Formwork for Concrete Structures by R.L.Peurifoy and G.D- By EasyEngineering.net

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Properties of Form Material 71
Plywood Thickness,
in.
Minimum Bending Radii, ft
Across the
Grain
¼ 2 5
5
⁄16 2 6
³⁄8 3 8
½ 6 12
5
⁄8 8 16
¾ 12 20
Parallel to
the Grain
Courtesy, APA—The Engineered Wood Association.
TABLE 4-19
Minimum Bending Radii for Plyform Dry
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The boards, which are available in large sheets, have a hard, smooth
surface that produces a concrete whose surface is relatively free of
blemishes and joint marks. The thin sheets can be bent to small radii,
which is an advantage when casting concrete members with curved
surfaces.
Table 4-20 gives the physical properties for tempered hardboard.
Standard sheets are 4 ft wide by 6, 8, 12, and 16 ft long. Shorter lengths
may be obtained by special order.
Table 4-21 gives the minimum bending radii for various thicknesses
of hardboard when bending is performed under the specified
conditions. Because the values given in the table are based on bending
the hardboard around smooth cylinders, it is improbable that
smooth bends to these radii can be obtained with formwork.
Thickness,
in.
Weight,
lb per
sq ft
Tensile
Strength,
lb per sq in.
Modulus of
Rupture,
lb per sq in.
Punch
Shearing
Strength,
lb per sq in.
1
⁄8 0.71 5,100 10,000 5,800
3
⁄16 1.05 4,700 10,000 5,800
¼ 1.36 4,300 9,300 4,500
5
⁄16 1.78 3,900 8,300 4,200
TABLE 4-20
Physical Properties of Tempered Hardboard
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