Page 129 - Handbook of Civil Engineering Calculations, Second Edition

1.112 STRUCTURAL STEEL ENGINEERING AND DESIGN

Refer to Fig. 17. From B to D, s 1.25 in. (31.750 mm), g 2.5 in. (63.50 mm); from
D to F, s 3 in. (76.2 mm), g 2.5 in. (63.50 mm); w AC 7 – 0.875 6.12 in. (155.45
2
mm); w ABDE 7 – 2(0.875) + 1.25 /[4(2.5)] 5.41 in. (137.414 mm); w ABDFG 7 –
2
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3(0.875) + 1.25 /(4 2.5) + 3 /(4 2.5) 5.43 in. (137.922 mm); w max 0.85(7)
5.95 in. (151.13 mm). Selecting the lowest value gives w eff 5.41 in. (137.414 mm).
2. Compute the tensile stress on the effective net section
Thus, f 18,000/[5.41(0.25)] 13,300 lb/sq.in. (91,703.5 kPa).

DESIGN OF A DOUBLE-ANGLE
TENSION MEMBER

The bottom chord of a roof truss sustains a tensile force of 141 kps (627.2 kN). The mem-
3
ber will be spliced with /4-in. (19.05-mm) rivets as shown in Fig. 18a. Design a double-
angle member and specify the minimum rivet pitch.

FIGURE 18