- center-to-center spacing of pretensioning tendons at each end of a member shall not be less than 5db for wire, nor 4db for strands
MINIMUM CONCRETE COVER FOR CAST-IN-PLACE CONCRETE (NONPRESTRESSED)
- concrete cast against and permanently exposed to earth – 75mm
- concrete exposed to earth or weather:
* 20mm through 36mm diameter bar – 50mm
* 16mm diameter bar and smaller – 40mm
- concrete not exposed to weather or in contact with ground:
* slabs, walls, joists:
- 45 to 60mm diameter bars – 40mm
- 36mm diameter bar and smaller – 20mm
* beams, columns:
- primary reinforcement, ties, stirrups, spirals – 40mm
* shells, folded plate members:
- 20mm diameter bar and larger – 20mm
- 16mm diameter bar and smaller – 12mm
MINIMUM CONCRETE COVER FOR PRECAST CONCRETE
- concrete exposed to earth or weather:
* wall panels:
- 45mm and 60mm diameter bars – 40mm
- 36mm diameter bar and smaller – 20mm
* other members:
- 45mm and 60mm diameter bars – 50mm
- 20mm through 36mm diameter bar – 40mm
- 16mm diameter bar and smaller – 30mm
- concrete not exposed to earth or in contact with ground:
* slabs, walls, joists:
- 45mm and 60mm diameter bars – 30mm
- 36mm diameter bar and smaller – 15mm
* beams, columns:
- primary reinforcement – db but not less than 15mm and need not exceed 40mm
- ties, stirrups, spirals – 10mm
* shells, folded plate members:
- 20mm diameter bar and larger – 15mm
- 16mm diameter bar and smaller – 10mm
MINIMUM CONCRETE COVER FOR PRESTRESSED CONCRETE
- concrete cast against and permanently exposed to earth – 75mm
- concrete exposed to earth or weather:
* wall panels, slabs, joists – 25mm
* other members – 40mm
- concrete not exposed to earth or in contact with ground:
* slabs, walls, joists – 20mm
* beams, columns:
- primary reinforcement – 40mm
- ties, stirrups, spirals – 25mm
* shells, folded plate members:
- 16mm diameter bar and smaller – 10mm
- other reinforcement – db but not less than 20mm
OFFSET BARS
- slope of inclined portion of an offset bar with axis of column shall not exceed 1 in 6
- portions of bar above and below an offset shall be parallel to axis of column
- lateral ties or spirals, if used, shall be placed not more than 150mm from points of bend
- offset bars shall be bent before placement in the forms
- where a column face is offset 75mm or greater, longitudinal bars shall not be offset bent. Separate dowels, lap sliced with the longitudinal bars adjacent to the offset column faces, shall be provided
SPIRALS
- for cast-in-place construction, size of spirals shall not be less than 10mm diameter
- clear spacing between spirals shall not exceed 75mm or be less than 25mm
- anchorage of spiral reinforcement shall be provided by 1½ extra turns of spiral bar or wire at each end of a spiral unit
- spiral reinforcement shall be lap spliced by 48db but not less than 300mm or welded
- in columns with capitals, spirals shall extend to a level at which the diameter or width of capital is 2 times that of the column
- plain bars shall conform to one of the following specifications:
* ASTM A 615M
* ASTM A 616M
* ASTM A 617M
- plain wire shall conform to:
* ASTM A 82 – Steel Wire, Plain
TIES
- 10mm diameter lateral ties for longitudinal bars 32mm diameter or smaller
- 12mm diameter lateral ties for longitudinal bars 36 diameter and bundled bars
- vertical spacing of ties shall not exceed:
* 16db of longitudinal bars
* 48db of tie bars
* least dimension of compression member
- ties shall be arranged that no bar shall be farther than 150mm clear on each side along the tie
- ties shall be located vertically not more than ½ a tie spacing above the top of footing or slab in any story
- where beams or brackets frame from 4 directions into a column, termination of ties not more than 75mm below reinforcement in shallowest of such beams or brackets shall be permitted
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