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

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Forms for Columns 289
Depth
below Top
of Form, ft
Maximum
Pressure,
150h, lb
per sq ft
Maximum Span Length for
S4S Lumber Laid Flat Vertical
Nominal Thickness
1-in. 2-in.
4 600 15 31
5 750 14 28
6 900 12 25
7 1050 11 23
8 1200 11 22
9 1350 10 21
10 1500 10 20
11 1650 9 19
12 1800 9 19
13 1950 8 17
14 2100 8 17
15 2250 8 16
16 2400 7 15
17 2550 7 15
18 2700 7 15
19 2850 7 14
20 3000 7 14
21 3150 6 13
22 3300 6 13
23 3450 6 13
24 3600 6 12
25 3750 6 12
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Notes:
1. For S4S lumber, values based on F b
= 1,125 psi, F v
= 225 psi, and
E = 1,600,000 lb per sq in., with no splits.
2. Values shown for S4S lumber laid flat between column clamps,
without plywood.
3. Concrete pressure based on concrete of 150 lb per cu ft unit weight.
Spacing is governed by bending, shear, or deflection. Maximum
deflection of l/360, but not more than 1/16 in.
4. Spacing based on continuous members with four or more supports,
and on Eqs. (10-3) to (10-6).
TABLE 10-1 Maximum Span Lengths of S4S Lumber Laid Flat for
Column Sheathing, in.
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