145-1 Description.
This Section specifies the construction requirements for geosynthetics used in: geosynthetic reinforced soil slopes, and geosynthetic reinforced foundations constructed on soft in-situ soils. Furnish and place geosynthetics and any associated facing material or drainage blankets.
145-2 Responsibility.
Construct the geosynthetic reinforced feature, including materials, method, and installation based on information provided in the Contract Documents and the geosynthetic supplier’s recommendations. Submit shop drawings in accordance with Section 5 showing the details and distribution of the selected geosynthetics that meet the design shown in the Plans. Alternate designs optimizing the selected geosynthetic materials may be submitted. For alternate designs, submit complete design calculations and details which include plan view, elevation view, and details in accordance with the Contract Documents. These shall show the extent, numbe r of layers of geosynthetic reinforcement, minimum properties of each geosynthetic reinforcement layer, vertical spacing of geosynthetic reinforcement, orientation of geosynthetic facing details, details at special structures or obstructions, typical const ruction sequence, and top and bottom elevations of the geosynthetic reinforcement. Calculations shall be submitted to substantiate the design meets the requirements of Chapter 263 of the FDOT Design Manual and in accordance with the Plans. As a minimum , these shall clearly show the derivation of reinforcement requirements (i.e., type, spacing, length, etc.) and determination of all design parameters and factors. All plans and calculations are to be signed and sealed by a Professional Engineer registered in the State of Florida.
145-3 Materials.
145-3.1 Geosynthetic Materials: Use materials meeting the requirements of Section 985
and are listed on the Approved Product List (APL) . Deliver geosynthetic materials (including facing and drainage elements) to th e job site in unopened shipping packages labeled with the supplier’s name and product name. During shipping and storage, protect the geosynthetic from physical damage, debris and from temperatures greater than 140°F. Follow the supplier’s recommendations r egarding protection from direct sunlight. At the time of installation, the Engineer will reject the material if it has defects, tears, punctures, flaws, deterioration, or other damage. However, if approved by the Engineer, the Contractor may repair torn or punctured sections by placing a patch over the damaged area. Replace or repair any rejected geosynthetic at no additional expense to the Department.
145-3.2 Backfill Materials: Use only free draining backfill material in the reinforced fill
volume as sho wn in the Plans meeting the following gradation limits as determined in accordance with AASHTO T 27 and FM 1-T011: Table 145-1 Sieve Size Percent Passing 3-1/2 inches 100 FY 2023-24 Return to Table of Contents Table 145-1 Sieve Size Percent Passing 3/4 inch 70 to 100 No. 4 30 to 100 No. 40 15 to 100 No. 100 5 to 65 No. 200 0 to 15 Do not use backfill material containing more than an average of 2.0% by weight of organic material, as determined by FM 1-T267 and by averaging the test results for three randomly selected, representative samples from each stratum or stockp ile of a particular material. Consider the stratum or stockpile unsuitable for construction of the reinforced fill volume if an individual test value exceeds 3.0%. Use backfill with a maximum plasticity index of six as determined by AASHTO T 90, and a ma ximum liquid limit of 15 as determined by AASHTO T 89. Use backfill materials with a pH between 4.5 and 10.0 as determined by FM 5-550. When metal pipes or other metal items are embedded in the backfill, use backfill with a pH between 6.0 and 10.0. Do not use soil cement or lime stabilized backfill unless approved by the Engineer. Have the backfill material tested for every soil type for pH by a Department approved independent testing laboratory prior to placement. Submit a signed and sealed certification by a Professional Engineer registered in the State of Florida, that the results have met the requirements of this Section.
145-4 Construction.
145-4.1 General: Obtain from the geosynthetic supplier, technical instructions, guidance
in preconstruction activities, and on -site technical assistance during construction. Submit a copy of any instructions provided by the supplier to the Engineer prior to beginning installation.
145-4.2 Reinforced Soil Slopes:
145-4.2 1 Preparation: Remove all existing vegetation and all unsuitable
foundation materials. Prepare the founda tion in accordance with Section 110, except as noted herein. Proof roll the graded area with a vibratory roller weighing a minimum of 8 tons or a sheepsfoot roller, where appropriate, exerting a compression of at least 250 psi on the tamper foot for at least five passes in the presence of the Engineer or as directed by the Engineer. Remove and replace any soft or loose foundation subsoils that are, in the opinion of the Engineer, incapable of sustaining the required proof rolling, in accordance with Sect ion 125. Provide proof rolled ground surfaces which are uniform, smooth, and free of abrupt changes in slope, debris, and irregularities that might damage the reinforcement. Promptly repair and restore to their original condition any areas outside the l imits of disturbance shown in the Plans which are damaged as part of this work at no expense to the Department. Make every possible effort to avoid such damage.
145-4.2 2 Geosynthetic Placement: Place the geosynthetics at the proper
elevation, location a nd orientation as shown in the Plans. In general, place the geosynthetics used for slope stabilization such that its primary direction of tensile strength is perpendicular to the plan face of the slope. Pull the geosynthetic material tight, and secure it a s necessary to lay flat against the soil prior to fill placement. FY 2023-24 Return to Table of Contents Place adjacent rolls of geosynthetic to maintain 100% horizontal coverage at the face of the slope. When placing geosynthetic for curved embankments, do not allow less than 50% horizontal coverage or an unreinforced horizontal spacing greater than 3 feet at the end of the reinforcement farthest from the face of the slope. Do not allow vertical spacing of the geosynthetic layers to exceed the spacing shown on the shop drawings. Do not ma ke any splices or seams in the primary direction of tensile strength in the geosynthetic without approval of the Engineer. When splices in the primary direction are approved, make splices full width of the geosynthetic strip by using a similar material wit h similar strength. Use a splice mechanism that allows a minimum of 95% load transfer from piece to piece of geosynthetic. Make only one splice per length of geosynthetic. Do not place splices within 6 feet of the slope face, within 6 feet below top of slo pe, or horizontally adjacent to another splice. Place only that amount of geosynthetic material, including facing and drainage material, which will be covered in a single days’ production. Do not operate equipment directly on the geosynthetics. Opera te equipment such that no turning movements occur on the areas where geosynthetic is in place with less than 12 inches of fill cover. Fill and compact ruts of more than 3 inches in depth as they develop.
145-4.2 3 Backfill Placement: Perform work in acco rdance with an approved QC
Plan meeting the requirements of 105 -3. A LOT is defined as a single lift of finished embankment not to exceed 500 feet in length. Maintain uniform moisture content of the backfill material prior to and during compaction througho ut each layer of material. Use backfill material having a placement moisture content within 2% on the dry side of optimum. Do not place wet backfill with moisture content greater than optimum in the fill. Spread backfill material over the geosynthetic in t he direction of geosynthetic overlaps. Do not stockpile backfill materials on the installed geosynthetics. Avoid construction procedures or equipment which, in the opinion of the Engineer, will cause excessive mudwaving. Compact the backfill using eithe r smooth wheel or rubber tire rollers. Do not use sheepsfoot, grid rollers, or other types of equipment employing a foot. At the end of each day’s operation, slope the backfill surface in order to permit runoff of rainwater away from the slope face, or pro vide some other positive drainage. Do not exceed the maximum allowable lift thickness in Section 120. 145.4.2.4 Repairs: Replace geosynthetic reinforcement damaged during or after installation at no expense to the Department. Repair geosynthetics damaged during or after installation only after the supplier establishes that the interior and exterior stability is not affected and after obtaining the Engineer’s approval. Make such repairs as follows: Remove all backfill material from the damaged area of t he reinforcement geosynthetic plus an additional 4 feet in all directions beyond the limits of damage. Place a patch consisting of the same material as the reinforcement geosynthetic over the damaged area. Overlap the undamaged reinforcement geosynthetic w ith the patch a minimum of 3 feet in all directions. Then replace and compact backfill material in accordance with 145 -4.2.3.
145-4.3 Reinforced Foundations Constructed on Soft In -Situ Soils:
145-4.3 1 Preparation: For some applications involving reinfo rcement of soft
insitu soils, the Engineer may require that some vegetation be left in place. If directed in the Plans or by the Engineer, cut trees to within 6 inches of the existing surface, and leave the stumps in place. Remove fallen trunks, limbs, etc . greater than 3 inches in diameter. FY 2023-24 Return to Table of Contents
145-4.3 2 Backfill Placement: Meet the requirements of 145 -4.2.3.
145-4.3 3 Geosynthetic Placement: Position and orient the geosynthetics over
prepared surfaces. Place a geotextile filter of a type recommended by th e designer of the geosynthetic system under the reinforcement geosynthetic. Cut and overlap geosynthetics as necessary to accommodate curves. Overlap or join ends and sides of adjacent geosynthetic courses as shown in the Plans and in accordance with 145 -4.2.2. Make any overlaps in geosynthetics in the same direction that covering embankment will be spread. Take care to ensure that the geosynthetic sections do not separate at overlaps during construction. Pull the geosynthetic material tight by hand to a te nsion that removes all slack.
145-4.3 4 Repairs: Meet the requirements of 145 -4.2.4.
145-5 Certification.
Submit certification from the supplier, at least ten days prior to placement, that the products used are the same products listed on the APL, are in accordance with the project design requirements and is recommended by the supplier for use at this location. Acceptance of furnished material will be based on the supplier ’s certification and visual inspection by the Engineer.
145-6 Acceptance Program.
145-6.1 General Requirements: Meet the requirements of 120 -10 except delete the
requirements of 120 -10.1.4.1, 120 -10.1.6, 120 -10.2 and 120 -10.3.
145-6.2 Maximum Density Determination: 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 145-6.3.1.1, 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.
145-6.3 Density Testing Requirements: Ensure compliance with the requirements of
nuclear density testing in ac cordance with FM 1-T238. Determine the in -place moisture content for each density test. Use 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 b y Granular Soils by Use of a Microwave Oven) for moisture determination.
145-6.3 1 Acceptance Criteria: For select backfill, obtain a density in each LOT
of at least 95% of the maximum density as determined by FM 1-T180.
145-6.3 1.1 Optional Acceptanc e Criteria for A-3 and A-2-4 Materials :
Obtain a minimum dens ity of 100 % of the maximum dry density as determined by FM 1-T099. The combined width from both reinforced fill volume and retained fill material may be considered the same LOT if both volumes co mprise the same material and both are compacted with the same procedure, lift thickness, equipment and compacting effort.
145-6.4 Frequency: Conduct sampling and testing at a minimum frequency listed in the
table below. The Engineer will perform verificat ion sampling and tests at a minimum frequency listed in the table below. FY 2023-24 Return to Table of Contents Table 145-2 Test Name Quality Control (QC) Verification Maximum Density One per soil type One per soil type Density One per LOT One per four LOTs Soil Classification , Gradation, LL & PI One per Maximum Density One per Maximum Density Organic Content One per soil type One per soil type In addition, test for pH at a minimum frequency of one test per soil type at point of placement according to 145-3. 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.
145-6.5 Test Selection and Reporting: Determine test location s including stations and
offsets, using the random number generator approved by the Engineer. Do not use notepads or worksheets to record data for later transfer into the Earthwork Records System (ERS) section of the Department’s database. Notify the Engin eer upon successful completion of QC testing on each LOT.
145-7 Verification Comparison Criteria and Resolution Procedures.
145-7.1 Maximum Density Determination: The Engineer will collect enough material
to split and create two separate samples and retai n one for resolution until LOTs represented by the samples are accepted. 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.
145-7.2 Density Testing: Meet the requirements of 120 -10.4.2.
145-7.3 Gradation: The Engineer will verify the QC results if the verification result
meets the gradation limits set forth in the gradat ion table of 145 -3.2. Otherwise, the Engineer will test the sample retained in 145 -6.1. 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 ac cordance 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 mate rial. The Engineer will perform new verification testing.
145-7.4 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 145 -6.1. 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.
145-7.5 Soil Classification: The Engineer will meet the requirements of 120 -10.4.3
except test the sample retained in 145 -6.1 instead of taking the additional one. FY 2023-24 Return to Table of Contents
145-7.6 Organic Content: The Engineer will verify t he QC results if the verification
result satisfies the organic content test criteria set forth in 145 -3.2. 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, mate rial 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.
145-7.7 pH: The Engineer will verify the QC results if the verification r esult satisfies the
pH test criteria set forth in 145 -3.2. Otherwise the Engineer will collect an additional sample. 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. 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.
145-8 Method of Measurement.
145-8.1 Geosynthetic Reinforced Soil Slopes: The quantity to be pa id for will be the
plan quantity area, in square feet, of the projected vertical height of the slope face, measured from the top of slope to the finished graded surface at the toe of slope and from the beginning to end limits as shown in the Plans, regardl ess of the length or number of layers of geosynthetic within the reinforced volume and including any reinforcement required below the toe of slope elevation.
145-8.2 Geosynthetic Reinforced Foundations over Soft Soils: The quantity to be paid
for will be the plan quantity area, in square yards, of the embankment to be reinforced as shown in the Plans, regardless of the length or number of layers of geosynthetic within the reinforced soil volume, and including any reinforcement required below the original g round elevation.
145-9 Basis of Payment.
145-9.1 Geosynthetic Reinforced Soil Slopes: Price and payment will be full
compensation for all work, materials, and services specified in this Section, including design and shop drawings, geosynthetic materials, facing materials and/or treatment, installation, testing, and required submittals. The cost and placement of all backfill material will be included in the pay quantity for embankment or borrow excavation, as applicable.
145-9.2 Geosynthetic Reinforced Fou ndations over Soft Soils: Price and payment will
be full compensation for all work, materials, and services specified in this Section, including geosynthetic materials, geotextile filter materials, facing materials, drainage materials, installation, testin g, and required submittals. The cost and placement of all backfill will be included in the pay quantity for embankment or borrow excavation, as applicable.
145-9.3 Payment Items: Payment will be made under:
Item No. 145 - 1- Geosynthetic Reinforced Soil S lopes - per square foot. Item No. 145 - 2- Geosynthetic Reinforced Foundations over Soft Soils - per square yard. FY 2023-24 Return to Table of Contents SECTION 160 STABILIZING
160-1 Description.
Stabilize designated portions of the roadbed to provide a firm and unyielding subgrade, having the required bearing value specified in the Plans.
160-2 Materials.
160-2.1 Commercial Material: Meet the requirements of Section 914-2.1.
160-2.2 Local Material: Submit test results to the Engineer at least 14 days prior to the
stabilization operation.
160-2.2 1 Local Stabilizing Material: Sample and test material from each source
and meet the requirements of Section 914. The Engineer will verify the Quality Control (QC) test results meet the requirements of Section 914. If the QC and Verification results do not compare, the Engineer will take one additional sample of material from the s ource in question and the State Materials Office (SMO) or an AASHTO accredited laboratory designated by the SMO will perform Resolution testing. If the Resolution test results satisfy the required criteria, material from that source will be verified and ac cepted. If the Resolution test results do not meet the required criteria, reject the material.
160-2.2 2 Reclaimed Asphalt Pavement (RAP) : Obtain the Engineer’s approval
in writing for the option to use 100% RAP material . Material must be milled and stoc kpiled without blending or contaminating with any other material .
160-2.2 3 Reclaimed Asphalt Pavement (RAP ) Blended Material : RAP
blended material is defined as material meeting the requirements of 914 -1 and 914 -2.2 except for the limits for organic content. If the RAP blended material meets the requirements of 914 -1 and 914-2, then the blended material will be classified as local stabilizing material . Provide test results to the Engineer and obtain their approval in writing before using RAP blended material. The Engineer will verify that the QC test results meet the acceptance criteria, otherwise the Engineer will perform Resolut ion testing procedures specified in 160 -2.2.1.
160-2.3 Existing Base: Obtain the Engineer’s approval in writing before using existing
base. When the material from an existing base is used as all, or a portion, of the stabilizing additives, no further test ing is required unless directed by the Engineer.
160-2.4 Granular Subbase : The Engineer may allow, at no additional cost to the
Department, the substitution of 6 inches of granular subbase meeting the requirements of 290 -2 and 290-3, only when 12 inches of Type B stabilization requiring a Limerock Bearing Ratio (LBR) value of 40 is specified in accordance with Standard Plans, Index 120-001.
160-3 Construction Methods.
160-3.1 General: Prior to the beginning of stabilizing operations, construct the area to be
stabilized to an elevation such that, upon completion of stabilizing operations, the completed stabilized subgrade will conform to the lines and grades shown in the Plans. Prior to spreading any additive stabilizing material, bring the surface of the r oadbed to a plane approximately parallel to the plane of the finished graded surface shown in the Plans. Construct mainline pavement lanes, turn lanes, ramps, parking lots, concrete box culverts, retaining wall systems, shoulder -only areas, sidewalk, and shared use path areas meeting the requirements of 120 -8.1, except replace “embankment” with “subgrade”. FY 2023-24 Return to Table of Contents