Item No. 406

Reinforcing Steel

406.1 Description

This item shall consist of the furnishing and placing of reinforcing steel, deformed and smooth, of the size and quantity indicated and in accordance with these specifications.

406.2 Materials

(1)  Bars

Bar reinforcement shall be deformed and shall conform to ASTM A 615, A 616, Grades 40, 60 or 75 and shall be open-hearth, basic oxygen or electric furnace new billet steel, unless otherwise indicated.  Large diameter new billet steel (Nos. 14 and 18), Grade 75, will be permitted for straight bars only.

Where bending of bar sizes No. 14 or No. 18 of Grades 40 or 60 is required, bend testing shall be performed on representative specimens as described for smaller bars in the applicable ASTM specification.  The required bend shall be 90 degrees at a minimum temperature of 60 F around a pin having a diameter of 10 times the nominal diameter of the bar and shall be free of cracking.

Spiral reinforcement shall be either smooth or deformed bars or wire of the minimum diameter indicated.  Bars for spiral reinforcement shall comply with ASTM A 675, A 615 or A 617.  Wire shall comply with ASTM A 82.  The minimum yield strength for spiral reinforcement shall be 40,000 psi.

In cases where the provisions of this item are in conflict with the provisions of the ASTM Designation to which reference is made, the provisions of this item shall govern.

Report of chemical analysis showing the percentages of carbon, manganese, phosphorus and sulphur will be required for all reinforcing steel when it is to be welded, except for drill shafts.  No tack welding will be allowed.  All welding shall conform to the requirements of AWS D-1-72.

The nominal size and area and the theoretical weight (lbs.) of reinforcing steel bars covered by these specifications are as follows:

 

Bar Size Number

Nom. Diameter, inches

Nom. Area, Sq. ins.

Weight/Linear Foot

2

0.250

0.05

0.167

3

0.375

0.11

0.376

4

0.500

0.20

0.668

5

0.625

0.31

1.043

6

0.750

0.44

1.502

7

0.875

0.60

2.044

8

1.000

0.79

2.670

9

1.128

1.00

3.400

10

1.270

1.27

4.303

11

1.410

1.56

5.313

14

1.693

2.25

7.65

18

2.257

4.00

13.60

Smooth bars, larger than No. 4, may be steel conforming to the above or may be furnished in any steel that meets the physical requirements of ASTM A 36.

Smooth, round bars shall be designated by size number through No. 4.  Smooth bars above No. 4 shall be designated by diameter in inches.

(2)  Welded Wire Fabric

Wire for fabric reinforcement shall be cold-drawn from rods hot-rolled from open-hearth, basic oxygen or electric furnace billet.  Wire shall conform to the requirements of the Standard Specifications for Cold-Drawn Steel Wire for Concrete Reinforcement, ASTM A 82 or A 496.  Wire fabric, when used as reinforcement, shall conform to ASTM A 185 or A 497.

When wire is ordered by size numbers, the following relation between size number, diameter in inches and area shall apply unless otherwise indicated:

Size, W Number

Nom. Diameter (inch)

Nom. Area, sq. inches

31

0.628

0.310

30

0.618

0.300

28

0.597

0.280

26

0.575

0.260

24

0.553

0.240

22

0.529

0.220

20

0.505

0.200

18

0.479

0.180

16

0.451

0.160

14

0.422

0.140

12

0.391

0.120

10

0.357

0.100

8

0.319

0.080

7

0.299

0.070

6

0.276

0.060

5.5

0.265

0.055

5

0.252

0.050

4.5

0.239

0.045

4

0.226

0.040

3.5

0.211

0.035

3

0.195

0.030

2.5

0.178

0.025

2

0.160

0.020

1.5

0.138

0.015

1.2

0.124

0.012

1

0.113

0.010

0.5

0.080

0.005

 

Where deformed wire is required, the size number shall be preceded by D and for smooth wire the prefix W shall be shown.

 

(3)  Chairs and Supports

Chairs and Supports shall be steel, precast mortar or concrete blocks cast in molds meeting the approval of the Engineer/Architect of sufficient strength to position the reinforcement as indicated when supporting the dead load of the reinforcement, the weight of the workers placing concrete and the weight of the concrete bearing on the steel.  Chairs shall be plastic coated when indicated.

Chair Types and Applicable Uses

Structural or Architectural Elements (columns, beams, walls, slabs) exposed to weather, not subjected to sand blasting, water blasting or grinding.

Galvanized steel or steel chairs with plastic coated feet.

Structural or Architectural Elements exposed to weather and subject to sand blasting, water blasting or grinding.

Stainless steel chairs.

Structural or Architectural Elements not exposed to weather or corrosive conditions.

Uncoated steel chairs

 

Slabs and grade beams cast on grade.

Steel chairs with a base with 9 inch² minimum area or sufficient area to prevent the chair from sinking into fill or subgrade.  Precast mortar or concrete blocks meeting the requirements of this item may be used.

 

406.3 Bending

The reinforcement shall be bent cold, true to the shapes indicated.  Bending shall preferably be done in the shop.  Irregularities in bending shall be cause for rejection.

Unless otherwise indicated, the inside diameter of bar bends, in terms of the nominal bar diameter (d), shall be as follows:

Bends of 90 degrees and greater in stirrups, ties and other secondary bars that enclose another bar in the bend.

Bar Number
Grade 40
Grade 60

3, 4, 5

3d

4d

6, 7, 8

4d

5d

All bends in main bars and in secondary bars not covered above.

Bar Number
Grade 40

Grade 60

Grade 75

3 thru 8

6d

6d

--

9, 10

8d

8d

--

11

8d

8d

8d

14, 18

10d

10d

--

406.4 Tolerances

Fabricating tolerances for bars shall not be greater than shown on Standard 406-1.

406.5 Storing

Steel reinforcement shall be stored above the surface of the ground upon platforms, skids or other supports and shall be protected as far as practicable from mechanical injury and surface deterioration caused by exposure to conditions producing rust.  When placed in the work, reinforcement shall be free from dirt, paint, grease, oil or other foreign materials.  Reinforcement shall be free from injurious defects such as cracks and laminations.  Rust, surface seams, surface irregularities or mill scale will not be cause for rejection, provided the minimum dimensions, cross sectional area and tensile properties of a hand wire brushed specimen meets the physical requirements for the size and grade of steel indicated.

406.6 Splices

No splicing of bars, except when indicated or specified herein, will be permitted without written approval of the Engineer/Architect.  No substitution of bars will be allowed without the approval of the Engineer/Architect.  Any splicing of substituted bars shall conform to Table 1.

Splices not indicated will be permitted in slabs not more than 15 inches in thickness, columns, walls and parapets, but not included for measurement, subject to the following:

Splices will not be permitted in bars 30 feet or less in plan length.  For bars exceeding 30 feet in plan length, the distance center to center of splices shall not be less than 30 feet minus 1 splice length, with no more than 1 individual bar length less than 10 feet.  Splices not indicated, but permitted hereby, shall conform to Table 1.  The specified concrete cover shall be maintained at such splices and the bars placed in contact and securely tied together.

Table 1:        Minimum Lap Requirements

Bar Number

Grade 40

Grade 60

3

1 foot 0 inches

1 foot 0 inches

4

1 foot 2 inches

1 foot 9 inches

5

1 foot 5 inches

2 feet 2 inches

6

1 foot 9 inches

2 feet 7 inches

7

2 feet 4 inches

3 feet 5 inches

No. 8

 3 feet 0 inches

4 feet 6 inches

No. 9

3 feet 10 inches

5 feet 8 inches

No. 10

4 feet 10 inches

7 feet 3 inches

No. 11

5 feet 11 inches

8 feet 11 inches

 

Spiral steel shall be lapped a minimum of 1 turn.  Bar No. 14 and No. 18 may not be lapped.

Welding of reinforcing bars may be used only where indicated or as permitted herein.  All welding operations, processes, equipment, materials, workmanship and inspection shall conform to the requirements indicated.  All splices shall be of such dimension and character as to develop the full strength of the bar being spliced.

 

End preparation for butt welding reinforcing bars shall be done in the field, except Bar No. 6 and larger shall be done in the shop.  Delivered bars shall be of sufficient length to permit this practice.

For box culvert extensions with less than 1 foot of fill, the existing longitudinal bars shall have a lap with the new bars as shown in Table 1.  For box culvert extensions with more than 1 foot of fill, a minimum lap of 6 inches will be required.

Unless otherwise indicated, dowel bars transferring tensile stresses shall have a minimum embedment equal to the minimum lap requirements shown in Table 1.  Shear transfer dowels shall have a minimum embedment of 12 inches.

406.7 Placing

Reinforcement shall be placed as near as possible in the position indicated.  Unless otherwise indicated, dimensions shown for reinforcement are to the centers of the bars.  In the plane of the steel parallel to the nearest surface of concrete, bars shall not vary from plan placement by more than 1/12 of the spacing between bars.  In the plane of the steel perpendicular to the nearest surface of concrete, bars shall not vary from plan placement by more than 1/4 inch.  Cover of concrete to the nearest surface of steel shall be as follows:

 

 

Minimum Cover, Inches

(a)  Concrete cast against and permanently exposed to earth

3

(b)  Concrete exposed to earth or weather:

 

           Bar No. 6 through 18 bars          

2

           Bar No. 5, W31 or D31 wire and smaller

1 1/2

(c)  Concrete not exposed to weather or in contact with ground:

 

      Slabs, walls, joists:

 

           Bar No. 14 and 18

1 1/2

           Bar No. 11 and smaller

1

      Beams, columns:

 

           Primary reinforcement, ties, stirrups, spirals

1 1/2

      Shells, folded plate members:

 

           Bar No. 6 and larger

1

           Bar No. 5, W31 or D31 wire, and smaller

1

 

Vertical stirrups shall always pass around the main tension members and be attached securely thereto.  The reinforcing steel shall be spaced its required distance from the form surface by means of approved galvanized metal spacers, metal spacers with plastic coated tips, stainless steel spacers, plastic spacers or approved precast mortar or concrete blocks.  For approval of plastic spacers on a project, representative samples of the plastic shall show no visible indications of deterioration after immersion in a 5 percent solution of sodium hydroxide for 120 hours.

 

All reinforcing steel shall be tied at all intersections, except that where spacing is less than 1 foot in each direction, alternate intersections only need be tied.  For reinforcing steel cages for other structural members, the steel shall be tied at enough intersections to provide a rigid cage of steel.  Mats of wire fabric shall overlap each other 1 full space as a minimum to maintain a uniform strength and shall be tied at the ends and edges.

 

Where prefabricated deformed wire mats are specified or if the Contractor requests, welded wire fabric may be substituted for a comparable area of steel reinforcing bar plan, subject to the approval of the Engineer/Architect.

A suitable tie wire shall be provided in each block, to be used for anchoring to the steel.  Except in unusual cases and when specifically authorized by the Engineer, the size of the surface to be placed adjacent to the forms shall not exceed 2 1/2 inches square or the equivalent thereof in cases where circular or rectangular areas are provided.  Blocks shall be cast accurately to the thickness required and the surface to be placed adjacent to the forms shall be a true plane, free of surface imperfections.

Reinforcement shall be supported and tied in such a manner that a sufficiently rigid cage of steel is provided.  If the cage is not adequately supported to resist settlement or floating upward of the steel, overturning of truss bars or movement in any direction during concrete placement, permission to continue concrete placement will be withheld until corrective measures are taken.  Sufficient measurements shall be made during concrete placement to insure compliance with the above.

No concrete shall be deposited until the Engineer/Architect has reviewed the placement of the reinforcing steel and all mortar, mud, dirt, etc, shall be cleaned from the reinforcement, forms, workers' boots and tools.

406.8 Measurement

The measurement of quantities of reinforcement furnished and placed will be based on the calculated weight of the steel actually placed as indicated, with no allowance made for added bar lengths for splices requested by the Contractor nor for extra steel used when bars larger than those indicated or with a higher grade of steel are substituted with the permission of the Engineer/Architect. Tie wires and supporting devices will not be included in the calculated weights.  The calculated weight of bar reinforcement will be determined using the theoretical bar weight set forth in this item.

Measurement required by a change in design will be computed as described above for the actual steel required to complete the work.

406.9 Payment

All work performed by this item will be considered subsidiary to other bid items unless it is included as a separate bid item in the contract documents then all work performed as required herein and measured as provided under "Measurement" will be paid for at the unit bid price.  The bid prices shall include full compensation for furnishing all labor; all materials; all royalty and freight involved; all hauling and delivering; and all tools, equipment and incidentals necessary to complete the work.  Payment will not be made for unauthorized work.

 

 

End