450 RETAINING WALLS

From MDOT Policy Manual
Jump to: navigation, search
450.01 DESCRIPTION.
Construct cast-in-place reinforced concrete footings and stems conforming to the AASHTOAmerican Association of State Highway and Transportation Officials definitions of rigid retaining walls. When retaining wall mounted noise barriers are specified, the anchorage assemblies are included in the retaining wall. All components shall be as specified unless prior approval for alternatives is obtained from the AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02..
When piles or drilled shafts (caissons) are specified, refer to Sections 410 and 412, respectively.
450.01.01 Preapproved Alternate Retaining Walls. Alternate retaining walls may only be used when specified. Only those retaining walls specified will be permitted. All other retaining walls, even though they are preapproved or have been previously used on AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02. projects, are prohibited for use. The AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02. will not consider any other alternate retaining walls as a value engineering change proposal.
Enforcement. These requirements will be enforced on all projects.
Preapproved Alternate Retaining Wall List. Alternate retaining walls are selected from the list of Preapproved Alternate Retaining Walls, which is maintained by the Office of StructuresBridges, culverts, catch basins, drop inlets, retaining walls, cribbing, manholes, end walls, buildings, sewers, service pipes, underdrains, foundation drains, steps, fences, and other features that may be encountered in the work and not otherwise classified.. Procedures for adding products to the prequalified list may be obtained from the Office of StructuresBridges, culverts, catch basins, drop inlets, retaining walls, cribbing, manholes, end walls, buildings, sewers, service pipes, underdrains, foundation drains, steps, fences, and other features that may be encountered in the work and not otherwise classified..
Alternate retaining walls that have been previously used on AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02. projects without complying with the preapproval requirements shall be formally submitted through these procedures before they will be added to the Preapproved Lists for consideration to be used on future projects. These and other retaining wall systems may be submitted for addition to the Preapproved Lists, but the AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02. will not permit these submittals to be used on an advertised or awarded project.
Deviations. Submit any proposed deviation in materials, post size or shape; panel size or shape; reinforcing type, size, or placement from what is shown in the Contract DocumentsThe written agreement executed between an Administration and the successful bidder, covering the performance of the work and furnishing of labor, equipment and materials, by which the Contractor is bound to perform the work and furnish the labor, equipment and materials, and by which the Administration is obligated to compensate him therefore at the mutually established and accepted rate or price. The Contract Documents shall include the Invitation for Bids, Notice to Contractors, Instructions to Bidders, Proposal, Contract Forms and Bonds, General Provisions, Specifications, Supplemental Specifications, all Special Provisions, all Technical Provisions, all Plans and Notices to Proceed, also any written Change Orders and Supplemental Agreements that are required to complete the construction of the work in an acceptable manner, including authorized extension thereof or from the preapproved alternate retaining wall details on file in the AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02.’s Office of StructuresBridges, culverts, catch basins, drop inlets, retaining walls, cribbing, manholes, end walls, buildings, sewers, service pipes, underdrains, foundation drains, steps, fences, and other features that may be encountered in the work and not otherwise classified.. All costs for reviews, whether the details are accepted or rejected, shall be borne by the ContractorAny person having a Contract with a procurement agency. Contractor does not include an employee with an employment Contract, or an employee organization with a collective bargaining agreement.. Any fabrication or creation of any retaining wall element that is a deviation and is made prior to written approval of the AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02. shall be at the risk of the ContractorAny person having a Contract with a procurement agency. Contractor does not include an employee with an employment Contract, or an employee organization with a collective bargaining agreement..
Contract DocumentsThe written agreement executed between an Administration and the successful bidder, covering the performance of the work and furnishing of labor, equipment and materials, by which the Contractor is bound to perform the work and furnish the labor, equipment and materials, and by which the Administration is obligated to compensate him therefore at the mutually established and accepted rate or price. The Contract Documents shall include the Invitation for Bids, Notice to Contractors, Instructions to Bidders, Proposal, Contract Forms and Bonds, General Provisions, Specifications, Supplemental Specifications, all Special Provisions, all Technical Provisions, all Plans and Notices to Proceed, also any written Change Orders and Supplemental Agreements that are required to complete the construction of the work in an acceptable manner, including authorized extension thereof for Preapproved Alternates. If electing to use preapproved alternate retaining wall systems, only one type retaining wall may be constructed throughout the ContractAny agreement entered into by a procurement agency for the acquisition of supplies, services, construction, construction related services, architectural services or engineering services.Contract does not include: Collective bargaining agreements with employee organizations or agreements creating employer employee relationships, as defined in Article 64A, Section 15A(a)(3), Annotated Code of Maryland, Medicaid, Medicare, Judicare, or similar reimbursement contracts which user eligibility and cost are set by law or regulation.. Submit substitute plans, design calculations, and specifications. PlansThe official drawings issued by the Administration as part of the Contract Documents, including those incorporated in the Contract Documents by reference. shall be similar in size and detail to advertised documents. Working drawings from the fabricator are not acceptable as substitute plan submissions. Include drainage details and all revisions required to construct the alternate retaining wall system. All plans, calculations, and specifications shall be prepared, signed, and sealed by a professional engineer registered in the State of Maryland, and who has experience in design of the proposed alternate retaining wall system. The substitute plans shall bear the AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02.’s title block and be furnished on reproducible paper, linen, or mylar. Contract DocumentsThe written agreement executed between an Administration and the successful bidder, covering the performance of the work and furnishing of labor, equipment and materials, by which the Contractor is bound to perform the work and furnish the labor, equipment and materials, and by which the Administration is obligated to compensate him therefore at the mutually established and accepted rate or price. The Contract Documents shall include the Invitation for Bids, Notice to Contractors, Instructions to Bidders, Proposal, Contract Forms and Bonds, General Provisions, Specifications, Supplemental Specifications, all Special Provisions, all Technical Provisions, all Plans and Notices to Proceed, also any written Change Orders and Supplemental Agreements that are required to complete the construction of the work in an acceptable manner, including authorized extension thereof for construction of alternate retaining walls shall conform to the Policy and Procedures of the Office of StructuresBridges, culverts, catch basins, drop inlets, retaining walls, cribbing, manholes, end walls, buildings, sewers, service pipes, underdrains, foundation drains, steps, fences, and other features that may be encountered in the work and not otherwise classified.. These PlansThe official drawings issued by the Administration as part of the Contract Documents, including those incorporated in the Contract Documents by reference. will be issued as a Contract revision replacing the AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02.’s PlansThe official drawings issued by the Administration as part of the Contract Documents, including those incorporated in the Contract Documents by reference. and be kept by the AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02. as permanent records. All work pertaining to Contract DocumentsThe written agreement executed between an Administration and the successful bidder, covering the performance of the work and furnishing of labor, equipment and materials, by which the Contractor is bound to perform the work and furnish the labor, equipment and materials, and by which the Administration is obligated to compensate him therefore at the mutually established and accepted rate or price. The Contract Documents shall include the Invitation for Bids, Notice to Contractors, Instructions to Bidders, Proposal, Contract Forms and Bonds, General Provisions, Specifications, Supplemental Specifications, all Special Provisions, all Technical Provisions, all Plans and Notices to Proceed, also any written Change Orders and Supplemental Agreements that are required to complete the construction of the work in an acceptable manner, including authorized extension thereof for preapproved alternates shall be at no additional cost to the AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02..
After substitute PlansThe official drawings issued by the Administration as part of the Contract Documents, including those incorporated in the Contract Documents by reference. are approved and issued as a redline revision, submit working drawings bearing the fabricator or supplier’s title block for review and approval to the AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02. or directly to the consulting engineer as directed by Section 499.
450.02 MATERIALS.
Refer to 420.02. When retaining wall mounted noise barriers are specified, refer to 455.02 for the anchorage materials.
Sample Panel. Refer to Section 456 and the Contract DocumentsThe written agreement executed between an Administration and the successful bidder, covering the performance of the work and furnishing of labor, equipment and materials, by which the Contractor is bound to perform the work and furnish the labor, equipment and materials, and by which the Administration is obligated to compensate him therefore at the mutually established and accepted rate or price. The Contract Documents shall include the Invitation for Bids, Notice to Contractors, Instructions to Bidders, Proposal, Contract Forms and Bonds, General Provisions, Specifications, Supplemental Specifications, all Special Provisions, all Technical Provisions, all Plans and Notices to Proceed, also any written Change Orders and Supplemental Agreements that are required to complete the construction of the work in an acceptable manner, including authorized extension thereof for Architectural Treatment specifications.
Some projects may require a specified surface such as an ashlar stone pattern, or matching a similar structure or stonework in the area. The ContractorAny person having a Contract with a procurement agency. Contractor does not include an employee with an employment Contract, or an employee organization with a collective bargaining agreement. may request or the EngineerAny person designated by the Administrator or the procurement officer, acting directly or through his duly authorized representative, such representative acting within the scope of the particular duties assigned to him or of the authority given him. may direct that the sample of the texture be submitted for approval prior to submission of the sample panel containing the specified stain.
450.02.01 Reinforcement. Reinforcing bars and welded wire fabric in retaining walls that are less than 10 ft from the edge of paved surface (includes shoulders) shall be epoxy coated. Supports for epoxy coated reinforcement shall be coated the same as the reinforcing steel.
450.02.02 Backfill for Preapproved Alternates. Use size No. 57 stone as backfill for all preapproved alternate retaining walls, regardless of the type backfill recommended or specified by the retaining wall manufacturer. Use geotextile when specified.
450.02.03 Concrete Stain. 902.18. When a color is specified for the exposed surfaces of the retaining wall, select the producer of the stain from the Qualified Products List (QPL) maintained by the Office of Materials Technology. The color number shall meet Federal Standard 595.
450.02.04 Textures.
(a) Unless otherwise specified, the exposed surfaces of the retaining wall shall receive a special surface treatment as specified in 420.03.07(b).
(b) When a special texture is specified, it shall be produced by using an approved form liner.
450.02.05 Preapproved Alternate Retaining Wall. Match the materials and details as approved and on file in the Office of StructuresBridges, culverts, catch basins, drop inlets, retaining walls, cribbing, manholes, end walls, buildings, sewers, service pipes, underdrains, foundation drains, steps, fences, and other features that may be encountered in the work and not otherwise classified..
450.03 CONSTRUCTION.
Construct retaining walls as shown on the PlansThe official drawings issued by the Administration as part of the Contract Documents, including those incorporated in the Contract Documents by reference., as specified in 420.03, and herein. Construct alternate retaining walls according to the details and specifications that are on file with the Office of StructuresBridges, culverts, catch basins, drop inlets, retaining walls, cribbing, manholes, end walls, buildings, sewers, service pipes, underdrains, foundation drains, steps, fences, and other features that may be encountered in the work and not otherwise classified.. Should any detail or specification change, the retaining wall firm shall submit the revision for review and approval prior to using that revision on AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02. projects. Revisions shall not be submitted for projects that are already bid.
Do not apply any loading to retaining wall concrete until the concrete in that portion has attained a compressive strength of at least 3000 psi. In addition, complete the backfilling prior to placing any other loads on the wall.
450.03.01 Concrete Stain. When stain is specified, apply two coats according to the manufacturer’s recommendations or as directed. Before application, ensure that all surfaces are structurally sound, clean, dry, fully cured, and free from dust, curing agents, form release agents, efflorescence, scale, and other foreign materials.
450.03.02 Anchor Bolt Assemblies. When required, install as specified. Refer to Section 455. All holes and welding required in the assemblies shall be done before galvanizing. Keep all assemblies free of oil and mill coatings.
450.04 MEASUREMENT AND PAYMENT.
Retaining walls will not be measured but will be paid for at the Contract lump sum price for the pertinent Retaining Wall item. The payment will be full compensation for all piles, caissons, footings, forms and form removal, architectural treatment, reinforcement steel, concrete, curing, anchorage assemblies, stains and coatings, excavation, sheeting and shoring, drainage systems, backfill (including size no. 57 stone and geotextiles for alternate retaining walls), and for all material, labor, equipment, tools, and incidentals necessary to complete the work.
When specific items for Piles for Retaining Walls are included in the Contract DocumentsThe written agreement executed between an Administration and the successful bidder, covering the performance of the work and furnishing of labor, equipment and materials, by which the Contractor is bound to perform the work and furnish the labor, equipment and materials, and by which the Administration is obligated to compensate him therefore at the mutually established and accepted rate or price. The Contract Documents shall include the Invitation for Bids, Notice to Contractors, Instructions to Bidders, Proposal, Contract Forms and Bonds, General Provisions, Specifications, Supplemental Specifications, all Special Provisions, all Technical Provisions, all Plans and Notices to Proceed, also any written Change Orders and Supplemental Agreements that are required to complete the construction of the work in an acceptable manner, including authorized extension thereof, they will be measured and paid for as specified in 410.04.
When specific items for Drilled Shafts (Caissons) for Retaining Walls are included in the Contract DocumentsThe written agreement executed between an Administration and the successful bidder, covering the performance of the work and furnishing of labor, equipment and materials, by which the Contractor is bound to perform the work and furnish the labor, equipment and materials, and by which the Administration is obligated to compensate him therefore at the mutually established and accepted rate or price. The Contract Documents shall include the Invitation for Bids, Notice to Contractors, Instructions to Bidders, Proposal, Contract Forms and Bonds, General Provisions, Specifications, Supplemental Specifications, all Special Provisions, all Technical Provisions, all Plans and Notices to Proceed, also any written Change Orders and Supplemental Agreements that are required to complete the construction of the work in an acceptable manner, including authorized extension thereof, they will be measured and paid for as specified in 412.04.
SPECIAL PROVISION INSERTS

The following Special Provision Inserts update Section 450 after the official publication of the Standard SpecificationA written description of functional characteristics, or the nature of a construction item to be procured. It may include a. Updated documents may be found within the Standard and Supplemental Specifications for Construction and Materials on the MDOTMaryland Department of Transportation SHA web page.

SPI-Section 450-Concrete Stain. Dated 5/11/2018.