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

64 Chapter Four
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Plywood
Thickness,
in.
¹ 5 ⁄32 2,715
(2,715)
½ 2,945
(2,945)
¹ 9 ⁄32 3,110
(3,110)
5
⁄8 3,270
(3,270)
23
⁄32 4,010
(4,010)
¾ 4,110
(4,110)
1 1 ⁄8 5,965
(5,965)
Support Spacing, in.
4 8 12 16 20 24 32
885
(885)
970
(970)
1,195
(1,195)
1,260
(1,260)
1,540
(1,540)
1,580
(1,580)
355
(395)
405
(430)
540
(540)
575
(575)
695
(695)
730
(730)
150
(200)
175
(230)
245
(305)
265
(325)
345
(325)
370
(410)
–
115
100
(135)
145
(190)
160
(210)
210
(270)
225
(285)
–
–
–
–
–
(100)
–
(100)
110
(145)
120
(160)
ww.EasyEngineering.n
–
–
–
–
–
–
–
–
–
–
–
–
2,295 1,370 740 485 275 130
(2,295) (1,370) (770) (535) (340) (170)
Notes:
1. Courtesy APA—The Engineered Wood Association, “Concrete Forming,” 2004.
2. Deflection limited to l/360th of the span, l/270th for values in parentheses.
3. Plywood continuous across two or more spans.
Recommended Maximum Pressure on Plyform Class I—Values
in Pounds per Square Foot with Face Grain across Supports
TABLE 4-13
Tables for Determining the Allowable Concrete
Pressure on Plyform
Tables 4-13 through 4-16 give the recommended maximum pressures
of Class I and Structural I Plyform. Calculations for these pressures
were based on deflection limitations of l/360 and l/270 of the span, or
shear or bending strength, whichever provided the most conservative
(lowest load) value.
Maximum Spans for Lumber Framing Used to
Support Plywood
Tables 4-17 and 4-18 give the maximum spans for lumber framing
members, such as studs and joists that are used to support plywood
subjected to pressure from concrete. The spans listed in Table 4-17 are
based on using No. 2 Douglas Fir or No. 2 Southern Pine. The spans
listed in Table 4-18 are based on using No. 2 Hem-Fir.
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