CATEGORY 400 STRUCTURES SECTION 421 — REINFORCING STEEL
421.01 Description
Furnish and place uncoated and epoxy coated reinforcing steel.
421.02 Materials
Grout 902.11(c) Deformed Steel Bars 908.01 Plain Round Steel Bars for Column Spirals 908.02 Wire Mesh 908.05 and 908.06 Fusion Bonded Epoxy Powder Coating for Section 465 and 917.02 Steel and Touch Up System Galvanizing Reinforcing Steel A123 Hardware A153 Stainless Steel Bars 908.03 Low Carbon Chromium Bars 908.13
421.02.01 Supports. Use approved coated metal, plastic, plastic tipped, or galvanized material.
Aluminum is unacceptable. All materials are subject to approval. For epoxy coated steel, use wire supports completely covered with 1.5 mils to 9.0 mils of adherent epoxy coating except for minimum necessary contact marks. Hold the reinforcing steel in place with plastic coated tie wires fabricated for this purpose. Steel bars used as supports for epoxy coated steel shall be coated in the same manner as reinforcing steel.
421.03 Construction
421.03.01 Working Drawings. Submit working drawings for approval prior to the start of any
fabrication, unless otherwise specified. Refer to Section 499.
421.03.02 Plan Dimensions. All dimensions related to reinforcing steel are out to out
measurement except the spacing is measured center to center. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
421.03.03 Cutting and Bending. Cut and bend reinforcing bars at the mill or shop to the shapes
specified before shipment to the job site. Bending shall not be performed in the field except to correct errors, damage by handling and shipping, or minor omissions in shop bending. Saw or shear epoxy coated reinforcing bars on skewed bridges and in other locations that are specified to be cut in the field; flame cutting is prohibited. Ensure that all bending conforms to the tolerances specified in the Contract Documents. 421.03.04 Shipping, Handling, and Protection of Material. Ship reinforcing steel bars in standard bundles; tagged and marked in accordance with the provisions of the Code of Standard Practice of the Concrete Reinforcing Steel Institute. Keep bundles intact, undamaged, and properly identified until ready for use. Bundle coated steel together for shipment using excelsior or other approved materials, and banded using plastic or padded metal bands. Perform all lifting with a lifting beam and multiple supports consisting of a sufficient quantity of straps or slings to prevent abrasion within the bundle from excessive bending or distortion. Store bundles at the site on suitable blocking or platforms at least 4 in. above any type of surface and vegetation. Keep free from vegetation growth, accumulations of dirt, oil, or other foreign material. Keep blocking sufficiently close to avoid bending and distortion of the bars. Correct any distortion of the bars or damage to epoxy coating as directed. Touch up any damage to the epoxy coating as specified in 465.03. Adequately cover epoxy coated bars for protection from ultraviolet rays from the time of delivery when they are to be stored outside for more than 90 days.
421.03.05 Placing and Fastening. Accurately place all reinforcing steel, including dowel bars,
in the position specified in the Contract Documents or working drawings, and hold firmly during the depositing and setting of the concrete. Do not insert into the plastic concrete. Tie all intersections, except alternate intersections need not be tied where spacing is less than 1 ft in each direction. On bridge decks and the top slabs of box culverts, tie all intersections in the top mat of reinforcing. Do not bend reinforcing steel bars after embedment in concrete. Before placing concrete, clean all mortar from the reinforcing. Do not place concrete until the reinforcing bars are inspected and approved. Approval shall not relieve the Contractor of the responsibility for correcting problems caused by any shifting of the bars during the placement of concrete. Support reinforcing bars and maintain their distances from faces of forms by using approved templates, blocks, ties, hangers, or other supports. Support bars in the bottom of footings on approved precast concrete blocks with embedded tie wires or suspend in place. Support bars in the tops of footings by using approved supports. Do not use metal, metal with plastic tipped legs, or plastic chairs against formed surfaces that will be exposed in the finished structure. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS The Engineer will perform a final visual inspection of epoxy coated steel at the construction site after the steel is in place and immediately prior to placing the concrete. Patch designated repair areas using epoxy as specified in 465.03. Do not place concrete on a patched area until the patching material has cured for one hour. Allow four hours of normal working time after the reinforcing and forms are in place for the inspection.
421.03.06 Splicing. Furnish bar lengths and splices as specified in the Contract Documents, and
as detailed in the working drawings stamped as accepted by the Administration. Do not perform additional splicing without approval. Make lap splices with the bars in contact and wired together. Do not weld reinforcing steel or weld attachments to reinforcing steel without approval. Perform welding according to AWS D1.4.
421.03.07 Tying New Concrete into Existing Concrete. On all projects where portions of
existing structures are to be used in the finished structure and existing concrete is to be removed, straighten, clean, and protect the existing reinforcing steel to be incorporated in the final structure. For exposed existing reinforcing steel that is to be incorporated into the final structure:
a.Cut out any that has lost 20 percent or more of its original cross sectional area as determined by the Engineer. Provide and place a new bar of the same diameter so as to have the minimum required lap at each end of the new bar, or modified as per (c).
b.Where the required bar lap length is available, use it as a dowel.
c.Where the required bar lap is not available or limits of concrete removal to achieve bar lap are too great, make a welded or approved mechanical splice. When existing reinforcing steel extends into an area in which epoxy coated reinforcing steel is required, abrasive blast clean and epoxy coat using the touch up system. Refer to Section 465. If expected reinforcing steel is missing, or a pattern differing from that shown on the existing Contract Documents is uncovered, contact the Office of Structures for evaluation. Where dowel bars are required to tie new concrete into an existing structure, install as specified in 406.03.
421.03.08 Substitution. Low carbon chromium or stainless steel reinforcing may be substituted
on a one-for-one basis for the specified epoxy coated or non-epoxy coated deformed steel bar reinforcing, at the option of the Contractor, as approved by the Engineer. Welding of low carbon chromium bars is prohibited. No adjustment shall be allowed in the size, number, spacing, laps and configuration of the reinforcing for any increase in strength or other properties provided by the substitute reinforcing bars. There will be no additional compensation for bars of differing material composition in lieu of the bars specified. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
421.04 Measurement and Payment
in the pertinent Concrete item. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS The payment will be full compensation for cleaning, coating, and for all material, labor, equipment, tools, and incidentals necessary to complete the work.
421.04.01 Reinforcing steel bars or epoxy coated reinforcing steel bars will not be measured but
the cost will be incidental to other pertinent items specified unless a Reinforcing Steel Bars or Epoxy Coated Reinforcing Steel Bars item appears in the Contract Documents.
421.04.02 Reinforcing Steel Bars or Epoxy Coated Reinforcing Steel Bars will not be measured
but will be paid for at the pertinent Contract lump sum price. 421.04.03 Reinforcing Steel Bars or Epoxy Coated Reinforcing Steel Bars will be measured and paid for at the Contract unit price per pound based on the original approved overall lengths of bars computed on the basis of the nominal unit weight per linear foot.
421.04.04 Incorporating existing reinforcing steel in the final structure including straightening,
bending, splicing, and removal and replacement will not be measured but the cost will be included 422 — DAMPPROOFING AND MEMBRANE WATERPROOFING CATEGORY 400 STRUCTURES SECTION 422 — DAMPPROOFING AND MEMBRANE WATERPROOFING
422.01 Description
Furnish and apply dampproofing and waterproofing to concrete surfaces.
422.02 Materials
Asphaltic Materials 913.01 Asphalt Primer 913.02 Fabric for Use with Asphalt 913.03 Membrane Waterproofing and Dampproofing 913.04
422.03 Construction
Apply dampproofing and waterproofing using asphaltic materials, primers, and fabric; or by the roll or sheet method as specified in 422.03.07.
422.03.01 Storage. Store waterproofing fabrics and membranes in a dry protected place. Keep
containers of asphalt materials closed when not in use. 422.03.02 Surface Preparation. Do not apply dampproofing or membrane waterproofing until curing is complete and surfaces are protected from the cold. Ensure that all surfaces are dry, smooth, and free from projections and holes. When dampproofing and membrane waterproofing are both specified for application, apply the membrane waterproofing first. Do not apply dampproofing or membrane waterproofing when the temperature is less than 40 F.
422.03.03 Dampproofing. If asphaltic coatings are used for dampproofing, use two prime coats
and one seal coat. Apply dampproofing to the following concrete surfaces that will be in contact with backfill:
a.Rear face of abutments and abutment wing wall stems.
b.Rear faces of headwalls and wing walls for pipes 36 in. in diameter or larger and for culverts. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
Source: Maryland Standard Specifications for Construction and Materials, 2025 Edition. Pages 455–458 of 1,113.