627Mechanically Stabilized Embankment Retaining Wall—Contractor Design

Retaining Wall—Contractor Design

627.1General Description

This Specification covers the required materials, design, fabrication, construction, measurement, and payment for Contractor designed Mechanically Stabilized Embankment (MSE) retaining walls. The scope of work of wall erection includes: • Grading for wall construction • Compacting the wall foundation • General and local dewatering as required • Constructing leveling pads • Erecting precast panels • Placing soil reinforcing devices • Placing and compacting special embankment backfill within the reinforced volume • Providing downdrag protection for piles • Furnishing and placing precast or cast-in-place concrete coping and precast or cast-in-place traffic barrier on the top of the wall if these items are shown in the Plans. For patented mechanically stabilized embankment retaining walls, obtain panels, soil reinforcing devices, connecting devices, joint materials, attachments, and expertise to construct the walls. 627.1.01 Definitions Wall foundation—the area underlying the leveling pad and the reinforced volume. 627.1.02 Related References

1059 1059 1059 1059 1059

AASHTO M 243 AASHTO T 22 ASTM A 123/A 123M ASTM A 153/A 153M ASTM A 307 ASTM A 563 ASTM A 709 (ASTM A 709M) ASTM A 1011 (ASTM A 1011M) ASTM A 1064 (ASTM A 1064M) ASTM B 695 ASTM D 2240 ASTM F 436 (ASTM F 436M) ASTM F 3125 (ASTM F 3125M) GDT 7 GDT 24a GDT 24b GDT 35 GDT 75 QPL 9 QPL 28 QPL 58 QPL 107 Standard Operating Procedure 3, Precast/Prestressed Concrete Bridge Members Standard Operating Procedure 33, Certification of Mechanically Stabilized Embankment Retaining Walls. AASHTO LRFD Bridge Design Specifications 627.1.03 Submittals Submit to the Engineer shop drawings and calculations for the wall system, coping, and any special details for review and approval. Submission should be made electronically in a portable document format (pdf) and include an index. Format all drawings to fit 11 in. x 17 in. (279 mm x 432 mm) paper. Present calculations to fit 8.5 in. x 11 in. (216 mm x 297 mm) paper. The submission shall be prepared and stamped by the Design Engineer who shall be registered as a Professional Engineer in the State of Georgia. Include in the submission:

suggested in AASHTO LRFD Bridge Design Specifications are used in design 1060 1060 1060 1060 1060

• Evaluate Pullout • Evaluate Tension in reinforcement and connections • Evaluate Tension in reinforcement and connections due to vehicular collision load

• Evaluate Sliding Stability • Evaluate Eccentricity • Evaluate Bearing Capacity Consider the final construction configuration and loads on the wall when preparing calculations.

See Section 627.3.03.B.4.c for barrier coping design requirements.

Traffic Barriers H and Coping B may be precast, cast in place, or a combination thereof. In all cases the moment slab shall be cast in place. Align the joints through all elements of the Traffic Barrier H or Coping B sections and detail such that there is no reinforcement crossing the joints. Omit joints in the moment slab as required by design. Provide transition details to allow for guardrail connection when necessary.

facing to the backfill reinforcement.

certification process outlined in SOP 33.

drainage elements, noise barriers, traffic structures, etc. Ensure that Plans match GDOT plans in size, format, borders, title block, etc. Include the Project Identification Number (P.I.) in or directly above the title block. Itemize the wall quantities as follows:

Envelope.

Wall Envelope Quantities are required in all cases. The time required for preparation and review of plans and calculations will be charged to the allowable contract time. The final plans and calculations for a wall shall be approved prior to beginning construction on the wall. 1061 1061 1061 1061 1061

The Department will be allowed 45 days to review the plans and calculations and provide either approval or review comments to the contractor. The 45-day review time will begin when the Department has received all of the calculations and drawings concerning the structure. Each new submittal from the Contractor as a result of corrections resulting from the Department's review or changes that are made by the contractor to expedite construction or to correct for field errors will have a 45-day review time. The Department will be the sole judge of the adequacy of the information submitted. The review and acceptance of the final plans and methods of construction by the Department will not in any way relieve the Contractor of responsibility for the successful completion of the work. Contractor delays due to untimely submissions and insufficient information will not be considered as justification for time extensions.

627.2Materials

Ensure that items used to construct the mechanically stabilized embankment retaining walls but not mentioned in this Specification conform to the applicable sections of the Standard Specifications.

Use tie strips shop-fabricated of hot rolled steel that conform to the minimum requirements of ASTM A 1011 Grade 50 (ASTM A 1011M Grade 345). Hot roll reinforcing strips from bars to the required shape and dimensions. Their physical and mechanical properties shall conform to ASTM A 709 Grade 36 (ASTM A 709M Grade 250).

Use soil reinforcing mesh shop-fabricated of cold drawn steel conforming to the minimum requirements of ASTM A 1064/A 1064M.

Use Backfill Stabilizing Geogrid that conforms to the requirements of Section 809.

Use high-strength bolts and nuts that are hexagonal cap screw and that conform to ASTM F3125, grade A325 (F3125M, A325), galvanized. Ensure that they are of the diameter shown in the Plans - 1-1/2 in. (40 mm) long with 3/4 in. (20 mm) thread length. Use galvanized washers with galvanizing fastener elements conforming to ASTM A 153/A 153M.

Use materials that conform to the following standards: Material Conforms to the Requirements of: Steel strap connection bar and plate ASTM A 709 Grade 36 steel (ASTM A 709 Grade 250) Bolts ASTM A 307 (ASTM A 307M) Nuts ASTM A 563 Washers ASTM F 436 (ASTM F 436M) Coatings for connecting devices As specified in the Subsection below

are welded according to ASTM A 1064/A 1064M. Ensure that they develop a stress of at least 0.9 times the steel’s yield strength. Use loops galvanized according to ASTM A 153/A 153M, Class B 3, or ASTM A 123/A 123M.

galvanized according to ASTM A 123/A123M. 1062 1062 1062 1062 1062

inches meeting the same physical and chemical properties as the backfill stabilizing geogrid.

Use Class AA concrete for precast panels, Traffic Barrier H, and Coping B, except ensure that the 28-day strength is at least 4,000 psi (28 MPa). Except as indicated in the approved mix design, admixtures will not be allowed. Do not use admixtures containing chlorides. Use Class A concrete for leveling pads and Coping A.

Ribbed bearing pads shall be made of SBR rubber with a durometer hardness of 80 plus or minus 10 as determined by ASTM D 2240. Elastomeric pads shall be made of 100% virgin chloroprene (neoprene) and meet the requirements of the AASHTO LRFD Bridge Design Specifications, Section 14, Elastomeric Bearings.

In flood plains or other intermittently inundated areas, cover the different joint types as follows: Joint Type Action Joints between panels from an elevation 3 ft. (1 m) above the 100-year flood elevation to the bottom of the wall Cover on the back side of the wall with a woven plastic filter fabric sheet. Joints between panels from 3 ft. (1 m) above the 100-year flood elevation to the top of the wall Cover on the back side of the wall with a woven or nonwoven plastic filter fabric sheet. All other locations Cover joints between panels with a woven or nonwoven plastic filter fabric sheet Use woven and nonwoven plastic filter fabric listed on QPL 28 for work in this Specification, subject to the above requirements. Use adhesive listed on QPL 58 for attaching filter fabric to panels.

Use material in the MSE Wall Backfill volume that conforms to the requirements of Subsection 812.2.04. In addition, obtain approval for use of the material by the Office of Materials and Testing.

Apply coatings to the soil reinforcing devices as follows:

123/A 123M. Or galvanize it mechanically according to ASTM B 695, Class 110, unless otherwise specified on the Plans. Also galvanize the surfaces created by punching holes for bolts.

fabrication, storage, or erection according to Section 645. Repair by brush coating with an approved galvanizing repair compound as specified in Subsection

870.2.05.A.2 to the Engineer’s satisfaction at no increase in Contract cost.

Hot dip galvanize alignment pins. 10631063106310631063

Plans with a two-component coal tar epoxy system indicated in Subsection 535.3.03.D, “Prepare Steel

Piling, Swaybracing, and Concrete Piling Surfaces for Special Protective Coatings,” for a Type 2P coating

according to Subsection 870.2.05.A.1.

strips. Repair damage to the coating on connecting devices or reinforcing devices from shipping, storage,

or erection to the Engineer’s satisfaction at no additional cost.

reinforcing devices.

strips.

reinforcing devices.

erection to the Engineer’s satisfaction at no additional cost.

Use reinforcing steel that conforms to the requirements of Section 511.

Use welded wire fabric that conforms to the requirements of ASTM A 1064.

The Department will use certified test report as specified in Subsection 106.05, Materials Certification and perform

routine tests as a basis for material acceptance furnished for The Work.

For the corrosion inhibiting material, use a bituminous plastic cement material that conforms to the requirements

of Section 848, AASHTO M 243 Trowel Grade Asphalt Mastic, or use an approved corrosion-inhibiting grease.

627.2.01 Delivery, Storage, and Handling

Handle, store, and ship panels to eliminate the danger of chipping, cracking, discoloring, fracturing, and excessive

bending stresses.

Repair at the plant the panels damaged during handling or storage at the casting plant as directed by the Engineer.

Panels damaged during handling, storing, or shipping may be rejected upon delivery at the Engineer’s discretion.

Support panels in storage on firm blocking located immediately adjacent to embedded connecting devices to avoid

bending the connecting devices. Repair the coating on ties or soil-reinforcing devices damaged during handling or

placing to the Engineer’s satisfaction. 10641064106410641064

627.3Construction Requirements

627.3.01 Personnel

Meet the following personnel requirements:

Use a Design Engineer with the following qualifications to design the wall and prepare and submit plans for

approval:

• Is registered as a Professional Engineer in the State of Georgia.

• Has knowledge and experience with the design and construction of MSE walls.

• Is available at any time during the life of the Contract to discuss the design of the walls directly with the

Department.

The Contractor or Subcontractor shall meet the following requirements:

• Be experienced in the construction of Mechanically Stabilized Embankment Walls.

• Include on staff, a supervising engineer for the Project with at least five years of experience in the construction

of Mechanically Stabilized Embankment Walls.

Submit the following proof, whenever requested by the Department, of the ability to design and/or construct

Mechanically Stabilized Embankment Walls.

• Evidence of the successful completion of at least five Projects similar in concept and scope to the proposed

wall.

• Resumes of the supervising engineer and foremen to be employed on this Project showing the type and

number of Mechanically Stabilized Embankment Walls each worked on within the past five (5) years.

The Department will be the sole judge of the acceptability of the qualifications of the design engineer, supervising

engineer and foreman.

627.3.02 Equipment

General Provisions 101 through 150.

627.3.03 Preparation

The Department’s plans will include a Wall Envelope. The Wall Envelope will show:

• The existing and proposed ground line,

• The maximum elevation of the top of the leveling pad

• The proposed top of coping or the proposed gutterline elevations where the barrier is attached to the wall

• The soil parameters for the wall design

• The location of any internal walls required

• The location of other appurtenances including but not limited to:

--Light standards

-- Noise barriers

--Sign supports

• Other obstructions in the wall backfill including but not limited to:

-- Drainage structures and pipes

-- Bridge columns, caps, wingwalls

-- Bridge piles 10651065106510651065

• Details of any proposed ditches at the top of the wall

• Proposed pay quantities

Ensure that the wall design is compatible with all horizontal and vertical criteria and backfill loading conditions.

Verify the wall location according to Subsection 149.1.03.E and Subsection 149.3.03.D before the final wall design

is submitted. Include in the verification:

• The top and bottom of the wall envelope

• Backfill design conditions

• Depth of wall embedment

• Location of drainage structures and other obstructions in the wall backfill

• Other appurtenances located on the wall.

If any changes to the wall envelope are required by the field survey, submit plan sheets to the Engineer for

approval showing the wall envelope as detailed in the plans with the required changes noted.

Use the following design criteria for a Contractor designed wall:

11.10, except as modified by these specifications

including the remainder of walls greater than 100 ft away from a bridge may be designed to a service life

of 75 years.

overhead signs, noise barriers and other appurtenances located on top and adjacent to the wall. Design

MSE walls to account for all external forces. Also, design abutment walls for all horizontal and vertical

loads applied by the bridge. Use the following load definitions as minimums for design:

• Apply a live load surcharge of 0.25 KSF for walls with a pressure surface located within H/2 of a

traffic load

• Apply a live load surcharge of 0.10 KSF for all other walls to account for construction activities

Provide soil reinforcement devices for the back side of abutments supported on piling that is

encased in the MSE backfill. Design these soil reinforcement devices to resist the lateral forces from

the bridge. If the lateral forces are not specifically stated on the retaining wall plans, use a minimum

factored load of 1.0 k/ft along the length of the abutment cap, applied at the bearing seat height.

Include this lateral loading from the bridge in the external stability calculations for the wall.

Traffic Barrier H, Coping B, and walls that include them should be designed for vehicular impact as

follows:

Evaluate precast or cast in place concrete barrier coping for sliding and eccentricity. For this

analysis assume a 15 kip load applied over a width of 5 ft at the top of the barrier and distributed in

to a maximum length equal to the minimum joint spacing in the moment resisting slab. Apply this

same 15 kip load when considering internal and external stability of the reinforced wall mass.

Design the barrier portion of the coping to resist an 80 kip load applied over a width of 5 ft at the top

of the barrier. Evaluate the barrier using the yield line analysis procedures presented in the AASHTO

LRFD Bridge Design Specifications, Section A13.

Detail the moment slab and connecting elements such that all sections will satisfy a design moment equal

to the moment capacity at the base of the barrier about its horizontal axis. For this calculation, take the

base of the barrier as the section at the finished grade on the traffic side of the barrier. 10661066106610661066

to a length equal to the soil reinforcement devices in the adjacent sections.

shoring using sound engineering principles.

whichever is greater.

corrosive protection.

reinforcement.

Ensure that MSE wall backfill extends vertically to the bottom of the approach slab.

Ensure that the MSE wall backfill extends horizontally to the back limit of the MSE backfill for the wall below

the approach slab or 12 inches (300 mm) beyond the end of the stabilizing devices attached to the bridge,

whichever is greater.

Show details of attachments to be cast into the bridge end bent and backwall.

Do not make attachments to bridge endwalls that are integral to the bridge superstructure and are subject to

movement due to superstructure expansion and contraction.

galvanized wire or concrete facing. Ensure as a minimum that the facing of the internal walls extend to the

back limit of the MSE Wall Backfill for the permanent wall.

Department. The information contained in this report may be used by the Contractor to assist in evaluating

existing conditions for design as well as construction. However, the accuracy of the information is not

guaranteed and no requests for additional monies or time extensions will be considered as a result of the

Contractor relying on the information in this report.

The gutterline grade on the proposed top of wall submitted matches the gutter elevations required by the plans.

The top of coping is at or above the top of coping shown on the envelope.

The leveling pad is at or below the elevation shown on the wall envelope.

Any approved changes in Wall Envelope quantities due to the approved survey verification are noted in the

contractor’s plans as Adjusted Wall Envelope Quantities.

All changes in quantities due to the proposed walls being outside the wall envelope (step locations, ending wall at full

panel, etc.) are shown as Material Quantities.

away from the bottom of the wall, lower the bottom of the wall to provide a minimum horizontal distance of 10

ft. (3 m) to the slope. [i.e. a 2:1 slope in front of the wall requires 5 ft. (1.5 m) of embedment; a 4:1 slope in

front of the wall requires 2.5 ft. (750 mm) of embedment]

627.3.04 Fabrication

Have steel soil-reinforcing devices shop fabricated. Use shop fabricated steel mesh of cold drawn steel welded into

the finished mesh fabric according to ASTM A 1064/A 1064M.

Cut soil-reinforcing devices to lengths and tolerances shown on the Plans. Punch holes for bolts in the location shown.

Ensure that soil-reinforcing devices are true to size and free of defects that may impair the strength or durability. 10671067106710671067

Use connecting devices of the dimensions shown on the Plans. Assemble connecting members and soil-reinforcing

devices before galvanizing the connecting devices. Ensure that the connecting devices are true to size and are free of

defects that may impair the strength or durability.

Tie strips may be partially bent to no more than a 1 in. (25 mm) radius before they are shipped to the precast yard.

Perform final bending at the precast yard.

Do not allow connecting devices, reinforcing steel, or welded wire fabric used in the panels to contact each other.

Use bolts and nuts that meet the requirements defined in Subsection 627.2.B, Connecting Devices.

Use precast panel materials as specified in Subsection 627.2, Materials. Before casting, set the following in place to

the dimensions and tolerances shown on the drawings:

• Tie strips

• Mesh attachment straps

• Coil embeds

• Coil bolts

• Reinforcing steel

• Welded wire fabric

• Connecting pins

• Handling devices

Do not allow the metal connecting devices and reinforcing steel to contact each other when in their final position in the

panel.

Use precast concrete panels that are cast at a Class A or B plant that conforms to Standard Operating

Procedure 3, Precast/Prestressed Concrete Bridge Members. See QPL 9 for a list of approved plants.

Cast the panels using steel forms.

or architectural form liner. Float finish the back face.

Supplement vibration with hand tamping as necessary to force the concrete into the corners of the forms

and prevent the formation of stone pockets or cleavage planes from forming.

Cure the panels as specified in Subsection 500.3.05.Z, Cure Concrete, or Subsection 865.2.01.B.10, Concrete

Curing. Cure for at least 12 hours or until the concrete develops the specified compressive strength. The

Engineer will reject panels that do not reach specified strength within 28 days.

Keep forms in place until they can be removed without damaging the panel. 10681068106810681068

Finish the concrete surface for the front face as designated on the Plans. Float-finish the rear face enough to

eliminate open aggregate pockets and distortions greater than 1/4 in. (6 mm).

Only use panels manufactured within the following tolerances:

All dimensions are within 3/16 in. (5 mm).

Angular distortion in the panel’s height does not exceed 3/16 in. (5 mm) in 5 ft. (1.5 m).

Diagonal tolerance from Plan dimensions is no more than 3/8 in. (10 mm).

For textured finishes, surface defects greater than 5/16 in. (8 mm) in 5 ft (1.5 m) will be rejected.

Perform compression tests to determine the minimum strength requirements on cylinders.

production and cure according to GDT 35.D.1.

placed, whichever is the lesser amount of concrete, to determine the 28-day strength.

or for each 10 yd³ (7.5 m³) of concrete placed, whichever amount of concrete is less.

MPa). Perform compressive strength tests according to AASHTO T 22.

Panels will be rejected if they do not meet the requirements above. The following defects are also cause for

rejection:

Indications of imperfect molding that result in tolerances being exceeded

Honeycombed or open texture concrete

Clearly and permanently mark on the rear face of each panel the date of manufacture, lot number, and type of

panel.

To construct the precast portion of the coping or precast traffic barrier, use materials that conform to

Subsection 627.2.C, Concrete. Use the same procedures for precasting, testing, and inspection as those for precast

panels.

627.3.05 Construction

Place precast panels so that their final position at the completion of the wall is vertical.

movement.

during backfill placement and compaction.

temporary wooden wedges in the joints at the junction of two adjacent panels on the external side of the

wall.

then remove the bottom layer of wedges.

pads.

10691069106910691069

is 7/8 in. ± 3/8 in. (22 mm ± 10 mm).

constructed does not exceed 3/4 in. (20 mm) when measured along a 10 ft. (3 m) straightedge.

does not exceed 1/2 in. per 10 ft. (13 mm per 3 m) of wall height.

top of the wall to proper grade. See the plans or construction details.

Before placing special backfill material on a soil-reinforcing device, complete the connections to the

panels.

Treat joints between the panels as follows:

Ensure that horizontal joints between panels contain two 4 by 3 by ¾ in (100 by 75 by 20 mm) ribbed bearing

pads or elastomeric pads as specified on the Plans.

Cover all horizontal and vertical joints with 12 in. (300 mm) wide plastic filter fabric sheet glued securely to the

backside of precast concrete panels. Overlap the filter fabric with the joint at least 4 in. (100 mm). When

piecing the filter fabric together, overlap at least 4 in. (100 mm).

In flood plains or other intermittently inundated areas, cover the joints as follows:

• Use a woven plastic filter fabric sheet to cover the joint on the back side of the wall between panels

from 3 ft. (1 m) above the 100-year flood elevation to the bottom of the wall.

• Use a woven or nonwoven plastic filter fabric sheet to cover the joint on the back side of the wall

between panels from 3 ft. (1 m) above the 100-year flood elevation to the top of the wall.

Place backfill shortly after erecting each lift panel. Follow these guidelines:

the end of the soil-reinforcing devices.

to drain away from the wall before placing and attaching the next layer of reinforcing devices.

by the Engineer.

this lift thickness to obtain the specified density, if required.

determined by GDT 7 or GDT 24a, GDT 24b Method A or B, for full depth of the material.

panels.

wide adjacent to the backside of the wall.

After compacting the remainder of the layer, compact this 3 ft. (1 m) strip with light mechanical tampers

without causing the panels to move outward.

that area until the lift is re-compacted and obtains a passing compaction test. 10701070107010701070

undulations until the special backfill material has been placed and compacted above the restrained layer to

the level of the next layer of stabilizing geogrid. Release the uppermost layer of stabilizing geogrid after the

final layer of special backfill is placed and compacted.

Provide precast panels that have the appropriate storm drain openings in panels at the elevation and locations

indicated on drainage profiles.

Place catch basins so that pipes will enter perpendicular (plan view) to the panels or below the leveling pads as

shown on the Plans. Coordinate the catch basin construction and the storm drain placement with the wall

construction.

Furnish, install, operate, and maintain satisfactory dewatering systems to maintain the site in a dry and workable

condition to permit grading, compacting the wall foundation, and erecting and backfilling the wall. Furnish

dewatering system equipment and materials and continue the system as long as necessary.

When catch basins are located behind the wall and the Wall Plans do not indicate a specific construction method,

use the method outlined in the construction details.

When longitudinal pipes are located behind the wall, follow this procedure if specific details are not shown on the

Wall Plans:

the precast panel. See the construction details.

investigate relocating the pipe. The Engineer will contact the design office that designed the drainage system

or the office responsible for the pipe and will investigate the pipe relocation.

procedure indicated on the construction details.

Use precast concrete or cast-in-place concrete for:

• Drainage structures that are within the special embankment backfill

• Drainage structures that are outside the special embankment backfill but that are within 5 ft. (1.5 m) of

the front face of the wall

627.3.06 Quality Acceptance

General Provisions 101 through 150.

627.3.07 Contractor Warranty and Maintenance

General Provisions 101 through 150.

627.4Measurement

Excavation, including any required removal of unstable material, and shoring necessary for construction of the

MSE Wall will not be measured for payment. 10711071107110711071

MSE wall face area, complete in place and accepted, will be measured by the square foot (meter) in vertical bands

bounded by the limits of each specific height range pay item in the plans. The height will be measured from the

maximum top of leveling pad elevation on the wall envelope to the top of Coping A, the top of sidewalk elevation

for Coping B, or the proposed gutterline elevation for Traffic Barrier H. Dividing the wall area into segments such

as this provides the opportunity for the contractor to bid graduated unit prices that consider backfill volumes and

reinforcement lengths.

Any area of cast-in-place facing around drainage structures within the approved wall envelope will be measured

as MSE Wall Face. “Dummy” panels will not be measured for payment.

No separate measurement will be made for internal wall facing.

No deduction in area will be made for pipe passing through the wall facing. The area of box culverts that interrupt

the wall envelope will not be included in the wall area measured for payment.

The backfill stabilizing devices will not be measured separately.

The MSE backfill material used in the MSE wall volume will not be measured separately except as noted below.

• The MSE Backfill required behind bridge endwalls or backwalls and above the top of coping will be measured

as additional MSE wall backfill.

• Any additional MSE backfill required as a result of an undercut ordered by the Engineer and requiring the MSE

backfill material to provide stability, as determined by the Engineer, will be measured and paid for as additional

MSE wall backfill.

Backfill of undercut areas not requiring classes of soils higher than common excavation soils will not be measured

separately.

Backfill material required by construction procedures to extend outside the MSE wall volume shall be considered

incidental and will not be measured separately.

Concrete Leveling Pads will not be measured separately.

These units complete in place and accepted, will be designated on the Plans and measured per linear foot (meter)

for each type unit.

The quantities of coping and barrier will be measured as horizontal lengths in linear feet (meters).

627.4.01 Limits

General Provisions 101 through 150.

627.5Payment

The pay quantities will be the Wall Envelope quantities shown in the Plans unless the Engineer approves Adjusted Wall

Envelope. In this case, the pay quantities will be the Adjusted

Wall Envelope quantities.

No additional compensation will be made for any additional material, equipment, design, or other items found

necessary to comply with the project Specifications as a result of the Department's review except for changes made

necessary by the survey verification required by Subsection 149.1.03.E and Subsection 149.3.03.D, or other changes

approved by the Engineer.

Include in the unit bid prices all costs necessary to comply with the requirements of this specification. No payment will

be made for wall area outside of the Adjusted Wall Envelope. 10721072107210721072

Excavation, including removing unstable material and shoring for construction of the mechanically stabilized

embankment retaining wall, will not be paid for separately.

MSE Wall Face area will be paid for at the Contract Unit Price bid per square foot (meter) for each height range in

the wall envelope. Payment is full compensation for furnishing materials, including bearing pads, filter fabric, and

graffiti-proof coating.

Any area of cast-in-place facing around drainage structures within the approved wall envelope will be paid as wall

face. Payment will include all costs for concrete, reinforcing steel in the cast-in-place areas. No additional

payment will be made for any “dummy” panels required.

If the wall height changes to a height greater than the maximum height range included in the pay items, the area of

wall with a height greater than the maximum will be paid at 120% of the bid price of the maximum height range

pay item included in the plans.

No separate payment will be made for architectural treatment.

No separate payment will be made for internal wall facing, internal wall backfill stabilizing devices or additional

MSE backfill necessitated by the internal wall.

The backfill stabilizing devices will not be paid for separately. Include this cost in the unit price bid for MSE wall

face.

The MSE backfill material used in the MSE wall volume will not be paid for separately except as noted below.

When not paid for separately, include the cost in the unit price bid for MSE wall face.

Exceptions:

• The cost of MSE Backfill required behind bridge endwalls or backwalls and above the top coping will be

paid for as Additional MSE Wall Backfill.

• Any additional MSE backfill required as a result of an undercut ordered by the Engineer and requiring the

MSE backfill material to provide stability, as determined by the Engineer, will be paid as additional MSE

wall backfill.

Backfill of undercut areas not requiring materials of grades higher than common excavation soils will not be paid

for separately. Include the cost in the overall bid price submitted.

Any backfill material required by construction procedures to extend outside the MSE Wall volume is considered

incidental. Include this cost in the price bid for contract items.

Concrete leveling pads, including steps shown in the Plans will not be paid for separately.

These units, complete in place and accepted, will be designated on the Plans and paid for at the Contract Unit

Price bid per linear foot (meter) for each type unit.

No separate payment will be made for dewatering. Include the cost of dewatering in the price bid for special

embankment backfill. 10731073107310731073

Payment will be made under:

Item No. 627 MSE wall face, wall No. __0 -10 ft. (0 -3 m) Per square foot (meter)

Item No. 627 MSE wall face, wall No. __>10 -20 ft. (3 -6 m) Per square foot (meter)

Item No. 627 MSE wall face, wall No. __>20- 30 ft. (6 -9 m) Per square foot (meter)

Item No. 627 MSE wall face, wall No. __>30 ft. (>9 m) Per square foot (meter)

Item No. 627 Coping, A, wall No. ___ Per linear foot (meter)

Item No. 627 Coping, B, wall No.___ Per linear foot (meter)

Item No. 627 Traffic barrier, H, wall No.___ Per linear foot (meter)

Item No. 627 Additional MSE backfill Per cubic yard (meter)

627.5.01 Adjustments

General Provisions 101 through 150.. 1074 1074 1074 1074 1074