HomeMy WebLinkAboutHDP 91-23; WELDON RESIDENCE; GEOTECHNICAL INVESTIGATION AND COASTAL ENGINEERING STUDY; 1988-10-26)
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Project No. 8851268E-COS1
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GEOTECHNICAL INVESTIGATION
AND COAST AL ENGINEERING
STUDY
TIERRA DEL ORO PROPERTY
CARLSBAD, CALIFORNIA
Prepared for:
Mr. Charles Weldon
c/o D.L. Frischer
11300 Sorrento Valley Road, Suite 103
San Diego, California
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1550.Hotel Circle North
San Diego, California 92108
(619) 294-9400
Fax: (619) 293-7920
October 26, 1988
Project No. 8851268E-SI01/COS1
Mr. Charles Weldon
c/o D.L. Frischer
11300 Sorrento Valley Road, Suite 103
San Diego, California 92121
GEOTECHNICAL INVESTIGATION
AND COASTAL ENGINEERING STUDY
TIERRA DEL ORO PROPERTY
CARLSBAD, CALIFORNIA
Gentlemen:
Woodward-Clyde Consultants
In accordance with your request and our proposal dated August 12, 1988, we have
performed a geotechnical investigation and coastal engineering study at the subject property
located on the west side of Tierra Del Oro Street along the coastal bluff in Carlsbad,
California. The purpose of our study was to evaluate the existing site conditions and
provide geotechnical and coastal information to assist you and your consultants in design of
the proposed residence foundations and stone revetment shore protection at the subject site.
The design will be submitted to the California Coastal Commission to obtain a coastal
permit for construction and will be subject to their development conditions.
Our geotechnical investigation was designed to address the following:
• General subsurface soil conditions;
• Groundwater;
• Types and depths of foundations;
• Allowable soil bearing pressures;
• Estimated Settlements;
• Design pressures for retaining walls; and
• Set-back for structures from top of bluff.
Our coastal study was designed to address the following:
• Tidal range in the area of Carlsbad;
• Average beach slope at the site; estimated offshore slope;
• Estimated still water level;
• Estimated storm surge and wave set-up;
Consulting Engineers, Geologists
and Environmental Scientists
Offices In Other Principal Cities
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Project No. 8851268E-SI01/COS1
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• Estimated design wave height breaking on the shore protection; and
• Stone revetment shore protection design.
PROJECT DESCRIPTION
The subject site is located along the coast in Carlsbad, California just south of Agua
Hedionda Lagoon and adjacent to the SDG&E Encina Power Plant facility and Carlsbad
State Beach. The site consists of Lot 16 of Map No. 3052 in the City of Carlsbad,
California. The site is· currently planned for development of a 2-level, wood frame, single
family house of approximately 50 x 75 feet in plan dimension. The house will be above
and below grade with westward projecting tiered decks. The estimated finish floor
elevations for the house levels are +44.3 and 34.5 feet (MSL Datum) for the upper and
lower levels, respectively. It is also our understanding that the proposed residence will be
located behind the string lines between existing residences on either side of the lot. A
general plan of the site is shown on the attached sheet 1 of 1.
The extreme west edge of the site is exposed to the Pacific Ocean and has a nearly vertical
eroded slope face of terrace deposits which descends to the shoreline. At the toe of the
slope is an exposed level shelf of which is fronted by a berm composed of large cobbles
and beach sand. Adjacent to the project site along both the northern and southern property
boundaries are developed residential lots which have rock revetment at the shoreline. It is
proposed that a similar rock revetment be constructed on the subject property that will tie
into the adjacent revetments. This is the only type of shore protection structure that has
been used in this area .
REVJEW OF AVAILABLE INFORMATION
We have been provided with proposed plans for the residence entitled "Residence for Mr.
& Mrs. Charles Weldon, Tierra Del Oro, Carlsbad, California," prepared by Durand
Designs, last dated September, 1977 (we understand that this design is being revised). We
have also been provided with a current topographic plan entitled "Survey & Topo for
Charles Weldon," prepared by Brian Smith Engineers, Inc., dated September 6, 1988 and
a past topographic map also prepared by Brian Smith in 1976. In addition, we have
reviewed our project files for similar projects in the Carlsbad area and have conducted a
search of related information regarding coastal conditions in Carlsbad including available
topographic maps, offshore bathmetric data, and geologic reports,. Topographic elevations
shown on the plan provided to us refer to Mean Sea Level Datum. For our analysis, we
have used Mean Low Low Water Datum. The Mean Sea Level (MSL) Datum of 1929 is
equivalent to +2.88 feet Mean Lower Low Water (MLLW). We have also discussed the
project with Ms. Debra Frischer ofD.L. Frischer Development Planning Consultants.
FIELD AND LABORATORY INVESTIGATIONS
On September 23, 1988, an engineer and geologist from our firm made a visual
reconnaissance of the subject site, conducted one exploratory boring to a depth of 37-1/2
feet and obtained representative soil samples, conducted a ground surface profile survey in
the general east-west direction of the site and a beach slope profile during low tide,
assessed the current geologic conditions of the general vicinity, and conducted a general
survey of the existing stone revetments on the adjacent properties. The beach portion of
our survey extended west about 200 feet beyond the nearly vertical eroded coastal bluff
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slope on the property. The boring location and results of our surface profile are presented
on the attached Sheet 1 of 1.
A Key to Logs is presented in Appendix A-1. A final log of the boring is presented in
Appendix A on Figures A-2 and A-3. The descriptions on the log are based on the field
log, sample inspection, and laboratory test results. Results of laboratory tests are shown at
the corresponding sample locations on the logs and in Appendix B. The field investigation
and laboratory testing programs are discussed in Appendices A and B.
GENERAL SITE CONDIDONS
Topography
The subject site is generally located on a coastal bluff which has a steeply descending slope
down to the shoreline of the Pacific Ocean to the west. The elevation of the relatively flat
bluff top is on the order of +46 feet (MLL W). The inclination of the upper portion of the
descending slope is on the order of 2: 1 (horizontal:vertical); the lower portion of the slope
is a 15 feet high, nearly vertical, eroded bluff. The upper portion of the slope is covered
with iceplant vegetation. Eroded slope material and scattered debris is present at the toe.
The toe of this slope is at an approximate elevation of+ 15 feet (MLL W). A relatively level,
narrow shelf of hard siltstone is exposed at this elevation. Approximately 20 to 25 feet out
from the bluff the siltstone is covered with cobbles that have accumulated as a berm along
the beach. Beyond the cobbles, a thin layer of sandy beach deposits is present. The
surveyed beach slope was at an approximate 10: 1 inclination at the time of our study .
Local and seasonal variations of the beach slope should be expected. Published
information indicates that offshore bottom inclinations are about 60:1 to as far as 2 miles
off shore. There is also some indication of a small submarine canyon starting
approximately starting about 1 mile offshore.
Subsurface Soil and Geology
Several geologic units are exposed along the sea coast at the subject site: the Santiago
Formation, the Bay Point Formation, and Beach Deposits.
The Tertiary age Santiago Formation is composed of very dense and hard, light gray to
gray, silty to clayey sand to sandy clay. These sediments were observed to be massively
bedded and generally poorly to slightly indurated as observed in O"Qr test boring. Samples
penetration values in this material were over 100 blows per foot. The unit is exposed as a
relatively flat lying siltstone shelf at the toe of the nearly vertical eroded slope. Erosion of
the Santiago Formation is due primarily to direct wave run-up and abrasion by beach sand,
gravel and cobbles.
A Pleistocene age terrace deposit overlies the Santiago Formation above an approximate
elevation of +15 feet (MLLW). This unit consists of poorly consolidated, fine-to medium
grained light reddish brown to yellowish brown sand. Sampler penetration values in the
material were generally above 50 blows per foot. The terrace deposits are approximately
30 feet thick within the building pad area at the site and are exposed in the slope along the
west side of the property. Erosion of the terrace deposits is due to direct wave run-up and
abrasion by beach sand, gravel and cobbles. Much of this formation exposed at the nearly
vertical portion of the slope appears to have experienced relatively rapid erosion in the past
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decade. Coincident high tide and storm surge conditions may accelerate erosion rates of
this material during brief peak periods.
Beach deposits consisting of medium-and fine-grained sand and extensive beds of cobble
overlie the Santiago Formation along the shoreline. The sandy beach deposits generally
accumulate during the summer and are eroded during the winter. Recent studies for the
Oceanside Littoral Cell and Carlsbad Beach areas indicate that sand-starvation of the area is
currently in progress. The sandy beach deposits at the time of our study were generally
below an approximate elevation of+ 10 feet (MLL W). Cobbles underly the beach sand
and, a cobble berm is exposed along the toe of the bluff between approximate elevations of
+ 15 and+ 10 feet (MLLW) west of the exposed Santiago Formation shelf. The cobbles
extend below the beach sand at about elevation + 10 feet and were covered with about 2 feet
of sand as far out as 100 feet at the time of our study .
Beach Sand
Beach sand level and profile measurements have been made in the subject area by Waldorf,
Flick and Hicks between April 1982 and February 1983 and by Teckrnarine, Inc. between
July 2, 1984 and April 27, 1988. A site specific beach profile was made by Woodward
Clyde Consultants on September 23, 1988 as a part of this study. Based on our past
studies along the San Diego coast line it has been our experience that the sandy beach
profiles typically have slopes on the order of 10:1 to 15:1, whereas the cobble berms have
slopes on the order of 2: 1 to 3:1. This information has been used to help interpret sand
levels from profiles done by others .
During 1982 the maximum sand level in the subject area generally ranged between
approximate elevations +9 and + 10 feet (MLL W) and sand thickness within the first 100
feet of shore varied on the order of 1 foot or less. After the storms in January and
February 1983 the maximum sand level was eroded down to approximate elevations +4
feet (MLL W) and there was about a 5-foot decrease in sand thickness. During the period
between July 1984 and April 1988 the maximum sand level generally ranged between
approximate elevations +5 and +9 feet (MLL W) and sand thickness generally varied by 2 to
3 feet. Our survey in September 1988 indicated a maximum sand level of+ 10 feet and the
top of the cobble berm at approximate elevation + 15 feet (MLL W).
Based on our evaluation of the available beach profile data for the subject area, it appears
that the beach sand level at this site has not been above approximate elevation + 10 feet
(MLL W) for the last seven years.
Bluff Erosion
The terrace sands above approximate elevation+ 15 feet are relatively easily eroded by the
action of high tides and storm waves. A comparison of topographic maps made for the
subject site indicate that approximately 12 feet of material at the toe of the bluff has been
eroded landward during the period between 1976 and 1988. It is our opinion that most of
this erosion occurs episodically during major storm periods.
The siltstone of the Santiago Formation which is exposed below elevation + 15 feet is more
resistant to erosion. It is estimated that the erosion of this material occurs at a much slower
rate on the order of 1 to 2 inches per year or less.
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Groundwater
Woodward-Clyde Consultants
Groundwater was encountered in our test boring at a depth of about 30 feet which was in
the form of a minor seep at the terrace sand/Santiago Formation contact. Minor
groundwater seepage was also observed at the slope toe just above the exposed contact.
This groundwater appears to be perched along the contact surf ace .
Tide Levels
The tides along the Pacific Coast and at Carlsbad have a semidiurnal inequality. The lowest
tide each year is about -2.0 feet (MLLW). The highest tide is about +7.6 feet (MLLW).
Relative sea levels on the coast of California are projected to be increasing at a rate of about
0.7 feet per century.
Wave Climate
Determining the wave potential at a given coastal location requires a number of critical
assumption regarding the budget of deep water waves, the sheltering effect of offshore
islands, the refraction of waves and water at variable depths along the shoreline. Waves
that break along the San Diego County shoreline generally range in height from 2 to 5 feet;
however, large waves ranging from 6 to 10 feet in height are not uncommon. Such large
waves can be expected to arrive at almost any time during the year and to continue for 3 to
4 days at a time. These high-wave episodes may be accompanied by strong winds. Waves
12 to 15 feet in height have been observed on occasion, and breakers with estimated
heights of 15 to 20 feet have been observed off the San Diego County coastline.
Seasonal changes in the general wave regime have been observed all along the coast.
Usually, winter waves have shorter periods and greater heights, and approach the shore
more obliquely than summer waves. The direction of wave approach varies but is usually
within a few degrees (5 to 15 degrees) of normal to shore during all seasons.·
The shoreline of Carlsbad is exposed to wave action, unaffected by island interference,
through three relatively well-defined corridors of wave approach. Waves with periods of 8
seconds or shorter have an unobstructed approach from the northwest between the
mainland and Santa Catalina Island, from the west between Santa Catalina Island and San
Clemente Island, and from the southwest between Cortez Bank and Los Coronados
Islands. These short period waves approach this shore segment with limited fetchs of 130
to 140 nautical miles. Waves with periods longer than 12 seconds approach the shore from
the northwest between Santa Catalina Island and the mainland and from the southwest
between Cortez Bank and Los Coronados Islands. The longer period waves approaching
from the west are obstructed by Santa Catalina Island, San Nicolas Island, San Clemente
Island and Cortez Bank .
Winds
Sea breezes attaining velocities of 10 to 20 miles per hour blow landward across the
shoreline nearly every afternoon. Reciprocal and land breezes at night have much lower
velocities. Storms moving in from the Pacific Ocean occasionally bring somewhat stronger
winds to the Carlsbad area, but their duration is usually relatively short. Tropical cyclones
from the south reach Carlsbad on rare occasions. Winds along the coastline within the
study area come predominantly from the west, northwest, and southwest; average wind
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velocities are less than 10 miles per hour. The maximum recorded wind velocity at the San
Diego airport is approximately 50 miles per hour.
DISCUSSIONS, CONCLUSIONS, AND RECOMMENDATIONS
The discussions, conclusions, and recommendations presented in this report are based on
the information provided to us, results of our current observations, field and laboratory
studies, geotechnical and coastal analyses, and professional judgement.
General Subsurface Soil Conditions
The existing subsurface soils at the site, which generally follow the surface form of a flat
lying lot at street level to a steeply descending iceplant covered slope to the west with a
nearly vertical eroded slope toe near beach level, consist of very dense undisturbed natural
formational soils of the Pleistocene terrace deposits and Santiago Formations. The terrace
deposits primarily consists of poorly-consolidated, lightly cemented poorly-graded fine
sand and silty medium to fine sands. These soils are considered nonexpansive with respect
to their grain size distribution and relatively low clay content as observed in the grain size
distribution on Figures B-1 and B-2. The Santiago Formation is generally below elevation
+ 15 and is predominantly a more fine-grained material consisting of sandy to silty lean
clays and silty medium to fine sand. This unit is partially cemented and may be considered
more rock-like than soil. It should be anticipated that excavation into this material will be
difficult .
Shallow fill and residual soils exist over the majority of the lot but are on the average
1 foot or less within the proposed development area. Cobbles and beach deposits exist
west of the slope toe and are seasonally varied in thickness and extent. Perched
groundwater conditions exist at the formational contact as observed in our test boring and
visual observations of the western slope toe .
The available evidence indicates that the upper terrace sands are eroding at a relatively rapid
rate. It also appears that this erosion is beginning to effect existing rock revetments on
either side of the property. It is therefore our opinion that a rock revetment (or other
suitable shore protection) is necessary at the subject site to mitigate future erosion
problems .
Earthwork and Grading
Review of the provided preliminary project plans indicate that cutting up to as much as 10
feet of existing native material may be required for the lower level building area and
possibly backfilling of low retaining walls, lower level walls, and utility trenches may be
required. It may also be desirable to place some fill in the area of the eroded slope to
buttress this area against future instability .
We recommend that the materials in the upper 3 feet of finish grade be composed of select
material. Select soil should consist of material that contains no rocks or hard lumps greater
than 6 inches in maximum dimension and that has an Expansion Index of 30 or less when
tested in accordance with UBC Standard 29-2. The available information indicates that the
majority of the soils within the proposed cut area may be classified as select. Soils not
meeting the requirements of select material may be encountered and should be either placed
in landscape areas or exported from the site.
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We recommend that all site grading be done in accordance with the most recent edition of
the Standard Specifications for Public Works Construction, prepared by the Joint
Cooperative Committee of the Southern California Chapter, American Public Works
Association, and Southern California Districts, Associated Contractors of California, and
the Standard Special Provisions, prepared by County of San Diego, Department of Public
Works .
We recommend that at the start of site grading, abandoned improvements, debris, and other
rubble be removed and disposed offsite. We also recommend that the surface vegetation
and soil containing organic matter be removed from the proposed development area.
Loose, porous soils within the building and driveway pavement area that are not removed
during grading should be excavated or scarified as required, brought to proper moisture
content, and then compacted prior to placing additional fill.
Materials for compacted fill shall contain no rocks or hard lumps greater than 6 inches in
maximum dimension and shall contain at least 40% of materials smaller than 1/4 inch in
size. Material of a perishable, spongy, or otherwise improper nature shall not be used in
fills .
Compacted fill soils should have a relative compaction that is indicated by test to be not less
than 90 percent. Relative compaction is defined as the ratio (expressed in percent) of the
in-place dry density of the compacted fill divided by the maximum laboratory dry density
evaluated in accordance with the ASTM D1557-78. Unless otherwise specified, fill
material shall be compacted by the Contractor while at a moisture content at or above the
optimum moisture content determined in accordance with the above test method .
The fill material shall be placed by the Contractor in layers that, when compacted, shall not
exceed 6 inches. Each layer shall be spread evenly and shall be thoroughly mixed during
the spreading to obtain uniformity of moisture and material in each layer. The entire fill
shall be constructed as a unit, in nearly level lifts starting up from the lowest area to receive
fill. Compaction shall be continuous over the entire area, and the equipment shall make
sufficient uniform trips so that the desired density has been obtained throughout the entire
fill. Compaction equipment shall be of such a design that it will be capable of compacting
the fill to the specified density at the specified moisture content.
Surface Drainage
We recommend that positive measures be taken to properly finish grade the site so that
drainage waters from the site and adjacent properties are directed off and away from
foundations, floor slabs, and slope tops. Even when these measures have been taken,
experience has shown that a shallow groundwater or surf ace water condition can and may
develop in areas where no such water condition existed prior to site development. This is
particularly true where a substantial increase in surface water infiltration results from
landscape irrigation.
To further reduce the possibility of moisture related problems, we recommend that all
landscaping and irrigation be kept as far away from the building perimeter as possible.
Irrigation water, especially close to the building, should be kept to the minimum required
level. We recommend that the ground surface in all areas be graded to slope away from the
building foundations and floor slabs and that all runoff water be directed to proper drainage
areas and not be allowed to pond. A minimum ground slope of 2 percent is suggested.
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In order to provide a subsurface barrier to reduce the potential for moisture migration, we
recommend that the structures be provided with a continuous perimeter concrete footing
extending at least 18 inches below lowest adjacent grade and 12 inches wide.
Recommendations for floor slab underlays are provided later in this report.
Slope Stability
Our analyses indicate that the natural approximately 30 feet high coastal bluff with an
approximately 2: 1 (horizontal to vertical) inclined upper slope and an approximately 15 feet
high, near vertical eroded area at the toe of the slope on the subject property is only
marginally stable. If left unsupported, it should be expected to slough back to an
approximate overall 1: 1 to 1-1/2: 1 inclination with time. In order to mitigate this condition
it is recommended that this eroded area either be buttressed as a part of the rock revetment
construction or that the design of foundations for the proposed structure assume that the
slope will slough back to a 1-1/2: 1 inclination up from the existing toe.
Foundations
In our opinion, the proposed structure can be supported on conventional spread or
continuous footings founded in undisturbed, select formational soils. We recommend that
spread or continuous footings founded in the formational soils have a minimum width of
12 inches and a minimum depth of 18 inches below lowest adjacent grade and be designed
for an ~lowable soil bearing pressure of 2,000 psf (dead plus live loads). In our opinion,
design bearing capacities can be increased by no more than one-third for loads that include
wind or seismic forces .
We recommend that the structure be provided with a continuous perimeter footing at least
18 inches below lowest adjacent grade. We recommend that continuous foundation
elements be at least nominally reinforced top and bottom in accordance with the structural
engineers recommendations. We recommend that the foundation excavations be hand
cleaned of loose material and observed by our firm to verify compliance with the design
assumptions.
We recommend that foundations for settlement sensitive improvements that are located
closer than 8 feet to the top of the existing slope be extended in depth such that a minimum
set-back horizontal clear distance of 8 feet exists between the outside bottom edge of the
footing and the slope face. The slope face is considered to be the existing 2: 1 slope if the
lower eroded portion is buttressed or the assumed 1-1/2: 1 line up from the existing toe at
elevation+ 15 feet (MLLW), if the eroded portion of the slope is not buttressed.
Estimated Settlements
We estimate that for the anticipated light structural loads supported on shallow footings, the
total settlements should not exceed 1/2 inch. Differential settlements are generally about
one-half of the total settlement for the same load. It is anticipated that these settlements will
occur relatively fast as the loads are applied.
Concrete Slabs-on-Grade
We recommend that slab-on-grade concrete floors subject to normal residential use be at
least 4 inches thick and be nominally reinforced at mid-depth with at least 6 x 6, 10/10
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welded wire mesh or equivalent. We recommend that the slab thickness and reinforcement
be properly designed by the structural engineer for the design floor loads and the
anticipated settlements.
We recommend that concrete slabs-on-grade be underlain by a minimum 4-inch underlay of
clean, coarse sand. A vapor barrier (e.g., 10-mil visqueen) with a 2-inch protective sand
cover should be placed over coarse sand if moisture-sensitive floor coverings (such as
carpeting or tiles) are used.
Lateral Earth Pressures and Resistance
We recommend that laterally loaded foundation elements be designed to be resisted by a
passive earth pressure equal to an equivalent fluid weight of 350 pcf. Foundations
resisting lateral pressures should have concrete poured neat against undisturbed natural
soil. The upper 1 foot of soil, if not protected by concrete slabs or pavement, should not
be utilized in the calculation of passive resistance. If the resistance is obtained from friction
between concrete and soil, we recommend that a friction coefficient of 0.4 be used for
design. If friction and passive pressure are used together, the friction coefficient should be
reduced to 0.3.
It is anticipated that some low cantilever retaining walls and restrained basement walls may
be utilized at the site. We recommend that cantilever retaining walls that are less than 10
feet in height, have a level backfill surf ace, and are backfilled using onsite select material,
be designed for an active lateral earth pressure equal to an equivalent fluid weight of
35 pcf. We recommend that restrained basement walls up to 10 feet in height be designed
for an at-rest lateral earth pressure equal to an equivalent fluid weight of 35 pcf plus a
uniform lateral pressure of lOH psf, where His the height of wall in feet. We recommend
that restrained basement walls also have level backfill surf aces using onsite select material.
We recommend that all backfilled walls be provided with proper surface and backfill
subsurface drainage to prevent the buildup of hydrostatic pressures behind the walls.
Subsurface drains consisting of filter gravel with perforated pipe or crushed rock wrapped
entirely in filter fabric and placed at the base of the wall should be considered. A Guide
Specifications for Wall Drains is presented in Appendix C. Composite in-place drains such
as Mirafi's Miradrain may also be used .
Stone Revetment Shore Protection
It is anticipated that future high tides, rising sea level and extreme storm waves could result,
in further erosion of the sandy Bay Point Formation terrace deposits at the subject site. It is
our opinion that a shore protection structure should be constructed to mitigate erosion
behind rock revetments on adjoining property and to protect the proposed construction on
the subject site. In general accordance with the U.S. Army Corps of Engineers' Shore
Protection Manual, Volume I and II, 1984, the following information has been used for
design of a proposed stone revetment shore protection to mitigate this anticipated future.
erosion .
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Project No. 8851268E-SIO 1/COS 1
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Extreme tide + 7 .60 feet (MLL W)
(Carlsbad correction) X (.905)
50 year sea level rise 0.35 feet
Local wave set-up 0.50 feet
Meteorological anomality (surge) 0.80 feet
Design Still Water Level +8.55 feet
Use: +8.6 feet (MLLW)
Offshore slope 60: 1 (horizontal:vertical)
Revetment inclination 2: 1
Depth of Scour at toe + 3 feet (MLL W)
Wave period 10 to 16 seconds
Breaking wave height 6 feet
Estimated wave run-up elevation + 20 feet (MLL W)
It is recommended that the rock revetment have a top elevation of +20 feet (MLLW), a toe
elevation of + 3 feet and slope inclination of 2: 1. The revetment should consist of two
layers of 2-ton armor rock underlain by two layers of 1/4 ton underlayer rock. Filter cloth
with a protective layer of sand should be placed between the terrace sands or sand fill and
the rock. A typical design section is shown on the attached Sheet 1 of 1. Construction
Specifications for Rockwork (Appendix D) and Construction Specifications for Plastic
Filter Fabric (Appendix E) are also included for your information.
It is recommended that the rock revetment be located such that the revetment slope
approximately coincides with the existing cobble berm slope. At this location the revetment
should not effect the useable beach area for normal variations in sand levels and would still
provide room for construction of a buttress for the eroded area.
We recommend that the area behind the proposed stone revetment shore protection be
backfilled to provide a buttress for the nearly vertical eroded slope. The buttress should be
composed of properly compacted select fill and should have a maximum slope inclination
of 2: 1 (horizontal:vertical).
It is anticipated that the excavation for the revetment will extend into the relatively hard
siltstone of the Santiago Formation. The contractor should take this difficult excavation,
the groundwater seepage and the tidal and waves conditions into consideration in planning
his work .
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UNCERTAINTY AND LIMITATIONS
Woodward-Clyde Consultants
We have observed only a small portion of the pertinent geologic, topographic, and coastal
conditions at the subject site. The conclusions and design criteria presented herein are
based on the assumptions that these conditions do not change appreciably from those found
or assumed during our investigation. If variation or undesirable geotechnical or coastal
conditions are encountered during the proposed construction, Woodward-Clyde
Consultants should be consulted for further recommendations.
Geotechnical and Coastal engineering and the geologic sciences are characterized by
uncertainty. Professional judgements presented herein are based partly on our evaluations
of the technical information gathered, partly on our understanding of the proposed
construction, and partly on our general experience. Our engineering work and judgements
rendered meet current professional standards; we do not guarantee the performance of the
project in any respect.
This report is intended for design purposes only and may not be sufficient to prepare an
accurate bid .
This firm does not practice or consult in the field of safety engineering. We do not direct
the contractor's operations, and we cannot be responsible for the safety of personnel other
than our own on the site; the safety of others is the responsibility of the contractor. The
contractor should notify the owner if he considers any of the recommended actions
presented herein to be unsafe .
Very truly yours,
WOODWARD-CLYDE CONSULTANTS
~/~
R.E. 14121 ·L. ~~~
/JA//(.~/4~
David L. Schu;~ •• v-/
C.E.G. 1212
LJL/DLS!MA/lm
Attachment
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Project No. 8851268E-SI01/COS1
APPENDIX A
FIELD INVESTIGATION
Woodward-Clyde Consultants
One exploratory boring was advanced at the approximate location shown on the Site Plan
(Figure 1). The drilling was performed on September 23, 1988, under the direction of a
geologist from our firm, using a Mobile B-61 drill rig, with a 8-inch hollow-stem auger.
Samples of the subsurface materials were obtained from the exploratory boring using a
modified California drive sampler (2-inch inside diameter and 2-1/2-inch outside diameter) with
thin brass liners. The sampler was generally driven 18 inches into the material at the bottom of
the hole by a 140-pound hammer falling 30 inches; thin metal liner tubes containing the sample
were removed from the sampler, sealed to preserve the natural moisture content of the sample,
and returned to the laboratory for examination and testing.
The location of the exploratory boring and the elevation of the ground surface was estimated by
the geologist from the information provided to us. A Key to Logs is presented in Figure A-1.
Logs of the exploratory boring is shown in Figures A-2 and A-3 .
a/ljl2 A-1
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Project: TIERRA DEL ORO PROPERTY KEY TO LOGS
Date Drilled:
Type of Boring:
Cf) ....
.c: Q) 't::: a-ci. Cf) 3: Q) .... E 0 0 111 m (/)
0-~: -... -
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5-
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10-
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15-
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20-
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30 ....
Project No: 8851329E-SI01
*
I
Water Depth:
Type of Drill Rig:
Material Description
Surface Elevation:
DRIVE SAMPLE LOCATION
Sample with recorded blows per foot was obtained with a
Modified California drive sampler (2" inside diameter, 2.5"
outside diameter) lined with sample tubes. The sampler
was driven into the soil at the bottom of the hole with a
140 pound hammer falling 30 inches.
Sand
Clay
GS -Grain Size Distribution Analysis
Measured:
Hammer:
Woodward-Clyde Consultants @
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Figure: A-1
.... « Q) Cf) ;W
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Project: TIERRA DEL ORO PROPERTY Log of Boring No: 1
Date Drilled: 9-23-88
Type of Boring: 8" HSA
* see Key to Logs, Fig. A-1
Cf) .c Q) a-0..
Q) -E Cl cu Cl)
o-1-1 X ----
-1-2 IX --
5-
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1-3 ~ 56 -
;
--
10-
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-1-4 X 58 --
15-i -
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1-5 ~ 43 ---
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1-6 X 100 ----
25-
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Project No: 8851329E-SI01 I
Water Depth: 30'
Type of Drill Rig: 8-61
Measured: At time of drilling
Hammer: 140 lbs. at 30" drop
Material Description
Surface Elevation: Approximately +44' (MSL)
Dense, moist, pale brown, silty medium to fine sand (SM)
FILL/TOPSOIL
Very dense, moist, reddish brown, slightly silty medium to fine
sand (SM), porous and slightly cemented
TERRACE DEPOSITS
Very dense, moist, pale reddish brown, poorly graded sand with
silt (SP-SM), friable
TERRACE DEPOSITS
Very dense, moist, pale yellowish brown to white, poorly graded
sand (SP), friable
TERRACE DEPOSITS
very aense, moist to wet, yellowish gray, poorly graaea tine sana
with silt (SP-SM) TERRACE DEPOSITS
With some small gravels
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Q) -~-to ... -:::, C: en.!~ ·-C: 0 Cl ~ a. 0 0
~(.) Cl
3 98 -
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4 109 -
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-3 107 -
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Figure: A-2
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.c: iii .... Q) 01--
GS
GS
GS
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Project: TIERRA DEL ORO PROPERTY Log of Boring No: 1 (Cont'd)
.c a.-a, ....
C)
30--
V)
Q) a. E Cll Cl)
-1-8
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35-
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Material Description
Very dense, moist, gray, silty medium sand (SM)
SANTIAGO FORMATION
Concretion
-11 -
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1 •9 8 5012 iH¥i Grading to _ 17
......
Q) .e! .c: V)
0~
87 GS
93 GS 1-10 5i1 63/6"177"•------------------------------
1'._ Hard, moist, gray, sandy silty clay (CL-ML) /,.--_-i---+-----1-----1
I '-. SANTIAGO FORMATION ---Bottom of Boring at 37.5 feet
40--
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45--
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50--
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55--
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60--
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65 ....
Project No: 8851329E-SI01 I Woodward-Clyde Consultants e Figure: A-3
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Project No. 8851268E-SI01/COS1
APPENDIXB
LABORATORY TESTS
The materials observed in the exploratory boring were visually classified and evaluated with
respect to strength, swelling, and compressibility characteristics; dry density; and moisture
content. The classifications were substantiated by performing grain size analyses on
representative samples of the soils. The strength of the soils was evaluated by considering the
density and moisture content of the samples and the penetration resistance of the sampler.
The results of the moisture content and dry density tests on drive samples are shown with the
penetration resistance of the sampler at the corresponding sample location on the logs, Figures
A-2 and A-3. The grain size distribution curves are shown in Figures B-1 and B-2 .
a/ljl2 B-1
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UNIFIED SOIL CLASSIFICATION
COBBLES GRAVEL SAND SILT OR CLAY COARSE ANE CCWIS~ MEDIUM I FINE
• U.S. SIEVE SIZE IN INCHF.S U.S. srANDARD SIEVE No. HYDROMITER
3 3/4 3/8 4 10 ...,20 40 60 140 200
100
1l
0
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80 20 E-i
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E-i s a 0 .... .... ~ ~ ti >-J
~ 60 40 A
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~ I ~ 00 ~ 11. ~
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~ 40 ~ 60 ~
r:il i l":tl u u
~ ~
l:z:1 l:z:1 p,,. \ ',
11. ~~ 20 80 \ .... ) -
~) 100 0
103 102 I . I 1' 10'"2 1cr3 10 1 10-
• GRAIN SIZE lN MILLIMETER
SYMBOL BORING DffuTH A A DESCRIPTION
0 1-1-4 1 SILlY FINE SAND (SM)
• □ 1-2-4 3 SILlY FINE SAND (SM)
D.. 1-3-4 8 POORLY GRADED SAND WITH SILT (SP-SM)
◊ 1-5-4 18 POORLY GRADED SAND (SP)
Remark: • 8851329E SI01 TIERRA DEL ORO PROPERTY
Woodward Clyde
Consultants GRAIN SIZE DISTRIBUTION Figure ·No. B-1
• San Diego, CA
-UNIFIED SOIL CLASSIFICATION -,
COBBLES GRAVEL SAND SILT OR CLAY
COARSE FINE Cll'RS~ MEDIUM I FINE
U.S. SlEVE SIZE IN INCBFS U.S. S?ANDARD SIEVE No . HYDROMETER •
I 3 3/4 3/8 4 10 20 40 60 140 200
100 --' 0 "-l N \
\ . '
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60
~' \ 20 .; ' [) \ E-t
E-t ' ffi ::c: ~ ) --~ ;; l
.. '\ ~ ::,..
~ 60 40 4!~ A
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t!, I ~ l1l ~ I ~ ll-t
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~ 40 60 i f::i:l • --4 -u ' u
~ \ ~
f::i:l ~
ll-t ' p..
20
I\
80 I U
\ • \}
0 -~ 100
10'3 ,. 2 . I " . 1h·2 1cr8 10 10 1 1(f1
GRAIN SIZE IN MILLIMETER
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SYMBOL BORING DffuTH A A DESCRIPTION
0 1-7-4 28 POORLY GRADED FINE SAND WITH SILT (SP-SM)
D 1-8-4 32 SlllY FINE SAND (SM) • A 1-10-4 37 SANDY,SILlY CLAY (CL-Ml)
◊ BEACH POORLY GRADED FINE SAND (SP)
Remark:
• 8851329E SI01 TIERRA DEL ORO PROPERTY
Woodward Clyde
Consultants GRAIN SIZE DISTRIBUTION Figure No. B-2
San Diego, CA • s;--.
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APPENDIXC
GUIDE SPECIFICATIONS FOR WALL DRAINS
I. DESCRIPTION
Subsurface drains consisting of filter gravel or crushed rock wrapped in filter fabric
with perforated pipe shall be installed as shown on the plans in accordance with
these specifications, unless otherwise specified by the engineer.
II. MANUFACTURE
Subsurface drain pipe shall be manufactured in accordance with the following
requirements.
Perforated PVC pipe or ABS pipe shall conform to the ASTM Designations 1785
and 2751, respectively .
III. FILTER MATERIAL
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Filter material for use in backfilling trenches around and over drains shall consist of
either of the following alternatives:
(a) Clean, coarse sand and gravel or crushed stone conforming to the following
grading requirements.
Sieve Size
1"
3/411
3/8"
4
8
30
50
200
Percentage Passing Sieve
100
90 -100
40 -100
25 -40
18 -33
5 -15
0 -7
0 -3
This material generally conforms with Class 2 permeable material in accordance
with Section 68-1.025 of the Standard Specifications of the State of California,
Department of Transponation.
(b) Open-graded crushed rock or gravel (l-1/2" maximum size) surrounded
entirely by a geotechnical filter fabric (such as Mirafi 140N or equivalent) .
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IV.
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LAYING
Trenches for drains shall be excavated to a minimum width equal to the outside
diameter of the pipe plus 1 foot and to the depth shown on the plans or as directed
by the engineer. The bottom of the trench shall then be covered full width by
4 inches of filter material and the drainpipe shall be laid with the perforations at the
bottom and sections shall be joined with couplers. The pipe shall be laid on a
minimum slope of 0.2 percent.
After the pipe has been placed, the trench shall be backfilled with filter material to
the elevation shown on the plans, or as directed by the engineer .
TYPICAL SECTION
• A o
... 0 .
, ., .
..,, :
✓ .....
Impervious Soil
i.--~-.-c+----~aterproof Membrane
~ O O • 0:, JO 0
p ,7 0
,, ,, ---. 4-----
0, •
p-0 0 • . ~
0 0
0 O
0 0"'
0 <)
Filter Material-
16" Minimum Width
4 ' Minimum Above Pipe
r--------4" Diameter
Perforated Pipe
~--6 11 Minimum Pipe
Bedding of Filter .Material
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GENERAL
APPENDIXD
CONSTRUCTION SPECIFICATIONS
ROCKWORK
The work provided herein consists of furnishing all plant, labor, material, and equipment
and performing all operations required for furnishing, hauling, and placing rock and sand,
complete, as specified herein and shown on the contract drawings .
Rock shall conform to applicable requirements of Section 200 -Rock Materials of the
Standard Specifications for Public Works Construction and this Special Provision.
The publications listed below form a part of this Special Provision to the extent referenced.
The publications are referred to in the text by the basic designation only .
American Society for Testing and Materials (ASTM) Publications:
C 122-77
C 535-69
SUBMITrALS
Specific Gravity and Absorption of Coarse Aggregate
Resistance to Abrasion of Large Size Coarse Aggregate by Use of
the Los Angeles Machine
Certificates of Compliance: In lieu of specified testing, submit certificates of compliance
for all rock materials. Furnish one certificate of compliance for each source of supply.
MATERIALS
Rock: Provide rock that is sound, durable, hard, free from laminations, weak cleavages,
and undesirable weathering, and of such character that it will not disintegrate from the
action of air, ocean water, or the conditions to be met in handling and placing.
Source: Furnish rock conforming to the requirements herein from a source approved by
the Engineer. Notify the Engineer in writing within five (5) calendar days after date of
Notice to Proceed the source or sources of rock to be furnished.
Quality: Conduct suitable tests to determine the acceptability of the rock, including
specific gravity, absorption, and abrasion tests considered necessary to demonstrate to the
Engineer that the materials are acceptable for use in the Work; or submit certified test
reports from the materials supplier that the rock materials furnished comply with
specification requirements. Approval of the source shall not be construed as a waiver of
the right of the Engineer to require the Contractor to furnish rock complying with
specifications requirements. Furnish rock with the greatest dimension not greater than 3
times the least dimension and conforming to the following requirements .
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Project No. 8851268E-SI01/COS1
Requirement
Bulle specific gravity (saturated-surlace
dry basis minimum):
Armor Rock 2.60
Underlayer Rock 2.60
Abrasion, maximum percentage: 45
2-Ton Armor Rock (A-Stone)
Weight of Pieces (Pounds)
8,000
4,000
2,000
Woodward-Clyde Consultants
ASTM
Designation
C 127
C 127
C535
Percent Larger by Weight
0-5
50-100
95-100
1/4 Ton Underlayer Rock CB-Stone)
Weight of Pieces (Pounds)
1,000
Percent Larger by Weight
500
75
0-5
50-100
95-100
Sand Cover: Sand shall be any select granular nonexpansive material imported or
excavated from the cut areas that in the opinion of the Soil Engineer is suitable for use as a
protective layer for the filter cloth. The material shall contain no rocks or hard lumps
greater than 3 inches in size .
SCHEDULE
Rock and sand cover shall be placed in the zones designated on the plan.
PLACEMENT
General: Place rock of the types specified such that the limits of rock in place follow with
reasonable variation the indicated lines and slopes without continuous under building or
overbuilding. Construct the rock work to a full section so as to produce a stable revetment.
Place all rock from bottom of the slope upwards. Do not dump rock from excessive
heights or employ placement methods that may cause misplacement of rock. In order to
achieve slope uniformity and solid seating of armor rock, nudge all high-riding rocks with
a normal-to-slope strike of the placement bucket, rock grab, or another rock held in a rock
grab. Nudging shall be carefully controlled to prevent dislodgement of more distant rocks
in the mound, with impact sufficient only to consolidate the immediate area around the rock
being nudged so as to bring it within tolerance limits and lock it firmly in place. Where
nudging fails to achieve this purpose, the rock shall be lifted and re-seated for better fit or
replaced with a better fitting rock. Placement methods are subject to approval of the
Engineer.
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Sand: Sand shall be used to form the back of the revetment and the bedding layer against
the filter cloth at this structure. Sand material may be placed by controlled dumping.
2-Ton and 1/4 Ton Armor and Underlayer Rock: No rock weighing less than the normal
armor weight shall be placed in the outer course without the express approval of the
Engineer. Each rock shall be carefully fitted and nudged to achieve a solid three-point
bearing and to lock solidly in place. Placement shall start at the bottom of the slope and
work upward. In general, the longitudinal axis of each outer rock shall be perpendicular to
the face of the slope. The top of the slope transitions shall be reasonably smooth.
Placement of Stone Protection on Plastic Filter Cloth: In areas when plastic filter cloth is
shown to be placed, the. filter cloth and sand cover shall be in place prior to placement of
the stone thereon. Placement of the filter cloth is specified in "Construction Specifications
Plastic Filter Cloth." The stone shall be placed on the plastic filter cloth and sand cover
with care so as not to rupture the cloth. During placement of stone, any damage to the cloth
shall be repaired in an approved manner by the contractor, at no additional expense to the
owner .
Misplacement Material: All rock which is misplaced, laying beyond the limits of the
construction indicated on the Plans or in the opinion of the Engineer is unacceptable shall
be removed by the Contractor prior to completion of the work of this Special Provision of
these Specifications, at no additional cost to the Owner .
TOLERANCE
Rock shall be within 1 foot inside or outside the neat slope lines, measured perpendicular to
the slope, indicated for each type ofrock.
CLEAN-UP
Upon completion of the work of this Special Provision, immediately remove all equipment
not required for other work, debris, and excess rock materials from the site.
MEASUREMENT
All rock shall be measured in tons determined by scale weighing.
Weighting Rock by Scales: Scales shall be standard truck scales of the beam type. The
scales shall be of sufficient size and capacity to accommodate all trucks used in hauling the
material. Scales shall be tested, approved, and sealed by an inspector of the State
Inspection Bureau charged with scales inspection within California. Scales shall be
calibrated and resealed as often as necessary to ensure continuous accuracy. The necessary
number of standard weights for testing the scales shall be on hand at all times.
Scale Tickets and Records: Copies of scale tickets and/or records of weights shall be
submitted to the Engineer during the progress of the work. Each scale ticket and/or record
shall include the gross, tare, and net weight of rock. Copies of scale tickets and/or records
shall accompany each load of rock and a copy shall be delivered to the Engineer on delivery
of the rock. Before the final statement is allowed, the Contractor shall file with the
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Engineer certified scale tickets and/or certified records for all rock used in the construction
covered by the contract.
PAYMENT
All Rock: All rock will be paid for at the applicable contract price per ton for the various
types of rock designated in the Engineer's estimate, which payment shall constitute full
compensation for furnishing all labor, materials, tools, equipment, and incidentals, and for
doing all the work involved in providing the rock complete and acceptably placed within the
limits shown on the Plans, as specified in these Specifications and the special provisions,
and as directed by the Engineer.
Sand: Sand ·wm be measured in tons and paid for on the basis of equivalent solid cubic
yards to be computed by the Engineer from samples taken from each source of supply.
Payment for sand will be made at the applicable contract price, which shall constitute full
compensation for furnishing all labor, materials, tools, equipment, and incidentals, and for
doing all work involved in providing sand complete and acceptably placed within the limits
shown on the Plans, as specified in these Specifications and the special provisions, and as
directed by the Engineer .
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Project No. 8851268E-SI01/COS1 Woodward-Clyde Consultants
GENERAL
APPENDIXE
CONSTRUCTION SPECIFICATIONS
PLASTIC FILTER FABRIC
The work provided for herein consists of furnishing all plant, labor, material, and
equipment and performing all operations required for furnishing, hauling, and placing the
plastic filter fabric, complete, as specified herein and shown on the contract drawings, and
maintaining the plastic filter fabric until placement of sand and the riprap cover is completed
and accepted. •
The following publications of the current issues listed below, but referred to thereafter by
basic designation only, form a part of this specification to the extent indicated by the
references thereto:
American Society for Testing and Materials (ASTM)
D 751-73
D 1175-71
D 1682-64
D 1683-68
MATERIALS
Testing Coated Fabrics
Abrasion Resistance of Textile Fabrics
Breaking Load and Elongation of Textile Fabrics
Seam Breaking Strength of Woven Textile Fabrics
Fabric: Plastic filter fabric shall be a pervious sheet of plastic yarn. The plastic filter fabric
shall provide an Equivalent Opening Size (EOS) no finer than the U.S. Standard Sieve No.
100 and no coarser than the U.S. Standard Sieve No. 70 .
The plastic yard shall consist of a long-chain synthetic polymer composed of at least 85
percent by weight of propylene, ethylene, ester, amide or vinylidene-chloride, and shall
contain stabilizers and/or inhibitors added to the base plastic if necessary to make the
filaments resistant to deterioration due to ultra-violet and heat exposure. The fabric shall
conform to the physical strength requirements in Table No. 1. The fabric should be fixed
so that the yards will retain their relative position with respect to each other. The edges of
the fabric shall be finished to prevent the outer yarn from pulling away from the fabric. If
requested by the Engineer, the Contractor shall provide to the Owner plastic filter fabric
samples for testing to determine compliance with any or all of the requirements in this
specification. When samples are to be provided, they shall be submitted a minimum of 5
days prior to the beginning of installation of the same plastic filter fabric material.
Seams: The seams of the fabric shall be sewn with thread of a material meeting the
chemical requirements given above for plastic yarn or shall be bonded by cementing or by
heat. The sheets of filter fabric shall be attached at the factor or another approved location
to form sections not less than 36 feet wide. Seams shall be tested in accordance with
Method ASTM D 1683, using 1-inch square jaws and 12 inches per minute constant rate of
traverse. The strengths shall be not less than 90 percent of the required tensile strength
(Table 1) of the unaged fabric in any principal direction.
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Project No. 8851268E-SI01/COS1 Woodward-Clyde Consultants
Acceptance Requirements: All brands of plastic filter fabric and all seams to be used shall
be accepted on the following basis. The Contractor shall furnish the Engineer, in duplicate,
a mill certificate or affidavit signed by a legally authorized official from the company
manufacturing the fabric. The mill certificate or affidavit shall attest that the fabric meets
the chemical, physical, and manufacturing requirements stated in this specification .
Securing Pins: Securing pins shall be 3/16 inch in diameter, of steel, pointed at one end
and fabricated with a head to retain a steel washer having an outside diameter of no less
than 1.5 inches. The lengths of the pins shall be no less than 24 inches.
SHIPMENT AND STORAGE
During all periods of shipment and storage, the fabric shall be protected from direct
sunlight, ultra-violet rays, temperatures greater than 140°F, mud, dirt, and debris. To the
extent possible, the fabric shall be maintained wrapped in a heavy-duty protective covering.
INSTALLATION OF PLASTIC FILTER FABRIC
Filter fabric shall be placed in the manner and at the locations shown on the drawings. At
the time of installation, fabric shall be rejected if it has defects, rips, holes, flaws,
deterioration or damage incurred during manufacture, transportation or storage. The
surface to receive fabric shall be prepared to a relatively smooth condition free of
obstructions, depressions, debris, and soft or low density pockets of material. The fabric
shall be placed with the long dimension parallel to the shoreline or creases. The strips shall
be placed to provide a minimum width of 36 inches of overlap for each joint or joints shall
be stitched.
The fabric shall be placed loosely so that it will conform to the ground surface without
stretching when rock is placed .
Securing pins with washers shall be inserted through both strips of overlapped fabric at not
greater than 2-foot intervals along a line through the mid-point of the overlap.
Additional pins, regardless of location, shall be installed as necessary to prevent any
slippage of the filter fabric. The fabric shall be placed so that the upper strip of fabric will
overlap the next lower strip. Each securing pin shall be pushed through the fabric until the
washer bears against the fabric and secures it firmly to the foundation. The fabric shall be
protected at all times during construction from contamination by surface runoff and any
fabric so contaminated shall be removed and replaced with uncontaminated fabric. Any
damage to the fabric during its installation or during placement of riprap shall be replaced
by the Contractor at no cost to the Owner. The work shall be scheduled so that the
covering of the fabric with a layer of the specified material is accomplished within 5 days
after placement of the fabric. Failure to comply shall require replacement of fabric. The
filter fabric shall be protected from damage due to the placement of riprap or other materials
by placing a cushioning layer of sand on top of the fabric before the material. Before
placement of riprap, the Contractor shall demonstrate that the plae:ement technique will
prevent damage to the fabric .
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Project No. 8851268E-SI01/C0S1 Woodward-Clyde Consultants
MEASUREMENT AND PAYMENT
Plastic filter fabric will be measured for payment by the square yard in place. No
allowance will be made for material in laps and seams. Payment, therefore, will be made at
the contract unit price for "Plastic filter fabric," which price and payment shall constitute
full compensation for furnishing all plant, labor, material, and equipment filter fabric
complete. No measurement of, nor payment for, will be made for plastic filter fabric
replaced because of either contamination or damage due to either fault or negligence of the
Contractor .
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Project No. 8851268E-SI01/COS1 Woodward-Clyde Consultants
TABLE 1
PHYSICAL STRENGTH REQUIREMENTS
Physical Property
Tensile Strength
(unaged fabric)*
Puncture Strength
Abrasion Resistance
Test Procedure
ASTM D 1682 Grab Test
Method using 1 inch square
jaws and a travel rate of 12
inches per minute .
ASTM D 751 Tensions
Testing Machine with Rink
Clamp; steel ball replaced with
5/16-inch diameter solid steel
cylinder with a hemispherical
tip centered with the ring
clamp.
ASTM D 1682 as above, after
abraded as in ASTM D 117 5
Rotary Platform, Double
Head Method; rubber-base
abrasive wheels equal to CS-
17 "Calibrase" by Taber
Instrument Comp any; 1
kilogram load per wheel;
1,000 revolutions .
Acceptable Test Results
260 pound minimum in
any principal direction.
100 pound minimum.
55-pound minimum in
any principal direction.
*Unaged fabric is defined as fabric in the condition received from the manufacturer .
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