HomeMy WebLinkAbout03180 - Technical Information Report - Geotechnical (�__
_ '� ,rv� c � � 3f �U �
- ���'�,�r,ttG:d
. .� � =
JUN p y �
—..:�.:.-�i.�1.:,,:....
��
� Group Northwest, Inc.
� Geotechnical Engineers,Geologists&Environmental Scientists
�
- - s�3l8 p �
GEOTECHNICAL ENGINEERING STUDY
BARONE GARDENS STATUARY
LAKE WASHINGTON BLVD.NE&NE 48"'STREET
RENTON,WASHINGTON
G-1762
Prepared for
� Ms. Cheryl Girard
American Engineering Corporation
4032 148`" Avenue NE
Redmond, WA 98052
April 2, 2004
By
GEO Group Northwest, Inc.
c„vc�r,�rTC.�
13240 N.E. 20th Street, Suite 12 , .;�J� �'_'
Bellevue, WA 98005 JUN 0 4 2004
Phone: (425)649-8757
Fax: (425)649-8758 -� �-_.;•.,��,�;�,�,
�
Geotechnical Engineers,Geologists
� r o u p N o r t h w e s t, I n c• &Environmental Scientists
�
Apri12, 2004 Project No. G-1762
Ms. Cheryl Girard
American Engineering Corporation
4032 143`'' Avenue NE
Redmond, WA 98052
Subject: Geotechnicai Engineering Study
Barone Gardens Statuary
Lake Washington Blvd. �tE & �1E 48"` Street
Renton, Washington
Dear Ms. Girard:
� `�e are pleased to subm�` �ur geotechnical engineering study for the proposed Barone Gardens
Statuary development, located at the northeast corner of the intersection of Lake Washington
Blvd. NE and NE 48'� Street in Renton, Washington. The project consists of creating a level
parking area, driveways, walking paths, and the construction of a pole barn-style building, This
report presents the results of our findings and our geotechnical design criteria and
recommendations.
We explored the subsurface site conditions by excavating seven test pits on March 22, 2004. In
generai, the subsurface conditions appear to be suitable for constructing the proposed fills,
rockery supported cuts of up to 4 feet, and construction of the proposed parking, driveways, and
building. The project site is located in an area of known hillside instability. Fracturing was
observed in the site soils which indicates past slope movement.
Compressible organic silts, about 4 feet thick, were encountered in the proposed driveway area at
the northwestern corner of the site, west of the sanitary sewer easement. We estimate ground
settlement on the order of 3 inches for a fill height of 6 feet. Organic soils below the sewer line
should be removed and replaced with structural fill prior to placin� the fill across the sewer
easement to avoid potential damage to the line.
13240 NE 20th Street, Suite 12 • Bellevue, Washington 98005
Phone 425/649-8757 • FAX 425/649-8758
April 2, 2004 G-1762
Barone Gardens Statuary, Renton, Washington Page ii
�Ye appreciate the opportunity to provide geotechnical engineering services on this project and
look forward working with you during the construction phase. If you have any nuestions about
this report, or if we can be of further assistance, please cait.
Sincerely, `�°t W a s h��9
GEO GROUP NORTHWEST, INC. a �a
~ � a
� , .,.
G%��`" - �
ro�q GecloQst 4
��� 1�16 q�`�
P�s�d Gea�c
Wade J. Lassey
Engineering Geologist ���� ��
lAM C�
3~�°� W�'�.�'
� William Chang, P.E. �� �' �
. �z
Principal .,
�,�Gottd� �
ISTE
SSj�1VA1- �'
PIRE : 2/19/o
Geo Group Northwest, Inc.
TABLE OF CONTENTS
G-1762
1.0 INTRODUCTION Paee
1.1 Project Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Scope of Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2.0 SITE CONDITIONS
2.1 Surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.2 Subsurface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.3 Groundwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.0 SEISMICIT'Y
3.1 Uniform Building Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.2 Liquefaction Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.0 SLOPE STABILITY EVALUATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5.0 D�SCUSSION AND RECOMMENDATIONS
5.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5.2 Site Preparation and General Earthwork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5.2.1 Temporary Erosion Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5.2.2 Excavations, Slopes, Cuts, and Fills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
� 5.2.3 Onsite& Import Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.2.4 Structural Fill& Compaction Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
5.2.5 Removal of Compressible Soils Below Eacisting Sanitary Sewer . . . . . . . . . . . . . . . . 7
5.3 Foundations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.4 Slab-On-Grade Floors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.5 Drainage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.6 Pavement Subgrade and Section Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.7 Rockeries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6.0 LIMITATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
'I , 7.Q PLAN REVIEW & CONSTRUCTION MONITORING . . . . . . . . . . . . . . . . . . . . 12
ILLUSTRATIONS
Plate 1 - Vicinity Map
Plate 2 - Site Plan
�
f APPENDIX A: Test Pit Logs �
I APPENDIX B: Rockery Construction Guidelines
� I
,
�
Geo Grour Northwest,Inc.
�
__
I
I GEOTECHNICAL ENGINEERiNG STUDY
BARONE GARDENS STATUARI'
LAKE WASHINGTON BLVD.NE&NE 48"�STREE'r
RENTON,`YASHINGTON
G-1762
1.0 INTRODUCTION
l.l PROJECT DESCRIPTION
The Barone Gardens Statuary project site is located at the northeast corner of the intersection of
Lake Washington Blvd. NE and NE 48`'' Street, in Renton, Washington as illustrated on the
Vicinity Map, Plate 1. The property is currently undeveloped.
The majority of the site slopes down to the west and southwest. The west portion of the site is
relatively flat. The proposed site development consists of creating a level parking area near the
base of the slope, with seventeen parking spaces, driveway access oPF of Lake Washington Blvd.
NE and NE 48`'' Street, a 30 foot by 60 foot pole barn-style building, and foot-paths behind the
building, as shown on the Site Plan, Plate 2. The parking area and driveways will be created with
cuts and fills of up to 8 feet (�) with the fill being placed near the base oFthe existing slope. The
building will have a slab-on-grade floor with a proposed finished floor elevation of 41.0 feet.
Vertical cuts will be limited ta 4 feet in height and permanent open cuts sloped at 2.SH:1 V
(Horizontal:Vertical). Rockeries retaining walls are planned to support both cuts and fills and do i
not exceed 4 feet in height. The southwest corner of the fill will be retained with a rockery to '
avoid filling over the existing sanitary sewer manholes.
Vertical cuts will be limited to 4 feet and will be spaced a minimum of 10 feet apart, per our
recommendations. Permanent open cuts are planned above and below the rockeries, with the
exception of up to 3 feet of fill to be placed above the upper rockery, east of the buildin�. A '
maximum cut of 8 feet is planned at the southeast corner of the building. This cut will be
supported with a 4 foot rockery and an open cut above the rockery that is sloped at 2.SH:1V.
1.2 SCOPE OF SERVICES
The scope of work performed is in general accordance with our proposal dated March 16, 2004.
Our scope of services performed for this project included:
1. Exploration of the subsurface soil and groundwater conditions. I'�,
,I
Geo Group Northwest, Inc.
I
�
April 2, 2004 G-1762
Barone Gardens Statuary, Renton, Washington Page 2
2. Logging of the test pits, collection of representative soil samples, classification of the soils,
laboratory testing, and preparation of test pit logs.
3. Engineering analyses, evaluation of the stability of the proposed cuts and fills, preparation
of geotechnical design criteria and recommendations addressing site preparation,
earthwork, structural fill, rockeries, foundations, slab-on-grade floors, pavement, and
drainage.
4. Preparation of this geotechnical report describing our activities, findings, conclusions and
recommendations.
2.0 SiTE COn`DITIONS
2.1 SURFACE
The subject property is generally rectangular in shape, measuring roughly 171 feet N/S and 329
feet E/W. The property is approximately 69,000 sc�uare feet (1.6 acres) in size and is bounded to
the west by Lake Washington Blvd. NE, to the south by NE 48't` Street, to the north by
commercially developed property (Kiewit office building), and to the east by residential apartment
buildings.
The western quarter of the property is relatively flat and the remainder of the property slopes up
to the east at an average gradient of 17.5 percent (f) and to the northeast at an average gradient
of 35 percent (t). A localized area sloped up to 48 percent (f) is present in the north central
portion of the property, as shown on the Site Plan, Plate 2. Elevations across the property range
from approximately 70 feet in the northeast corner to 26 feet at the southwest corner. There is an
existing �round depressior�/surface water catchment area located in the south�vest corner of the
site. The depression is about 4 feet deep.
Easements on the property include a 15 foot wide sewer line easement that crosses the western
portion of the site and a 15 foot wide utility easement that crosses the east end of the site. The
property is vegetated primarily with blackberries and soine small deciduous trees and brush.
Geo Group Northwest, Inc.
April 2, 2004 G-1762
Barone Gardens Statuary, Renton, Washington Page 3
2.2 SUBSURFACE
According to the Preliminary Geolo i� c Map of Seattle and Vicinity, Washington, published by the
U.S. Geological Survey in 1962, soils in the western portion of the property consists of Alluvium
(Qa). Alluvium is described as consisting predominately of sand and silt, but may include clay and
peat. The geolo�ic map also identifies Older clay, till, and gravel (Qc) in the immediate area,
described as consisting of silt, clay, fine sand, and till (commonly referred to as"Lawton Clay").
The subsurface conditions were explored by excavatin� seven test pits to depths of up to 10.5
feet. The approximate test pit locations are shown on the Site Plan, Plate 2. In general, the
subsurface soils encountered at the northwestern corner of the site (TP-1) consisted of loose silty
sand fill to a depth of 6 feet, underlain by topsoil and soft or�anic silt to a depth of 10 feet.
Below 10 feet, very stiff silt was encountered. At the eastern edge of the flat western portion of
the site (TP-2 & TP-3) we encountered dense to very dense sand and gravel at a shallow depth.
On the sloped portion of the site the soils consisted predominately of sands and silts. In TP-4, the
sands ��ere loose to a depth of 5 feet and the silts were stiff. In TP-5 the soils consisted of
medium stiff to stiff silts, medium dense silty sand, and medium stiff clay. Very dense gravelly
material was encountered at a depth of 9 feet. In TP-6 the soils consisted of stii'�to very stiff silt
�nd silt with some clay to a total depth of 8.5 feet. In TP-7 the soils consisted of stiff silt
underlain by medium dense silty sand. Fracturing was observed in the silts in TP-5, TP-6, and
TP-7. A more complete description of the soils encountered is contained in the Test Pit Logs, in
Appendix A af this report.
' 2.3 GROUNDWATER
Only a minor amount of perched groundwater was encountered at a depth of 5.3 feet below the
existing ground surface in Test Pit TP-6. Generally, the site soils were moist to wet, but minimal
groundwater seepage is anticipated during construction based on our stibsurface observations and
the limited perched groundwater encountered.
Geo Group Northwest, Inc.
April 2, 2004 G-1762
Barone Gardens Statuary, Renton, Washington Page 4
3.0 SEIS1171CITY
3.1 UNIFORM BUILDING CODE
According to the 1997 Uniform Building Code (UBC), western Washin�ton is classified as
Seismic Zone 3 (Figure 16-2), ��hich is assigned a Seismic Zone Factor, Z, of 0.30 (Table 16-I).
The soil conditions encountered at the site during our im�estigation correspond best to a Stiff Soil
Profile Type SD (Table 16-J).
3.2 LIQUEFACTION ASSESSMENT
Liquefaction is a phenomenon where loose granular materials below the water table temporarily
behaves as a liquid due to strong shaking or vibrations, such as earthquakes. Clean, loose, and
saturated granular materials are the soils susceptible to liquefaction. Based on the type and
density of the subsurface soil encountered and on the absence of groundwater, it is our
professional opinion that there is minimal risk of lic�uefaction at tl�e site.
4.0 SLOPE STABILITY EVALL'AT10N
Based on discussions with Mr. Larry Jones of the Coal Creek Utility District, Mr. Jason Fritzler '�
with the City of Renton, and Mr. Mike Mengelt with the geotechnical firm Golder and Associates,
hillside movement has forced the replacement of about 60 feet of the sewer line in Lake
�'Vashington Blvd NE,just south of the intersection ofNE 50`" Street. In general the area of
instability appears to be located north of the Kiewit office btiilding property, with no known slope
instability located at the project site.
We observed fracturing in the silts on the sloped portion of the site which may indicate some past
shallow slope movement, the a�e of which is unknown. The site soils appeared to be stable in the
test pits, with minimal groundwater seepage encountered.
The proposed placement of the fill at the base of the slope will have a buttress af�'ect and should
improve the overall stability of the hillside. From a geotechnical perspective, is acceptable to
place fill against the 40 percent steep slope area in the nort}� central portio�i of t}ie site in order to
expand the parking area. The placing of fill along the base of the slopc will improve the overall
stability ofthe slope. Temporary cuts, permanent cuts, and filis should follow t}ie
recommendations in Section 5.2.2, E.rcm�alions, Slol�es, Cr�ts crnc!1�ill.s.
Geo Group Northwest, inc.
April 2, 2004 G-1762
Barone Gardens Statuary, Renton, Washington Pa�e 5
5.0 DISCUSSION AND RECOMl1'IENDATIONS
5.1 GE[vERAL
Based on the results of our study, it is our opinion that the subject property can be developed as
shown on the Site Plan, Plate 2. The main geotechnical issues for the project are the stability of
the proposed open cuts and fills, site preparation, structural fill placement and compaction,
building support, drainage, pavement section design, and rockery construction guidelines.
If possible, earthwork and grading shoi�ld be performed during dry weather. The site soils are
moistiire sensitive and we recommend they be protected with a minimum of 4 inches of crushed
rock base material where exposed in the parking lot and building areas.
5.2 SITE PREPARATION AND GENERAL EARTHWORK
The site should be stripped of surface vegetation. Organic topsoil, underlying the pavements and
building should be removed. This material can be saved for later use in landscaping areas.
5.2.1 Temporary Erosion Control
Temporary erosion control measures should be installed prior to the start of stripping and �rading.
The existing site grades will drain the surface water toward the southwest corner of the site. A
crushed rock construction entrance should be installed adjacent to the streets to minimize tracking
of mud onto the streets. �Ve recommend installin� erosion control measures, such as temporary
sediment control traps, silt fences, check dams, and other erosion control devices and techniques
to provide temporary erosion and sediment transport control. Exposed soils will require
protection with straw, mulch, or plastic sheeting. Loose surfaces should be sealed by compacting
the surface to redtice moisture infiltration. Good site surface drainage should be maintained and
water should not be allowed to stand in areas where structural fill is to be placed, or where
footings and slabs are to be constructed. Stockpiled soils should be covered to prevent rainwater
infiltration and erosion.
All permanently exposed slopes should be hydro-seeded,with grass or mulched and planted with
an appropriate species of vegetation to reduce erosion and improve the stability of the surficial
soils at the completion of construction and gradin�, prior to removal of the temporary erosion
controls.
Geo Group Northwest, Inc.
Apri12, 2004 G-1762
Barone Gardens Statuary, Renton, Washington Page 6
5.2.2 Excavations, Slopes, C�rts, and Filis
Temporary excavations should not be inclined greater than the limits specified in local, state and
national government safety regulations. It is the contractors responsibility to maintain a safe work
environment. Temporary cuts should be sloped at an inclination no steeper than 1H:1 V
(HorizontaL Vertical). Utility trench sidewalls should be sloped at an inclination no steeper than
1H:1 V, unless a trench box is used.
Based on the site conditions, permanent vertical cuts should be limited to a height of 4 feet, faced
with rockeries or modular block walls, and spaced a minimum of 10 feet apart. Permanent cut
slopes should be inclined no steeper than 2.SH:1 V. Fill slopes may be inclined up to 2H:1 V,
without lateral reinforcement. If a permanent slope is to be maintained or mowed, we recommend
it be inclined no steeper than 3H:1 V. Based on the grading shown on the Proposed Site Plan,
Plate 2, the proposed permanent cuts will be sloped at 2.SI�:1 V or less, and the permanent fills at
2H:1 V or less. All proposed cuts are outside the 40 percent slope area and the tiered cuts have a
minimum spacing of 10 feet.
The above slope and design criteria should provide for stable cut slopes, provided water seepage
is not encountered. If water seepage is encountered, please contact us to review the site
conditions and provide recommendations.
From a geotechnical perspective it is acceptable to place fill against the 40 percent steep slope j
area in the north central portion of the site in order to expand the parking area. The placing of fill
along the base of the slope will improve the stability of the slope. ,
5.2.3 Onsite and Import Soils
Site soils containing organics (top soil) and the silts will not be usable as structural fill. When
preparing the building area subgrade, the organic top soils should be removed and segregated for
possible later use in landscape areas. The sandy site soils contain silt and may not be usable as
structural fill during wet weather. We recommend protecting exposed native subgrade soils in the
parking lot and building areas with a minimum of 4 inch�es of crushed rock base material. �I,
During dry weather, any compactable non-organic granular soil having a maximum rock size of i
� three (3) inches may be used as structural fill, provided the material is near its optimum moisture �
Geo Group Northwest, Inc.
April 2, 2004 G-1762
Barone Gardens Statuary, Renton, Washington Page 7
content. During wet weather we recommend using a granular impart material that contains no
more than five (5) percent fines (silt and clay-size particles passin�the No. 200 mesh sieve).
5.2.4 Structural Fill & Compaction Specifications
All fill material used to acl�ieve design site elevations below building foundations, slabs, sidewalks
and pavement areas should meet the compaction rec�uirements for structural fill. Structural fill
material should be placed at or near its optimum moisture content. The optimum moisture
content is the water content in soil that enables it to be compacted to the highest dry density for a
given compaction effort. Structural fill should be placed in thin horizontal lifts not exceeding ten
inches in loose thickness. Each lift should be compacted to the following structural fill
compaction specifications:
STRUCTURAL FILL COMPACTION SPECIFICAT�ONS
APPLICATION MINIMUNi C011'IPACTION
% of Maximum Dry Density
Under Pavements, Side«alks, Patios 9�5%for the top 12-inches
& Backfill of FoundationsBasement�Walls 90/o beloc�tt�e top 12-inches
Based on ASTM D-1557 -Modified Proctor
All Road«�a_y Fills 95��"
Within the Se�ver Easement Based on ASTM D-1�57 -h��odified Proctor
(Per Coal Creek Utility District}
Under Foundation Footings 95%
& Slab-On-Grade Floors Based on ASTM D-1557 -Modified Proctor
5.2.5 Removal of Compressible Soils Below Existing Sanitary Sewer
About four feet of compressible organic silt was encountered at a depth of 6 feet and 10 feet in
Test Pit No. TP-1. �Ve estimate that placing 6 feet of fill over this material could cause
settlements on the order of 2.6 inches(�). To protect the existing sanitary sewer from settlement,
compressible soils below the line, if present, should be removed and replaced as specified by the
Geo Group Northwest, Inc.
���111 _� "UV-F U-i �i l.�_
narone Gardens Statuary, Renton, Washington Page 8
Coal Creek Water& Sewer District, prior to placing fills over the sewer easement. Our contact
at Coal Creek Water & Sewer District is Mr. Larry Jones (425) 235-9200.
5.3 FOUNDATIONS
The type of foundation system for the pole barn-style building was not provided. For
conventional spread footings, the footings should be supported on the very stiff or dense soils or
on structural fill that e�ends down to suitable bearing soils. Structural fill below the building
should extend out at 1H:1V below the outside of the building and be compacted to 95% of the
i materiats maximum dry density. The material's compaction should be tested during placement to
verify that the compaction specifications are achieved. Individ�ial spread footings may be used for
supporting columns and str�p foot�ngs for bearing walis. Our recommended design criter�a for
foundations are as follows:
-Allowable bearin ressure, includin all dead and live loads:
gP
�
Dense/very stiff site soils and structural fill = 2,000 psf
- Minimum depth to bottom of perimeter footing below
adjacent final earterior grade: = 18 inches
- Minimum depth to bottom of interior footings
below top of floor slab: = 12 inches
- Minimum width of wall footings: = 16 inches
- Minimum lateral dimension of column footings: = 24 inches
- Estimated post-co�istruction settlement: _ '/4 inch
- Estimated post-construction differential settlement;
across building width: _ '/4 inch
A one-third increase in the above allowable bearing pressure can be used when considering short-
term transitory wind or seismic loads. Lateral loads can also be resisted by friction between the
foundation and the subgrade or by passive earth pressure acting on the buried portion of the
foundation. For the latter; the foundation must be poureci "neat" against undisturbed soil or
backfilled with structural fill. Our recommended design parameter� �,-? a� fnll���;
Geo Grou� Nnrtl��ti�est, i��
Apri12, 2004 G-1762
Barone Gardens Statuary, Renton, Washington Page 9
- Passive Pressure (Lateral Resistance)
• 350 pcf equivalent fluid weight for dense/very stiffnative soils or structural fill
- Coef�icient of Friction(Friction Factor)
• 0.35 for dense/very stiff native soils or structural fill
Please contact us if additional foundation design criteria is required by the structura] engineer.
5.4 SLAB-ON-GRADE FLOORS
Slab-on-grade floors should be supported on very stiff or dense native soils or on structural fill
that extends do�vn to suitable bearing soils. The structural fill should be compacted to 95% of the
materials maximum dry density. The material's compaction should be tested during placement to
verify that the compaction specifications are achieved.
If the building is to be used for dry storage or heated office space, the slab should be placed on a
capillary break to prevent wicking of moisture up to the slab and a 10-mil reinforced vapor barrier
should be placed between the capillary break and slab, such as Moistop�by Fortifiber, to reduce
water vapor transmission through the slab. The capillary break should consist of a minimum of ',
six (6) inch thick free-draining layer of 1.S inch minus gravel or 2 inch size crushed rock
containing no more than five (5) percent fines passing the I�To. 4 (1/4-inc}i) sieve. Two to four
inches of sand may be placed over the membrane for protection during constniction. '
i
5.5 DRAiNAGE I�
The finished ground at the site should be graded such that surface water is directed away from the
building. Water should not be allowed to stand in areas where footin�s, slabs or pavements are to
be constructed. �
I
A footing drain should be installed around the perimeter foundation of the building. The drain
should consist of a four(4) inch minimum diameter, perforated or slotted, rigid PVC drain pipe �
laid at or near the bottom of the footing with a gradient sufficient to generate flow. The drain line '
should be bedded on, surrounded by, and covered with a free-draining rock or free-draining
1
�ranular material. The drain rock should be wrapped witli a non-�voven geotextile filter fabric,
such as 1�7irafi 140N, or equivalent. Once the drain is installed, the excavation should be Uackfilled
��vith granular material, compacted, and capped with relatively impermeable material or be paved_
Geo Group Northwest, Inc.
April 2, 2004 G-1762
Barone Gardens Statuary, Renton, Washington Page 10
Roof drains should be separately tightlined and should not be connected to the footing drain
system. Cleanouts should be installed to allow for periodic maintenance of the footing drain and
roof drain systems.
5.6 PAVEMENT SUBGRADE AND SECTION DESIGN
The adec�uacy of site pavements is strictly related to the condition of the underlying subgrade. If
this is inadequate, no matter what pavement section is constructed, settlement or movement of the
subgrade will be reflected up through the paving. To avoid this situation, the subgrade should be
compacted to the structural fill specifications and proof-rolled with a loaded dump tn�ck under the
observation of the geotechnical engineer prior to paving. Areas of soft, wet or unstable subgrade
may rec�uire over-excavati�n and replacement witti compacted structural fill or cn�shed rock.
Subgrade stabilization recommendations should be provided by the geotechnical en�ineer based
on an evaluation of the sit�; conditions
The fill below the pavement over the sewer easement will require compaction to 95 percent of the
materials maximium dry density, as indicated in Section 5.2.4, Struc/ural Fill cPc Compaction
Specifrcations. Provided the subgrade is dense and iinyieldin�, the parking and driveway
pavement section design may consist of the followin�:
11-1TNIMUM PAVFR'IENT SECTION
IIEAVY TRAFFIC(DRIVE�i'AY�AREAS
Class "B" Asphalt Concrete (AC) 3-inches
Crushed Rock IIase (CRII) 6-inches ,
LIGHT 7�2AFFIC(FARKING�AREAS
Class "II" Asphalt Concrete (AC) 2-inches
Crushed Rock Base (CRB) 4-inches
Geo Group Northwest,Inc. ;
April 2, 2004 G-1762
Barone Gardens Statuary, Renton, Washington Page 11
5.7 ROCKERiES
Rockeries, up to 4 feet in height, are proposed to retain both cuts and fills at the site. Vertical
cuts should be limited to a height of 4 feet, or less, so the rockeries retaining the cuts should be
limited to a height of 4 feet, or less. Vertical cuts should be spaced a minimum of 10 feet apart,
so rockeries should be spaced a minimum of 10 feet apart. The maximum rockery height shown
on the Proposed Site Plan; Plate 2, is 4 feet, for both cuts and fills, with a rockeries facin� cuts
spaced 10 feet between tiers, which confonns to our recommendations.
Rockeries should be constructed to the American Association oPRockery Contractors {ARC)
Standard Rockery Construction Guidelines, included in Appendix B. No lateral reinforcement is
required for rockeries 4 feet in hei�ht or smaller tl�at retain stable cuts.
The Proposed Site Plan, Plate 2, silows minimal sloped fill above the rockery at the southwest
corner of the parking lot. The parking lot is located 8 feet from the rockery wall and no
surcharge from the parking lot is anticipated on the rockery. About 3 feet of fill is planned behind
the upper rockery east of the proposed building. No geogrid reinforcement is required behind
rockeries supporting fills based on the current site confi�uration, provided the fill bel�ind the
rockery is compacted to a minimum of 90 percent of the materials maximum dry density and
proper drainage is installed behind the wall.
Rockeries retaining fill can be constructed to be taller, potentially providing more parking space
or allowing grade adjustments to the parking lot or driveway. Rockeries taller than 4 feet, and
rockeries that are surcharged with a fill slope or parking/traf'fic, should be reviewed by the
geotechnical engineer, and be laterally reinforced with geoerid. Geo Group Northwest can
provide geogrid design recommendations, if required.
6.0 LIIIZITATIONS
This report has been prepared for the specific application to the subject project site, for the
exclusive use of the project owner, American Engineerin� Corporation, and the rest of the project
design team. The findings and the recommendations stated herein are based on our field
observations, the subsurfa:,e conditions encountered in our site exploration, our experience, and
judgement. The recommendations are our professional opinion derived in a ma►Iner consistent
Geo Croup Norlhwest, Inc.
April 2, 2004 G-1762
Barone Gardens Statuary, Renton, Washington Page 12
�vith the level of care and skill ordinarily exercised by other members of the profession currently
practicin�i�nder similar conditions in this area, within the scope of work, and within the budget
constraint. I�To warranty is expressed or implied. In the event that soil conditions vary during site
work, Geo Grotzp Northwest, Inc. should be notified and the recommendations herein re-
evaluated, and where necessary, be revised.
7.0 PLAN REVIEW AND CONSTRUCTION MO�TITORII�'G
It is recommended that we be retained to perform a genera.l review of the final design and
specifications to verify that tlie earthwork, foundation, and other recommendations have been
properly interpreted and irnplemented in the design and engineering plan documents.
It is recommended that we be retained to provide geoteclmical monitorin� services during
construction. This will allow us to confirm that the siibsiirface conditions are consistent with �
those described in this report and allow for design changes in the event subsurface conditions
differ from those anticipated prior to the start of construction. It will allaw us to evaluate '
whether the erosion control, earthwork, and foundation construction activities conform to the
intent of the contract plans and specifications. While on the site during construction, we will not
direct or supervise the contractor or the contractors tivork, nor will we be responsible for �I
providing or revie�ving on-site safety or dimensional measurements. j
rtvsPECTioNs �I
The following items should be inspected by the geotechnical engineer during construction: ��,
• Erosion control, clearing and gnibbing below parl:ing, driveways, and building areas II
• Excavations, grouridwater seepa�e, sijns of instability of slopes or cuts �
• Structural fill compaction testing below the parking lot, driveways, and building
• Verification of suitable bearing conditions for foundations
• Placement of capillary break and moistt�re barrier below slabs
� Installation of subsurface drainage
• Pipe beddin�, trench backfill, and compaction testing below pavement
• Subgrade preparation below pavements, proof-rolling, and subgrade stabilization
Geo Group Northwest, Inc.
April 2, 2004 G-1762
Barone Gardens Statuary, Renton, Washington Page 13
The contractor should provide us with a minimum of 24 hours advance notice to perform the
above inspections so that ��ve can arrange to have personnel available.
We appreciate the opporti�nity to provide you with this geotecl�nical engineering study. If you
have any c�uestions regardin�this report or need additional information, please call us.
•:
Sincerely, at �a s h;,� :
GEO GROUP NORTH«'F,ST, INC. �'►�� 9�0
y � � �
,�
G� � � +
� �'• rp`roern+p Geai� 4��..
� 1116 �
��Sed G��\�4
Wade J. Lassey W��B J. Lasse
Engineerin� Geologist • • '
l�M c�9
. ,�ti'�o�,�t.��G�
William Chang, P.E.
�'r #' ` �'�
Principal �=' �
��so����
�NAI. �
XPIRE : 2/19/ D
Geo Group Nortl►west, Inc.
1
TT T I-�TR �TTI�ti�
�
Geo Group Northwest, Inc.
i. � � � �a+-'��
n � �� �
;
:,:,
.
y : ,.. , ; W
�., , . _. � : 4� � .
[�7 , }. r �
�-' -�.. �
II � mf.�, ' + �
� !7M �1�,t.1� � .
O �I 1 M��„�',Wll,S ..,yy
,�e � � i � . l "t: t t�n�5 r��.y„p��'� c t j W M-yYn # n1:ir� a--^:.r. r 1RN��nai a,.Y.. .�� r�. �. ^: .� . ..
'�+: t,
� 0 . � `A• �'r t.� .� i .,. �� " . »wM',�r.wv4�^ ;r�•i»4� �rrw?taakA�+^u tt..,,. . .. i ��n+w., ..
1 N 4-9
N � .. � ' � ta,�, ��t4�3 � '•. � .. .. • 'i .
0 � �ti � ' ? � '� ..� , li� .
�...3 � J Z . � !� �� � t� ; ���.)�r t.�"�,,;.. .. ��':' � . �
.i5' O fti.��. � � . � b . �
C�f o o' ''� � i' l � 1 � � �j �
� � � � `� k.� i-� � �� � 1�-I 0 ' rti �'� .
W � � !"� .�•t+wti'A1�,'?w1Y'ai'tl .' '� � i� �j �y � . , . '�
� � � I.�+ . �� t�, . ' � �rnt �� �7 , (
W � ~ � �1 .� �'. �1. �„ }; � ('� . � (. .
O ? � � � ��� �`�°'",ny '{��� �--1 FF �
* .
� B �' !�/ '�. v ' I
N� � � �; t.�� .. �a � � A . � .
� -��, �.,� �:�.s;.S�.7�.. «� � '. � ��, r�., ���`� � 5y 1;rt y � �* � k,
� � 'ia�� �� � "��,w.,��h'`�;, � �fr, 5 i
� • "`,:;�; �, "� H/�2�'�1.V1
.a. � � , t� ,�y� r,.., ('� L Y L/w�'�N 1 � y
� .., . ., � . .. . ��ti. -�e,, i .'' 1'i�,�s.a`�(�rXrr r`,A•444✓•.ti�}... ..6.��.����.�-.
� M�A t x
��� �} �^ l � .4-� :{. 4.. �..r.
�" tr 1" n wi�XG
� r.�tqS�r:,,,:x. �..+:�f�R:�. ru�+t�w;.�t,S,c�.t6i?..� w"`Y•%"' c�,: y +v ' � �'��
�1� �j � � �,,��ar' �,
rA � �'. . . �.�!�� . M�t +Nyy�7� �W�
� ' ` ��` �� ��� ��
� �� ����.;„��.� � � � m�
�� ����; � 109Y',�' 5� ��
� 1 � � '�'41�f
� ? . � � • .1}J��
r t�. Y }::� �r. �t�� �t' w� ?};�A:�,;.o�;:i,vrr� .F�/
n y I�i�� '.��t'ir�',�� --i '�� � �(y,'j�'���(';�'' � '��-v� rC ` a
� K � ""I� iP�M �pp. . 1 'C �
yp C ��� � � , � ttt H P •� �'►E ' ` ��' >��'� �,�'� o
� � � � �.��,�� ; �:��,��.�. �,,�,,��. ,�. �� t,,.�� t� �
� x � ('� w�' }�. '� m m � �'�'i �������� F:,� 1��T �.
'L
O � �f � . . .' �. ��. .��. t.• �1•t,:AM.' �.ry.ti•.h:Y.vf.••.�l:4tWCti�V.tiS• ,�.� Yt.�. �IIMIM��/� �y
� O ►� ^ � ��I..SJ:qL ...A>.�,1..'n.vf.��.'.v.�YNhvhS�Y✓:'7Y�V7S . „ ' .� � � i� '� ���iy� Y!� � ^ ~ (/�
r�
o : z � � > �-�i 1 13 T�, ��" ..�r A V. �.E. � �. y 4.•_r,>� � �� ` � �
� � � y � � m ��x�� € ���, .N �f�,;�k � :�,; cn � 1� � o
� z � � � y �� � � 1 1�4� ' :..,�� �� ,� «» w � v1 � '��� ~ �
� y � � `� t '��' � �� � «� � � � �.�.� �� � n
n.� � '-� � � f"' �f � l!'► ,� "" s
I � z r M� i � ,, ,�j r"". ��� Cf) (n I'T'I � t/� ��, ;!
� � � • c7�y. �.�>y.¢>�ri�.,•>:,.A�V �E � � ��'1 15TH�,, �� � o
� � o
,, ,� � ► 1, /� �' rWr 1 5TH u► cyn�� o v' � N
� (R I�M,•]C�JCWSR�'!MF`a'�R'rK`Y'{Yi+.'�N�1�.GMG s,4V .1 .�Y.tii:`I.4444��Iv 1}]GSV7M '!�M }jY/WI�}OGa'.-0AA'-0hM1W YA7vYV�4C4G�V�V�Ikb'Y(�1:kLh'iY.\4'."����'�'M"��'.Qa�i�. NN YJJ'���'�OG K Q
�] �.,� .,,.� ... �.:.. .�..- ... ... .:..:. r ....�, ...�. .. .....� .� � . ... �,..�, ........i...�� .. ...,...,. . �,,.,, .�.� ,..��... . ..,.. . . �
� ... �t . .,�.,,�, . ... ,, „�1��,..,,> .
<tiSu4
� -q � 4��� �r� ��` !`►� ,� � .�►t�.d�.�
� �'� CY J�E .W � �_�l
j �i�r� s � �� r�. ..�"� . ... ,_ .��„ d
��L205 N - � - I
/ I
�
LEGE�TD / / �
-�- � � � �
Test Pit Number& / � ena_S OF BEARING
�,�-,�.�. / � �
Tp_1 Approximate Locatian �-���M� i sa,n, uNE oF�oT,
�,�Yx�e-qp / 7 PER SNORT PLAT 056-Q86
/�t� � / KIEWIT BUILDING i bORIZONTAL DATUTA
� ASSUMED
/� / �p Q BF�C��iY � I
t VERTICAL DA7UM
-/�i� / I N�w i�ea
/ 1
+� --"�� � �r. I BENCN MARK ' ,
/ ./�. 1 / � GTr oF r�Ta+ /�aa+ t,
/ � �v= �.+a'
/ _--- ��j/ svw,ieu-a.�. toT _ ^ p` , � ',_�
� rrv-mea(a'�U . I
�U
+�-�(e'� t `� � `,r- -
� ��� 'I �
,.r � � ��� _`�'�r � �
� ��� �
� n nca �_r�- � LEGAL DESCRIPTION � �
i a �
� ` � .�}.I ^� � ,� � nucr�e� co.�s u��ae ow�ar � �
I mo��oana�to gwrnE.n�Ma�,iccao�c ro �
/��� / ,r. �I -�\�� y � TE PIAT RECAmm N YOLl11E It OF M7S P�M.N � (�
���� N� J / , _ w�c munr,�awc�Lr�c sounEwsmd7 oF x
� 1 I souiH�sr r�aF u�a rr�vwomu aa�rFVMu �' �
'a � �"��' '��- � � N L 5 S `b N q 3� ?r g, °a q `r► 's. � '� t �� P� �. i �n�asr(�m�w�roxr Rowk � �
� ' '� 9� \ ` , 1 \ � � � � � • o '•` - • mct��x wirn t�u�r wrtrow ai v�i[o cvunn eaw
//��,� '..�5�Y , , �` 1 ` �\ � �\ \\� \•. �\\p,` �� _ t y- /,- i �x.�rwc Mcsmn.r av nc Fnuorwc� � O
r ,�.� �� _ �, 1, � � � � �� \ �• � `\� t�-� I EGNMG AT TNE SQJTHEAST COWIF7t OF SIiD 7RACf 191; �.�, 'C
��' .� t _- t �� � ; ` ` �. � ���. � ���'•, ` � I n��r�uaMc n��srrar uwe oe sao p" fx
/ //, � � m�cr�m: ro nf sanfr�esrtar ur�aF s�o
�o' ,S'� ��i'_� � ,�,' T�- \ \�"��_ \ ra's�w ��-�---�5-� � __-�=N� � vucnim Ra�o No.w nmia cn+nwuwc wan�mr � C
/ � :i j_-- -� \ ` ♦ � ` � � _ �t���� � , �ar�wn����s�r�aK u�i�� � p
� � � ; _ - � \ . � �� ♦ �� � �� �� t �� ; \ Fs�wrar eouevwro�ameEtisr t�rWtE rEMPortr '�
/ / � L� � � . � \���1 _ � � \ -- auo),wo�ro+�wus oF s�m u�. ca iC
fJ//� w/ `�• �f, �i.� % � i � ' �\� � � � �\� \�\�� �\ -��� i t` � � O
O - � � � \ \ . \\ � � `\ \ �'\ _ . / � i ^ .�i'
/ ' �, ���/ ' .� ' ` \ �� �\ \ \ \ `I`1 ' �� ` � _-__ � � O
� �'/ / r- I i \ �` �• \ � K _ � �-r. i\ _ 1__ s. O
�°'�4���' i i � � \� \ � � < " i. cC �
/ -Y �-isr.�r � _'- � �� �� � � �� � ' '� � �ee W
�// ,�,'ti s / 1O° � TP-4 � ` .. , - au
/ / �orx � � i � � �__� \ .\��\���� �'� -__ i z�m � ,�
i' / � 1 \ \ �\ ��'__-�- �J_- �
� � 1 \ \ �
+y er ��PU _. � T7]�1 I j C •\ r�1p\ ' ` K` \ `` .` % _ __._..� w �
y Lr 1
��i / �� /� ' , __ _____ �� \ � ��� � \ � �� `\ � .C".
�,�..� .-- � j;� ; � � � . �� - � . . , � �
,� . � , , � , , � , ��, ; � � �
• . � �4 ; t � ° � F1� � \ �� o � �\ �� �� , ; 'asmie�� ie�n m arr ac�iaw f� W
i.�`'.. . '-.�
y,/� ,- � % � , � � � `. � `.\ � . �. ' < .\ `� `•�\ �\ � �� ------ ---,-_� w�i.s�zac.�asT �C C
/� �`/ /; ' �ti ';� \..� /�.1� '''� � �� � cC �O
�� /i � � . i \ \ i ti .- 1 \ � \ �� � � i \ � ��.
� W 3x'as� :1,, ----j� __. TP-2 1 � � -.\ �� ��-, i i� N
� , � , ._
G-'� � � C' �� � � �, - ' . I /' r ' 1 � \ \ ' ' a �
`: � � :'..�. ta' 1 ' �� Lo�t � �! �1• \ �t � � 'T �? d
� - , _` ..:. , � , � .�.: `, , � � � `;� �, r.s3 NAUTICA BUILDING � �
�'. /. � � � � , I -'W- � � � i �. � i � ' � � ," � �
/ / / ��/ °.�y '/I /�' \\ � .�Y.�. � I.�� r' � Y '�. ' I �� � �/ i / / O '�
� i �a f�/I ¢' �_-'- � i '.'S.'• i� I 1� ( '� � I I � i o � ccS
,/ /�� I ;%�, , ` � � � �.��.-..• i ; < � .TP-7 , � � i i � � I � ��� o a
� � � 1 •-�o..- : + � � i� � � � � �
����� f'/' �' •./ '� I� I�-� g a SS k7 Y`d !C • _ 1 � � • I TP-S � i � � � ;: "� i
� � g '� ,1 •'.-�'..'- � � � ' l ; l � I � i C+ f1�
�� s � �� i S I `�, f I ; ; �'.�'-'.• a o' � t �. j ,' l� � -'.- ' �, � j 1 � i
/ /� ' ���_- � � �e13 �s � � � � ' '°".� � .�/ l cQ� :`'�. ! I ( � /� i
/ - � ��- ,� r i T"� / • � � � i
y I '1' I � I � � _'� ,y4 -' ! . I � J � �� � � � �
� '// /1 I 1 / �����/ i .��"�21bt � i l i ,�' % � 11 � i '! / � � r I ! � i /� 1
� -�� ��� � � <, � � , �TP'3 6��L� ,z � ,' ! � �_.: � •' , � , � , ; �.�
�' - -'3 .� � `.� � ',� �� �'� ' '' f" � ' �+ �� / i� �� �i�
' �� �-•1� -� I i. � � ��. i i ,ar- �I � i j ' r/I ��� i �, IJ + ;+ i/ ILLL
/ � wv�Y/.9 � f � � I �� /
_ �� � -\ `�. -J � ';: ; a-,«ir . �� � TP-6 ! x � � � ;� �
� �; - : Y S 4 �
� ,r �r�� �-���\ I �a, v z�.sa str _'f'_ �' �, /'i_ / . . \ l � 1` `1 1 , �i ;I cs ar-e�.as
� ,�\ ��.� �sr� xw_s..p 1; .� zs' / `?' .. �Q.�, -----� -1- rt- f—� —.� wv-es.�(e'cav�
r'`-�-
/ � � �\ /�,, � ���---7-==..��a'om)� ✓ res�?s��1"6 � ,n m•�,ymsc,wE , I , � i J', Nv-ea.sa(�r wv s�
� cs ar���.ss\�i,��, / ! � � / i �Ac•sstir 7- 1 � , " � '�-T- �;�R.._ �
. l����iaw�sj �1�" '�'---.�.--z-#--.j-�F-.- -- - - �-- - � - ��-�---;.-..-',--_,-:_ !- � --+---'-�-- ` _
�- • �=- .:' .:" ; -- '-"- -•`_",..,i.
nv-w.97(tYC��q _/ J'��� /�J � 7"%. �7 �J_ ' .� :. � . ..�...';�i .•" yi:_ ... y .":.y. 'a:- -�r,-.�
•t •�� � � `�� /-�i�7 � �7T �7��'�/�i�� T�j r �. �
ff � i � � �� �� �T�—�S �
- - � _ �' � � �� � r � � r ; �'�-�,n
�-_, ,� . , i , i �� � i i �' � ; .�_,�� -
�'-__._ - i- ��--T— ' i�'._ �¢$�q 4TRF.F.�� �'� � ] � /I � ' �� ��
, � i` i � i � ''"r' � ,I I
� ' � � � � � � '� � ` , = PROPOSED SITE PLAN
" L11_/11L-!✓1L_1/11 �L�1 L�_ 1U�/1./� Ll]LL_�1�1L/�y 1dL! � L�L� _�_ BARONE GARDEN STATURARY
a �
a � � � � x R � � : . � $ 91 Group Northwest, Inc.
_ w'>"' �'ro-,�r� ~ - - LAI�E WASHINGTON BLVD i�TE& NE 48TH ST
� - - - =r�B'eS'Tr � ���� Geotechnical Engineers,Geobgists.8
- / ur� "" �- -- - - -' - - ��' ��, Envrconmental ScieMsts RENTON,WASHINGTON
� � /� pIV.4S
,� � ��'�-� � _ _ __ ���+0.3M SC�I.E AS Sh0�VI1 DATE �/2/O4 �L4DE W.TL CHKD WC JOB NO. G-17fiZ PLaTE 2
rrv-v c�ep m •••< <
APPENDIX A
TE5T PIT i3OGS
r._�,
�
Geo Group Northwest, Inc.
LEGEND OF SOIL CLASSIFiCATION AND PENETRATION TEST
UNIFIED SOtL CLASSIFICATION SYSTEM (USCS)
i
MAJOR DMSION � 5��� TYPICAL DESCRIPTION i LABORATORY GLASSIFlCATION CRITERIA
I
�� � GW WELL GRAO�GRAVELS.GRAVfl.SAND Cu=(D80!D10)yreater M�n 4
GRAVELS i MIXTURE,LfTRE OR NO RI�S j �E7ERAYNE �_(���)�(�0'�)bewveen 1 and 3
, I PERCENTAGES OF
�Rqydg (IRtle w no I POORLY GRAD�GRAVH.S,AND GRAYELSAND GRAVEL AND SAND
COARSE- ��°��f R�� � ; NOT MEE7ING ABOVE REQUIREMENTS
MIXTURES LfTTLE OR NO RNES FROM GRAIN StZE
GRAINED SOILS Co�ss Grams DISTRIBUTION
LarpxThan No.4 � CURVE ATTSt6ERG LIMI7S BELOW
Siava) DIfZTY GM � SIL7Y CY2AVEiS,GRAVELSAND-SILT MDCTURE3 ��T "A'L1NE
GRAVQS j � ar P.I.LESS TNAN 4
OF FINES
(wiy spne CLAYEY GRAVELS,GRAVELSAND-CLAY DCCEED6�2% ATTERBERG IJMfTS ABOVE
fines) GC MIXTURES COARSE GRAWm "A"LWE
��q(ZE or P.1.MORE 7HAN 7
CLASSIFI�AS
WELI.GRADED SANDS.GRAVE1lY SANDS. FOLLOWS C�'�/D7�greater than 8
SANDS � CLEAN � UTTLE OR NO FINES Cc=(D30�)1(D1�'OBOI between 1 and 3
SAPI0.S
(AAave Than HaM I
hlore Than Half by �fO G�� �Im��� gp ��Y GRADED SANDS,GRAVEELY SANDS, <$9`Fins G�ainned: NOT MEETUJG ABOVE REQUIRH�AENTS
WdgM Larger
Srtnller Than Na. flnss) LITTI�OR NO FINES GW.GP,SW.SP
Than Na 200 4��^°� ATTER882G Uatl75 BELOW
>�2%Fns Grained
�O DIRTY SW SN.TY SAN[�.SANDSILT MDCTi1RES 13M,GC,SM,SC CONTH�(T OF ,.A.•LINE
�N� FlNES � P.1.LESS 7HAN 4
� 5 h�12%Flne IXC�DS 12% ATTERBERa UMfTS A80VE
�1° SC CUYEY SANDS;SANO�CUY h�CTURES Gnined;usa dval "A"LINE
finea) Sy���y with P.L MORETHAN 7 ',
�
SQTS UVuid Llmk NORGAMC SILT3,ROp(FtOUR�Y SILTS
(Bdow A-Line on <r`�% M� OF SLJGHT PLASfIGTY � i �
p�H Ch�R PLASTIGTY CHART ' A-Line
FlNEIR/UNED Nepliyible �jq�b� INORGANIC SILTS,MICACEOUS OR � FOR SOIL PASSiNG
SOILS a9�^� >50% � DIATOMACEOUS,FINE SANDY OR SiL7Y SOIL NO.�0 SiEVE CN or OH � , �
� � i �
a�yg Liquid LImR ��GANIC CLAYS OF LOW PlAST1CffY, W�p
� �� CL GRAVaLY,SANDY,OR S�LTY CLAYS,CLEAN �
p���� CLAYS Z
Neglipible Uq���� INOROANIC CLAYS OF HIGH PLAST1CfTY,FAT ��
Oryan�c) >� � CLAYS V CL or OL
F-
More Than Half by <tI�ZO
Weight Lupar Uquid Limit OROANC SILTS AND OROAWC SILT/C1AYS OF a MH or OH
Than No.200 �GANIC SIL7S <Spq� � LOW PLAST1CtIY
�a CLAYS �0
���Y��q ���� OH ORGANIC CLAYS OF HIGH PLAST1CfiY � � M �
0
0 10 ZO 30 40 50 80 70 80 90 100 1�0
HIGNLY ORGANIC SOILS R PEAT AND OTHER WGHL.Y ORGAWC SOILS L1QUtD W1MT(%)
SOIL PARTiCLE SIZE _ r GENQiAL GUfDANCE OF SOIL ENGINEERING
U.S.STANDARD SIEVE PROPERTIES FROM STANDARD PENETRATION TEST(SP'�
FRACTION I Passlny Retained SANDY SOILS SILTY 3 CLAYEY SOILS
uncadned
Sieva �u Sieve Blow Relativs Friction e�ow �
(mm) �n'"d cow�� oe�ey ti,9w oa«��no� ca,� �"�^ ; o��,
3ILT I CLAY N200 0.075 N � � +•�W°1 N q�,�}
�
SAND 0-1 0-15 � Vay Loas� <2 <0.25 ; Very soft
fINE iF0 0.425 � 0200 0.075 4-10 15-35 28-30 Loow 2-4 0.25-0.50 i SoR
I
MEDIUM 1110 20D � IHO 0.d25 10-30 35-efi � 28-95 ! Medium Denss 4-8 0.50-7.Q0 Madium Stirt
i
COARSE M4 4.75 #10 200 30-50 �-� 35-42 i Dense 8-15 1.00-200 Sdff
GRAVEL >50 85-100 38-48 ; Very Dense 15-30 � 200-4.00 Very Stift
i
FiNE � 1B M4 4.75
>30 � >4.00 Fiud
COARSE 78 19 �
COggLEg � 78 mm to 203 mm
BOUtDER3 i >20.3mm � Group Northwest� �C•
- GeotechnicalEnpinssrs,Geobgists,S
�x �� Emrhonmental Scientlsu
>78 mm
FRAGYENTS : 13240 NE 20th Straet,Suite 12 BeYevu�,WA 98005
ROCK
,� >0.78 cuhic me0er in wlume Phons(425�848-8757 F�c(425�849�8758 P LAT E A 1
TEST PIT NO. TP-1
LOGGED BY WJL EXCAVATION DATE: 3/22/04 GROUND ELEV. 34 feet(f)
DEPTH SAMPLE MOISTURE OTHER
(t. USCS SOIL DESCRIPTION No. % COMMENTS
Sl 15.5 Probe:
rt 1.5'=0.5"
SM
Siltv SAND,brown to gray,dense at surface then loose,moist, S2 �6.g (�2,5'_3-}-fr
some gravel(FII.L) (very loose)
S3 22.5
6
- - - - - - - - - - - - - - - � 19.4
� TonSoil&Oreanic SILT,dark brown,amorphous,soft,moist
OL
SS 55.8
—— ———————————————————————
OL/ Oreanic SILT&Siltv SAND,interbedded,soft/loose,wet S6 57•7
�p SM
MiL SILT,gray,with sand,very stiff,moist(rock flour) S7 17.2
Total Depth= 10.5 feet
No Water Seepage
� TEST PIT NO. TP-2
LOGGED BY WJL EXCAVATION DATE: 3/22/04 GROUND ELEV. 32 feet(t)
DEPTH SAMPLE MOISTURE OTHER
ft. USCS SOIL DESCRIPTION No. °/. COMMENTS
Sh•f Siltv SAl�il),dark broH-n,«�Ui organics,loose,moist(Top Soil).
Probe: '
SM Gravellv SAND,brown,medium, some silt,dense to very S1 6.6 (�2�=p��
dense, damp,�vith interbeds of gray Sand with gravel,wet
S2 8.2 i
5
Total Depth=4.2 feet
No Water Seepage
10
� TEST PIT LOGS
� Grou� Northwest, IIIC. BARONEGARDENSSTATUARY
�� RENTON,WASI�INGTON
.� Geotechnicat rngineers,Geologsts,8
Envronmental Scientists Project No. G-1762 PLATE A2
TEST PIT NO. TP-7
LOGGED BY WJL EXCAVATION DATE: 3/22/O�l GROUND ELEV. 38 feet(f)
DEPTH SAMPLE MOISTURE OTHER
it. USCS SOIL DESCRIPTION No. °10 COIUIMENTS
6" To�Soil �
�- — — — —— ————— — —— — ———
S 1 ]6.9 Probe:
na.s�_�°
ML SiLT,mottled tan-brow�n-gray,stif2,some fracturing,moist
S2 36.8
b
— — — — — — — — — — — — — — — —
SM Siltv SAND,mottled brown-gray,medium dense,moist to wet
S3 21.6
Total Depth=7.5 feet
No Water Seepage
10
� TEST PIT NO. TP-
LOGGED BY W7L EXCAVATION DATE: GROUND ELEV. XX feet(f)
DEPTH SAMPLE MOISTURE OTHER
ft. USCS SOIL DESCRIPTION No. °� COMMENTS
�
i
I
5
10
I
= TEST PIT LOGS
_
�I GI-ou� North�vest, II1C. B�ONE GARDENS STATUARY
��, RENTON,WASHINGTON
� Geotechnical�gineers,Geobgsts,8
Environmenta�scientists PCojeCt No. G17C2 PLATE Aj
.�P�'E\lll.�. �
ROCKERY CONSTRUCTION
GUIDELT'�'F�
C�-i
Geo Group '�orthwest, lnc.
Ra� �f Y
oeQ ::::t,._`-�
o'dac
Cneo -r�^�:
�$
I�'. `�.
aD P �'i ``..`
O " �,
.>Y�, �:
i
.D _:"t^ �.:
°o ^�" `Assoeiated Rockery Contractors
Standard
Rock Wall Construction
Guidelines �
�
. r
. • '
P.O. Box 1794 Woodinville, Washin ton 98072
9
Association Representatives '
(425) 481-3456 or (425) 481-7222
Co nte nts
1.01 Introduction:....................................................................................................................................................1
1.01.1 Historical 8ackground.........................................................•---•--............................_..1
I1.01.2 Goal .....................................................................................•---................................----�
2.01 Materials:.........................................................................................................................................................1
2.01.1 Rock �uality ............................................................................._..................._.....----....1
2.01.2 Frequency of Testing ................................................................................................2
2.01.3 Rock Density ................................................................................................ .........2
2.01.4 Submittafs..........................................................................................•-... ................2
3.01 Rock Wall Constructian: ...................................................................._............---...........................................2
, 3.01.1 General..........................................................••••-••••-•.............._....................................2
3.01.2 Geotechnicai Engineer ............................•---....................---•-------..............................3
3.01.3 Responsibility................................••-•-•--••-.............._._.................................................3
3.01.4 Workmanship.................................................................•-......_....................................3
3.01.5 Changes to Finished Product ..................................................................................3
3.01.6 Slopes .....................................•...---..._..............--•--...--•--....................__.....3
...................
3.01.7 Monitoring...................................................................................................................4
3.01.8 Fill Compaction ..........................................................................................................4
3.01_9 Fill Construction and Reinforcement......................................................................4
3.01.10 Rock Wal! Keyway........................•-..............................................................-•-•--.....5
3.01.11 Keyway D�ainage.......................................................................:....................•--......5
3.01.12 Rock Wall Thickness........................................•---........................................._.._......5
3.01.13 Rock Selection.........................................................................................................6
3.01.14 Rock Placement.........................................•-•--••--•-•.........................................._..._...6
3.01.15 Face Inclination ..........................................................................................•--•--.......6
3.01.16 Voids ............................................................................................................•--....
3.01.17 Drain Rock Layer.............................................................----............................,.......6
3.01.18 Surface Drainage.................�---.....................----...---�--�-�--..............._.....................---.7
PostCons#ruclion Guideline Figure A.................................................................................................................8
TYPICAL DETAIL Native Cut, Any Height Over 4 Feet....................................................................................9
TYPfCAI DETAIL Overbuild Fill Construction, Aock VUall less than 8 Feet in Height .............................. 1�
TYPICAL DETAiL Geogrid Reinforced Fill Construction, Rock 1Nall 8 Feet or More �r, Height . .... ... ... � '
L
ARC STANDARD ROCKERY CONSTRUCTION GUIDELINES
1.01 Introduction:
1.01.1 These standard rock wall construction guidelines have been devetoped in an
Aistorical effort to provide a more stringent degree of control on materials and construction
Background methodology in the Pacific Northwest. They have been assembled from numerous
other standards presently in use in the area, from expertise provided by local
geotechnical engineers, and from the wide experience of the members of the
Associated Rockery Contractors (ARC).
1.01.2 The primary goals of this document are to standardize the methods of construc-
Goal tion for rock walls over four feet in height, and to provide a means of verifying
the quality of materials used in construction and the workmanship employed in
construction. This standard has also been developed in a manner that makes it, to
the best of ARC's knowledge, more stringent than the other standards presently
in use by Iocal municipalities.
2.01 Materiais:
2.01.1 All rock shall be sound, angular ledge rock ihat is resistant to weathering. The
Rock Quality longest dimension of any individual rock should not exceed three times its
� shortest dimension. Accep[ability of rock will be determined by laboratory tests
as hereinafter specified, geologic examination and historical usage records.
All rock delivered to and incorporated in the project shall meet the following minimum
specifications:
a. Absorption Not more than 2.0°lo for igrrevus
ASTM C127 a�:d metamorphic rock types and
AASHTO T-85 3.0°dv for sedirnentary rock types.
b. Accelerated Expansion(15 days) Nvt more than IS°b breakctowri.
CRD-C-148 *I, *2
c. Soundness(MsSO4 at S cycles) Not greater tha►t 5%lnss. II
ASTM C88
CRD-C-137
d. Unconfined Compressive Strength bitact sire�:gih of 6,000 p.ri, or
ASTM D 2938 greater.
e. Bulk Speci�c Gravity (155pc� Greater thaui 2.48
ASTM C 127 �
AASHTO T-85
*1. The [est sample will be prepared�nd tested in accordance with Corps of Engineers
Testing procedure CRD-C-148, "Method of Testing Stone for Expansive Breakdown
on Soaldng in Ethylene Glycol.".
*2. Accelerated expansion tests should also include analyses af the fractures and veins
found in the rock.
� — - --
ARC STANDAi�D ROCKERY CONSTRUCTION GUIDELINES
2.01.2 Quarry sources shall begin a testing program when either becoming a supplier or
Frequency when a new area of the source pit is oQened. The tests described in Section
of Testing 2.01.1 shall be performed for every four thousand (4000) tons for the first twelve
thousand (12,000} tons of wall rock supplied to establish that specific rock
source. The tests shall then be performed once a year, every 40,000 tons, or at an
apparent change in material. lf problems with a specific area in a pit or with a
particular material are encountered, the initial testing cycle shall be restarted.
2.01.3 Recognizing that numerous sources of rock exist, and that the nature of rock will
Rock vary not only between sources but also within each source, the density of the
Density rock shall be equal to, or greater than, one hundred fifty-five (155) pcf. Typi-
cally, rocks used for rock wall construction shall be sized approximately as
follows:
Rock Size Rock Weight Average Dimension
One man 50-200 pounds 12 to 18 inches
Two man 200-700 pounds 18 to 28 inches
Three man 700-2000 pounds 28 to 36 inches
, _ Four man 2000-4000 pounds 36 to 48 inches
Five Man 4000-6000 pounds 48 to 54 inches
Six Man 6000-8000 pounds 54 to 60 inches
In rock walls eight feet and over in heigh[, it should not be possible to move the large sized
rocks(four to six-man size)with a pry bar. If these rocks can be moved,the rock wall
should not be considered capabie of restraining any significant lateral load. However, it is
both practical and even desirable that smaller rocks, particularly those used for"chinking"
purposes,can be moved with a pry bar to achieve the"best fit".
2.01.4 The rock source shall present current geologic and test data for the minimum
Submittals guidelines described in Section 2.01.1 on request by either the rock wall contrac-
,� �i._ „� „ .- „ ., . ,., ,i.? . ,. ..
.. . ' 4`. .:��r. � . , �.`.T ' i".. . - . .
3.��..1 K�JC1� L4':1ii .;U?]�'liui:i]UIi :) i.i ::I�lll �1ilU Ql:�:;:iUJ 1:1:�;;1�� Jt; i:ti; �t�lll �,lill': :;.�.�'... ,.':�, �_
General of the builder. A rock wall is a protective' sysiem which helps to retard thr
weathering and erosion process acting on an exposed cut or fill soil face. `L hilr
by its nature (the mass, size and shape of the rocks) it will provide some undece;-
mined degree of reteniion, it is not a designed or engineered system in the sense
a reinforced concrete retaining wall would be considered designed or engineered.
The deg�ee of retention achieved is dependant o❑ the size of rock used; that is,
the "mass" or weight, and the height of the rock wall being constructed. The
larger the rock. the more competent the rock wall. To accomplish an appropriate
12/2/92 a e r_F � ��,
ARC STANDARD ROCKERY CONSTRUCTION GUIDELINES
degree of competency, all rock walls in excess of four feet in height should be
built on a "mass" basis, i.e. by the ton.
To provide a competent and adequate rocic wall structure, all rock walls con-
structed in front of either cuts or fills eight feet and over in height should be bid
and constructed in accordance with these standard guidelines and the
geotechnical engineer's supplemental recommendations. Both [he standard '
guidelines and the supplemental geotechnical recommendations should be pro-
vided to prospective bidders before bidding and the start of construciion. '�
3.01.2 The geotechnical engineer retained to provide necessary supplemental rock wall ��
Geotechnical construction guidelines shall be a practicing geotechnical/civil engineer licensed
Engineer as a professional civil engineer in the State of Washington who has had at least ;
four years of professional employment as a geotechnical engineer in responsible �,
charge, including experience with fill construction and stability and rock wall
construction. The geotechnical engineer should be hired either by the rock wall
contractor or the owner.
3.01.3 The ultimate responsibility for standard rock wall construction should remain
Responsibilety with the rock wall builder. However, rock walls proteciing moderate to thick I
fills, with steep sloping surfaces above or below them, with multiple steps, with �
foundation or other loads affecting them, protecting sandy or gravelly soils '
� subject to ravelling, with seepage or wet conditions, or that are eight feet or
more in height, all represent special design conditions and require consultation
and/or advice from qualified experts.
3.01.4 All workmanship is guaranteed by the rock wall contractor and all materials are
Workmanship guazanteed by the supplying quarry for a period of six years from the date of
completion of erection, providing no modification or changes to the conditions
existing at the time of completion are made.
3.01.5 Such changes include, bui are not necessarily limited to, temporary excavation of
Changes ta ditches or trenches for any utility within a distance of less than five feet from the
Finished back of the top of the rock wall; excavation made either within a distance equal
Product to at least two thirds of the free-standing wall height in front of the toe of a rock
wall, or that wili penetrate an imaginary line extended at a 1H:1V (Horizontal:
Vertical) slope from the front edge of the rock wall toe (see Figure A); removal
of any material fram the subgrade in front of the wall, excav�tion of material
from any location behind the rock wall within a distance at least equal to the
rock wall's height, the addition of any surcharge or other loads within a similar
distance of the [op of the roc3c wail, or surface or subsurface water forced, di-
rected, or otherwise caused to flow behind the rock wall in any quantity.
3.01.6 Slopes above rock walls should be l�ept as flat as possible, but should not exceed
Slopes 2H:1 V unless the rocic wall is designed specifically to proyidc ,ome restraint to
the load imposed by the stope. Any slope existing above a comp(eted rock wall
should be covered with vegetation by the owner to help reduce the potential for
surface water flow induced erosion. It should consist of a deep rooted, rapid
growth vegetative mat, wiil typicaliy be placed by hydroseeding and covered
with a mulch. It is often useful to overlay the seed and maich with either pegged
ARC STANDARD ROCKERY CONSTRUCTION GUIDELlNES
in-place jute matting, or some other form of approved geotextile, to help main-
tain the seed in-place until the root mat has an opportunity to germinate and Eake
hold.
3.01.7 All rock walls cons[ructed against cuts or fills eight feet and over in height shall
Monitoring be periodically, monitored during construction by the geotechnical engineer to
verify that the nature and quality of the materials being used are appropriate, that
the construction procedures are appropriate, and that the rock wall is being
constructed in a generally professional manner and in accordance with this ARC
guideline and any supplemental recommendations.
On completion of the rock wall, the geotechnical engineer should submit to the
client, the rock wall contractor, and to the appropriate municipality, copies of his
rock wall examination reports along with a final report summarizing rock wall
construction.
3.01.8 Where rock walls are constructed in front of a fill, it is imperative that the owner
FiII ensure the fiil be placed and c�mpacted in a manner that will provide a compe-
Compaction tent fill mass. To achieve this goal, all fills should consist of relatively clean,
organic and debris free granular materiais with a maximum size of four inches.
Ideally, but particularly if placement and compaction is to take place during [he
wet season, they shauld contain no more fhan seven percent fines (silt and clay
� sized particles) passing the nurnber 200 mesh sieve.
All fills should be placed in thin lifts not exceeding ten (10) inches in loose
thickness. Each lift should be compacted to at least 95 percent of the maximum
dry density, as determined by ASTM Test Method D-1557-78 (Modified Proc-
tor), before any additional fill is placed and compacted. In-place density tests
should be performed at random locations within each lift of the fill to verify that
this degree of compaction is being achieved.
3.01.9 There are two methods of constructing a fill. The first, which typically applies to ,
Fill rock walls of less than eight feet in height, is to overbuild and then cut back the ,
Construction fill. The second, which applies to all rock walls eight feet and over in height, is
Reinforcement to construct the �11 using a geogrid or geotextile reinforcement.
Overbuilding the fill allows for satisfactory compaction of the fill mass out �
beyond the location of the fiil face to be protected. Overbuilding also ailows the
earthwork contractor to use larger and more effective compaction equipment in
his comQactive efforts, thereby typically achieving a more competent fill mass.
Cutting back into the well compacted fill also typically results in construction of
a competent near vertical fill face against which to build the rock wall.
�
For the higher rock walls the use of a.geogrid or geotextile fabric to help rein-
force the fill results in construction of a more stable fill face againsc which to
construct the rock wall. This form of construction leads to a longer lasting and
more stable rock wall and helps reduce the risk of significant long term mainte-
nance.
i ni�inn n w r►c e
� _
ARC STANDARD ROCKERY CONSTRUCTI�N GUIDELINES
This latter form of construction requires a design by the geotechnical engineer
for each speci�c case. The vertical spacing of the reinforcement, the specific
type af reinforcement and the distance to which it musi extend back into the fill,
the amount of lapping and the construction sequence must be determined on a
case by case basis.
3.01.10 The first step in rock wall construction, after general excavation, is to construct a
Rock Wall keyway in which to build the rock wall. The keyway shall comprise a shallow
Beyway trench of at least twelve {12) inches in depth, eztending for the full length of the
rock wall. The keyway subgrade shouid be slightly inciined back towards the
face being protected. It is typically dug as wide as the rock wall (including the
width of the rock filter layer). If the condition of the cut face is of concem, the
keyway should be constructed in sections of manageable length, that is, of a
length that can be constructed in one shift or one day's work.
The competency of the keyway subgrade to support the rock wall shall be veri-
fied by probing with a small diameter steel rod. The rod shall have a diameter of
between three-eig�ths and one-half inch, and shall be pushed into the subgrade in
a smooth unaided manner under the body weight of the prober only. Penetration
of up to six inches, with same difficulty, shall indicate a "competent" keyway
subgrade unless other factors in the geotechnical engineer's opinion shall indi-
cate otherwise.
� Penetration in excess of six inches, with ease, shall indicate a "soft" subgraci
and one that could require treatment. Shallow soft areas of the subgrade can �:
"firmed up" by tamping a layer of coazse quarry spalls into the subgrade.
3.01.11 Upon completion of keyway excavation, a shallow ditch or trench, approxima�eiy
Keyway twelve (12) inches wide and deep, should be dug along the rear edge of the key
Drainage way. A minimum four-inch diameter perforated or slotted rigid ADS drain pipe,
or equivalent, approved by an engineer, should be placed in this shallow trench '
and should be bedded on and surrounded by a free-draining crushed rock. Burial
of che drain pipe in this shallow trench provides protection to the pipe and heips
prevent it from being inadvertently crushed by pieces of the rock wall rock. This
drain pipe should be installed with sufficient gradient to initiate flow, and the
outfall should be connected to a positive and permanent discharge.
Positive and permanent drainage should be considered to mean an existing or to
be installed storm drain system, a swale, ditch or other form of surface water
flow collection system, a detention or retention pond, or other stable native site
feature or previously installed collection system.
3.01.12 The individual rock wall thickness should be equal to the thic�Cness of the recom-
Rock Waii mended size of rock plus the thickness of the drain rock layer. This thickness,
Thicicness which will be deiermined on a case by case basis, will be dependant on the
specific rock sizes recommended for each individual rock wall. For example, if
four-man rock is ased the rock wall thickness will be approximately five feet.
ARC STANDARD R4CKERY CONSTRUCTION CUIDELINES
3:01.13 The contractor should have sufficient space available so that he can select from
Rock among a number of stockpiled rocks for each space in the rock wall to be filled.
Selection Rocks which have shapes which do not match the spaces offered by the previous
conrse of rock should be placed elsewhere to obtain a better fit. Rock shouId be
of a generally cubical, tabular or rectangular shape and selected in accordance
with Section 2.OI.3. Any rocks of basicaily raunded or tetrahedral form should
be rejected or used for filling large void spaces.
3.01.14 The first course of rock should be placed on firm unyielding soil. There should
Rock be full contact between the rock and soil, which may require shaping of the
Ptacement ground surface or slamming or dropping the rocks into place so that the soil
foundation canforms to the rock face bearing on it. The bottom of the first course
of rock should be a minimum of tweive (12) inches below the ]owest adjacent
site grade.
As the rock wall is constructed, the rocks should be placed so that there are no
continuous joint planes in either the vertical or lateral direction. Wherever
possible, each rock should bear on at least [wo rocks below it. Rocks should be
placed so that there is some bearing between flat rock faces rather than on joints.
Joints between courses ([he top surface of rock), should slope back towards the
cut face and away from the face of the rock wall.
� Smailer rocks (one to two-man size) are often used to create an aesthetically pleasing
"top edge" to a rock wall. This is an acceptable practice provided none of the
events described in Section 3.01.5 occur, and that people are prevented from
climbing or walking on the finished wall. This is the owner's responsibility.
3.01.15 The face of the rock wall should be inclined at a gradient of about 1 H:6V b
Face towards the face being protected. The inclination shouid not be constructed
Inclination flatter than 1H:4V.
3.01.16 Because of the nature of the product used to construct a rock wall, it is virtually
Voids impossible to avoid creating void spaces between individuai rocks. However, it
should be recognized that voids do not necessarily constitute a problem in rock
wall constrvction. As the size of rock used to build a rock wall increases, i.e. to
six-rnan size, the void spaces between individual rocks should be expected to be
larger.
Where voids of greater than six inches in dimension exist in the face of a rock
wall they should be visually examined to determine if contact between the rocks
exists within the thickness of the rock wall. If contact does exist, no further
action is required. However, if [here is no rock contact within the rock wall
thickness the void should be "chinked" with a smaller piece of rock.
3.01.17 In order to provide some degree of drainage control behind the rock wall, and as
Drain Rock a means of helping to prevent loss of soil through the face of the rock wall, a
Layer rock drainage �lter shail be installed between the rear face of the rock wall and
the soil face being protected. This drain rock layer shouid be at least twelve (12)
inches [hick; a�d for rock walls eight feet in height or higher, it shouid be at
�A/v\�AA 1'��/�r r
ARC STANDARD ROCKERY CONSTRUCTI�N CUIDELJNES
least eighteen (18) inches thick. It should be composed of 4 to 2-inc� sized
crushed rock quany spalls, crushed concrete, or other material approved by the
geotechnical engineer. If a random wall rock extends back to the exposed soil �
face, it is not necessary that the filter rock layer extend between it and the soil
face.
Depending on soil type and potential water seepage, a geotextile fabric may or i
may not be required. This can be determined on a case by case basis by the I
geotechnical engineer during design and prior to bidding. '
''
3.01.18 It is the owner's responsibility to intercept surface drainage from above the rock �,
Surface wall and direct it away from the rock wall to a positive and permanent discharge
Drainage well below and beyond the toe of the rock wall. Use of other drainage control
measures should be determined on a case-by-case basis by the geotechnical
engineer prior to bidding on the project.
C��'�N Mqti'L
�� �
�� a
�f Z
-C �
90� q�G,S���a ��
�ss�ONAtE�G
ARC STANDARD ROCKERY CONSTRUCTION GUIDEI.INES
Post Construction Guidline
Schematic Onfy-Not to Scale
H2
�
SFT.-�
�
�
� . ,
> •�,�1?�Q i
/ � a 48� � �
,`---_l 'v:p.o ' � i
o�QQ� i
'9'D c" �
� � o.' � I
��-� =�a:n o0
i ?� o o�� j
�,d��
H �-:-.�.
,l-_,,���Qa
a
�� �� .00,.
\
o:A:�•,
� a 0•
t � •o
i j-��' .04 I
i
a..p 'I
p�Q�oo� i
��— I
/ `� �A�
/ Q:
—H� ���—�
�/ �` ..Q O
I ��� 0
!�_2�3 i� i
i
i� j'
%
I
I�' 'I
%i'' �
%
�� /
/
I
�' /
%
/
/
2H:1V ;'
,
.
.
.
:
.
,
,
,
�' Figure A
r' _
t H:1 V H Height of rock wall.
5" No temporary excavation or trenching.
'/�H No temporary excavation or�renching.
H' No permanent removal of subgrade allowed.
H' No excavation of material or any surcharge allowed.
1 H:l V I�10 excavation below allowed_
2H:1 V 1�a�cimum �nished grade or permanent excavation .
Schemadc Only-Not to Scale
2
1�—
� , _ , _- �
�� O°� � r�' `� : - �
� `—' .(�QQ.(Q:: . � �-•.
� "4:q'a`o'�.. '/ � � • �
6 -_ `� •O�ooaQ: '�-".'� " -� � ` --_, '.
3 pp0-p� , � 1 � _ �� ���
� I ; ��
Q' �Q.'•�' • I I
:�:�Q:: �
H �;� ;�\ o•�- •�-,�; `� ' � �� .
'l�.i` B '
� ' � . ��� ��—� -'�
- .:o.y..._ / o; �
. �aC'O' - __ J�_
., f ✓ ,1 I ,
_� -°�� , .,- '
; •.v: -- -%' '--, -�.
1 ,��. ��.��'q: ___}._- _ �� � ;
_-L:�"^ _o.C o -
/ D , � �a�'o� p •
o- _ .
� --�-- . . . .
W Rock Wall Elevation
Rock Wali Section •The long dimension of Ihe rodcs should extend bacictowards the
cut or fil{face to provide maprnum stability.Rodcs should not be
stacked Idce shoe boxes.Tliey shouid be ptaced to avoid �
NOTFS: co►rtinuous joirn pianes�vertica!a lateral directi�ons.Whenever
possible ead�rocic should bear on two or more rocks below it,wdh
• Rodc wall constructbn is a cratt and depends largely an the skill good flat-fo-fNat contact. �
and e�erience of ihe b�ilder. •All rodc walls over 4 feet in height should be co�tructed on basis �
! • A rodc wall is a proteciive system which helps retard the of wall mass,not square footage of face. '
� weathering and erosan process on an exposed so�face.
i • While by its nature(mass,size and shape of the rocks)rt will Approxenate Approximate
j provide some degree of retention,it is not a designed ar S¢e Weic�t-Ibs. Diameter I
j engineered system in the sense a reinforced conaete retaining
wall woukf be considered designed or engineered. 1 Man 50- 200 12 - 18' i �
2 Man 200- 7U0 18 -28' �,
• The degree ot retemion achieved is dependent on the size of ihe �,
� rodc used;that is,the rtrass or weight,and the height of 1he wall 3 Man 700 • 2000 28 - 36" i
� being construded.The larger the rock,the more crompetent the 4 Man 2000- 4000 36 - 48° �
� rodc wall should be. 5 Man 400Q- 6000 48 - 54'
� • Rock walls should be considered maintenance items th�wiii 6 Man 6000- 80Q0 54-60°
� require periodic inspection and repair.They should be bcated so
that they can be reached by a contractor if repairs become Reference:Locai quarry weight study using average weights of r�o
���ry, less than six�odcs ot eadi man size conduded in January 1, 1988.
• Maximum inclination oi the slopes above and behind rack walls LEGEfVD:
shauld be 2:1 (HorizoMal:Vertical). Drainage mater'rals to consist of clean angular 4 to �
• Minimum thicfiness af rodc filter layer B=12 inches,Minimum ��4:a:a: 2 inch spalls,or other material,approved by the
embedment D=12 inches undisturbed native soil or compacted fill geatechnical eng�eer
placed in accordance witli report recommendations.
• Maximum rock wa(!height H= feet � Surface seal:may consist af impervious soil or a
• Rodc walls greater than 8 feet in height to be�siailed under fine free draining granular material.
periodic or full time obseroatian of the geotechnical engineer. ����
• Rodc should be placed to gra�ally decrease rt�size wAh Undistu�bed firm Native soil
increasing wall heigM in accordance with geotechnical engineers
recommendalions. Drainpipe:4-inch minimum diameier,perforated or
•Minimum width o1 keyway excavation,W,should be equal to the sbbed agid piastic ADS pipe laid wilh a positive
thickness of the basal rock(as determined by geotechnical Q gradient to c�scharge under conVol well away from
engineers design)pius B. the wall. i
�
' . 4❑ Designates size of rock required,i.e. `}' man. (
I
TYPICAL DETAIL Plate
NATIVE CUT, ANY HEIGHT OVER 4 FEET A
� _ �
i_
i Schematic Onfy-Not to Scale
I
I �J . 0. � o�
.o-
� / � 2 ,_ . °b�? o . - : ' . - . -
� . o..
r "6 ' :a��o: � � � :: � .� � :
� _ 3 - , �.�� .. _ .. .. .. ..
H � —' \ —` qg _ � . .
. _cv.c,,. . . � • • .. - �
� ,�s 3 ` �` Q�'.o.. . . � .. . � �.
1 , _ .p=:4 � � . � � � �
� j , 4 . ,
,
, _ _
� � ; �.a°p- I
I♦--- w I
� +
LEGEND
n:o v>�g_o. Cr�shed rock or other apporved material ranging between 4 to 2 inches in size and free of organics,with less than 5 per�er�t f�es
� ��D�4•0�a' (sitt and clay size partictes passing the No.200 mesh sleve).
I F Stnx:tural fi11 rnerbudd,compactad to at least 95%of maximum dry density as deterrnined by ASTM Test Method D-1558-78
L!___L__d nx
(Modified Proctor).
� Cort�pacted�ruciural fdl wnsisting of free-draining,organic-free material wdh a maximum s¢e of 4 nches. Should contain no more
thar►7 percent foes(desaibed above),compacted W at least 95 pe�cent of ASTM D-1557-78 maximum dry densRy.
, � Undisturbed firm Native soil
( O Perforated or sbtted drae�pipe with 4 inch minimum diameter bedded on arxi surrounded by crushed rock f�ter material,descrB�ed
j above_
t
QDesiqiates size of rodc required,i.e. 4 man.
NOTES
• All fill should Ge placed'm thin I�ts not exceeding 10 inches n loose thickness.Each layer should be compacted to no less than 95 per�ent of I�
maximum dry density,as determined by ASTM 0-1557-78(Mod'rfied Prodor). �
� • Thickness of crushed fifter rodc layer,B,should be no tess than 12 inches. �
i • Depth of burral of basal layer of rcek,D,should be no less than 12 inches. I
i • Height of rock wall,H,should nd ezceed feet.
I • Lateral extent of fill overbuild,Lp should be no less than H feet.
i
� •Muixnum widh ot keyway excavaUon,W.sho�ld be equal to the thiclmess of the basal rodc(as detertni�ed by qeotechnical enginee�s designl Plus B.
�
TYPICAL DETAIL Plate
OVERBUILD F1LL CONSTRUCTlON B
; _ ROCK WALL LESS THAN 8 FEET iN HEIGHT
�