548RETAINING WALL SYSTEMS

548-1Description

Construct permanent and temporary retaining wall systems in accordance with this Section and in conformance with the lines, grades, design, and dimensions shown in the Contract or established by the Engineer. Sheet pile walls and cast -in-place walls are not included in this Section. Construct all walls of a specific type ( mechanically stabilized earth (MSE), counterfort, etc.), using the same wall system and supplier. If different t ypes of wall systems must be used in such a manner that causes one wall to interact with or influence another wall, coordinate the detailing of these areas of interaction/influence with the assistance of the Contractor’s Engineer of Record. Obtain each reinforced concrete precast concrete retaining wall system from a plant that is currently on the Department’s Production Facility Listing. Producers seeking inclusion on the list shall meet the requirements of Section 105. Ensure that each wall system compo nent is marked in accordance with 548 -5.3. Ensure that each shipment of products to the job site includes a signed or stamped delivery ticket in accordance with the Materials Manual, Section 8.2 Volume II, and the required written certification statement for each product shipped. Submit these tickets and certifications to the Engineer. When shown in the Plans or approved by the Engineer, a segmental block MSE retaining wall (SBW) system may be provided as a substitute for a reinforced concrete panel MSE w all system. All SBW systems must comprise:

the requirements of 548 -5.

length without splices normal to the facing blocks and laterally without horizontal gaps, and with a vertical spacing of not more than every other course of blocks or 30 inches, whichever is less.

facing blocks and spaced laterally and vertically not more than every other block or 30 inches, whichever is less, with a positive mechanical or shear connection to the facing blocks.

vertically.

548-2Materials

Provide a wall system listed on the Department’s Approved Product List (APL) based on the wall type shown in the Plans. Purchase components, soil reinforcement, attachment devices, joint filler, filter fabric, and all necessary incidentals for each wall from the same wall supplier.

548-2.1Concrete: Ensure that concrete utilized for all wall components is consistent

with the concrete class, environmental classification and admixture requirements for durability as stated in the Contract Documents . Produce and supply concrete for all reinforced concrete wall components meeting the requirements of Section 346. Produce and supply concrete for the leveling pad meeting the requirements of 759 FY 2023-24 Return to Table of Contents

548-2.2Reinf orcing Steel: Meet the requirements of Section 931 for steel reinforcing

and Section 932 for FRP reinforcing, as identified in the Contract Documents and APL drawings.

548-2.3Backfill Reinforcement: For walls utilizing backfill reinforcement, use

reinforcement consisting of steel wire mesh, metal strips or structural geosynthetics as required for the wall system chosen. Use backfill reinforcement of the same length from top to bottom of wall at any section. For tiered walls, use backfill reinforcement of the same length within the height of each tier at any section. Use plain steel wire mesh and embedded loops shop fabricated from cold drawn steel wire and weld into the finished mesh fabric meeting the requirements of ASTM A1064. Use longitudinal and tra nsverse wires of equal and constant diameter within a given piece of mesh reinforcement. Use steel strips hot rolled from bars to the required shape and dimensions with physical and mechanical properties meeting ASTM A572 Grade 65 or as shown in the Contra ct. Use shop-fabricated hot rolled steel tie straps meeting the minimum requirements of ASTM A1011/A1011 M, Grade 50, or as shown in the Contract. Ensure that steel reinforcing strips, tie strips, reinforcing mesh and connectors used in permanent walls a re galvanized in accordance with ASTM A123 or ASTM A153, as applicable. For typical applications, punch or drill holes in metal items before galvanizing. Field drilled holes for bin walls are permitted. Repair field drilled holes; field cut ends and other damage to galvanized surfaces in accordance with Section 562. Use Type R-3 structural geosynthetics made of polypropylene, select high density polyethylene or high -tenacity polyester fibers having cross -sections sufficient to permit significant mechanica l interlock with the backfill. Use geosynthetics having a high tensile modulus in relation to the backfill. Use geosynthetics having high resistance to deformation under sustained long term design load while in service and resistant to ultraviolet degradation, to damage under normal construction practices and to all forms of biological or chemical degradation normally encountered in the material being reinforced. Do not use uncoated polyester (PET) reinforcements or reinforcements weakened or damaged by hig h pH environments within any portion of the flowable fill , or within coarse aggregate backfill below the design high water elevation (DHW) shown in the Plans . Store the geosynthetics in conditions above 20ºF and not greater than 140ºF. Prevent mud, wet cement, epoxy, and like materials from coming into contact with and affixing to the geosynthetic material. Rolled geosynthetic may be laid flat or stood on end fo r storage. Cover the geosynthetic and protect from sunlight prior to placement in the wall system. Carefully inspect all reinforcement, steel and geosynthetics to ensure they are the proper size and free from defects that may impair their strength and du rability.

548-2.4Attachment Devices: Use backfill reinforcement attachment devices as required

by the wall system chosen.

548-2.5Joint Materials and Filter Fabrics :

548-2.5.1 Horizontal Joint Pads: Use elastomeric or polymeric pads in all horizontal joints between precast components as recommended by the wall manufacturer. Ensure that the pads are of sufficient size and hardness to limit vertical stresses on the pad and concrete surface and to prevent concrete to concrete contact at the joints. 548-2.5.2 Joint Covers for Non-SBW Walls : For walls supporting bridge abutments on spread footings, cover joints and other wall openings within a horizontal distance equal to the larger of:

760 FY 2023-24 Return to Table of Contents

measured from the nearest edge of the footing, surrounding the reinforced backfill for the abutment with Type D-2 geotextile fabric meeting the requirements of Section 985. Cover all joints and wall openings in portions of the wall backfilled with coarse aggregate with Type D-2 geotextile fabric meeting the requirements of Section 985. Cover all other joints and wall openings with Type D-2 or D-3 geotextile fa bric with a maximum apparent opening size ( AOS) equal to US Sieve No. 70 meeting the requirements of Section 985. Apply an adhesive approved by the Engineer to the back of the precast component for attachment of the fabric material. 548-2.5.3 Alignment P ins: Ensure that pins used to align the precast components during construction are of the size, shape and material required for the wall system chosen. 548-2.5.4 Separation Geotextile: Provide a Type D-2, D-3, or D-5 separation geotextile meeting the req uirements of Section 985 between the coarse aggregate and the select backfill/embankment at the bottom, top and sides of the coarse aggregate.

548-2.6Backfill Material:

548-2.6.1 General: Provide compacted select backfill or coarse aggregate backfill within the retaining wall volume as shown in the Plans. For permanent walls, p rovide coarse aggregate backfill in lieu of compacted select backfill to an elevation at least one foot above the DHW shown in the Plans when the DHW is above the lowest adjacent ground surface. Provide flowable fill within the retaining wall volume in lieu of compacted select backfill or coarse aggregate backfill only when the option for flowable fill is shown in the Plans. The retaining wall volume is defined to extend from the top of the leveling pad or footing, or bottom of walls which do not have footi ng or leveling pads, to the finish grade line and from the face of the wall to a vertical plane passing through the end of the extreme wall component (straps, counterforts, etc.) plus one foot. 548-2.6.2 Compacted Select Backfill: Meet the requirements o f Sections 105 and 120 except as noted within this Section. Have the backfill material tested for every soil type for pH, resistivity, sulfate and chloride content by a Department approved independent testing laboratory prior to placement. Submit a certifi cation, signed and sealed by a Professional Engineer registered in the State of Florida, that the results have met the requirements of this Section. The pH, as determined by FM 5-550, shall not be lower than 5.0 and not higher than 9.0 when metallic elements or pipes are placed within the backfill . Sources of select backfill material having a pH between 4.5 and 5.0 for walls utilizing metallic reinforcement and between 3.0 and 5.0 for walls utilizing geosynthetic , may be used provided the interior face of the MSE wall panels have three inches of concrete cover over the reinforcement and the concrete used in the panels contains the following ingredients and proportions:

20% by weight.

weight.

70% of total cementitious material. 761 FY 2023-24 Return to Table of Contents In lieu of the mix design described above, a mix design with a highly reactive pozzolan meeting the requirements of 346 -2.3 can be substituted. Examples of mix designs meeting this re quirement are :

Provide proper curing for these materials to prevent surface cracking. Do not place metallic pipe in backfill materials having a pH less than 5.0. In addition, for permanent walls utilizing metallic soil reinforcement, use backfill that meets the following electro -chemical test criteria for determining corrosiveness:

Table 548-1 Electro-Chemical Test Criteria Criteria Test Method Resistivity: > 3000 ohm -·cm FM 5-551 Soluble sulfate content: < 200 PPM FM 5-553 Soluble chloride content < 100 PPM FM 5-552

For constructing the retaining wall volume, do not use backfill material containing more than 2.0% by weight of organic material, as determined by FM 1-T267 and by averaging the test results for three randomly selected samples from each stratum or stockpile of a particular material. If an individual test value of the three samples exceeds 3%, the stratum or stockpile will not be suitable for constructing the retaining wall volume. Ensure that the material is non -plastic as determined by AASHTO T 90 and the liquid limit as determined by AASHTO T 89 is less than 15.

For walls using soil reinforcement, use backfill that meets the following

gradation limits determined in accordance with AASHTO T 27 and FM 1-T011:

Table 548-2

Gradation Limits

Sieve Size Percent Passing

3-1/2 inches 100

3/4 inch 70-100

No. 4 30-100

No. 40 15-100

No. 100 0-65

No. 200 0-12

For walls not using soil reinforcement, use backfill that meets the

following gradation limits determined in accordance with AASHTO T 27 and FM 1-T 011:

Table 548-3

Gradation Limits Not Using Soil Reinforcement

Sieve Size Percent Passing

3-1/2 inches 100

No. 200 0-12 762FY 2023-24Return to Table of Contents

548-2.6.3 Flowable Fill: Meet the requirements of Section 121 except as noted

within this Section and the Plans.

548-2.6.4 Coarse Aggregate Backfill and Drainage Aggregate: Provide coarse

aggregate comprised of natural stones meeting the requirements of Section 901 with a size

distribution of any of the listed aggregate gradations from Size No 57 through Size No 89,

inclusive, except as noted on the Plans. Have all coarse aggregate backfill materials tested for

pH, resistivity, sulfate and chloride content by a Department approved independent testing

laboratory prior to placement. Submit a certification, signed and sealed by a Professional

Engineer registered in the State of Florida, that the results of these tests meet the requirements of

548-2.6.2.

For SBW systems, provide drainage aggregate comprised of coarse

aggregate backfill and a drainage geotextile to separate the drainage aggregate from the

reinforced backfill as specified for each approved wall system.

548-3Approved Product List (APL)

All proprietary retaining wall systems shall be listed on the APL. Manufacturers seeking

evaluation of products for inclusion on the APL shall submit an application in accordance with

Section 6, independently certified test reports, and calculations and drawings in accordance with

the latest edition of the AASHTO LRFD Bridge Design Specifications and the Department’s

Structures Design Guidelines (SDG) signed and sealed by a Professional Engineer registered in

the State of Florida. Submit calculations and drawings showing details, notes, materials,

dimensions, sizes, and other information as described below for a complete description of the

retaining wall system.

stress range of the soil reinforcement and wall facing, or the construction tolerances in this

Section;

hand or by a wall company program with hand calculations verifying the program output. It is

only necessary to include sample hand calculations for a 20 foot height for each soil condition.

cutting;

interior corner angle is less than 70 degrees); 763FY 2023-24Return to Table of Contents

settlement in excess of four inches without attaching soil reinforcement to the abutment; and,

type of soil reinforcement for wall system. Testing shall be done by an independent soil testing

laboratory or testing agency certified by the Department. Ensure test data includes all sizes and

types of soil reinforcement to be utilized on Department projects. Default AASHTO values may

be used for conventional soil reinforcement. For soil reinforcement grids, include all various

configurations and combinations of longitudinal and transverse wires.

as necessary.

sequencing for the wall system. Submit manual in 8-1/2 inch x 11 inch format in either pdf or

MS Word format.

548-4Shop Drawings

Submit shop drawings and calculations in accordance with Section 5. Provide

calculations and drawings showing details, notes, materials, dimensions, sizes and other

information necessary for the complete fabrication and erection of the retaining wall system. As

a minimum, provide the following:

the top and bottom of wall at the begin and end of wall, all breaks in vertical alignment and all

whole stations and 25 foot station increments.

horizontal control line to the exterior face of the wall; the location of utilities, drainage structures

and other items that impact the wall; the limits of the reinforced soil volume; and, the location of

piles within the reinforced earth volume.

items that impact the wall; for placement of soil reinforcement at acute corners; for addressing

conflicts between soil reinforcement and obstructions in the reinforced soil volume; for

addressing different wall types intersecting and impacting each other.

characteristics; factored bearing resistance and factored bearing pressure for each wall height

increment and other notes required for construction of the walls.

drawings.

30 degrees for sand backfill or 34 degrees for limerock backfill, provide laboratory test results in

accordance with 548-9.5 verifying the backfill to be used for the wall meets the design soil

characteristics for the shop drawings.

aggregate, drainage pipes and separation geotextile. Drawings should be similar to details for

Type II or Type III underdrains in Standard Plans, Index 440-001. Do not directly cover

perforated drainage pipes with a geotextile filter fabric (such as a filter sock).

geosynthetic reinforcement and the facing blocks, include the results of connection capacity 764FY 2023-24Return to Table of Contents

testing. Tests must be performed using the materials to be used on the project and tested in

accordance with ASTM D6638 to justify the short-term ultimate connection strength reduction

factor (CRu) used to determine the long-term connection strength reduction factor (CRcr) value in

the design calculations for each wall height increment detailed in the shop drawings.

548-5Concrete Component Construction

Construct reinforced concrete components in accordance with Section 400. Precast wall

components are produced using certification acceptance; therefore, assume responsibility for

performance of all quality control testing and inspections required by Sections 346 and 400 for

the precast component construction. Perform all quality control (QC) inspection and testing

using Construction Training and Qualification Program (CTQP) qualified personnel. Perform

compressive strength testing in a laboratory meeting and maintaining at all times the

qualification requirements listed in Section 105. The minimum time for form removal is

12 hours. Unless otherwise indicated in the Contract, apply a Class 3 finish to the concrete

surface for the front face, and roughly screed the rear face to eliminate open pockets of aggregate

and surface distortions in excess of 1/4 inch.

Construct unreinforced concrete SBW components (facing blocks) with a minimum

compressive strength of 4,000 psi at 28 days and a maximum absorption of 6.5% in accordance

with ASTM C140. Units must have a normal weight density classification meeting the

requirements of ASTM C1372, except as modified in this Section.

548-5.1Curing: Cure reinforced concrete components in accordance with Section 400

548-5.2Tolerances: Meet the following manufactured tolerances:

548-5.2.1 Reinforced Concrete Components:

attachment devices - within 1 inch. All other dimensions - within 3/16 inch.

must not exceed 0.2 inches in 5 feet.

surfaces measured on a length of 5 feet must not exceed more than 0.1 inches. Surface defects on

textured finished surfaces measured on a length of 5 feet must not exceed 5/16 inch.

548-5.2.2 Unreinforced Concrete SBW Components:

1/16 inch of the specified dimension. Hollow units must have a minimum wall thickness of 1-

1/4 inches.

placing of the unit or impair the integrity of the wall construction. Minor cracks with a width less

than 1/32 inch and a length less than 25% of the unit height may be acceptable.

or tan color, unless shown otherwise in the Plans.

548-5.3Marking of Precast Components:

548-5.3.1 Reinforced Concrete Components: Permanently and legibly mark the

following information on the back of each reinforced precast wall panel by etching: the panel

number or type, piece mark, project number (if applicable), date cast and precast manufacturer’s

name or symbol with the approved producer’s QC stamp affixed.

548-5.3.2 Unreinforced Concrete SBW Components: Label each pallet of dry-

cast unreinforced concrete SBW facing blocks with the component identification number or type, 765FY 2023-24Return to Table of Contents

project number (if applicable), LOT number, date cast, and the manufacturer’s name or symbol.

Labels must be clearly legible until the component is installed.

548-6Repairs or Rejection of Precast Components

548-6.1Reinforced Concrete Components: For precast concrete wall components that

have not been installed, evaluate cracks, spalls and other deficiencies in accordance with 450-12.

Repair deficiencies in accordance with 450-13 or the plant’s approved repair methods that are

included as part of the Producer Quality Control Plan. The original performance and durability of

repaired wall components must be maintained. Use materials for concrete repair that meet or

exceed the strength requirement for the class of concrete used. Materials meeting the

requirements of Section 930 may be substituted for non shrink grout when required by 450-13.

For precast concrete wall components that have been installed, the disposition of

concrete cracks will be determined in accordance with 400-21.

The Department will reject all precast concrete wall components not meeting the

quality standard of this Section and referenced Specifications. In addition, any of the following

defects will be sufficient cause for rejection by the Department:

installed/damaged

from that shown in the Contract Documents

face of the precast component is stained or discolored to the point of rejection, the stain or

discoloration may be removed, or a Department approved stain or a Class 5 finish may be

applied to attain a uniform appearance for the entire structure, to the satisfaction of the Engineer.

548-6.2Unreinforced Concrete SBW Components: The Department will reject all

segmental retaining wall blocks not meeting the requirements of this Section and the Contract

Documents. In addition, any of the following defects will be sufficient cause for rejection of

SBW facing blocks by the Department:

d, Excessive concrete absorption

766FY 2023-24Return to Table of Contents

Correct cracks or spalls occurring after installation in accordance with 400-21.

548-7Handling Storage and Shipping

Handle, store and ship all components in a manner that prevents chipping, cracks,

fractures, excessive bending stresses, mud, dirt and debris. Support precast panel wall and

counterfort components in storage on firm blocking located immediately adjacent to the

attachment device.

Do not ship precast concrete wall components to the project site prior to the completion

of the 72 hour curing period and attainment of the required 28 day strength.

The Contractor is permitted to verify the shipping strength test, before 28 days, by testing

compressive strength cylinders that are cured under the conditions similar to the product or by

testing temperature match cured cylinders. The shipping strength test is the average compressive

strength of two test cylinders. Do not ship reinforced concrete products until accepted and

stamped by the QC Manager or the inspectors under the direct observation of the QC Manager.

548-8Construction Requirements

548-8.1General: Due to the unique nature of the structure and concept, procure from the

wall supplier fully detailed shop drawings, technical instructions, guidance in preconstruction

activities and on-site technical assistance during construction. Closely follow any instructions

from the wall supplier, unless otherwise directed by the Engineer. Submit any instructions from

the wall supplier to the Engineer. Verify all pertinent retaining wall information (soil parameters,

wall alignment, utility locations, conflicting structures) prior to the wall supplier finalizing shop

drawings. Bring any conflicts not shown in the Contract to the Engineer’s attention.

548-8.2Wall Excavation: Excavate to the limits shown in the Contract and in

conformance with Section 125.

548-8.3Foundation Preparation: Grade the foundation for the structure level for a

width equal to or exceeding the limits of the retaining wall volume or as shown in the Contract.

Prepare the foundation in conformance with Section 125.

In addition to the compaction requirements of Section 125, compact the graded

area with an appropriate vibratory roller weighing a minimum of eight tons for at least five

passes or as directed by the Department’s District Geotechnical Engineer. Remove and replace

any soft or loose foundation subsoils incapable of sustaining the required compaction to the

Engineer’s satisfaction.

For permanent MSE wall systems, provide an unreinforced concrete leveling pad

as shown in the Contract Documents. Cure the leveling pad a minimum of 12 hours before

placement of precast wall components.

For SBW MSE wall systems, a geogrid reinforced, geotextile wrapped,

compacted aggregate leveling pad may be used in lieu of the unreinforced concrete leveling pad.

The compacted aggregate leveling pad must be at least 24 inches wide and at least 8 inches thick

after compacting, and the geogrid must be at least 6 inches below the top of the leveling pad.

Wrap the aggregate leveling pad with a D-2, D-3, or D-5 separation geotextile. The geotextile

may run up the front and back of the first block course or between the aggregate leveling pad and

the first block course.

548-8.4Wall Erection: Assemble, connect and support wall components as

recommended by the wall supplier. As backfill material is placed behind the wall face of MSE

wall systems utilizing reinforced concrete panels, maintain the wall in the vertical position or

slightly battered into the backfill to provide a final vertical alignment (by means of bracing, 767FY 2023-24Return to Table of Contents

temporary wooden wedges placed in the joint at the junction of the two adjacent precast

components on the external side of the wall or other alignment aids). Remove wooden wedges as

soon as the precast component above the wedged precast component is completely erected and

backfilled. External bracing is required for the initial lift of MSE systems.

For SBW systems, carefully place the first course of concrete block units on the

leveling pad. Up to 1/2 inch of sand may be placed between the concrete leveling pad and the

buried first course of blocks to provide a level and stable base. A one inch gap between the first

course of facing units is allowed, provided a suitable filter fabric is placed behind the foundation

units as specified for each approved wall system. Each unit must be in full contact with the base

and checked for level and horizontal alignment. Voids must be kept to a minimum to prevent

point loading and cracking, unless otherwise indicated in the shop drawings. Place units side by

side for the full length of wall alignment. Fill the hollow cores or cells and the space within

blocks with drainage aggregate. Sweep away excess material from top of units and install the

next course.

Place soil reinforcement normal to the face of the wall, unless otherwise shown in

the Contract or as directed by the Engineer. Do not cut or kink soil reinforcement. Do not

connect soil reinforcement to piles or allow soil reinforcement to bear against piles. Field cut soil

reinforcement only at locations as shown in the approved shop drawings. Prior to placement of

the reinforcement, compact the backfill in accordance with 548-8.5.

For SBW systems, shims made of non-degradable materials may be used as

specified for each approved wall system. The shim thickness per course of block must not exceed

1/8 inch and must not be installed on reinforcement elevations when the reinforcement

connection relies on any friction.

548-8.4.1 Tolerances for Permanent Walls: Walls that do not meet the

following tolerances will not be accepted by the Department and must be removed and

reconstructed at no cost to the Department.

548-8.4.1.1 Reinforced Concrete MSE Wall Systems: Vertical

tolerances (plumbness) and horizontal alignment tolerances must not exceed 3/4 inch when

measured with a 10 foot straightedge. The maximum allowable offset in the joint between

precast components is 3/4 inch. The final overall vertical tolerance of the completed wall

(plumbness from top to bottom) must not exceed 1/2 inch per 10 feet of wall height. Horizontal

and vertical joints between precast components must not be less than 1/2 inch or more than 1-

1/4 inches.

548-8.4.1.2 SBW Systems: Horizontal alignment tolerances must

not exceed 3/4 inch per10 feet of wall length. The maximum allowable gap between segmental

retaining wall blocks above the first course must not exceed 1/16 inch. The final overall vertical

tolerance of the completed wall (deviation from plumbness from top to bottom or batter shown in

the Plans) must not exceed 1/2 inch per 10 feet of wall height.

548-8.4.2 Tolerances for Temporary Walls: Vertical tolerances (plumbness)

and horizontal alignment tolerances must not exceed three inches when measured with a 10 foot

straightedge. The final overall vertical tolerance of the completed wall (plumbness from top to

bottom) must not exceed one inch per three feet of wall height, not to exceed a total of six

inches.

548-8.5Backfill Placement:

548-8.5.1 Compacted Select and Coarse Aggregate Backfill: A LOT is defined

as a single lift of finished embankment not to exceed 500 feet in length of continuous or 768FY 2023-24Return to Table of Contents

interconnected walls. Backfill within 3 feet from the panels and backfill beyond 3 feet from the

panels are separate LOTs. Overlapping retaining wall volumes may be considered one LOT,

excluding the 3-foot width behind the panels. Strips up to 8 feet wide between two retaining wall

volumes constructed with the same material in a single operation may be considered as one LOT

with the retaining wall volumes. Isolated compaction operations will be considered as separate

LOTs. For multiple phase construction, a LOT will not extend beyond the limits of the phase.

When bridge abutments on spread footings are shown in the Plans, the material within 3 feet

behind the wall face and within the limits defined in 548-9.4.2 are considered as separate LOTs.

Remove wrinkles in geosynthetic reinforcement prior to covering with

backfill. Place the backfill closely following the erection of each course of precast components

or soil reinforcement layers and spread by moving the machinery parallel to the wall face. Do not

allow equipment heavier than eight tons closer than three feet behind the wall face. Place backfill

in a manner to avoid any damage or disturbance to the wall materials or misalignment of the

facing materials. Remove and replace any wall materials which become damaged or disturbed

during backfill placement at no cost to the Department, or correct as directed by the Engineer.

Remove and reconstruct any misalignment or distortion of the wall facing due to placement of

backfill outside the limits of this specification at no cost to the Department.

Compact coarse aggregate backfill with a minimum of three passes of a

vibratory compactor weighing between 600 and 1000 pounds or two passes of vibratory

compactor weighing over 1000 pounds. Use the highest vibration level that does not cause

excessive fracture of the aggregate in the opinion of the Engineer. Continue compaction until

there is no additional movement. Sheepsfoot, grid rollers or other types of equipment employing

a foot are not allowed for any backfill type. Achieve compaction of all backfill types within three

feet of the back of the wall face using a power operated roller or plate weighing less than

1,000 pounds. At a distance greater than three feet from the back of the wall, a vibratory roller

may be used, provided that the frequency and amplitude combined with bulk weight of the roller

has performed satisfactorily at a trial section of the same type of wall. For select backfill, a

smooth wheel or rubber tire roller is considered adequate. For walls employing geosynthetic

reinforcement, limit the weight of compaction equipment to 25,000 pounds. Ensure that the

maximum lift thickness after compaction does not exceed six inches. Decrease the lift thickness

if necessary, to obtain specified density.

All transitions from coarse aggregate backfill to select backfill must occur

at least six inches above and below any layers of backfill reinforcement. Place a separation

geotextile in accordance with 548-2.5.4 between the coarse aggregate backfill and select backfill

and embankment.

Perform backfill compaction in a way that the compactor moves in a

direction parallel to the wall face and proceeds from a distance not less than three feet behind the

wall face toward the end of the soil reinforcement element.

When placing select backfill, the moisture content of the backfill material

prior to and during compaction must be uniformly distributed throughout each layer of material.

Use backfill material having a placement moisture content at the dry side of the optimum

moisture content. To achieve the required compaction moisture content, use water that meets the

requirements of Section 923. Do not transport excessively moist backfill materials to the site for

any reason. Determine the optimum moisture content in accordance with the test method used to

determine maximum density in 548-9. 769FY 2023-24Return to Table of Contents

At the end of each day’s operation, shape the last level of backfill to

permit runoff of rainwater away from the wall face or provide a positive means of controlling run

off away from the wall such as temporary pipe.

548-8.5.2 Thick Lift Option for Compacted Select Backfill: If through field

tests, the Contractor can demonstrate that the compaction equipment can achieve density for the

full depth of a thicker lift, the backfill may be constructed in successive courses of not more than

10 inches compacted thickness.

Based on the results of a full-height test wall constructed by each

Contractor or MSE wall sub-contractor, the Engineer will approve each Contractor’s or MSE

wall sub-contractor’s specified compaction procedures. The length of the test wall shall be the

length required to produce one LOT of 500 feet at the top of the wall. When all individual walls

using this option are less than 500-feet long, the test wall may be broken into two segments

comprising separate LOTs. Both segments must be accepted to determine the required percent

compaction for the remaining walls. For each Contractor or MSE wall sub-contractor, the height

of the test wall shall be 20 feet or the highest wall using this option, whichever is less. Lower

height walls may be constructed using these procedures until a full height test wall is

constructed. Notify the Engineer prior to beginning construction of a test wall.

Perform one set of QC density tests per thick lift of the test wall on the

backfill within three feet behind the wall face and one set of QC density tests per thick lift of the

test wall on the backfill placed beyond three feet behind the wall face, at random locations within

each LOT. At each QC density test, the set will include testing the entire lift thickness and a dig

down test of the bottom 6 inches. Excavate materials as needed to allow testing of the bottom

6 inches, at no expense to the Department. Maintain the exposed surface as close to undisturbed

as possible; no further compaction will be permitted during the test preparation. The Department

will perform verification testing of density for the bottom 6 inches and the entire lift thickness at

the frequency indicated in 548-9.6. All QC tests and a Department Verification test must meet

the density required by 548-9.4.

Identify the test wall with the required percent compaction effort and

thickness in the Earthwork Records System (ERS) portion of the Department’s database. If the

thick lift density does not meet or exceed the thick lift density results during the test wall,

perform dig-down density tests to verify the density of the bottom 6 inches of the lift. The

Contractor may elect to place material in 6 inches compacted thickness at any time. Once

approved, a change in the source of backfill material will require the construction of a new test

wall. Do not change the compaction effort once the test wall is approved. The Engineer will

periodically verify the density of the bottom 6 inches during thick lift operations. If unable to

achieve the required density, remove and replace or repair the test wall to comply with the

specifications at no additional expense to the Department. The Engineer may terminate the use of

thick lift construction and instruct the Contractor to revert to the 6 inches maximum lift thickness

if the Contractor fails to achieve satisfactory results or meet the requirements of this Section.

548-8.5.3 Flowable Fill: Metallic wall components (including metallic soil

reinforcements) must not be in partial contact with the flowable fill. If the metallic components

contact the flowable fill, the metallic components must be completely encapsulated by the

flowable fill.

548-8.6Compressible Free Draining Seal: Seal all joints between panels of reinforced

concrete panel MSE walls with compressible free draining material (open cell) to prevent plant

growth from seeds or spores that may be in the joints or transported to the joints by wind or rain. 770FY 2023-24Return to Table of Contents

Install the seal at least 1-1/2-inches from both the front and rear faces of the panel. Protect the

free draining seal during the application of coatings and sealants. Should the seal become coated

or clogged, remove and replace the coated or clogged free draining seal. The installation must be

secure and free draining to keep the seal securely in place until uninstalled and to prevent

hydrostatic forces from building up behind the panel.

548-9Acceptance Program

548-9.1General Requirements: Meet the requirements of 120-10 except delete the

requirements of 120-10.1.4.1, 120-10.1.4.3, 120-10.1.6, 120-10.2 and 120-10.3.

548-9.2Maximum Density Determination: For select backfill, determine the maximum

QC density in accordance with FM 1-T180. When compacting A-3 or A-2-4 materials to meet

the alternate acceptance criteria in 548-9.4.1, determine the maximum density in accordance with

FM 1-T099.

Perform gradation tests on the sample collected in accordance with

AASHTO T 27 and FM 1-T011. Classify soils in accordance with AASHTO M 145 to determine

compliance with embankment utilization requirements.

548-9.3Density Testing Requirements: Ensure compliance with the requirements of

nuclear density testing in accordance with FM 1-T238. Determine the in-place moisture content

for each density test. Use FM 1-T238, FM 5-507 (Determination of Moisture Content by Means

of a Calcium Carbide Gas Pressure Moisture Tester), or FM 5-535 (Laboratory Determination of

Moisture Content of Granular Soils by Use of a Microwave Oven) for moisture determination.

Perform these tests at a minimum frequency of one set of tests per LOT.

Determine test locations including stations and offsets, using the random number

generator provided by the Engineer. Do not use notepads or worksheets to record data for later

transfer to the ERS section of the Department’s database. Notify the Engineer upon successful

completion of QC testing on each LOT.

548-9.4Acceptance Criteria: For select backfill, obtain a minimum density of 90% of

the maximum dry density as determined by FM 1-T180 within three feet behind the wall face

and obtain a minimum density of 95% of the maximum dry density as determined by FM 1-T180

from beyond three feet behind the wall face.

For flowable fill, meet the requirements of 121-6. For coarse aggregate backfill,

compact with a minimum of three passes of a vibratory compactor weighing between 600 and

1000 pounds or two passes of a vibratory compactor weighing over 1000 pounds. Use the highest

vibration level that does not cause excessive fracture of the aggregate in the opinion of the

Engineer. Continue compaction until there is no additional movement.

548-9.4.1 Optional Acceptance Criteria for A-3 and A-2-4 Materials: Obtain a

minimum density of 95% of the maximum dry density as determined by FM 1-T099 within 3

feet behind the wall face and obtain a minimum density of 100% of the maximum dry density as

determined by FM 1-T099 beyond 3 feet behind the wall face.

The combined width from both MSE wall backfill (excluding the 3-foot

zone from the panels) and embankment material may be considered the same LOT if the same

material is used; the material in both wall backfill and embankment is compacted with the same

procedure, equipment and compacting effort; and the maximum lift thickness after compaction in

both wall backfill and embankment is 6-inches.

548-9.4.2 Acceptance Criteria for Wall Backfill Supporting Spread Footings:

When spread footings at bridge abutments are shown in the Plans, obtain a minimum of 95% of 771FY 2023-24Return to Table of Contents

the maximum dry density as determined by FM 1-T180 on the material within 3 feet behind the

wall face, and underneath the footing as defined by the following limits:

footing width

If the optional criteria specified in 548-9.4.1 is used, compact the backfill

material within the limits specified above to obtain a minimum density of 100% of the maximum

dry density as determined by FM 1-T099. Compact the remainder of the backfill in accordance

with 548-9.4 or 548-9.4.1 as applicable. Do not use compaction equipment larger than permitted

in 548-8.5 within 3 feet behind the wall face; decrease the lift thickness if necessary.

548-9.5Friction Angle: When the friction angle depicted in the shop drawings exceeds

30 degrees for sand backfill or 34 degrees for limerock backfill, ensure the friction angle of the

backfill material tested in accordance with FM 3-D3080 equals or exceeds the backfill friction

angle depicted in the shop drawings.

548-9.6Frequency: Conduct sampling and testing at a minimum frequency listed in the

table below. The Engineer will perform verification sampling and tests at a minimum frequency

listed in Table 548-4 below.

Table 548-4

Minimum Frequency Testing

Test Name Quality Control (QC) Verification

Maximum Density One per soil type One per soil type

Density One per LOT One per four LOTs for each type of QC

test

Gradation One per Maximum Density One per Maximum Density

LL&PI One per Maximum Density One per Maximum Density

Soil Classification One per Maximum Density One per Maximum Density

Organic Content One per soil type One per soil type

pH One per soil type One per soil type

Direct Shear Three per soil type when required

by 548-9.5 One per soil type

*Verification testing for pH will be performed on samples taken at the point of placement.

In addition, for permanent walls utilizing metallic soil reinforcement, test for

corrosiveness at a minimum frequency of one test per soil type at point of placement according

to the electro-chemical table in 548-2.6. The Engineer will collect enough material to split and

create two separate samples and retain one for resolution at point of placement until LOTs

represented by the samples are accepted. The Engineer will perform verification tests for

corrosiveness at a minimum frequency of one test per soil type.

548-9.7Verification Comparison Criteria and Resolution Procedures:

548-9.7.1 Maximum Density Determination: The Engineer will collect enough

material to split and create two separate samples and retain one for resolution until LOTs

represented by the samples are accepted. 772FY 2023-24Return to Table of Contents

The Engineer will meet the requirements of 120-10.4.1 except replace

FM 1-T099 with FM 1-T180. If the Contractor selects the Optional Acceptance Criteria, the

Engineer will verify the QC results of FM 1-T099 in accordance with 120-10.4.1.

548-9.7.2 Density Testing: Meet the requirements of 120-10.4.2.

548-9.7.3 Soil Classification: The Engineer will meet the requirements of

120-10.4.3 except test the sample retained in 548-9.7.1 instead of taking the additional one.

548-9.7.4 Gradation: The Engineer will verify the QC results if the verification

result meets the gradation limits set forth in the gradation table of 548-2.6. Otherwise, the

Engineer will test the sample retained in 548-9.7.1. The State Materials Office (SMO) or an

AASHTO accredited laboratory designated by the SMO will perform resolution testing. The

material will be sampled and tested in accordance with AASHTO T 27 and FM 1-T011.

If the resolution test result satisfies the required gradation limits, the LOTs

will be verified. If the resolution test results do not meet the required gradation limits,

reconstruct the LOTs with acceptable material. The Engineer will perform new verification

testing.

548-9.7.5 Liquid Limit and Plasticity Index (LL&PI): The Engineer will verify

the QC results if the verification result satisfies the plasticity index and liquid limit criteria set

forth in 548-2.6. Otherwise, the Engineer will test the sample retained in 548-9.7.1. The SMO or

an AASHTO accredited laboratory designated by the SMO will perform resolution testing. The

material will be sampled and tested in accordance with AASHTO T 90 and AASHTO T 89,

respectively.

If the resolution test result satisfies the required criteria, LOTs of that soil

type will be verified. If the resolution test results do not meet the required criteria, reconstruct the

corresponding LOTs with acceptable material. The Engineer will perform new verification

testing.

548-9.7.6 Corrosiveness: The Engineer will verify the QC results if the

verification result satisfies the electro-chemical and pH test criteria set forth in 548-2.6.

Otherwise, the Engineer will test the sample retained in 548-9.7.1. The SMO or an AASHTO

accredited laboratory designated by the SMO will perform resolution testing. The material will

be sampled and tested in accordance with FM 5-550, FM 5-551, FM 5-552 and FM 5-553.

If the resolution test result satisfies the required criteria, material of that

soil type will be verified and accepted. If the resolution test results do not meet the required

criteria, reject the material and reconstruct with acceptable material.

548-9.7.7 Organic Content: The Engineer will verify the QC results if the

verification result satisfies the organic content test criteria set forth in 548-2.6. Otherwise, the

Engineer will collect three additional samples. The material will be sampled and tested in

accordance with FM 1-T267 and by averaging the test results for three randomly selected

samples from at least one lift per soil type. The SMO or an AASHTO accredited laboratory

designated by the SMO will perform resolution testing.

If the resolution test result satisfies the required criteria, material of that soil type

will be verified and accepted. If the resolution test results do not meet the required criteria, reject

the material and reconstruct with acceptable material.

548-9.7.8 Friction Angle: When the friction angle depicted in the shop drawings

exceeds 30 degrees for sand backfill or 34 degrees for limerock backfill, the Engineer will take a

verification sample at the point of placement to perform a direct shear verification test in

accordance with FM 3-D3080. The SMO or a consultant qualified to perform geotechnical 773FY 2023-24Return to Table of Contents

specialty lab testing (Type of Work 9.5), per Rule 14-75 of the Florida Administrative Code will

perform the verification testing. If the test verifies the material has a friction angle greater than or

equal to the friction angle depicted in the shop drawings, the material in the LOTs will be

verified. If the verification test does not meet the required friction angle, reconstruct the LOTs

with acceptable material.

The Contractor may request to redesign the wall and resubmit the shop

drawings with the lower friction angle indicated by the verification test. Employ a Professional

Engineer to redesign and submit signed and sealed drawings and computations. Do not begin any

reconstruction until the proposed redesign has been reviewed and approved by the Engineer. The

Contractor shall bear the costs of the redesign and any work resulting from the design changes.

548-10Certification

Submit all test reports to the Engineer necessary to document compliance with the

Specifications, at least ten days prior to wall construction.

Also submit a certificate of compliance certifying that the retaining wall materials,

backfill and construction practices comply with this Section.

For SBW systems, the Engineer will randomly select samples of each type of block used

in the segmental block retaining wall system and review a copy of the certified test report

corresponding the sample at a frequency of one sample per type of block for each wall.

Acceptance of furnished material will be based on the certificate of compliance,

accompanying test reports, and visual inspection by the Engineer.

548-11Method of Measurement

The quantity to be paid for will be the plan quantity, in square feet, completed and

accepted, of the area bounded by the following:

For permanent retaining wall systems: the top of the coping, the top of the

leveling pad or top of structural footings and the begin and end wall limits as shown on the wall

control drawings.

For temporary retaining wall systems: the top of wall, the ground line and the

begin and end wall limits as shown on the wall control drawings.

548-12Basis of Payment

Price and payment will be full compensation for all work specified in this Section,

including the design of the wall system, excavation required specifically for wall construction

below the finished graded surface, backfill reinforcement, leveling pad, footings, copings, light

pole pedestals, fabric material, horizontal joint materials, alignment pins, repairs, labor,

equipment, and other materials necessary to complete the wall in an acceptable manner as shown

in the Contract. The cost of backfill for the finished graded surface will be included in the cost of

embankment or borrow excavation, as applicable.

Payment will be made under:

Item No. 548- 12- Retaining Wall System (Permanent) - per square foot.

Item No. 548- 13- Retaining Wall System (Temporary) - per square foot. 774FY 2023-24Return to Table of Contents FENCING

550-1Description

Furnish, erect and reset metal fence of the type and at the locations shown in the Plans.

550-2Types of Fence

The types of fence are designated as follows: Type A (Farm Fence). Type B (Chain-Link Fence). Type R (Chain-Link Fence for Pedestrian Overpass).

550-3Materials

550-3.1Type A Fence (Farm Fence): Meet the requirements of Section 954 for timber

posts and braces. For metal posts and braces, and for recycled plastic fence posts, meet the requirements of the Standard Plans . For the fabric and all other accessories, meet the requirements of the Standard Plans.

550-3.2Type B Fence (Chain -Link): For the posts, braces, fabric and all accessories

other than the concrete for bases, meet the re quirements of the Standard Plans . Use concrete as specified in Section 347, or a premix approved by the Engineer for bases. The requirements contained in 347 -2.2, and 347 -3 will not apply.

550-3.3Type R Fence (Chain -Link for Pedestrian Overpass): Use the fabric and

accessories specified in the Plans.

550-3.4Resetting Fence: Use material from the existing fence. For any additional

materials required, provide the same type of material as in the existing fence and as specified herein, including gates whe n applicable.

550-3.5Optional Use of Materials: For Type A Fence, a combination of steel,

aluminum, timber, recycled plastic or concrete posts may be used. Unless otherwise called for in the Plans, line posts of one material may be used with corner, pull and end post assemblies of a different material. The Engineer will permit the use of line posts of only one optional material and pull posts assemblies of only one optional material between corner and end post assemblies. Within individual corner and end post assemblies, the Engineer will allow the use of only one optional material. For Type B Fence, a combination of zinc -coated steel fence members, aluminum coated fence members and aluminum alloy fence members may be used. Unless otherwise indicated in the Plans, the Engineer will allow the use of only one type of fabric material, one type of line post material and one type of pull assembly material between corner and end post assemblies.

550-3.6Certification: Provide the Engineer with certified test r eports from the

manufacturer confirming that all materials (posts, braces, fabric and all other accessories) conform to the requirements of this Section, Section 6 and the Standard Plans . Provide the Engineer a copy of the certification at least ten days p rior to fence construction. Also furnish the Engineer a Certificate of Compliance certifying that the fencing system, materials and construction practices comply with the applicable Standard Plans and Specifications. 775 FY 2023-24 Return to Table of Contents