D. Service Loads
The following calculations assume that web crippling
or bearing and tearout is satis®ed.
1. LRFD
a. Uplift Loading
Using load combination 6 in Section A6.1.2,
Load Factors and Load Combinations, (0.9D ÿ
1.3W ), the controlling design load 98.1 lb=ft
(B.1), and applying Exception 3 ``For wind
load on individual purlins, girts, wall panels
and roof decks, multiply the load factor for W
by 0.9.''
0:9 13:5 ÿ1:3 0:9w
w
ÿ98:1 lb/ft
w
w
94:2 lb/ft
which is equivalent to a service uplift load of
18.1 psf for a 5-ft purlin spacing.
b. Gravity Loading
Using load combination 2 1:2D 1:6S and
the controlling design load 142 lb=ft (C.4) give
1:2 13:5 1:6w
s
142 lb/ft
w
s
78:6 lb/ft
which is equivalent to a service snow load of
15.7 psf for a 5-ft purlin spacing.
2. ASD
a. Uplift Loading
Using load combination 3 in Section A5.1.2,
Load Combinations D W and the control-
ling design load 65.3 lb=ft (B.1) give
13:5 ÿ w
w
65:3 lb/ft
w
w
78:8 lb/ft
Roof and Wall Systems
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