Rectangular Cross Section

Подпись: Figure 3.2 Rectangular cross section. Подпись: Copyright © Marcel Dekker, Inc. All rights reserved.

The most commonly used cross section in the design of formwork is the rectangular cross section with breadth b and depth d (Figure 3.2). These are usually measured in the units of inches or millime­ters.

For rectangular cross section, the formulas discussed in the previous section take the forms:

bd 3

Moments of intertia: Ixx = , in.4 or mm4

12

db3 4 4

= , in.4 or mm4

* 12

Подпись:d

f[12] [13]yy b •

Rectangular Cross Section

rxx=v j=^2,in.°rmm

c Iyy db2. 3 3 b

by* = — = —, in.3 or mm3 here c = –

Подпись: I bd 2 bxx = — = —, in.3 or mm3 ( here
Rectangular Cross Section Rectangular Cross Section

Section modules:

The section properties for selected standard sizes of board, dimension lumber, and timbers are given in Table 3.1. The values given in this table can be used to calculate the properties given above. Table 3.2 provides section properties of standard dressed (S4S) sawn lumber.