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

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Forms for Columns 291
Depth
below
Top of
Form, ft
Maximum
Concrete
Pressure
(P m
= wh),
lb per sq ft
Single Span
(2 supports)
Maximum Spacing, in.
Two Spans
(3 supports)
Multiple Spans
(4 or more
supports)
Thickness, in. Thickness, in. Thickness, in.
5
⁄8 ¾ 1 5
⁄8 ¾ 1 5
⁄8 ¾ 1
4 600 6 7 11 7 9 14 7 9 13
5 750 5 7 10 7 9 12 6 8 12
6 900 5 6 9 6 8 11 6 8 11
7 1050 5 6 9 5 7 10 6 7 11
8 1200 4 6 8 5 6 10 5 6 10
9 1350 4 6 8 5 6 8 5 6 9
10 1500 4 5 8 4 5 8 4 5 8
11 1650 4 5 8 4 5 7 4 5 7
12 1800 4 5 7 4 5 7 4 5 7
13 1950 4 5 7 4 4 7 4 4 7
14 2100 4 5 7 — 4 6 4 4 6
15 2250 4 5 7 — 4 6 — 4 6
16 2400 4 4 7 — 4 6 — 4 6
17 2550 — 4 6 — 4 5 — 4 5
18 2700 — 4 6 — 4 5 — 4 5
19 2850 — 4 6 — 4 5 — 4 5
20 3000 — 4 6 — — 5 — — 5
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Notes:
1. For Plyform, values based on F b
= 1,930 psi, F s
= 72 psi, and E = 1,650,000 psi, with face
grain installed in the weak direction, physical properties for stress applied perpendicular
to face grain.
2. Concrete pressure based on concrete with 150 lb per cu ft unit weight. Spacings are
governed by bending, shear, or deflection. Maximum deflection limited to l/360, but
not more than 1 / 16 in.
TABLE 10-2 Maximum Spans of Plyform with Face Grain Parallel to Supports
shown in Table 10-3 applies to conditions where the panels are
installed in the horizontal direction; therefore, the panels are placed
in the strong direction for transferring the concrete pressure horizontally
between vertical wood battens. The span length is the maximum
permissible horizontal distance between the vertical battens that are
used to support the panels.
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