Page 163 - Handbook of Civil Engineering Calculations, Second Edition

1.146 STRUCTURAL STEEL ENGINEERING AND DESIGN

3. Determine the welded section flexural strength
Determining flexural strengths, we obtain

36 kips/sq.in. × 1369 in. 3
M px F y Z x 4107 kip-ft (5569 kNm)
12 in./ft
36 kips/sq.in. × 1230 in. 3
M rx F y S x 3690 kip-ft (5004 kNm)
12 in./ft
The value of M n can be obtained by linear interpolation using Fig. 40 or AISC Eq.
(A-F1-3): M nx 3946 kip-ft (5351 kNm).
The design flexural strength b M nx 0.90 3946 kip-ft 3551 kip-ft (4815 kNm).
Shear strength for an unstiffened web is governed by one of the equations below, de-
pending on h/t w .

h 418
For V n 0.6F y A w [1]
t w F y
418 h 523 418/ F y
For < V n 0.6F y A w [2]
F y t w F y h/t w

h 523 132,000
For < V n A w [3]
t w F y (h/t w ) 2
where V n nominal shear strength, kips (kN)
A w area of the web, sq.in. dt w
d overall depth, in. (cm)
t w thickness of web, in. (cm)
h the following web dimensions, in: clear distance between fillets, for rolled
shapes; clear distance between flanges for welded sections

Here, h/t w 56 in./0.44 in. 128.0.
523 523
128 >

F y 36
Equation (3) governs:
132,000 (58 in. × 0.44 in.) × 132,000
V n A w
(h/t w ) 2 (128.0) 2
204.4 kips (909.2 kN)
The design shear strength V n 0.90 204.4 kips 184.0 kips (818.4 kN)

Related Calculations. This procedure is the work of Abraham J. Rokach, MSCE, As-
sociate Director of Education, American Institute of Steel Construction. SI values were
prepared by the handbook editor.