percent relative compaction, as determined by ASTM D1557-78.
The reported test results are representative of the soil conditions at the locations tested.
Our observation and field density testing methods are in accordance with normally
accepted procedures. The accuracy of the relative compaction values are subject to the
precision limitations of the ASTM test methods. The accuracy of the maximum dry density
determination (ASTM D1557-78) is discussed in the 1985 Annual Book of ASTM
Standards, Section 4, Volume 04.08, entitled, Soil and Rock: Building Stones. To date,
ASTM has not reported on the accuracy of the field density test procedure (ASTM
01556-82). Variations of relative compaction values should be expected, laterally and
vertically, from the actual test locations.
In general, it is our opinion that the fill soils placed at the locations tested, were compacted
to a minimum of 90 percent" relative compaction (based on ASTM D1557-78). The
geotechnical conditions encountered during grading and excavation of the site, were found
to be in general conformance with the conditions described in the geotechnical evaluation
report for the site. It is anticipated that the proposed additions will be founded on
formational sandstone materials. Where necessary, minimum required depths for footings
should be increased in order to meet this recommendation.
Page No.2
Job No. 961318-4
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4)
6)
The following items should be noted:
1)
Compaction testing should be conducted on any additional fills placed on the
subject site.
2)
Footing excavations should be observed by our representative prior to the
placement of reinforcement.
3)
Adequate drainage precautions at this site are imperative and will play an important
role on the performance of the structure. Under no circumstances should water be
allowed to pond against or adjacent to footings or retaining walls or to sheet flow
over slopes. The ground surface surrounding the building should be relatively
impervious in nature, and slope to drain away from the building in all directions, with
a minimum slope of 2% for a horizontal distance of 7 feet (where possible). Area
drains or surface swales should then be provided to accommodate runoff and avoid
any ponding of water. Roof gutters, downspouts and drains should be considered
on the entire structure. Surface and area drains should not be connected to any
wall drainage, french drain or underdrain system (see attached Homeowners
Maintenance Guidelines).
Adequate control joints (minimum of every 400 s.f., 1 inch vertical cut) should be
installed to control the unavoidable cracking of concrete that takes place when
undergoing its natural shrinkage during curing. The control joints should be well
located to direct unavoidable slab cracking to areas that are desirable by the
designer.
Brittle floor finishes placed directly on slab on grade floors may crack if concrete is
not adequately cured prior to installing the finish or if there is minor slab movement.
To minimize potential damage to movement sensitive flooring, we recommend the
use of slip sheeting which allows for foundation and slab movement without
transmitting this movement to the floor finishes.
BSERV A TION AND TE- TING
We recommend that any additional fill placement and foundation excavations, be observed
by a representative of this office, so that construction is performed in accordance with the
recommendations of this report and the referenced geotechnical report. We request a
minimum 24-hour notice prior to any observations, so that proper scheduling of our
personnel can be made. If variations of site conditions are encountered during
construction, this office should be notified, so that appropriate recommendations or design
changes may be implemented.
Page No.3
Job No. 961318-4
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We appreciate the opportunity to be of professional service to you in this matter. If you
have any questions regarding our report, please do not hesitate to contact this office.
Very truly yours,
-Zy~.f"'-Cf'\II. P
.... \ ~
-;¡- -
Steven Norris .. -~-- .
California RCE #47672
Attachments:
Figure No.1 - "Field Density Test Location Map"
Table No.1 - "Laboratory and Field Test Summary"
Homeowners Maintenance Guidelines
Page No.4
Job No. 961318-4
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TABLE NO.1
I LABORATORY AND FIELD TEST RESULTS
I Test"'"
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SOIL TYPE MAXIMUM DENSITY (PCF) OPTIMUM MOISTURE U.S.C.S. CLASSIFICATION
I (%)
1
BROWN, MEDIUM 118.3 9.5 SP
I GRAINED SAND
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I TEST NO: DATE ELEVATION SOIL DRY DENSITY FIELD MOISTURE RELATIVE
(FEET) TYPE (PCF) (PERCENT) COMPACTION
1 10/24/96 3.0 1 112.0 11 94.7
I 2 10/25/96 1.0 1 110.5 10 93.4
3 1 0/25/96 1.5 1 112.4 9.5 95.0
I 4 1 0/28/96 3.0 1 109.8 10.0 92.8
1 0/29/96 1.5 1 110.5 9.0 93.4
5
I 6 1 0/29/96 1.0 1 113.6 10 96.0
7 10/31/96 0.0* 1 109.8 10 92.8
8 10/31/96 0.0* 1 110.2 11 93.2
I 9 10/31/96 0.0* 1 108.9 11 92.1
*N )TE: FINISH PAD GRADE
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Residential homesites require periodic maintenance of irrigation and drainage systems to
insure proper performance and overall retention of property value. Often, homeowners
are not aware of the importance of these systems and allow them to deteriorate.
During the construction phase of development, governing agendes require property
developers to utilize specific methods of engineering and construction to protect the
public interest. For instance, the developer may be required to grade the property in
such a manner that rainwater wirr be drained away from the building pad, install brow
ditches & terrace drains, and to plant slopes to minimize erosion. However, once the lot
is purchased, it becomes the buyer's responsibility to maintain these safety features by
observing a prudent program of lot care and maintenance. Failure to make regular
inspection and perform necessary maintenance of drainage devices and sloping areas
may cause severe financial loss. In addition to his/her own property damage, the
property owner may be subject to civil liability for damage occurring to neighboring
properties as a result of negligence.
The forrowing maintenance guidelines are provided for the protection of the homeowner's
investment.
c.
o.
E.
A
All roof gutter and downspout systems, installed on the residence, should
be tightfined to a suitable outlet away from the structure. Under no
circumstances should water be allowed to pond onsite, particularly against
the perimeter foundation system.
Soils grades adjacent to the foundation of the structure should be sloped
to direct water away from the foundation' and into a corrective drainage
system. Soil grades should slope at a minimum of 2% for a horizontal
distance of 5 feet away from the structure.
B.
The irrigation of planter systems located immediately adjacent to the
foundation should be strictly controlled to avoid over watering. Saturation
of soils in these planters may result in soil settfement/ expansion and
associated distress.
Care should be taken to ensure that slopes, terraces, berm, and proper lot
drainage are not disturbed. .
In general, roof and yard runoff should be directed to either the street or
storm drain by non-erosive devices such as sidewalks, drainage pipes,
ground gutters, and driveways. Drainage systems should not be altered
without expert consultation.
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K.
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F.
AU drains shoul<;j be kept dean and undogged. induding gutters and
downspout's. Terrace drains or gunite ditches should be kept free of debris
to allow proper drainage. During periods of heavy rain, the performance of
the drainage systems should be inspected. Problems, such as gullying and
pending, if observed, should be corrected as soon as possible.
My leakage from pools, waterlines, etc. or surface runoff bypassing drains
should be repaired as soon as possible.
G.
H.
Mimaf burrows should be eliminated since they may cause diversion of
surface runoff, promote accelerated erosion, and even trigger shallow slope
failures.
I.
Slopes should not be altered without expert consultation. Whenever a
homeowner plans a topographic modification of a lot or sloPe, a qualified
geotechnical consultant should be contacted.
If unusual cracking, settling, or earth slippage occurs on the property, the
owner should consult a qualified geotechnical consultant immediately.
J.
The most common causes of sloPe erosion and shallow slope failures are
as follows:
.
Gross neglect of the care and maintenance of onsite slopes and
drainage devices
.
Inadequate and/or improper planting.
replanted.as soon as possible.
Excessive or insufficient irrigation or diversion of runoff over the
slope.
Barren areas should be
.
Property owners should not let conditions on their property adversely
impact their neighbors. Cooperation with neighbors could prevent problems
and increase the aesthetic attractiveness of the community.