16 ft
w’D = 30 lb/ft2
wsw = 10 lb/ft
2400 lb (live)
A
B
Figure 4a.
3 ft
3 ft
2400 lb (live)
Note: No aids are allowed for part 1. One side of a letter sized paper with notes is allowed
during part 2, along with a silent, non-programmable calculator. There are reference charts for
part 2, shown on pages 2-6.
Clearly show your work and answer.
Part 1) Worth 5 points (conceptual questions)
Part 2) Worth 45 points
(NOTE: The loading type and sizes can and will be changed for
the quiz with respect to the beam diagrams and formulas
provided. The support condition, section, and bracing for the
column can and will be changed.)
Wood beams (like shown in Figure 4a) spaced 4 ft on center are
needed to span 16 ft and support a roof having 30 lb/ft2 of dead load and two 2400
lb seven-day roof live loads at 3 feet from each end. The beam is simply supported
and fully braced. Idaho White Pine will be used and has the following tabular
design values for bending for single member uses and modulus of elasticity:
Fb = 1150 psi, Fv = 65 psi, E = 1.4 x 106 psi
a) Including a self weight of 10 lb/ft, design the most economical member for
strength (no consideration of serviceability).
A 6 m tall, 125 mm x 200 mm (metric) glu-lam column (Figure 4b) is braced in the
weak axis (y-y) at 3.2 m from the base. The ends can be considered to be pinned.
The timber has the following tabular design values:
Fc = 13.8 MPa, E = 12,400 MPa:
b) If the column is to support 180 kN, is it adequate for Allowable Stress Design
assuming a two month snow load duration? (A = 25.0 x 10-3 m2).
Answers – Not provided on actual quiz!
a) Sreq’d 94.83 in3, Areq’d 63.5in2
b) Pallowable = 136 kN No Good (Pweak= 182.9 kN weak direction)
3.2 m
x
y
2.9 m
6.0 m
P = 180 kN
x
y
Figure 4b.
