524REINFORCED CONCRETE BOX CULVERTS

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Details and design calculations, sealed by a Licensed Professional Engineer, shall be submitted as Shop Drawings in accordance with all of the requirements given in Article 105.02 when the conditions of loading differ from what is given in AASHTO M 259 {M 259M}. Details and design drawings shall be submitted as Working Drawings for all pipe entrances, connections to drainage structures, bends in culvert alignment, wingwalls, aprons and guardrail attachment in accordance with Article 105.02

A uniform transition shall be constructed where new or existing cast in place culverts are extended with precast units. A doweled or tongue and groove connection shall be provided at the junction of the precast unit and the cast in place section. Details and design calculations for the transition shall be submitted in accordance with the requirements given in Article 105.02 for the submittal of Working Drawings.

Precast units shall be laid to the same line and grade requirements noted in Item 530.03(a)2. for pipe. The units shall be connected so that there are no gaps between the ends of the units and the inner surfaces are flush and even. Sealant shall be applied to the mating surfaces of each unit. The method of sealing the joints shall be the method given for concrete pipe in Subitem 530.03(d)3a. Unless shown otherwise on the plans, the Contractor shall have the option to use any of the type joint sealers given for rigid pipe in Article 846.01.

Precast units shall be backfilled in accordance with the requirements given for pipe in Subarticle 530.03(e).

End sections for precast units, if required, shall be constructed in accordance with the details shown on the plans.

524.04Method of Measurement

Payment for reinforced concrete box culverts will be based on units of cubic yards {cubic meters} of Culvert Concrete and pounds {kilograms} of Steel Reinforcement. The quantity of concrete and reinforcing steel for both cast in place and precast concrete culverts shall be based on the height and width of the openings, the number of barrels, the length of the culvert, and the quantity of concrete and reinforcing steel per unit length of the culvert shown on the plans for the construction of cast in place culverts. The quantity of concrete and reinforcing steel shown for precast culverts will always be the quantity required for the construction of a cast in place culvert with the same height and width of openings, number of barrels and length. Wingwalls, parapets, toewalls, and apron quantities shall also always be based on the quantities given on the plans for cast in place construction regardless of a requirement for the installation of precast units. No additional payment will be made where barrel lengths, apron areas, backfilling, or items of work have to be increased due to the Contractor selecting the option to furnish and install precast units. Fill concrete required between barrels of precast units will not be measured or paid for separately. Steel Reinforcement will be measured and paid for under Section 502. Excavation and Backfill will be measured and paid for under Section 214 with the limitation that payment for foundation backfill for a bedding layer for precast concrete culverts will only be made for a thickness of 4 inches {100 mm} and a width of 2 feet {600 mm} wider than the extent of the outside walls. Separate payment will not be made for any other items of work involved.

524.05Basis of Payment

The contract price for Culvert Concrete and Culvert Concrete Extension shall be full compensation for all labor, tools, equipment, and incidentals necessary to construct the complete culvert and related structures (toe walls, wing walls, parapets, connections to drainage structures, etc.). The contract RETAINING WALL 401

price shall also be full compensation for design and submittals, construction of cofferdams, temporary diversion channels, protection of water quality at cofferdams and diversion channels, flood protection and falsework and formwork. Payment will not be separated for individual culverts.

524-A Culvert Concrete ( * ) - per cubic yard {cubic meter} 524-B Culvert Concrete Extension ( * ) - per cubic yard {cubic meter} * Enter either Cast In Place or Precast if the type of construction must be designated. RETAINING WALL

529.01Description

Retaining walls shall be constructed at the locations and within the limits shown on the plans. Standard details may be shown on the plans for the construction of cast-in-place reinforced concrete retaining walls. The details for the construction of other types of retaining walls may also be shown on the plans. The submittal and approval of the design and details of a retaining wall is required if the details of the retaining wall are not shown on the plans.

529.02Materials

Selected backfill material for Mechanically Stabilized Earth (MSE) Walls and Gravity Walls shall be well graded, angular, commercially produced sand or crushed stone (material containing slag will not be allowed) free from organic matter and/or other deleterious material. The following types of materials will be allowed:  Concrete sand meeting the requirements of Section 802, Fine Aggregates (F.M. waived).  Section 801 Coarse Aggregate crushed material that is smaller than #467 with 10% or less passing the #200 {75 µm} sieve.  Crusher run material with 100% passing a 2-inch {50 mm} sieve and with 10% or less passing the #200 {75 µm} sieve.

Concrete for cast-in-place reinforced concrete retaining walls shall be Class A concrete in accordance with the material requirements given in Section 501. Reinforcing steel shall be furnished and placed in accordance with the material requirements given in Section 502. The bituminous expansion joint filler and waterstop shall meet the requirements given in Section 832. Dowels at expansion joints shall be plain Grade 60 bars meeting the requirements given in AASHTO M 31. Pipe sleeves at expansion joints shall be Grade 36 sleeves meeting the requirements given in AASHTO M 270. Cast-in-place walls shall have a deposit (belt), not less than 1 foot {300 mm} wide and 1 foot {300 mm} deep, of approved local or commercial free draining material placed full length along the back face of the vertical walls at the line of weepholes. This material shall conform to the requirements given in Subarticle 214.02(b).

Approved ALDOT MSE wall systems are shown in the "Material, Sources and Devices with Special Acceptance Requirements" manual, List II-22, "MSE Wall Systems". The materials required for a mechanically stabilized earth retaining wall shall meet the requirements of the approved MSE wall system. The material and construction requirements shall be shown on the details of the wall submitted by the Contractor. The details of the wall will be distributed by the Engineer for inspection of the installation of the wall.

Approved ALDOT gravity wall systems are shown in the "Material, Sources and Devices with Special Acceptance Requirements" manual, List II-28, "Gravity Wall Systems". The materials required for a gravity wall shall meet the requirements of the approved gravity wall system. The material and RETAINING WALL 402

construction requirements shall be shown on the details of the wall submitted by the Contractor. The details of the wall will be distributed by the Engineer for inspection of the installation of the wall.

All precast and masonry concrete items shall meet the requirements given in Section 831. All precast and masonry concrete items shall meet the material requirements established by the ALDOT through the submittal and approval of wall designs, material requirements and details.

529.03Construction Requirements

The Contractor shall have the following four options for the construction of a retaining wall if the required type of wall is not shown on the plans:  ALDOT designed cast-in-place reinforced concrete retaining wall;  Contractor designed cast-in-place reinforced concrete retaining wall;  reinforced mechanically stabilized earth (MSE) retaining wall;  gravity wall. MSE and gravity walls shall be designed and fabricated by, or under the technical supervision of an ALDOT approved supplier. Approved ALDOT MSE walls systems are shown in the "Material, Sources and Devices with Special Acceptance Requirements" manual, List II-22, “MSE Wall Systems”. Approved ALDOT gravity walls systems are shown in List II-28, "Gravity Wall Systems". Information concerning these lists is given in Subarticle 106.01(f) and ALDOT-355.

The Contractor shall submit descriptions of the retaining wall projects completed in the last three years to serve as evidence of the capability to construct the chosen wall system. The descriptions of the retaining wall projects shall contain names and telephone numbers of owners’ representatives who can verify the Contractor’s participation on those projects. These descriptions shall be submitted with the "wall installation plan" and will be evaluated by the Engineer.

The submittal of the design and details of a retaining wall is required if the details of the retaining wall are not shown on the plans. The Contractor shall submit Working Drawings in accordance with Article 105.02. The contractor shall also submit a Wall Installation Plan that includes:

installation;

to the reinforcement during subsequent backfill placement. The design calculations shall include an analysis of the internal and external stability of the wall and all structural connection details of the wall. The design shall be in conformance with the requirements given in the current AASHTO Standard Specifications for Highway Bridges as amended by interim revisions. The Engineer will not approve the submittal but will review it to make sure that it is sufficiently complete to allow the construction of the wall. s. Any proposed modification of the installation plan during construction shall be submitted to the Construction Engineer for review and distribution.

The Contractor shall perform the excavation in a manner that will prevent damage to adjacent structures and maintain the stability of the ground adjacent to the excavation. Excavated material that remains after the construction of the wall shall be used in the formation of the embankment, roadbed, base layers, shoulders, slopes, bedding, backfill for culverts, and for other purposes as allowed or directed by the Engineer. The material shall be suitable for the use that is allowed or directed by the Engineer. Excavated material that cannot be used as a part of the construction in other areas of the project shall be disposed of in accordance with the requirements given in Section 210 for the disposal of surplus material.