HomeMy WebLinkAbout; Day Residence; Field Observation/Relative Compaction Test Results; 2000-05-24Uc. 360399
3197 JAMES DRIVE, CARLSBAD, CA 92008 / m. (760) 434-6104. FAX. (760) 729-0538
May 30, 2000
City of Carlsbad
Attn; Dale Schuk
REF: DAY RESIDENCE,
2479 Ocean St.
CARLSBAD, Ca. 92008
This is a formal request for tt^ release and approval of tbe grading performed on the Day residence located
at 2479 Ocean Street Attached are the copies (rf the field reports, copy (rf the compadion report and the
certification of tl»e grj^ pad
Your assistance in this matter is greatly appreciated
Sincerely,
Maric Turner
TURNER CONSTRUCTION
MELCHIOR LAND SURVEYING INC. ^
May 8, 2000 JN2012
Turner Constniction
Attn; Mark Turner
3197 James Drive
Carlsbad, CA 92008
RE: Day Residence - Pad Certification
Dear Mark:
This letter is to inform you that on May 5, 2000, Melchior Land Surveying, Inc., Field
Surveyed the Rough Grading on the above referenced project, and has found it to be in
substantial confonnance with the approved Grading Plan (Dravwng No. 385-3A). The pads are
generally +/- 0.10 foot of Pad Grade (Please see attached sketch).
If you have any questions, please call.
Sincerely,
MELCHIOR LAND SURVEYING, INC.
Dale A. Davis, P.L.S.
Associate Surveyor
NIAIM OFFICE:
5731 PALMER WAY • SUITE G • CARLSBAD. CA 92008
(760) 438-1726 • FAX [760) 438-3991
mlsi@access1 .net
L.S. 4611
1#
Job No. 98-261 IFC May 24,2000 Page 2
Available Plans
To assist m determmmg the location and elevations of our field density tests and to define the
general extent ofthe site grading for this phase ofwork, we reviewed Building Plans
prepared by THE DAVIS GROUP, ARCHITECTS
Site Preparation
Prior to grading, the existing residential builduig was removed from the site. Prior to the
placement of fill, all loose topsoil was removed from the building area to expose firm natural
ground. The maximum depth of removal was on the order of 2 feet below the original ground
surface. "The excavations were prepared to receive fill by scarifying to a depth of
approxunately 6 mches, moisture conditioning, and recompacting the soils to at least 90
percent of thek maximimi dry densities
The fill material, was obtained from on-site excavation, and consisted primarily of non-
expansive, fine to medium sands. The fill was placed in approximate eight inch layers,
watered to above optimum moisture contents, and compacted to at least 90 percent relative
compaction by means of track rolling with heavy construction equipment. Refer to the
attached plot plan for the location of placed slopes and fill materials.
Field Observation and Testing
Observations and field density tests were performed by a representative of C.W. La Monte
Conqpany during the grading operation. The density tests were taken according to A.S.T.M.
Test 1556-90 guideluies and the results of these tests are shown on the attached figures. The
accuracy ofthe m-situ density test locations and elevations is a function ofthe accuracy ofthe
survQy control provided by other than C.W. La Monte Company representatives. Unless
otherwise noted, theu* locations and elevations were determined by pacing methods and
should be considered accurate only to the degree implied by the method used.
As used herem, the term "observation" implies only that we observed the progress ofwork we
agreed to be involved with, and performed tests, on which, together, we based our opinion as
to whether the work essentially compiles with the job requirements, local graduig ordinances
and the Uniform Building Code.
Laboratory Tests
Maximum dry density determinations were performed on representative samples ofthe soils
used in the compacted fills according to A.S.T.M. Test 1557-91, Method A. guidelines
Method A specifies that a four (4) inch diameter cyluidrical mold of 1/30 cubic foot volume
be used and that the soil tested be placed in five (5) equal layers with each layer contacted by
twenty-five (25) blows of a 10-pound hammer within 18-inch drop. The results of these
tests, as presented on Plate Number II, were used in conjimction with the field density tests to
detemiine the degree of relative compaction of the contacted fill.
Additional Work
Additional grading and backfill operations will be required at the site for utility trench
Job No. 98-261 IFC May 24, 2000 Page 4
should not occur prior to our inspection of the excavations. Sometunes foundation excavation
observation reveals the need to deepen, redesign or otherwise mitigate unanticipated or
adverse conditions. Therefore, prior observation would eliminate the need to remove any
formwork or steel remforcement ui the affected footing excavation in order to correct the
observed problem.
Concrete Slabs-on-grade
General
Concrete floor slabs, if used shall be a minimum thickness of four inches and shall be
underlam by two inches of clean, washed sand overlying 6 mil visqueen, overlying an
additional two mches of clean sand.
Slab Reinforcement
The slab should be remforced #3 remforcing bars placed at 18 inch centers, each way or with
6x6-6/6 steel wire mesh. The remforcement should be placed on concrete "chairs" or spacers,
to within the middle third ofthe slab. Theoretically, the above-recommended rebar and wire
mesh options provide simiiar reinforcement strength. However, based on our past experience,
we have found that the wire mesh is often and is more easily pushed to the bottom ofthe slab
during the finishing process, thus significantly reducmg its mtended remforcing, function.
The rebar grid, if properly supported, is less likely to be dislodged durmg the finishing
process. Thus, unless the concrete finisher is diligent in this regard, the rebar option is the
preferred method of slab reinforcement.
Interior Slab Curing Time
Followmg placement of concrete floor slabs, sufficient drying time must be allowed prior to
placement of floor coverings. Premature placement of floor covermgs may result m
degradation of adhesive materials and loosening of the finish floor materials. Prior to
installation, standardized testing can be performed to determine if the slab moisture emissions
are within the limits recommended by the manufacturer of the specified floor-covering
product.
Design Parameters for Earth Retaining Structures
Active Pressure
The active earth pressure to be used ui the design of retammg walls, shall be based on an
Equivalent Fluid Weight of 30 pcf (pounds per cubic foot) at any depth. This active pressure
value is for level backfill and assumes an unrestrained condition, and that proper dramage is
provided behind the wall. This pressure value assumes the wall is backfilled with on-site
excavated sands.
Lateral Pressure
The passive earth pressure of the encountered natural-ground soils and any reconqjacted fill
soils (to be used for design of building foundations and footings to resist the lateral forces)
shall be based on an Equivalent Fluid Weight of 300 pcf (pounds per cubic foot). This
passive earth pressure shall only be considered valid for design ifthe ground adjacent to the
foundation structure is essentially level for a distance of at least three tunes the total depth of
Job No. 98-2611 FC May 24,2000 Page 3
backfill, and the preparation of subgrade material in the parkmg and driveway areas. It is
recommended that in-place density tests and field observations be performed by a
representative ofthis office during each of these operations to verify that they are performed
in accordance with job requirements.
Conclusions and Recommendations
Based on field observation and the density test results, it is the opmion of C.W. La Monte
Company that the grading was performed basically in accordance with the City ofCarlsbad
Grading Ordinance and the recommendations contained in the referenced Geotechnical
Report, and the recommendations contamed therein do apply to the subject site. In addition to
the references' recommendations the below items require consideration:
Foundations
Dimensions and Embedment
Conventional shallow foundations may be utilized m the support of the proposed structures.
All new foundations shall extend through all topsoil's and be embedded into compacted fill
or formational sands. Two story structures should have a minimum foundation depth of 15
mches below lowest adjacent finished grade and a 15-inch minimum width, per the Uniform
Building Code. Single story structures require a 12 mch deep foundatioa
Soil Bearing Value
A bearing capacity of 2000 psf may be assumed for said footmgs when founded a minimum
of 12 inches mto the existing contacted fill and/or formational materials. This bearing
capacity may be mcreased by one-third, when considering wmd and/or seismic loadmg.
Foundation Reinforcement
It is recommended that new contuiuous footings be remforced with at least two No.5 steel
bars; one reinforcing bar shall be located near the top of the foundation, and one bar near the
bottom. The steel remforcement will help prevent damage due to normal, post construction
settlement, resultmg from variations in the subsurface soil conditions. This recommendation
does not supersede reinforcement required for structural considerations.
Anticipated Settlements
Based on our experience with the soil types on the subject site, the soils should experience
settlement m the magnitude ofless than 0.75 inch under a structural load of 2,000 pounds per
square foot on a compacted fill mat.
It should be recognized that minor hairline cracks normally occur in concrete slabs and
foundations due to shrinkage durmg curing and/or redistribution of stresses and some cracks
may be anticipated. Such cracks are not necessarily an indication of excessive vertical
movements.
Foundation Excavation Observation
In order to minimize any work delays at the subject site during site development, this firm
should be contacted 48 hours prior to any need for inspection of footing excavations or to
perform grading observation or field density testing of conqjacted fill soils.
If possible, placement of forms, templates and steel reinforcement in footmg excavations
Job No. 98-261 IFC May 24,2000 Page 7
Foundations, footings, and floor slabs, to an adequate dramage facility.
Structure retaining walls shall be properly water proofed and provided with a subdrain
system. Our firm prior to implementation should review the water proofing system and
drainage design.
LABORATORY TESTS AND SOIL INFORMATION
The expansion potential of clayey soils is detennined utilizing the UBC Expansion Index
Test. Expansive soils are classified as follows:
Expansion Index Potential Expansion
0-20 Very Low (or considered "Non-expansive")
21-50 Low
51-90 Medium
91-130 High
130-Above Very High
Foundations located withm 7 feet of the top of fill slopes should be deepened so
that the outside, bottom edge ofthe footing is at least 7 feet from "daylight" ui the
slope face.
• The foundation soils at the subject site are mdicated to possess a very low
expansion potential using the UBC classification system Therefore foundations
recommendations detailed in the referenced geotechnical report are appropriate for
the as-graded site condition.
This report covers only the services performed between April 28 to May 5, 2000. As limited
by the scope ofthe services which we agreed to perform, our opmion presented herein are
based on our observations and the relative compaction test results. Our service was
performed m accordance with the currently accepted standard of practice and in such a
manner as to provide a reasonable measure of the conqsliance of the grading operations with
the job requirements. No warranty, express or implied, is given or intended with respect to
the services which we have performed, and neither the performance of those services nor the
submittal ofthis report should be construed as relievmg the gradmg contractor of his
responsibility to conform with the job requirements.
Ifyou should have any questions after reviewing this report, please do not hesitate to contact
this office.
Job No. 98-2611 FC May 24,2000 Page 6
Soil Profile Type - Table 16-J
The materials encountered at the subject site fell mto the Sd Soil Profile Type.
Seismic Coefficient Ca - Table 16-Q
The Seismic Coefficient is determmed from the above table using the Soil Profile Type and
the Seismic Zone Factor.
Cfl = 0.44 Nfl
Seismic Coefficient Cv-Table 16-R
The Seismic Coefficient is determmed from the above table using the Soil Profile Type and
the Seismic Zone Factor.
Cv = 0.64 Nv
Near Source Factor (Na 1) - Table 16-S
The near source fector is based on the Seismic Source Type and feult distance.
Nfll = 1.0
Near Source Factor (Nv 1) - Table 16-T
The near source fector is based on the Seismic Source Type and feult distance.
Nvl= 1.2
Seismic Source Type - Table 16-U
The seismic source types are listed in the below table, as determined from Table 16-U.
Seismic Source Distance Maximum Moment Slip rate, SR (mm/yr)
Type Magnitude (M)
B 3.5 km M<7.0 SR<2
Site Drainage Considerations
Adequate measures shall be taken to properly finish-grade the site after the additions and
other improvements are in place. Drainage waters from this site and adjacent properties are to
be directed away from foundations, floor slabs and footings, onto the natural dramage
direction for this area or into properly designed and approved dramage fecilities. Proper
subsurface and surface drainage will ensure drainage that no waters will seek the level ofthe
bearing soils under the foundations, footings and floor slabs. Failure to observe this
recommendation could result in uplift or undermining and differential settlement of the
structure or other improvements on the site.
In addition, appropriate erosion-control measures shall be taken at all times during
construction to prevent surfece runoff waters from entermg footing excavations, ponduig on
finished building pad or pavement areas, or running uncontrolled over the tops of newly-
constructed cut or fill slopes.
Planter areas and planter boxes shall be sloped to drain away from the foundations, footings,
and floor slabs. Planter boxes shall be constructed with a subsurfece drain, installed in gravel,
with the direction of subsurface and surfece flow away from the
Job No. 98-261 IFC May 24,2000 Page 5
the foundation. We recommend that the upper 1-foot of soil not protected by pavement or
concrete slabs be neglected when calculating passive resistance.
A Coefficient of Friction of 0.4 times the dead load may be used between the bearing soils
and concrete wall foundations or structure foundations and floor slabs founded on formational
or similar materials. When combining frictional and passive resistance, the former should be
reduced by one-tlurd.
Waterproofing and Subdrain Observation
The geotechnical engineer should be requested to verify that waterproofing has been applied
and that subdrains are properly installed behmd the walls. However, unless specifically asked
to do so, we will not verify proper application of the waterproofing.
Retaming walls that are not waterproofed and properly drained are potentially subject to
cosmetic staming (such as efflorescence), surficial spalling and decon^osition and excessive
moisture emissions (and resulting problems) into the ulterior space.
Backfill
All backfill soils should be compacted to at least 90% relative conqjaction. Expansive or
clayey soils should not be used for backfill material. The wall should not be backfilled until
the masonry has reached an adequate strength.
Factor of Safety
The above values, with the exception of the allowable soil bearmg pressure, do not include a
factor of safety. Appropriate fectors of safety should be mcorporated mto the design to
prevent the walls from overtummg and sliding.
Foundation Plan Review
The foundation plans for the proposed stmcture may be submitted to this office for review to
ascertain that the recommendations provided in this report have been followed and that the
assumptions utilized in its preparation are still valid
Slope Stabilitv
It is our opuiion that cut and or fill slopes constmcted at 2:1 (horizontal to vertical) mclination
will possess an adequate fector-or-safety to heights of at least ten feet.
UNIFORM BUILDING CODE DESIGN INFORMATION
The following design factors were obtained from the 1997 addition of the Uniform Building
Code and are based on site conditions and location.
Seismic Zone Factor (Z) - Table 16-1
The Seismic Zone Factor (Z) is determmed from Seismic Zone Map, Figure 16-2.
The project is located in Zone 4.
Z = 0.40
Job No. 98-2611 FC May 24, 2000
This opportunity to be of professional service is sincerely appreciated.
Respectfully submitted,
C.W. La Monte Company
Page 8
CliffotdTW. La Monte, R.C.E. 25241, G.E. 0495
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COMPACTION TEST RESULTS
Test Date Location Depth Fill Moisture
%
Field
Density
Soil
Type
Relative
Compaction
1 4/28/00 SEE SITE PLAN 2' 8.7 116.0 90.6
2 5/1/00 a it it 2' 9.9 116.9 I 91.2
3 5/5/00 ii ii ii F.G. 8.7 119.3 93.2
4 5/5/00 il ii ii F.G. 8.7 117.1 I 91.5
5 5/5/00 ll ii ii F.G. 8.7 117.6 I 92.1
SOIL TYPES
Type Description Optimum
Moisture %
Maximum Dry Density
I BROWN FINE TO MEDIUM SAND 10.7 128.0 pcf
Figure No.: II
Job No.: 98-2611-FC
MO ABORATORY SOIL DATA SUMMARY
130
ASSUItEU 5IIt/\it UAfA 1
ArrAncrir COMCSIOM (pifi 250
ArrAHEHr rniciiciri AriOLE 30°
120
3*nd
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US •
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t 1
itndt'd lit
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IIO
100
ZERO AIR VOIOS CUflVE S
20 • 30
LADORATOnY COMPACTION TEST
SOlU
T TPE SOIL CLASSIFICATION NO.
TREHCH
IIO. DEPTH
1 BROWN FINE TO MEDIUM SAND
SWELL TEST DATA
lliniAL OHT OEMSITY tpefl
INITIAL WATCn COHTEIITr/oI
LOAD (pill
rtflCEH r SWELL
JOU NO 98-2611
Fifiune MO III
WET WEATHER MAINTENANCE AT RESIDENTIAL SITES*
Southern Califomians, unlike oilier residents of the nation, are unaccuslomed to
heavy rainfall. Whenever unusually wet weather occurs, San Diegans, particularly
those living on slopes of filled land, become concerned (often unduly) about the
conditions of their building site.
They should not be, generally. The grading codes of lhe County of San Dlego, and
the various incorporated cites In the County, concerning filled land, excavation,
terracing, and slope construction, are among the most stringent In the stale, and
adequate to meet almost any natural occurrence. This is the opinion of the San
Diego Chapter of the California Council of Civil Engineers and Land Surveyors,
whose members help prepare and review the codes.
In 1967, the local Chapier of the California Council of Civll Engineers and Land
Surveyors compiled a list of some precautions Ihat homeowners can lake lo mainiain
Iheir building sites. This updated pamphlet reiterates Ihose precautions.
Everyone is accustomed to maintaining his house. Everyone realizes that periodic
termite inspections are a reasonable precaution, and lhal homes require a coat of
paint from time lo time. Homeowners are well used lo checking and replacing
wiring and plumbing, particularly In older homes. Roofs require occasional care.
However, the general public regards the natural ground as inviolate. They ought lo
realize that Nature is haphazard in her creation of all land, some of which becomes
building sites. Nature's imperfections have been largely compensated tlirough careful
engineering design and construction and enforcement of rigorous building and lol
development ordinances, ll is only reasonable lo assume thai an improved building
site requires the approximate same care that the building Ilself does. In most
instances, lol and site care are elementary steps that can be taken by the homeowner
at considerably less cost lhal building maintenance.
As a public service, engineers in private pracUce of the San Diego Chapier of the
California Council of Civil Engineers and Land Surveyors have compiled this
pamphlet of pertinent Do's and Don'ls as a guide lo homeowners.
The CCCELS respectfully advises lhal, in offering Uiese guides, it accepts no
responsibility for the actual performances of home sites or siruclures localed thei eon.
* Pamphlet prepared by the San Diego Chapter California Council of Civil Engineers
and Land Surveyors.
4550 Palm Ave., 5ult« 25. La Mc«a. CA 91941 - (619) 462-9B6I
DO'S
1. Do clear surface and terrace drains with a shovel, if necessary, and check
them frequently during the rainy season. Ask your neighbors to do likewise.
2. Do be sure that all drains have open outlets. Under the right condilions, this
can be lesled simply on a dry day wilh a hose. If blocl^age is evident, you
may Iiave lo clear llie drain meclianicaiiy.
3. . Do check roof drains, gutters and down spouts lo be sure they are clear.
Depending on your location, if you do not have roof gutters and down spouts,
you may wish to instali Ihem because roofs and their wide, flal space will shed
tremendous quantities of water. Without gutters or olher adequate drainage,
water falling from the eaves ponds against foundation and basement walls.
4. Do check all outlets al the top of slopes lo be sure lhal Ihey are clear and that
water will nol overflow lhe slope ilself, causing erosion.
5. Do keep drain openings (weep-holes) clear of debris and other material that
could block them in a slorm.
6. Do check for loose fill above and below your properly if you live on a slope
or terrace.
7. Do watch hoses and sprinklers. During the rainy season, lillie, is any,
irrigation is required. Over-saturation of lhe ground is not only unnecessary
and expensive, but can cause subsurface damage.
8. Do watch for backup in interior drains and toilets during a rainy season, this
may indicate drain or sewer blockage.
9. Do exercise ordinary precaution. Your house and building site were
constructed lo meel certain slandards lhal should protect againsi any natural
occurrences, if you do your part In mainlaining them.
4350 Falm Ave. Suit* 25. La Mcea. CA 91941 - (619) 462-9B6I
DON'TS
1. Don't block terrace drains and brow ditches on slopes or al the lops of cul
slopes on sloping ground. These are designed to carry away runoff lo a place
where it can be safely dislribuled. Generally, a litlle shovel work will remove
any accumulation of dirt and other debris that clogs the drain. If several
homes are located on the same terrace, it Is a good Idea to check wilh your
neighbors. Water backed up on llieir properly may eventually reach you.
Water backed up in surface drains will lend lo overflow and seep inlo.llie
terraces, creating less stable slopes.
2. Don'l permil water lo gather above or on the edges of slopes (ponding).
Water gathering here will lend lo either seep Inlo lhe ground, loosening fill or
natural ground, or will overflow on lhe slope and begin erosion. Once
erosion is started, it is difficult lo conlrol and severe damage may result rather
quickly.
3. Don'l connect roof drains and roof gutters and down spouts to subdrains.
Rather, arrange Ihem so that they will flow oul onto a paved driveway or the
street where the water may be dissipated over a wide surface. Subdrains are
constructed lo lake care of ordinary subsurface water and cannoi handle the
overload from roofs during a heavy rain. Overloading the subdrains lends lo
weaken the foundations.
4. Don't spill water over slopes, even where this may seem a good way lo
prevent ponding. This tends lo cause erosion and. In the case of fill, can eat
away carefully engineered and compacled land.
5. Don't drop loose fill slopes, ll is not compacled lo the same strength as lhe
slop ilself and will lend lo slide wilh heavy moisiure. The sliding may clog
terrace drains below, or may cause addilional damage by weakening the
slope. If you live below a slope, try lo be sure that no loose fill is dumped
above your properly.
6. Don't dischaige water inlo French drains close lo slopes. French drains are
sometimes used lo get rid of excess water when oUier way of disposing water
are not readily available. Overloading these drains saturates the ground and,
if the drains are localed close lo slopes, may cause slope failure in their
vicinity.
7. Don't discharge surface water inlo septic lanks (leaching fields). Nol only are
septic lanks conslrucled for a differenl purpose, bul tliey will lend, because of
their size, lo naturally accumulate addilional water from the ground during a
heavy rain. Overloading them arlicifially during the rainy season is bad for the
4350 Falm Ave. Sult« 25. La Me»B, CA 91941 - (619) 462-9061
same reason as subdrains and French drains, and is doubly dangerous because
their overflow can pose a serious health hazard.
8. Don't over-irrigale slopes. Naturally, ground cover of Ice plant and other
vegetation will require some moisture during the hot summer months, but
during the wet season, irrigation can cause Ice plant and olher heavy ground
cover lo pull loose, which nol only destroys the cover, but also starts serious
erosion. Planted slopes acquire sufficient moisiure when il rains.
9. Don'l lel water gather against foundations, retaining walls, and basement
walls. Tiiese walls are build lo willisland ordinary moisiure in llie ground.and
are, where necessary, accompanied by subdrains to carry off excess. If water
is permitted to pond againsi them. It may seep through them, causing
dampness and leakage inside the basement, more important, the water
pressure can cause heavy structural damage to walls.
10. Don'l try lo compact backfill behind walls near slopes by flooding. Not only
is flooding the least efficient way of compacting fine-grained soil, but will also
undermine or lip the wall.
11. Don't leave a hose and sprinkler remaining on or near a slope, particularly
during the rainy season. This will enliance ground saturation and may cause
damage.
12. Don'l block swales lhal have been graded around your house or the lot pad.
These shallow ditches have been put there for the purpose of quickly removing
water toward the driveway, streel or olher positive oulleL By all means, do
nol lel water become ponded above by blocked swales.
4350 Falm Ave. 5ult<! 25. U Mesa. CA 91941 - (619) 462-9561