DELETE ALL DESIGNER NOTES FROM YOUR SPECIAL PROVISIONS
Wall Modular Block Mechanically Stabilized Earth (structure), Item
SPV.0165.XX
A Description
This special provision describes designing, furnishing materials and erecting a permanent
earth retention system in accordance to the lines, dimension, elevations and details as
shown on the plans and provided in the contract. The design life of the wall and all wall
components shall be 75 years minimum.
This special provision describes the quality management program (QMP) for
Mechanically Stabilized Earth (MSE) walls. A quality management program is defined as
all activities, including process control, inspection, sampling and testing, and necessary
adjustments in the process that are related to the construction of the MSE wall, which
meets all the requirements of this provision.
This special provision describes contractor quality control (QC) sampling and testing for
backfill density testing, documenting those results, and documenting related production
and placement process changes. This special provision also describes department quality
verification (QV), independent assurance (IA), and dispute resolution.
Chapter 8 of the department’s construction and materials manual (CMM) provides
additional detailed guidance for QMP work and describes sampling and testing
procedures.
B Materials
B.1 Proprietary Wall Systems
The supplied wall system must be from the department’s approved list of Modular Block
Mechanically Stabilized Earth Wall systems. Proprietary wall systems must conform to
the requirements of this specification and be pre-approved for use by the department’s
Bureau of Structures. The department maintains a list of pre-approved proprietary wall
systems. The name of the pre-approved proprietary wall system selected shall be
furnished to the engineer within 25 days after the award of contract. The location of the
plant manufacturing the facing units shall be furnished to the engineer at least 14 days
prior to the project delivery.
To be eligible for use on this project, a system must have been pre-approved by the
Bureau of Structures and added to that list prior to the bid closing date. To receive pre-
approval, the retaining wall system must comply with all pertinent requirements of this
provision and be prepared in accordance to the requirements of Chapter 14 of the
department’s LRFD Bridge Manual. Information and assistance with the pre-approval
process can be obtained by contacting the Bureau of Structures, Structures Maintenance
Section at the following email address: DOTDLStructuresFabrication@dot.wi.gov.
B.2 Design Requirements
It is the responsibility of the Contractor to submit a design and supporting documentation
as required by this special provision, for review and acceptance by the department, to
show the proposed wall design is in compliance with the design specifications. The
submittal shall include the following items for review: detailed plans and shop drawings,
complete design calculations, explanatory notes, supporting materials, and specifications.
The detailed plans and shop drawings shall include all details, dimensions, quantities and
cross-sections necessary to construct the walls. Submit shop drawings to the engineer
conforming to 105.2 with electronic submittal to the fabrication library under 105.2.2.
Certify that shop drawings conform to quality control standards by submitting department
form DT2329 with each set of shop drawings. Department review does not relieve the
contractor from responsibility for errors or omissions on shop drawings. Submit no later
than 60 days from the date of notification to proceed with the project and a minimum of
30 days prior to the date proposed to begin wall construction.
The plans and shop drawings shall be prepared on reproducible sheets 11 inch x 17 inch,
including borders. Each sheet shall have a title block in the lower right corner. The title
block shall include the WisDOT project identification number and structure number.
Design calculations and notes shall be on 8 ½ inch x 11 inch sheets, and shall contain the
project identification number, name or designation of the wall, date of preparation,
initials of designer and checker, and page number at the top of the page. All plans, shop
drawings, and calculations shall be signed, sealed and dated by a professional engineer
licensed in the State of Wisconsin.
The design of the wall shall be in compliance with the current American Association of
State Highway and Transportation Officials LRFD (AASHTO LRFD) Bridge Design
Specifications with latest interim specifications for Mechanically Stabilized Earth Walls,
WisDOT’s current Standard Specifications for Highway and Structure Construction
(standard spec), Chapter 14 of the WisDOT LRFD Bridge Manual and standard
engineering design procedures as determined by the Department. Loads, load
combinations, load and resistance factors shall be as specified in AASHTO LRFD
Section 11. The associated resistance factors shall be defined in accordance with Table
11.5.7-1 in AASHTO LRFD.
Design and construct the walls in accordance to the lines, grades, heights and dimensions
shown on the plans, as herein specified, and as directed by the engineer.
Walls parallel to supporting highway traffic shall be designed for the effects of highway
surcharge loading equivalent of 2 feet soil surcharge weight or 240 psf. The design shall
also consider the traffic barrier impact where applicable. Walls that do not carry highway
traffic shall be designed for a live load surcharge of 100 psf in accordance with Chapter
14 of the WisDOT LRFD Bridge Manual or as stated on the plans.
A maximum value of the angle of internal friction of the wall backfill material used for
design shall be assumed to be 30 degrees without a certified report of tests. If a certified
report of tests yields an angle of internal friction greater than 30 degrees, the larger test
value may be used for design, up to a maximum value of 36 degrees.
An external stability check at critical wall stations showing Capacity Demand Ratio
(CDR) for sliding, eccentricity, and bearing checks is provided by the department and are
provided on the wall plans.
The design of the wall by the Contractor shall consider the internal and compound
stability of the wall mass in accordance with AASHTO LRFD 11.10.6. The internal
stability shall include soil reinforcement pullout, soil reinforcement rupture, and wall
facing-reinforcement connection failure at each soil reinforcement level. The design shall
be performed using the Simplified Method or Coherent Gravity Method. Calculations for
factored stresses and resistances shall be based upon assumed conditions at the end of the
design life. Compound stability shall be computed for the applicable strength limits.
Sample analyses and hand calculations shall be submitted to verify the output of any
software used. The design calculations and notes shall clearly indicate the Capacity to
Demand Ratios (CDR) for all internal and external stabilities as defined in AASHTO
LRFD.
Wall facing units shall be designed in accordance with AASHTO LRFD 11.10.2.3.
The minimum length of soil reinforcement measured from the back face of the wall shall
be equal to 0.7 of the wall height, or as shown on the plan. In no case shall this length be
less than 6.0 feet. The soil reinforcement length shall be the same from the bottom to the
top of the wall. All soil reinforcement layers shall be connected to facings. The soil
reinforcement shall extend a minimum of 3.0 feet beyond the theoretical failure plane in
all cases. The maximum vertical spacing of soil reinforcement layers shall be two times
the block width (front face to back face) or 32 inches, whichever is less. The first
(bottom) layer of reinforcement shall be placed no further than 12 inches above the top of
the leveling pad or the height of the block, but at least one block height above the
leveling pad. The last (top) layer of soil reinforcement shall be no further than 21 inches
below the top of the uppermost block.
All soil reinforcement required for the reinforced soil zone shall be connected to the wall
facing.
Soil reinforcement shall be fabricated or designed to avoid piling, drainage structures or
other obstacles in the fill without field modifications. Unless approved by the Bureau of
Structures cutting or altering of the basic structural section of either the strip or grid at the
site is prohibited, a minimum clearance of 3” shall be maintained between any
obstruction and reinforcement, and splicing reinforcement is not allowed.
The minimum embedment of the wall shall be 1 foot 6 inches below finished grade, or as
given on the plans. All walls shall be provided with a concrete leveling pad. Minimum
wall embedment does not include the leveling pad depth. Step the leveling pad to follow
the general slope of the ground line. Frost depth shall not be considered in designing the
wall for depth of leveling pad.
Wall facing units shall be installed on a concrete leveling pad. The bottom row of blocks
shall be horizontal and 100% of the block surface shall bear on the leveling pad.
Concrete leveling pads shall be as wide as the proposed blocks plus six inches, with six
inches of the leveling pad extending beyond the front face of the blocks. The minimum
thickness of the leveling pad shall be 6-inches.
B.3 Wall System Components
Materials furnished for wall system components under this contract shall conform to the
requirements of this specification. All documentation related to material and components
of the wall systems specified in this subsection shall be submitted to the engineer.
B.3.1 Wall Facing
Wall facing units shall consist of precast modular concrete blocks. Furnish concrete
produced by a dry-cast or wet-cast process. Concrete for all blocks shall not contain less
than 565 pounds of cementitious materials per cubic yard. The contractor may use cement
conforming to standard spec. 501.2.1 or may substitute for portland cement at the time of
batching conforming to standard spec. 501.2.6 for fly, 501.2.7 for slag, or 501.2.8 for
other pozzolans. In either case the maximum total supplementary cementitious content is
limited to 30% of the total cementitious content by weight.
Dry-cast concrete blocks shall be manufactured in accordance with ASTM C1372 and
this specification.
All units shall incorporate a mechanism or devices that develop a mechanical connection
between vertical block layers. Units that are broken, have cracks wider than 0.02” and
longer than 25% of the nominal height of the unit, chips larger than 1”, have excessive
efflorescence, or are otherwise deemed unacceptable by the engineer, shall not be used
within the wall. A single block front face style shall be used throughout each wall. The
color and surface texture of the block shall be as given on the plan.
The top course of facing units shall be as noted on the plans, either;
Solid precast concrete unit designed to be compatible with the remainder of the
wall. The finishing course shall be bonded to the underlying facing units with a
durable, high strength, flexible adhesive compound compatible with the block
material.
A formed cast-in-place concrete cap. A cap of this type shall have texture, color,
and appearance, as noted on the plans. The vertical dimension of the cap shall not
be less than 3 1/2 inches. Expansion joints shall be placed in the cap at a
maximum spacing of 20 feet unless noted otherwise on the plan. Use Grade A, A-
FA, A-S, A-T, A-IS, A-IP or A-IT concrete conforming to standard spec 501 as
modified in standard spec 716. Provide QMP for cast in place cap and coping
concrete as specified in standard spec 716, Class II Concrete.
Block dimensions may vary no more than ±1/8 inch from the standard values published
by the manufacturer. Blocks must have a minimum width (front face to back face) of 8
inches. The minimum front face thickness of blocks shall be 4 inches measured
perpendicular from the front face to inside voids greater than 4 square inches. The
minimum allowed thickness of any other portions of the block is 1¾ inches. The front
face of the blocks shall conform to plan requirements for color, texture, or patterns.
If pins are used to align modular block facing units, they shall consist of a non-degrading
polymer, or hot dipping galvanized steel and be made for the express use with the
modular block units supplied, to develop mechanical interlock between facing unit block
layers. Connecting pins shall be capable of holding the wall in the proper position during
backfilling. Furnish documentation that establishes and substantiates the design life of
such devices.
For concrete leveling pad, use Grade A, A-FA, A-S, A-T, A-IS, A-IP, or A-IT concrete
conforming to standard spec 501 as modified in standard spec 716. Provide QMP for
leveling pad concrete as specified in standard spec 716, Class III Concrete.
B.3.2 Material Testing
Provide independent quality verification testing of project materials according to the
following requirements:
Requirement
Test Method
Dry-cast Wet-cast
Compressive Strength (psi) ASTM C140 5000 min. 4000 min.
Air Content (%) AASHTO T152 N/A 6.0 +/-1.5
[3]
Water Absorption (%) ASTM C140 6 max. N/A
Freeze-Thaw Loss (%)
1.0 max.[2][3]
40 cycles, 5 of 5 samples ASTM C1262[1] N/A
1.5 max.[2][3]
50 cycles, 4 of 5 samples
[1] Test shall be run using a 3% saline solution and blocks greater than 45 days old.
[2] Test results that meet either of the listed requirements for Freeze-Thaw Loss are acceptable.
[3] The independent testing laboratory shall control and conduct all sampling and testing. Prior to
sampling, the manufacturer’s representative shall identify materials by lot. Five blocks per lot shall be
randomly selected for testing. Solid blocks used as a finishing or top course shall not be selected. The
selected blocks shall remain under the control of the person who conducted the sampling until shipped
or delivered to the testing laboratory. All pallets of blocks within a lot shall be strapped or wrapped to
secure the contents and tagged or marked for identification. The engineer will reject any pallet of
blocks delivered to the project without intact security measures. At no expense to the department, the
contractor shall remove all rejected blocks from the project. If a random sample of five blocks of any
lot tested by the department fails to meet any of the above testing requirements, the entire lot will be
considered non-conforming.
The contractor and fabricator shall coordinate with the independent testing agency to
ensure that strength and air content samples can be taken appropriately during
manufacturing. At the time of delivery of materials, furnish the engineer a certified report
of test from an AASHTO-registered or ASTM-accredited independent testing laboratory
for each lot.
The certified test report shall include the following:
Project ID
Production process used (dry-cast or wet-cast)
Name and location of testing facility
Name of sampling technician
Lot number and lot size
Testing of project materials shall be completed not more than 18 months prior to delivery.
Independent testing frequency shall not exceed 5000 blocks for dry-cast blocks and the
lesser of 150 CY or 1 day’s production for wet-cast blocks. The certified test results will
represent all blocks within the lot. Each pallet of blocks delivered shall bear lot
identification information. Block lots that do not meet the requirements of this
specification or blocks without supporting certified test reports will be rejected and shall
be removed from the project at no expense to the department.
Nonconforming materials will be subject to evaluation according to standard spec 106.5.
B.3.3 Backfill
Furnish and place backfill for the wall as shown on the plans and as hereinafter provided.
Wall Backfill, Type A, shall comply with the requirements for Coarse Aggregate No. 1 as
given in standard spec 501.2.5.4.4. All backfill placed within a zone from the top of the
leveling pad to the top of the final layer of wall facing units and within 1 foot behind the
back face of the wall shall be Wall Backfill, Type A. This includes all material used to fill
openings in the wall facing units.
Wall Backfill, Type B, shall be placed in a zone extending horizontally from 1 foot
behind the back face of the wall to 1 foot beyond the end of the reinforcement and
extending vertically from the top of the leveling pad to a minimum of 3 inches above the
final reinforcement layer.
Use natural sand or a mixture of sand with gravel, crushed gravel or crushed stone. Do
not use foundry sand, bottom ash, blast furnace slag, crushed/recycled concrete,
crushed/milled asphaltic concrete or other potentially corrosive material.
Provide material conforming to the following gradation requirements as per AASHTO
T27.
% by Weight
Sieve Size
Passing
1 inch 100
No. 40 0 - 60
No. 200 0 - 15
The material shall have a liquid limit not greater than 25, as per AASHTO T89, and a
plasticity index not greater than 6, as per AASHTO T90. Provide the percent by weight,
passing the #4 sieve.
In addition, backfill material Type A and Type B shall meet the following requirements.
Test Method Value
pH AASHTO T-289 4.5-9.0
Sulfate content [1] AASHTO T-290 200 ppm max.
Chloride content [1] AASHTO T-291 100 ppm max.
Electrical Resistivity AASHTO T-288 3000 ohm-cm min.
Organic Content [1] AASHTO T-267 1.0% max.
30 degrees min. (At 95.0% of
Angle of Internal maximum density and optimum
AASHTO T-236[2]
Friction moisture, per AASHTO T99, or as
modified by C.2)
[1] Requirement does not apply to walls with non-metallic reinforcement.
[2] If the amount of P-4 material is greater than 60%, use AASHTO 236 with a standard-size shear box.
Test results of this method may allow the use of larger angles of internal friction, up to the maximum
allowed by this specification.
If the amount of P-4 material is less than or equal to 60%, two options are available to determine the
angle of internal friction. The first method is to perform a fractured faces count, per ASTM D5821,
on the R-4 material. If more than 90% of the material is fractured on one face and more than 50% is
fractured on two faces, the material meets the specifications and the angle of internal friction can be
assumed to be 30 degrees. The second method allows testing all P-1” material, as per AASHTO T-
236, with a large shear box. Test results of this second method may allow the use of larger angles of
internal friction, up to the maximum allowed by this specification.
Prior to placement of the backfill, obtain and furnish to the engineer a certified report of
test results that the backfill material complies with the requirements of this specification.
Specify the method used to determine the angle of internal friction. This certified report
of test shall be less than 6 months old. Tests will be performed by a certified independent
laboratory. In addition, when backfill characteristics and/or sources change, provide a
certified report of tests for the new backfill material. Additional certified report of tests
are also required. These additional backfill tests may be completed at the time of
material production or material placement, with concurrence of the engineer. If this
additional testing is completed at the time of material production, complete testing for
every 2000 cubic yards of backfill or portion thereof. If this additional testing is
completed at the time of material placement, complete testing for every 2000 cubic yards
of backfill, or portion thereof, used per wall. For the additional required testing for every
2000 cubic yards of backfill placement, if the characteristic of the backfill and/or the
source has not changed then Angle of Internal Friction tests are not included in the
additional required testing. All certified reports of test results shall be less than 6 months
old and performed by a certified independent laboratory.
B.3.4 Soil Reinforcement
B.3.4.1 Geogrids
Geogrid supplied as reinforcing members shall be manufactured from long chain
polymers limited to polypropylene, high-density polyethylene, polyaramid, and polyester.
Geogrids shall form a uniform rectangular grid of bonded, formed, or fused polymer
tensile strands crossing with a nominal right angle orientation. The minimum grid
aperture shall be 0.5 inch. The geogrid shall maintain dimension stability during
handling, placing, and installation. The geogrid shall be insect, rodent, mildew, and rot
resistant. The geogrid shall be furnished in a protective wrapping that shall prevent
exposure to ultraviolet radiation and damage from shipping or handling. The geogrid
shall be kept dry until installed. Each roll shall be clearly marked to identify the material
contained.
The wall supplier shall provide the nominal long-term design strength (T al) and nominal
long-term connection strength, Talc as discussed below.
Nominal Long-Term Design Strength (Tal)
The wall supplier shall supply the nominal long-term design strength (Tal) used in the
design for each reinforcement layer and shall be determined by dividing the Ultimate
Tensile Strength (Tult) by the factors RFID, RFCR, RFD.
Hence,
T ult
T al
RF ID x RF CR x RF D
where:
Tult = Ultimate tensile strength of the reinforcement determined from
wide width tensile tests (ASTM D6637) for geogrids based on the
minimum average roll value (MARV) for the product.
RFID = Strength reduction factor to account for installation damage to the
reinforcement. In no case shall RFID be less than 1.1.
RFCR = Strength reduction factor to prevent long-term creep rupture of the
reinforcement. In no case shall RFCR be less than 1.2.
RFD = Strength reduction factor to prevent rupture of the reinforcement
due to chemical and biological degradation. In no case shall RF D
be less than 1.1.
Values for RFID, RFCR, and RFD shall be determined from product specific test results.
Guidelines for determining RFID, RFCR, and RFD from product specific data are provided
in FHWA Publication No. FHWA-NHI-10-024 and FHWA–NHI-10-025 “Design and
Construction of Mechanically Stabilized Earth Walls and Reinforced Soil Slopes”.
Nominal Long-term Connection Strength Tac
The nominal long term connection strength, Tac, shall be based on laboratory geogrid
connection tests between wall facing and geogrids. Tac shall be as given below
T ult *CRcr
T ac
RF D
where:
Tac = Nominal long-term reinforcement facing connection strength per
unit reinforcement width at a specified confining pressure.
Tult = Ultimate tensile strength of the reinforcement for geogrids defined
as the minimum average roll value (MARV) for the product.
CRcr = Long term connection strength reduction factor to account for
reduced ultimate strength resulting from connection.
RFD = Strength reduction factor to prevent rupture of the reinforcement
due to chemical and biological degradation.
Tac shall be developed from the tests conducted by an independent laboratory on the same
facing blocks and geogrids as proposed for the wall and shall cover a range of overburden
pressures comparable to those anticipated in the proposed wall. The connection strength
reduction factor CRcr shall be determined in accordance with long-term connection test as
described in Appendix B of FHWA Publication No. FHWA-NHI 10-025 “Design and
Construction of Mechanically Stabilized Earth Walls and Reinforced Soil Slopes”. CR cr
may also be obtained from the short term connection test meeting the requirements of
NCMA test method SRWU-1 in Simac et al 1993 or ASTM D4884.
The Contractor shall provide a manufacturer’s certificate that the Tult (MARV) of the
supplied geogrid has been determined in accordance with ASTM D4595 or ASTM D6637
as appropriate. Contractor shall also provide block to block and block to reinforcement
connection test reports prepared and certified by an independent laboratory. Also provide
calculations in accordance with AASHTO LRFD, and using the results of laboratory
tests, that the block-geogrid connections shall be capable of resisting 100% of the
maximum tension load in the soil reinforcements at any level within the wall, for the
design life of the wall system.
B.3.4.2 Galvanized Metal Reinforcement
In lieu of polymeric geogrid earth reinforcement, galvanized metal reinforcement may be
used. Design and materials shall be in accordance to AASHTO LRFD 11.10.6.4.2. The
design life of steel soil reinforcements shall also comply with AASHTO LRFD. Steel soil
reinforcement shall be prefabricated into single or multiple elements before galvanizing.
C Construction
C.1 Excavation and Backfill
Excavation and preparation of the foundation for the MSE wall and the leveling pad shall
be in accordance to standard spec 206. The volume of excavation covered is limited to
the width of the reinforced mass and to the depth of the leveling pad unless shown or
noted otherwise on the plan. At the end of each working day, provide good temporary
drainage such that the backfill shall not become contaminated with run-off soil or water if
it should rain. Do not stockpile or store materials or large equipment within 10 feet of the
back of the wall.
Place backfill materials in the areas as indicated on the plans and as detailed in this
specification. Backfill lifts shall be no more than 8-inches in depth, after compaction.
Backfilling shall closely follow erection of each course of wall facing units.
Conduct backfilling operations in such a manner as to prevent damage or misalignment
of the wall facing units, soil reinforcement, or other wall components. At no expense to
the department, correct any such damage or misalignment as directed by the engineer. A
field representative of the wall supplier shall be available during wall construction to
provide technical assistance to the contractor and the engineer.
Place and compact the MSE backfill to the level of the next higher layer of MSE
reinforcement before placing the MSE reinforcement or connecting it to the wall facing.
Place and compact material beyond the reinforced soil zone to allow for proper
compaction of material within the reinforced zone. The MSE reinforcement shall lay
horizontally on top of the most recently placed and compacted layer of MSE backfill.
Do not operate tracked or wheeled equipment on the backfill within 3 feet from the back
face of modular blocks. The engineer may order the removal of any large or heavy
equipment that may cause damage or misalignment of the wall facing units.
C.2 Compaction
Compact wall backfill Type A with at least three passes of lightweight manually operated
compaction equipment acceptable to the engineer.
Compact all backfill Type B as specified in standard spec 207.3.6. Compact the backfill
Type B to 95.0% of maximum dry density as determined by AASHTO T-99 (modified to
compute densities to the nearest 0.1 pcf).
Ensure adequate moisture is present in the backfill during placement and compaction to
prevent segregation and to help achieve compaction.
Compaction of backfill within 3 feet of the back face of the wall should be accomplished
using lightweight compaction devices. Use of heavy compaction equipment or vehicles
should be avoided within 3 feet of the modular blocks. Do not use sheepsfoot or padfoot
rollers within the reinforced soil zone.
A minimum of 6 inches of backfill shall be placed over the MSE reinforcement prior to
working above the reinforcement.
C.3 Wall Components
C.3.1 General
Erect wall facing units and other associated elements according to the wall
manufacturer’s construction guide and to the lines, elevations, batter, and tolerances as
shown on the plans. Center the initial layer of facing units on the leveling pad; then level
them and properly align them. Fill formed voids or openings in the facing units with wall
backfill, Type A. Remove all debris on the top of each layer of facing units, before
placing the next layer of facing units.
Install all pins, rods, clips, or other devices used to develop mechanical interlock between
facing unit layers in accordance with the manufacturer’s directions.
The MSE reinforcement shall lay horizontally on the top of the most recently placed and
compacted layer of MSE backfill. Bending of MSE reinforcement that result in a kink in
the reinforcement shall not be allowed. If skewing of the reinforcement is required due to
obstructions in the reinforced fill, the maximum skew angle shall not exceed 15 degrees
from the normal position unless a greater angle is shown on the plans. The adequacy of
the skewed reinforcement in such a case shall be addressed by supporting calculations.
C.3.2 Soil Reinforcement
C.3.2.1 Geogrid Layers
Place soil reinforcement at the positions and to the lengths as indicated on the accepted
shop drawings. Take care that backfill placement over the positioned soil reinforcement
elements does not cause damage or misalignment of these elements. Correct any such
damage or misalignment as directed by the engineer. Do not operate wheeled or tracked
equipment directly on the soil reinforcement. A minimum cover of 6 inches is required
before such operation is allowed.
Place and anchor geogrid material between wall unit layers in the same manner as used to
determine the Geogrid Block-to-Connection Strength. Place the grid material so that the
machine direction of the grid is perpendicular to the wall face. Each grid layer shall be
continuous throughout the lengths indicated on the plans. Join grid strips with straps,
rings, hooks or other mechanical devices to prevent movement during backfilling
operations. Prior to placing backfill on the grid, pull the grid taunt and hold in position
with pins, stakes or other methods approved by the engineer.
C.3.2.2 Steel Layers
Place the steel reinforcement full width in one piece as shown on the plans. No splicing
will be allowed. Maintain elements in position during backfilling.
C.4 Quality Management Program
C.4.1 Quality Control Plan
Submit a comprehensive written quality control plan to the engineer at or before the pre-
construction meeting. Do not perform MSE wall construction work before the engineer
reviews and accepts the plan. Construct the project as the plan provides.
Do not change the quality control plan without the engineer’s review and acceptance.
Update the plan with changes as they become effective. Provide a current copy of the
plan to the engineer and post in the contractor’s laboratory as changes are adopted.
Ensure that the plan provides the following elements:
1. An organizational chart with names, telephone numbers, current certifications
and/or titles, and roles and responsibilities of QC personnel.
2. The process used to disseminate QC information and corrective action efforts to
the appropriate persons. Include a list of recipients, the communication process
that will be used, and action time frames.
3. A list of source locations, section and quarter descriptions, for all aggregate
materials requiring QC testing.
4. Descriptions of stockpiling and hauling methods.
5. An outline for resolving a process control problem. Include responsible
personnel, required documentation, and appropriate communication steps.
6. Location of the QC laboratory, retained sample storage, and other
documentation.
7. A summary of the locations and calculated quantities to be tested under this
provision.
8. A proposed sequencing plan of wall construction operations and random test
locations.
C.4.2 Quality Control Personnel
Perform the quality control sampling, testing, and documentation required under this
provision using HTCP certified technicians. Have a HTCP Grading Technician I
(GRADINGTEC-I); or Assistant Certified Technician, Grading (ACT-GRADING); or
Aggregate Technician I (AGGTEC-I); or Assistant Certified Technician, Aggregate
(ACT-AGG) present at the each grading site during all wall backfill placement,
compaction, and nuclear testing activities. Have a HTCP Nuclear Density Technician I
(NUCDENSITYTEC-I) or Assistant Certified Technician, Nuclear Density Gauge
Operator (ACT-NUC) perform field density and field moisture content testing.
If an Assistant Certified Technician (ACT) is performing sampling or testing, a certified
technician must coordinate and take responsibility for the work an ACT performs. Have
a certified technician Ensure that all sampling and testing is performed correctly, analyze
test results, and post resulting data. No more than one ACT can work under a single
certified technician.
C.4.3 Equipment
Furnish the necessary equipment and supplies for performing quality control testing.
Ensure that all testing equipment conforms to the equipment specifications applicable to
the required testing methods. The engineer may inspect the measuring and testing devices
to confirm both calibration and condition. Calibrate all testing equipment according to the
CMM and maintain a calibration record at the laboratory.
Furnish nuclear gauges from the department’s approved product list at:
http://wisconsindot.gov/Pages/doing-bus/eng-consultants/cnslt-rsrces/tools/appr-
prod/default.aspx
Ensure that the nuclear gauge manufacturer or an approved calibration service calibrates
the gauge the same calendar year it is used on the project. Retain a copy of the calibration
certificate with the gauge.
Conform to ASTM D6938 and CMM 8-15 for density testing and gauge monitoring
methods. Perform nuclear gauge measurements using gamma radiation in the backscatter
or direct transmission position. Perform each test for 4 minutes of nuclear gauge count
time.
Split each Proctor sample and identify so as to provide comparison with the department's
test results. Unless the engineer directs otherwise, retain the QC split samples for 14
calendar days and promptly deliver the department’s split samples to the department.
C.4.4 Documentation
(1) Document all observations, inspection records, and process adjustments daily. Submit
test results to the department's project materials coordinator on the same day they
become available.
(2) Use forms provided in CMM Chapter 8. Note other information in a permanent field
record and as a part of process control documentation enumerated in the contractor's
quality control plan. Enter QC data and backfill material certified report results into
the applicable materials reporting system (MRS) software within 5 business days
after results are available.
(3) Submit final testing records and other documentation to the engineer electronically
within 10 business days after all contract-required information becomes available.
The engineer may allow submission of scanned copies of hand-written
documentation.
C.4.5 Quality Control (QC) Testing
Perform compaction testing on the backfill. Conform to CMM 8-15 for testing and gauge
monitoring methods. Conduct testing at a minimum frequency of 1 test per 150 cubic
yards of backfill, or major portion thereof in each lift. A minimum of one test for every
lift is required. Deliver documentation of all compaction testing results to the engineer at
the time of testing.
Perform 1 gradation test every 750 cubic yards of fill and one 5-point Proctor test (or as
modified in C.2) every 2,250 cubic yards of fill. Provide the region split samples of both
within 72 hours of sampling, at the region laboratory. Test sites shall be selected using
ASTM Method D3665. Provide Proctor test results to the engineer within 48 hours of
sampling. Provide gradation test results to the engineer within 24 hours of sampling.
C.4.6 Department Testing
C.4.6.1 General
(1) The department will conduct verification testing to validate the quality of the product
and independent assurance testing to evaluate the sampling and testing. The
department will provide the contractor with a listing of names and telephone numbers
of all QV and IA personnel for the project, and provide test results to the contractor
within 2 business days after the department obtains the sample.
C.4.6.2 Quality Verification (QV) Testing
(1) The department will have an HTCP technician, or ACT working under a certified
technician, perform QV sampling and testing. Department verification testing
personnel must meet the same certification level requirements specified in C.4.2 for
contractor testing personnel for each test result being verified. The department will
notify the contractor before sampling so the contractor can observe QV sampling.
(2) The department will conduct QV tests at the minimum frequency of 30% of the
required contractor density, Proctor and gradation tests.
(3) The department will locate density tests and gradation samples randomly, at locations
independent of the contractor’s QC work. The department will split each Proctor and
gradation QV sample, testing half for QV, and retaining the remaining half for 10
business days.
(4) The department will conduct QV Proctor and gradation tests in a separate laboratory
and with separate equipment from the contractor’s QC tests. The department will use
the same methods specified for QC testing.
(5) The department will assess QV results by comparing to the appropriate specification
limits. If QV test results conform to this special provision, the department will take no
further action. If density QV test results are nonconforming, the area shall be
reworked until the density requirements of this special provision are met. If the
gradation test results are nonconforming, standard spec 106.5 will apply. Differing
QC and QV nuclear density values of more than 1.5 pcf will be investigated and
resolved. QV density tests will be based on the appropriate QC Proctor test results,
unless the QV and QC Proctor result difference is greater than 3.0 pcf. Differing QC
and QV Proctor values of more than 3.0 pcf will be investigated and resolved.
C.4.6.3 Independent Assurance (IA)
(1) Independent assurance is unbiased testing the department performs to evaluate the
department’s QV and the contractor’s QC sampling and testing, including personnel
qualifications, procedures, and equipment. The department will perform an IA review
according to the department’s independent assurance program. That review may
include one or more of the following:
1. Split sample testing.
2. Proficiency sample testing.
3. Witnessing sampling and testing.
4. Test equipment calibration checks.
5. Reviewing required worksheets and control charts.
6. Requesting that testing personnel perform additional sampling and testing.
(2) If the department identifies a deficiency, and after further investigation confirms it,
correct that deficiency. If the contractor does not correct or fails to cooperate in
resolving identified deficiencies, the engineer may suspend placement until action is
taken. Resolve disputes as specified in C.4.6.4.
C.4.6.4 Dispute Resolution
(1) The engineer and contractor should make every effort to avoid conflict. If a dispute
between some aspect of the contractor’s and the engineer’s testing program does
occur, seek a solution mutually agreeable to the project personnel. The department
and contractor may review the data, examine data reduction and analysis methods,
evaluate sampling and testing procedures, and perform additional testing. Use ASTM
E178 to evaluate potential statistically outlying data.
(2) Production test results, and results from other process control testing, may be
considered when resolving a dispute.
(3) If the project personnel cannot resolve a dispute, and the dispute affects payment or
could result in incorporating non-conforming product or work, the department will
use third party testing to resolve the dispute. The department’s central office
laboratory, or a mutually agreed on independent testing laboratory, will provide this
testing. The engineer and contractor will abide by the results of the third party tests.
The party in error will pay service charges incurred for testing by an independent
laboratory. The department may use third party test results to evaluate the quality of
questionable materials and determine the appropriate payment. The department may
reject material or otherwise determine the final disposition of nonconforming material
as specified in standard spec 106.5.
C.5 Geotechnical Information
Geotechnical data to be used in the design of the wall is given on the wall plan. After
completing wall excavation of the entire reinforced soil zone, notify the department and
allow the Regional Soils Engineer two working days to review the foundation.
D Measurement
The department will measure Wall Modular Block Mechanically Stabilized Earth by the
square foot acceptably completed. The department will compute the measured quantity
from the theoretical pay limits the contract plans show. The department will make no
allowance for wall area constructed above or below the theoretical pay limits. All work
beyond the theoretical pay limits is incidental to the cost of work. The department will
make no allowance for as-built quantities.
E Payment
The department will pay for accepted measured quantities at the contract unit price under
the following bid item:
ITEM NUMBER DESCRIPTION UNIT
SPV.0165.XX Wall Modular Block Mechanically Stabilized Earth SF
(structure)
Payment is full compensation for supplying a design and shop drawings; preparing the
site, including all necessary excavation and disposal of materials; supplying all necessary
wall components to produce a functional wall system including cap, copings, leveling
pad, and leveling pad steps; constructing the retaining system and providing temporary
drainage; providing backfill, backfilling, compacting,
developing/completing/documenting the quality management program, and performing
compaction testing.
The department will pay separately for parapets, traffic barriers, railings, and other items
above the wall cap or coping.
SPV.0165.XX (20181023)
