Creekview II L3-SP010519CREEK VIEW 2 OFFICE BUILDING
COPPELL, TEXAS
ANCHOR DIAMOND BLOCK WITH
MIRAFI 3XT GEOGRID RETAINING WALL
SPECIFICATIONS
MAY 19, 2001
Prepared For
Adams Structural Inc.
1515 Boardwalk Drive
Arlington, TX 76011
Prepared By
Scott A. "Sam" Miller, P.E.
Consulting Engineer
2001 Reservoir Road, Suite 46
Little Rock, AR 72227
-- Job No.: 1085
PART "1": GF, NF, R AL TF, CHN1CA1, NOTES
1.01 Be~e~iption:
The work shall consist of furnishing and installing Anchor Diamond segmental retaining wall (SRW) units and
Mirafi geogrid reinforcement in accordance with this technical scope of work and in reasonably close
conformity to the lines, grades and dimensions shown on the plans and details.
A. Furnishing segmental concrete facing and cap units as shown on the construction shop drawings.
B. Furnishing reinforcement as shown on the constmetion d~awings.
C. Furnishing leveling pad and reinforced backfill material as specified herein and as shown on the construction
drawings.
D. Storing, cutting and placing structural reinforcement as specified herein and as shown on the construction
E. Installation of wall drainage system as shown on the construction drawings.
F. Excavation, placement and compaction of foundation uadercut, leveling pad, unit core fill, drainage fill and
reinforced backfill material as specified herein and as shown on the construction drawings.
G. Erection of segmental concrete units and placement of structural reinforcement.
1.03
A. {~eosynthe~ia Research lnqtiln~te
GG1-87
GG2-87
Gcn-(a&h)-91
GG5-9!
Standard Test Method for Geogrid Rib Tensile Strength
Standard Test Method for Geogrid Junction Strength
Determination of Long-TermDesign Strength of(Stiff& Flexible) Geogrids
Geogrid Pullout
B. American .qaaie~y for Te~fing and Materiala .qtandarda
ASTM D~5262
ASTM C-66
ASTM C-90-85
ASTM C-140-90
ASTM C-145-85
Tension Creep Testing of(Stiff& Flexible) Geogrids.
Specification for Concrete Aggregates
Hollow Load Bearing Masonry Units
Methods of Sampling and Testing Concrete Masonry Units
Solid Load Bearing Concrete Masonry Units
Page I
E
ASTM C-150-89
ASTM C-595-89
ASTM D-698
ASTM D-1557
ASTM D-422
ASTM D-4318
ASTM D-4595
ASTM D-4632
ASTM D-52
ASTM G-57-78
ASTM G-51-77
Specification for Portland Cement
Specification for Blended Hydraulic Cements
Moisture Density Relationship for Soils, Standard Method
Modified Proctor Density
Gradation Analysis
Atterberg Limits
Tensile Properties of Geotextiles by the Wide-Width Strip Method.
Tensile Properties of Geotextiles
Tensile Creep Testing of Geosyntheties
Resistivity
NCM A
Deqign Manual for R ~egmental Retaining Walk
NCMA TEK 50 A
NCMA SRWU-1
NCMA SRWU-2
Specifications for Segmental Retaining Wall Units
De~rmination of Connection Strength between Geosynthetics and Segmental
Concrete Units
Determination of Shear Strength between Segmental Concrete Units
A geotechnical report by Alpha Testing Inc. dated November 21, 2000 was provided for this project. All soil
properties used herein were correlated from the soil properties shown in the gentechnical report. The Testing
Agency of Record should verify all soil properties and the wall designer notified of any differences in the soil
properties.
Retaining wall profiles shown are based on the site Grading Plan by Nathan D. Maier Consulting Engineers,
Inc. shown on Sheet 5 of 7 of the project plans dated December 5, 2000. Any changes in the site conditions
observed in the field or wall layout must be reported to the wall designer.
1.04
A. Contractor shall submit a manufacturer's certification prior to start of work stating the SRW units meet the
requirements of this specification.
1.05 I~lJvery.: Rtor~e and l-landlin~o~
A. Contractor shall check the materials upon delivery to assure the specified type, grade, color and texture of
SRW units have been received.
B. Contractor shall prevent excessive mud, wet concrete, epoxies, and like materials, which may affix themselves,
from coming in contact with the materials.
C. Contractor shall protect the materials bom damage. Damaged material shall not be incorporated into the
reinforced soil wall.
Page 2
The designs submitted are based on soil parameters, foundation conditions and loadings stated in
documentation as outlined in Appendix D. The wall designer is not responsible for the accuracy of
information provided by others or information not verified, as specified herein.
B. The wall designer assumes no liability for the soil borings and accuracy of subsurface conditions, and
subsurface groundwater conditions made by others.
C. The Geotechnical Eng/neer of Record shall be responsible for interpretation of subsurface conditions and
accuracy of soft design parameters.
The Geotechnical Engineer of Record shall provide recommendation for allowable bearing capacity for
retaining walls, using allowable differential settlements limited to angular distortions of less than 1/100 and
shall provide recommendations for any subsoil improvements requ'ued. Foundation area of segmental
retaining walls shall be taken to extend fi.om a minimum of 12.0 inches fi.om the fi-om face of the block to the
horizontal extent of the reinforcement.
E. The Contractor shah be responsible for complying with all federal, state and local requirements for execution
of the work, including local building inspection and current OSHA excavation regulations.
F. Prior to undertaking any grading or excavation of the si~ the General Contractor shall confirm the location of
the retaining walls and all underground features, including utility locations within the area of construction.
G. The General Contractor shah coordinate installation of underground utilities with wall installation.
H. Heavy equipment provid'mg wheel loads in excess of 250-psflive load shall not be operated within 10.0 feet of
the face of the retaining walls during constmction.
PART "2": MATERIAL~
2.01 Definifi~n~:
A. Soil Reinforcement - a Mirafi 3XT structural reinforcement geogrid to function primarily as structural
reinforcement.
B. Segmental Concrete Facing Units - an Anchor Diamond SRW Unit made fi.om Portland Cement, water and
mineral aggregates.
C. Cap Unit - No cap required.
Page 3
Reinforced Backfill - Clayey sand or similar soil with a Plasticity Index between 4 & 15 and less than 50%
passing the No. 200 sieve, friction angle verified to meet the requirements outlined in Section 1.03 of these
specifications, which is within the reinforced soil volume as outline on the plans.
E. Foundation Soil - On-site undisturbed silty clay or similar soil with a friction angle verified by the Testing
Agency of Record to meet the Appendix D requirements.
Retained Soil - compacted or in-situ silty clay or similar soil verified by the Testing Agency of Record to meet
the requirements outlined in Appendix D of these specifications behind the reinforced zone of the retaining
wall.
G. Leveling Pad - 6" thick as shown on the profiles of level compacted TXDOT flexible road base crushed stone
or unreinforced lean concrete, upon which the first course of segmental concrete facing units are placed.
2.02 ~eg~mental Retaining Wall
A. SRW units shall be Anchor Diamond Retaining Wall Units as manufactured by a licensed representative.
B. SRW units shall meet the following structural requirements:
All concrete wall units including cap units shall have a minimum net 28-day compressive strength of
3000 psi. The concrete units shall have the required frecze/thaw protection with a maximum absorption
rate of 8 percent.
Cementitions materials used in the manufacture of the units shall be Type I, Type II or Type m
Portland cement in accordance with ASTM C 150.
Other constituents - Air entraining agents, color'mg pigments, integral water repellents, finely grotmd
silica and other constituent shall be previously established as suitable for use in segmental retaining wall
units and shall conform to applicable ASTM Standards or shall be shown by test or experience to be not
detrimental to the durability of the segmental concrete facing units or to any material used in masonry
conslructio~
Exterior molding d'nnensions of units may vary in accordance with ASTM C 90-85. SRW concrete
facing unit molding dimensions shall not differ more than 4-1/8 inch from the manufacturer's published
dimensions, or more than ±1/16 inch in height fxom to back of unit.
SRW units shall provide a minimum unit weight equivalent to I00 psf of wall face area. Fill placed
within the dimensions of the units may be considered at 80 percent of its effective unit weight.
Page 4
Finish and Appearance
1. All units shall be sound and free of cracks or other defects that would interfere with the proper placing
of the unit or significantly impair the strength or permanence of the construction.
2. Color of units shall be per Owner's selection.
D. Sampling and Testing
Compressive strength test specimens shall conform to the saw-cut coupon provisions of Section 5.2.4 of
ASTM C 140-90 with the following exception:
a. Coupon shall have a minimum thickness of 1-1/2 inches.
b. Coupon shall be not be oven dried before compressive testing.
2.03 Ra~e l ~velinE Pad Material and I Init Fill far RIc~k:
Base Leveling Pad Material: Base leveling pad material shall be TXDOT road base crushed stone or
unreinforced lean concrete a minimum of 6.0 inches in thickness as shown on the profiles, constructed to the
dimensions shown on the construction drawings.
2.04 Reinfnreed Wall Raeldill:
Reinforced wall backfill shall be clayey sand select fill or similar soil Plasticity Index between 4 & 15 and less
than 50% passing the No. 200 sieve, meeting the requirements outlined in Appendix D as verified by the
Testing Agency of Record.
B. Wall backfill material reinforced with geogrid shall have a pH in the range of 3 to 10 as determined in
accordance with ASTM G-51-77.
Do not mn mechanical vibrating plate compactors on top of the units. Compact fill between units and the 3.0-
foot zone behind the units by rurming hand-operated vibratory plate compaction equipment just behind units.
Compact with a minimum of two passes of the compactor with a lift thickness no greater than 8.0 inches.
D. The reinforced backfill shall be placed in maximum 8.0-inch thick compacted li~. Compact each lift to a
minimum of 95% Standard compaction (ASTM D698).
E. The Contractor shall furnish a Certificate of Comphance certifying the reinforced backfill materials comply
with this section of the specifications.
Page 5
-- 2.0~ R~ined l~eldill nr Cnmmn l~kflll:
A. Soil placed behind the reinforced backfill shall be as directed by the project specifications.
B. Retained backfill shall be compacted to the minimum compaction specified in the project plans and
specifications.
PART "3": EX'ECI1TION
3.01 Exeavafian_'
Contractor shall excavate reasonably close to the lines and grades shown on the project grading plans.
Contractor shall take precautions to minimize over-excavation. Over-excavation shall be filled with approved
compacted select silty clay soil.
B. The zone beneath the reinforced zone on all walls shall be excavated to the depths shown to install the leveling
pad.
C. The Engineer of Record shall inspect the excavations and approve prior to placement of leveling pad material.
D. Excavation of unsuitable soils and replacement with approved compacted material shall be performed as
directed by the Geotechnical Engineer of Record.
E. Over-excavated areas in fi'ont of wall face shall be filled with approved compacted select fill soil material as
before the wall is built to over 4.0 feet in height.
F. Contractor shall verify location of existing structures and utilities prior to excavation. Contractor shall ensure
all surrounding structures are protected fi.om the effects of wall excavation.
G. General Contractor shall coordinate installation of the new utilities and improvements to existing utilities with
wall installation.
3.02 l,evelinE Pad C?nnatr~w~inn:
Leveling pad shall be placed as shown on the construction drawings with a minimum thickness of 6.0 inches.
The leveling pad should extend laterally a minimum distance of 6.0 inches in fi.ont of the lower most SRW
Unit and at least 6.0 inches behind the lower most SRW Unit.
Foundation soil shall be proof rolled, where applicable, and the top 12.0 inches compacted to minimum 95%
Standard Proctor maximum dry density (ASTM D 698) and tested prior to placement of leveling pad
materials.
Leveling pad material shall be placed in maximum 6.0-inch thick compacted lif~s and compacted to a minimum
of 95% Standard compaction (ASTM D698). The leveling pad shall provide a level hard surface on which to
place the first course of units. Screenings may be used to smooth the top 1.0-inch to ¼ inch of the leveling
pad. Screenings shall meet the following gradation:
P~e6
,~e~ ,~7~ P~rc~nt P~n~
3/8 inch 100
No. 4 90 - I00
No. 10 50 - 70
No. 20 30 - 40
No. 40 20 - 30
No. 80 10 ~ 20
No. 200 <10
3.03 ~RW llnit ln~tsllafinn:
A. First course of SRW units shall be placed on the leveling pad. The units shall be first leveled side-to-side,
front-to-rear and aligned with adjacent units. The first course is the most important to ensure accurate and
acceptable results.
B. Insure units are in full contact with base.
C. Place the front of the units side-by-side. Do not leave gaps between the front of adjacent units. Alignment
may be done by means of a string line or offset fi'om base line to the back of the units. Layout of curves and
comers shall be in accordance with SRW manufacturer's installation guidelines.
D. Install block and connections per SRW manufacturer's recommendations
E. Place and compact unit core fill and drainage fill inside and behind units. Place and compact reinforced soil
behind the drainage fill.
F. Clean all excess debris from top of units.
G. Repeat procedures to the extent of wall he/ght, placing no more than two block courses without backfilling
behind the wall.
3.04 Tap gllaelt
A. Place SRW units per manufacturer's recommendations. Backfill and compact to finished grade.
B. Permanent mechanical connection of top of wall units to Wall Units shall be provided by construction
adhesive. Apply adhesive to bottom surface oftop unit and install on Units below.
END OF SECTION "A"
Page 7
SECTION "B": GEOSYNTHETIC SOIL REINFORCEMENT
PART "1": GF, NF~R AI ~
1.01 lh~eri.ntinn:
A. Work included furnishing and installing gcogrid soil reinforcement and filter fabric to thc lines and grades
designated on the plans.
1.02 Certification:
A. Contractor shall submit a manufacturer's certification stating the geosynthetic soil reinforcement geogrid meets
the requirements of this specification.
1.03 l~elivery: gtnraEe and glandlinE:
A~ Contractor shah check the geogrid soil reinforcement and falter fabric upon delivery to assure the proper grade
and type of material has been received. A product certification shah be provided with each shipment.
B. Rolled material shah be stored in accordance with manufacturer's recommendations.
PART "2": MATERIAI,g
2.01 l~efinifinng_'
A. Geogrid soil reinforcement shall be Mirafi 3XT geogrid
2.02 C~n~N~yn, thefie gnil Reinfnreement l~'~.n~rti~_'
A. The geogrid soil reinforcement shall possess the minimum strength and durability required by the design as
determined by product specific testing as defined in the NCMA Design Manual for Segmental Retaining Walls
(Section 3.5).
PART "3": I~,X'F~CITTION
3.01 Gen?i~ 'd g~il ReJnfnreenu~nl' ln~t~lhfinn_'
A. Reinforcement geogrid shall be oriented with the roll direction perpendicular to the wall ~ace.
B. The soil reinforcement geogrid shall be installed at the wall height, horizontal location, and to the extent as
shown on the project construction plans.
C. The soil reinforcement geogrid shall be lain horizontally on compacted backfill. The geogrid shall be pulled
taut and connected to the concrete SRW units prior to backfill placement on the geogrid.
Page 8
Soil reinforcement geogrid shall be continuous throughout their embedment lengths. Spliced connections
between shorter pieces ofgeogrid shall not be allowed unless shown on the construction plans.
Tracked construction equipment shall not be operated directly upon the soil reinforcement geogrid. A
minimum fill thickness of 6.0 inches is required prior to operation of tracked equipment over the geogrid.
Tracked vehicle turning should be kept to a minimum to prevem tracks fi.om displacing the fill and damaging
the geogrid.
Rubber tired equipment may pass over the geogrid at low speeds, less than 6 mph. Sudden braking and sharp
turning shall be avoided.
Any changes to geogrid layout, including, but not limited to, length, geogrid type, or elevation, shall be made
subject to approval of the wall designer.
Correct orientation (Roll direction) of the geogrid soil reinforcement shall be verified by the Contractor. All
geogrid must be installed perlx~dicular to the wall face.
Place segmental unit and fill in accordance with Section 3.03 - SRW Unit Installation.
3.02 1Reinforced llaelrfill Pla~n~nt~
A. Reinforced backfill shall be placed, spread and compacted in such a manner that does not develop slack in the
reinforcement geogrid.
B. Reinforced backfill shall be placed and compacted in compacted lifts not to exceed 8.0 inches.
C. Reinforced backfill shall be placed in maximum 8.0-inch thick compacted lifts and compacted to a minimum
of 95% Standard compaction (ASTM D698) with each llt~ tested to verify the compaction.
D. Reinforced backfill shall be compacted in all areas to the lines and grades shown on the plans including all
sloped areas above wails.
E. Only lightweight hand-operated compaction equipment shall be allowed within 3.0 feet of the face of the wall.
At the end of each day's operation, the Contractor shall slope the last lift of reinforced backfill away t~om the
wall facing to rapidly direct runoff away fi.om the wall face. In addition, the Contractor shall not allow surface
runoff fi.om adjacent areas to enter the wall construction site.
END OF SECTION "B"
Page 9
SECTION "C": WALL DRAINAGE
PART "1": GENI~,R Al ~
1.01 mscaaOt m
Retaining wall system shall be provided with positive draimge. Work shall include providing and installing all
drainage materials including drainage aggregate to the lines and grades designated on the project construction plans.
1.02 Reference ~tandardn:
A. ASTM D 3034 - Specification for Polyvinyl Chloride (PVC) Plastic Pipe
B. AASHTO T-27 - Test Method for Gradation Limits Fine Filter Material
C. ASTM D 1248 - Specification for Corrugated Plastic Pipe
D. Where specification and reference documents conflict, the specifications shall govern the final determination of
applicable document.
1.03 C~ertifit~afinn -'
A. Contractor shall submit a manufacturer's certification slating the drainage materials meet the requ'~rements of
this specification.
1.04 Delivery.: g~ora~oe and Handling_'
A. Plastic Pipe shall be stored in accordance with the manufacturer's recommendations to prevent damage and
deleterious materials from becoming affixed.
B. Drainage aggregate shall be stored to prevent contamination with other materials.
PART "2": MATI?,RIALq
2.01 Defln/tlnng-·
A. Drainage collection pipe shall be 4" perforated/slotted PVC or corrugated/kBS pipe wrapped in filter fabric.
Page 10
B. Drainage pipe shall be manufactured in accordance with ASTM D 3034 and/or ASTM D 1248.
C. All filter fabric must be Mirafi 140N non-woven filter fabric.
PART "3": I~,~F, CI rl'lON
3.01 I)r~inag~ Cnlle~tion
A. lnstall the drainage collection pipe according to the line, grades and sections shown on the wall construction
plans.
B. Install the drainage collection pipe to maintain gravity flow of water fi.om the reinforced soil zone. Daylight
the pipe through the wall a minimum of every 40.0 fe~t along the wall face and at each wall end.
C. The main collection drain pipe just behind the segmental units shall be a minimum 4.0 inches in diameter.
3.02 Drainage Ao,~or~nte:
A. Install the drainage aggregate to the line, grades, and sections shown on the project construction plans.
END OF SECTION "C"
Page 11
APPENDIX "D": DESIGN CRITERIA FOR RETAINING WALL SYSTEM
A. Design &the retaining wall system is based on the following soil parameters:
Friction An~le Coh~ion Unit We~ht
Reinforced Zone Backfill
Retained Backfill
26° 0 PSF 120 PCF
22° 75 PSF* 115 PCF
Foundation 22° 75 PSF* 115 PCF
*Used in global stability only.
lntemal Stability of Walls:
Minimum Factor of Safety on Tensile Overstress .......................................................
Minimm Factor of Safety on Geogrid Pullout
(peak load criterion) ....................................................................................................
Minimum Factor of Safety on Geogrid Pullout
(serviceability criterion) ...............................................................................................
Minimum Factor of Safety on Facing Shear
(peak load criterion) ....................................................................................................
Minimum Factor of Safety on Facing Shear
(servieaability criterion) ...............................................................................................
Minimum Factor of Safety Connections (peak load criterion) .....................................
Minimm Factor of Safety Connections (serviceability criterion) ...............................
Minimum Factor of Safety for Uncertainties ...............................................................
External Stability:
Minimum Factor of Safety Against Base Sliding .......................................................
Minimum Factor of Safety Against Overmming .........................................................
Minimum Factor of Safety for Global Stability .........................................................
Minimum Factor of Safety for Bearing Capacity ........................................................
Maximum Wall Bearing Pressure ...............................................................................
Wall Batter shall be 1.125-inch horizontal offset per course.
Wall Embedment ........................................................................................................
Maximum Live Load at Least 2.0 Feet Behind Wall ..................................................
1.0
1.5
1.0
1.5
1.0
1.5
1.0
1.5
1.5
2.0
1.3-1.5
2.0
800 PSF
1.0 Feet
150 PSF
Page 12
GLOBAL STABILITY CALCULATIONS
GLOBAL STABILITY
The global stability (slope stability) of the mechanically stabilized earth wall with masonry units
was evaluated at the tallest wall condition. The wall height of 5.5 feet (exposed height of 4.5 feet)
with a maximum 2.5(H):1 (V) slope in front of the wall and level slope behind the wall was used in
the analysis. A minimum 2.0-foot wide level pad must be installed directly in front of the wall. A
maximum 150 PSF live load for light duty car parking was considered at least 2.0 feet behind the
wall. The global stability was evaluated in a static condition with the groundwater assumed to be
well below the bottom of the wall (greater than 6.0 feet). The same soil properties used in the wall
geogrid design were used in the global stability analysis, except that a small cohesion value of 75
PSF was used for the undisturbed retained and foundation sandy clay soils.
The global stability analysis was conducted using the GSlope, version 4.1 software promulgated by
the Mitre Software Corporation. The Modified Bishop Method of slices with no seismic loading
was utilized. The resulting least factor of safety for static global slope stability was 1.4I, which is
greater than generally considered acceptable minimum value of 1.3 to 1.5 for the long-term slope
stability of the walls.
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