Page 121 - Structural Steel Designers Handbook AISC, AASHTO, AISI, ASTM, and ASCE-07 Design Standards

Brockenbrough_Ch03.qxd 9/29/05 5:05 PM Page 3.53

CONNECTIONS

CONNECTIONS 3.53

Tear-out at extreme bolt no. 1:
13
• At W18 × 50, φR n = 0.75 × 1.2 × (1.75 − / 32)
× 0.355 × 62 = 27.9 kips/bolt
• At angles, φR n =φ1.2L c tF u φR b = 0.75 × 1.2 ×
13
(3 − / 16) × (2 × 0.625) × 58 = 143 kips/bolt pair
Tear-out at extreme bolt no. 2:
• At W18 × 50, φR n = 0.75 × 1.2 × (3 − / 16) ×
13
0.355 × 65 = 45.4 kips/bolt
• At angles, φR n = 0.75 × 1.2 × (1.25 − / 32) ×
13
(2 × 0.625) × 58 = 55.1 kips/bolt pair
Tear-out at intermediate bolts:
• At W18 × 50, φR n = 0.75 × 1.2 × (3 − / 16) ×
13
0.355 × 65 = 45.4 kips/bolt
• At angles, φR n = 0.75 × 1.2 × (3 − 13 / 16) × FIGURE 3.34 Edge distances along line of action.
(Source: A. R. Tamboli, Handbook of Structural Steel
(2 × 0.625) × 58 = 143 kips/bolt pair Connection Design and Details, McGraw-Hill, 1999,
Design strength with three rows of bolts (n = 3): with permission.)
φR n =φR n ext bolt 1 min +φR n ext bolt 2 min +φR n int bolt min × (n − 2)
= 27.9 + 31.2 + 31.2 × (3 − 2) = 90.3 kips ≥ 33 kips OK
Design strength under combined forces:
Resultant force at connection = V + T = 51.1 kips.
2
2
Edge distances along line of resultant force are shown in Fig. 3.34.
Critical bearing (including tear-out) at top or bottom bolt per Eq. (3.28b):
φR n =φ1.2L c tF u ≤φ2.4d b tF u
13
φR n = 0.75 × 1.2 × (1.94 − / 32) × 0.355 × 65 ≤ 0.75 × 2.4 × 0.75 × 0.355 × 65
31.8 < 31.2 = 31.2 kips/bolt
Bearing at interior bolt per Eq. (3.28b):
13
φR n = 0.75 × 1.2 × (2.29 − / 32) × 0.355 × 65 ≤ 0.75 × 2.4 × 0.75 × 0.355 × 65
39.1 ≤ 31.2 = 31.2 kips/bolt
Design strength with three bolts (n = 3):
φR n = 2 ×φR n top or btm bolt min +φR n int bolt min × (n − 2)
= 2 × 31.2 + 31.2 × (3 − 2) = 93.6 kips ≥ 51.1 kips OK
Design strength for shear in angles and beam web:

Gross section shear on angles:
φR n =φ× 0.60A g F y = 0.90 × 0.60 × 8.5 × (2 × 0.625) × 36 = 207 kips ≥ 33 kips OK
Net section shear on angles:
φR n = φ × 0.60A nv F u = 0.75 × 0.60 × [8.5 − (3 × 0.875)] × (2 × 0.625) × 58
= 192 kips ≥ 33 kips OK
Gross shear on full beam web:
φR n = 0.90 × 0.60 × 18 × 0.355 × 50 = 173 kips ≥ 33 kips OK

Gross shear on remaining beam web:
φR v = 0.9 × 0.60 × 16.3 × 0.355 × 50 = 156 kips ≥ 33 kips OK

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