- 1/5 the narrowest dimension between side forms
- 1/3 the depth of slabs
- 3/4 the minimum clear spacing between individual reinforcing bars or wires, bundles of bars, or prestressing tendons or ducts
DEFORMED REINFORCEMENTS
- ASTM A 184 – Fabricated Deformed Steel Bar Mats
- ASTM A 185 – Steel Welded Wire Fabric, Plain
- ASTM A 496 – Steel Wire, Deformed
- ASTM A 497 – Steel Welded Wire Fabric, Deformed
- ASTM A 615M – Deformed and Plain-Billet Steel Bars
- ASTM A 616M – Rail-Steel Deformed and Plain Bars
- ASTM A 617M – Axle-Steel Deformed and Plain Bars
- ASTM A 706M – Low-Alloy Steel Deformed Bars
- ASTM A 767M – Zinc-Coated (Galvanized) Steel Bars
- ASTM A 775M – Epoxy-Coated Reinforcing Steel Bars
- ASTM A 884M – Epoxy-Coated Steel Wire and Welded Wire Fabric
- ASTM A 934M – Epoxy-Coated Prefabricated Steel Reinforcing Bars
PRESTRESSING TENDONS
- ASTM A 416M – Steel Strand, Uncoated Seven-Wire
- ASTM A 421 – Uncoated Stress-Relieved Steel Wire
- ASTM A 722 – Uncoated High-Strength Steel Bar
CURING
- concrete (other than high-early strength) shall be maintained above 10°C and in a moist condition for at least the first 7 days after placement
- high-early strength concrete shall be maintained above 10°C and in a moist condition for at least the first 3 days
CONDUITS AND PIPES EMBEDDED IN CONCRETE
- they (including their fittings) shall not displace more than 4% of the area of cross section when embedded within a column
- they shall not be larger in outside dimension than 1/3 the overall thickness of slab, wall or beam in which they are embedded
- they shall be spaced not closer than 3 diameters or widths on center
- conduits, pipes and sleeves may be considered as replacing structurally in compression the displaced concrete, provided:
* they are of uncoated or galvanized iron or steel not thinner than standard Schedule 40 steel pipe
* they have a nominal inside diameter not over 50mm and are spaced not less than 3 diameters on centers
- concrete cover shall not be less than 40mm for concrete exposed to earth or weather, or less than 20mm for concrete not exposed to weather or in contact with ground
- reinforcement with an area not less than 0.002 times the area of concrete section shall be provided normal to the piping
CONSTRUCTION JOINTS
- construction joints in floors shall be located within the middle third of spans of slabs, beams and girders
- joints in girders shall be offset a minimum distance of 2 times the width of intersecting beams
STANDARD HOOKS
- 180-degree bend plus 4db extension, but not less than 60mm at free end of bar
- 90-degree bend plus 12db extension at free end of bar
- for stirrup and tie hooks:
* 16mm diameter bar and smaller – 90-degree bend plus 6db extension at free end of bar, or
* 20 and 25mm diameter bar – 90-degree bend plus 12db extension at free end of bar, or
* 25mm diameter bar and smaller – 135-degree bend plus 6db extension at free end of bar
MINIMUM BEND DIAMETERS
- bar size of 16mm and smaller (for stirrups and ties) – 4db (inside diameter)
- bar size of 10mm through 25mm – 6db
- bar size of 28, 32 and 36mm – 8db
SPACING LIMITS FOR REINFORCEMENT
- the minimum clear spacing between parallel bars in a layer shall be db but not less than 25mm
- the minimum clear spacing between parallel bars in 2 or more layers shall not be less than 25mm between layers
- in spirally reinforced or tied reinforced compression members, clear distance between longitudinal bars shall not be less than 1.5db or less than 40mm
- in walls and slabs other than concrete joist construction, primary flexural reinforcement shall not be spaced farther apart than 3 times the wall or slab thickness, nor farther than 450mm
BUNDLED BARS
- shall be limited to 4 bars in 1 bundle
- shall be enclosed within stirrups or ties
- bars larger than 36mm diameter shall not be bundled in beams
- individual bars within a bundle terminated within the span of flexural members shall terminate at different points with at least 40db stagger
- where spacing limitations and minimum concrete cover are based on bar diameter db, a unit of bundled bars shall be treated as a single bar of a diameter derived from the equivalent total area
- minimum concrete cover shall be equal to the equivalent diameter of the bundle, but need not be greater than 50mm
No comments:
Post a Comment