Steel Connection Design

Design bolted and welded steel connections for beams, columns, and bracing.

Design a bolted shear connection for the following:
- Beam: W21×62 (A992 steel, Fy = 50 ksi)
- Column: W14×90
- Shear Force: V_u = 85 kips (LRFD)
- Connection Type: Double-angle shear connection
- Bolts: 3/4" A325-N (threads in shear plane)
- Angles: L4×4×3/8, A36 steel
- AISC 360-16 code

Determine number of bolts and check angle capacity.

BOLTED SHEAR CONNECTION DESIGN (AISC 360-16)

1. BOLT SHEAR CAPACITY (Table J3.2)
   3/4" A325-N bolt (threads in shear plane)
   r_n = 17.9 kips per shear plane

   Double Shear Connection:
   φR_n = 0.75 × 2 × 17.9 = 26.85 kips per bolt

2. NUMBER OF BOLTS REQUIRED
   n = V_u / φR_n
   n = 85 kips / 26.85 kips
   n = 3.17 bolts

   Use 4 bolts (vertical arrangement)

3. BOLT SPACING CHECK
   Min spacing = 2.67d = 2.67 × 0.75" = 2"
   Use 3" vertical spacing ✓ OK

   Edge distance:
   Min = 1.25" (Table J3.4)
   Use 1.5" from beam web ✓ OK

4. ANGLE CAPACITY (Block Shear)
   L4×4×3/8, gross area = 2.86 in²

   Shear yielding path:
   A_gv = (3 spaces × 3" + 1.5") × 0.375" = 4.22 in²

   Shear rupture path:
   A_nv = [10.5" - 3.5 × (0.75" + 0.125")] × 0.375"
   A_nv = 2.78 in²

   Tension rupture:
   A_nt = (4" - 0.5 × 0.875") × 0.375" = 1.34 in²

   φR_n = 0.75[0.6F_uA_nv + U_bsF_uA_nt]
   φR_n = 0.75[0.6(58)(2.78) + 1.0(58)(1.34)]
   φR_n = 130.7 kips > 85 kips ✓ OK

5. WELD TO COLUMN (If required)
   E70 fillet weld, 3/16" size
   Weld strength = 1.392 kips/in (AISC Table J2.4)

   Required length = 85 / (2 × 1.392)
   L_req = 30.5"

   Use (2) angles with 11" weld length each = 22" total
   Add 50% for end returns ≈ 33" > 30.5" ✓ OK

FINAL DESIGN:
✓ (2) L4×4×3/8 × 11" long angles
✓ (4) 3/4" A325-N bolts @ 3" o.c.
✓ 3/16" fillet weld to column flange
✓ Connection capacity = 107 kips > 85 kips

Key Results

Common Use Cases

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