(15%) Problem 3 (Pro 8.15 Textbook modified):

The cross-section of the rough-cut timber beam shown is loaded with (W) over six feet of the

span. Determine the maximum value of (W #/ft.) if the allowable bending stress is

Fb = 1,600 psi and the allowable shear stress is Fv = 85 psi.

6"

A = 72 in.?

Ir = ((123)

12

c = 6"

12"

864in

Ix864in.4

sz=-= - = 144in_3

6in.

늘

뽈

=10'

MMAX = WL²

LOAD

WL

기 다

M'