Section 15 Concrete Reinforcement

1 January 2008 15-1 Section 15 Concrete Reinforcement Introduction This Section is intended to aid the bridge designer and detailer in the area of Concrete reinforced design and detailing. The tables in this Section simplify the design and detailing of Concrete Reinforcement splices and required covers. Also included are suggested details intended to ease the construction process and provide seismic resistance. Spacing The minimum spacing shall meet NYSDOT LRFD Bridge Design Specification Section requirements. The maximum clear spacing between parallel bars shall not be more than 1N-6O. The clear space between bars shall also apply to the clear distances between the contact splices and adjacent splices of bars. Bar spacings as indicated are always between the center of the bars unless otherwise noted as a clear distance. When Reinforcement in beams or girders is placed in two or more layers, the bars in the upper layers shall be placed directly above those in the bottom layer.

2 Cover The following list pertains to the minimum cover for plain, epoxy and galvanized reinforcing bars. Refer to Section 5 for cover of monolithic decks. Top of sidewalk slabs .. 1 O Beams and Columns .. 2O Pedestal (Top) .. 2O Pedestal (Sides) .. 3O Walls and Piers above footing (Including those adjacent to water) .. 2O* Footings (Including unformed bottom) .. 3O** Approach slab (Top) .. 3O Approach slab (Bottom and Sides) .. 3O Bottom of bottom slab of cast-in-place culvert .. 3O Bottom of top slab of cast-in-place culverts and rigid frames .. 2O All other cast-in-place culvert faces .. 2O Top of top slab of precast culverts (Fill <2 feet) .. 2O Top of top slab of precast culverts (Fill 2 feet) .. 1O All other precast box culvert faces .. 1O Exposed faces of precast three-sided culverts .. 1 O All other faces of precast three-sided culverts .. 2O Arches (Intrados and extrados).

3 2O NYSDOT Bridge Manual 15-2 April 2014 Precast and cast-in-place piles .. 2O Precast piles exposed to sea water .. 3O Post-tensioned cylindrical piles (Centrifugally cast, no slump Concrete exposed to sea water) .. 1 O All other surfaces exposed to sea water .. 4O * When aesthetic treatment (formliner) is used, the maximum relief of the treatment shall be added to the minimum cover. ** May be increased to accommodate piles when necessary. Table 15-1 Minimum Reinforcement Cover Reinforcing Bar Guidelines Grade 60 is the standard strength reinforcing bar to be used on Department projects. Grade 75 reinforcing bar is available, though in limited quantities and at greater cost. Use of Grade 75 reinforcing bars should be limited to areas of high tensile stresses where the number of Grade 60 reinforcing bars results in insufficient spacing between the bars for Concrete placement.

4 TABLE A STANDARD REINFORCING BAR PROPERTIES Size #4 #5 #6 #7 #8 #9 #10 #11 Area (in2) Dia. (in) Maximum Bar Lengths Most reinforcing bar plants in the United States produce bars in a standard length of 60 feet except solid stainless steel larger than #6 is only available in maximum lengths of 40 feet. Therefore, plans should not include any straight bars or bent bars with a length in excess of 60 feet (40 feet for solid stainless larger than #6). Due to handling concerns, the maximum length of a bar that requires a hook on both ends should be limited to 30 feet. Deck Slab Bars Refer to Section Deck Overhangs for guidance on deck slab bars.

5 Concrete Reinforcement January 2008 15-3 Abutment and Pier Bars When designing abutments and piers, it is important to envision how the contractor may build the structure and to provide details that make construction easier. Vertical bars should not extend more than 16 ft. out of the placement that they originate in due to handling concerns. Instead, two bars with a lap splice should be used. This is suggested as a guide, and a designer s judgment must be used. Obviously, if a bar has a length of 17 ft., a lap should not be introduced for the small amount of extra length required.

6 Reinforcement Splicing General Splicing Guidelines For #11 bars or smaller, splices can be made by lap splices with wire ties, mechanical connectors (from the Materials Bureau approved list), or by welding provided it is in accordance with the NYSDOT Steel Construction Manual (SCM), Section 7, Part D. Tack welding is not permitted. Splices for bars larger than #11 shall use either mechanical connectors from the Materials Bureau Approved List or welds in accordance with the proper welding procedure. No additional payment is made for Reinforcement splices. However, if the situation mandates the use of mechanical connectors or welded splices, this shall be noted on the Contract Plans. Splicing Vertical Reinforcement in Walls For #5, #6, and #7 bars, the splicing of the main vertical Reinforcement to the Reinforcement emerging from the footing may be made directly over the footing.

7 In some cases, it may be practical to eliminate splices by extending the bars emerging from the footing to the top of the wall. Number 8 and larger bars emerging from the footing shall be extended to a distance above the footing where bars of a smaller diameter may be spliced to them. The lap length for such splices shall be based on the smaller bar. Minimum Anchorage, Lap and Embedment The following notes apply to the tables in this article: 1. All tables are based on formulas found in Section 5 Concrete Structures of the NYSDOT LRFD Bridge Design Specification. 2. Lengths are based on: 60 ksi and ksi. 3. When an area of steel provided is more than that required to develop the ultimate moment capacity of the Section , the basic development length indicated may be reduced by the ratio: As(required) As(provided). 4. Galvanized, stainless steel clad and solid stainless steel bars are treated as uncoated bars for splice and embedment lengths.

8 5. Top bars are defined as horizontal Reinforcement located where there is more than 1 ft. of fresh Concrete cast below the development length or splice. NYSDOT Bridge Manual 15-4 January 2008 Basic Development Length for Bars TABLE B BASIC DEVELOPMENT LENGTH FOR COMPRESSION BARS Size #4 #5 #6 #7 #8 #9 #10 #11 Ld 11 1 -2 1 -5 1 -8 1 -10 2 -1 2 -4 2 -7 TABLE C BASIC DEVELOPMENT LENGTH OF HOOKED DOWELS IN TENSION Size #4 #5 #6 #7 #8 #9 #10 #11 Uncoated - Ldh 1 -0 [1 -0 ] 1 -2 [1 -0 ] 1 -5 [1 -0 ] 1 -8 [1 -2 ] 1 -10 [1 -4 ] 2 -1 [1 -6 ] 2 -4 [1 -8 ] 2 -7 [1 -10 ] Epoxy-Coated Ldh 1 -2 [1 -0 ] 1 -5 [1 -0 ] 1 -8 [1 -2 ] 1 -11 [1 -5 ] 2 -3 [1 -7 ] 2 -6 [1 -9 ] 2 -10 [2 -0 ] 3 -1 [2 -2 ]

9 Table C Criteria (Length in Brackets requires following criteria to be met) #11 bar or smaller Side Cover 2 O 90 Hook: cover 2O See Article of the NYSDOT LRFD Bridge Design Specifications FIGURE Hooked Dowel Concrete Reinforcement January 2008 15-5 TABLE D BASIC DEVELOPMENT LENGTH FOR STRAIGHT UNCOATED DOWELS & TENSION BARS (NOT TOP BARS) Size #4 #5 #6 #7 #8 #9 #10 #11 Spacing 6 1 -0 1 -1 1 -5 1 -9 2 -6 3 -2 4 -0 4 -11 Spacing < 6 1 -1 1 -4 1 -9 2 -4 3 -1 3 -11 5 -0 6 -1 TABLE E BASIC DEVELOPMENT LENGTH FOR STRAIGHT UNCOATED DOWELS & TENSION BARS (TOP BARS)

10 Size #4 #5 #6 #7 #8 #9 #10 #11 Spacing 6O 1 -3 1 -6 2 -0 2 -8 3 -6 4 -5 5 -7 6 -10 Spacing < 6O 1 -6 1 -10 2 -5 3 -4 4 -4 5 -6 6 -11 8 -6 TABLE F DEVELOPMENT LENGTH FOR STRAIGHT EPOXY-COATED DOWELS & TENSION BARS (NOT TOP BARS) Size #4 #5 #6 #7 #8 #9 #10 #11 Spacing 6O 1 -4 [1 -1 ] 1 -7 [1 -4 ] 2 -1 [1 -8 ] 2 -10 [2 -3 ] 3 -9 [3 -0 ] 4 -8 [3 -9 ] 5 -11 [4 -8 ] 7 -4 [6 -8 ] Spacing < 6O 1 -7 [1 -4 ] 2 -0 [1 -7 ] 2 -7 [2 -1 ] 3 -7 (N/A) 4 -7 (N/A) 6 -8 (N/A) 7 -5 (N/A) 9 -1 (N/A) The lengths in parentheses can only be used as described in TABLE H NYSDOT Bridge Manual 15-6 January 2008 TABLE G DEVELOPMENT LENGTH FOR STRAIGHT EPOXY-COATED DOWELS & TENSION BARS (TOP BARS) Size #4 #5 #6 #7 #8 #9 #10 #11 Spacing 6OO 1 -6 1 -10 2 -4 3 -3 4 -2 5 -4 6 -9 8 -3 Spacing < 6O 1 -8 2 -3 2 -11 4 -0 5 -3 6 -11 8 -5 10 -4 TABLE H THE LENGTHS IN PARENTHESES CAN ONLY BE USED IF BOTH OF THE FOLLOWING CIRCUMSTANCES ARE TRUE Size #4 #5 #6 #7 #8 #9 #10 #11 Cover (in) 1 1 2 2 3 3 3 4 Bar Spacing (in)