Force to be resisted by a stiffener is;

F = Pbf - (2.5k + N)Fyw t w = 114 k - (2.5(1.0" ) + 0.420" )50ksi(0.285" ) = 72.4 k

with N = tbf

(F = 322.0KN)

Length available for welding stiffeners to the column web is;

L = 12" (assuming a 1/2" chamfer) x 2 sides x 2 stiffeners = 48" (1.22m)

The required weld size is;

For E70XX electrodes; *φ *w = 0.75[0.60(70ksi)] = 31.5ksi (265.0MPa)

Note;

F

72.4 k

3"

Ru

s=

=

= 0.068" <

(1.72mm < 4.76mm)

(0.707)L(*φ *w ) 0.707(48" )31.5ksi

16

F

Therefore, the minimum weld size governs

Check shear strength of the base metal;

R

72.4 k

F

=

(2.56KN/m > 0.53KN/m)

R

48"/2 L / 2

Stiffener to column flange;

Use full penetration groove welds

Design the single-plate web connection;

Note:

The governing load combination (1.2D+0.5L+1.6Lr) is based solely on gravity loads.

wu = 1.2D+0.5L+1.6Lr = 1.2(343plf)+0.5(0)+1.6(240plf) = 796plf (11.6KN/m)

w u (L - d c ) 796plf (30'- 13.98" (1'/12" ))

= 11.5k (51.2KN)

Vu =

=

2

2

Try a 3/8" (9.53mm) plate;

Determine the number of 3/4" (19.05mm) diameter A325-N bolts required for shear;

From AISC LRFD 2nd ed. table 8-11;

11.5k

Ru

=

=

= 0.72 bolts, Say 2 bolts

n min

r

Determine the number of 3/4" (19.05mm) diameter A325-N bolts required for bearing, assuming Le = 1-

1/2" (38.1mm), and s = 3" (76.2mm). The .255" (6.48mm) beam web is more critical then the 3/8"

(9.53mm).

From AISC LRFD 2nd ed. Table 8-13;

H4-53

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