Handbook of Civil Engineering Calculations

FIGURE 37

The case of no-stiffeners corresponds to k - 5.

2. Check the original assumptions for doubling the shear strength
   To double the shear strength, I fc = 2 x 5 = 10. Then in AISC Equation A-G3-4,

*=

5+

cir

10

This implies a/h = 1.0 or a= k; thus, the clear distance between transverse web stiffeners

a = I 1 =^55 in (142.2 cm). Checking the original assumption we obtain

/A = J6"L = i2 8 .9W234 /I 4 /BL 1233 ) O.k.

(tw 0.44 in J \ VFy V 36 /

3. Design the stiffener, trying a pair of stiffener plates
   Stiffener design can be performed thusly. Because tension field action is not utilized, the
   equation Ist > at^j must be satisfied, where

'-(S?-""

y-^-2-05

Ist > 56 in x (0.44 in)^3 x 0.5 - 2.34 in^4 (97.4 cm^4 )

Try a pair of stiffener plates, 2.5 in x 0.25 in (6.35 x 0.635 cm), as in Fig. 38. The mo-

ment of inertia of the stiffener pair about the web centerline

= 0.25 in x (5.44 in)

3

= 33g ^ 4 > 2 ^ ^ 4 ok (139.4 cm

4

> 97.4 cm

4

) o.k.

St J 2