OMF Beam-Column Connection

References

Seismic Design Manual

Details

Refer to Joint JT-1 in Figure 4-2 of the reference. Design a fully restrained (FR) moment connection for the configuration shown in Figure 4-3 of the reference. The beam and column are ASTM A992 W-shapes and the plate material is ASTM A36. Use 70-ksi electrodes and ASTM A325 bolts.

To avoid the field welding requirements associated with the prescriptive connection described in AISC Seismic Provisions Section E1.6b(c), an eight-bolt stiffened end-plate connection is used.

The required shear strengths for the column based on a second-order analysis are given in Example 4.2.2. The other shear forces acting at the beam end simultaneously with Emh are:
  • VD = 4.86 kips
  • VS = 6.49 kips

Refer to the figure in the reference for additional details.

Calculations

Calculations

VEV = 0.2SDSD = 0.2×(0.528)×(4.86 kips) = 0.513 kips

Results

Table 1. Comparison with AISC Seismic Design Example 4.2.4
Parameter RAM Connection Reference Difference
Necessary parameters for end plate thickness, s (in.) 2.65 2.65 none
Yp 231.8 232 < 1%
Necessary parameters for column flange flexural strength, s (in.) 2.56 2.56 none
Necessary parameters for column flange flexural strength (psi) 2.01 2.02 < 1%
Yc 239.0 239 none
Available strength of stiffened column flange (kips) 2,911 2,910 < 1%
Beam web weld strength to reach yield stress (kip/ft) 170.1 14.2 kip/in (170.4 kip/ft) < 1%
Available strength per stiffener (kips) 36.45 (72.9 kips over 2 stiffeners) 36.5 < 1%

Input

The following data is input into the New Joint dialog:

Joint Data tab:
  • Joint = BCF
  • Beam/Section = W 18x40
  • Beam/Material = ASTM A992 Gr50
  • Column/Section = W 12x35
  • Column/Material = ASTM A992 Gr50
  • Seismic load resisting system = OMF (set
Loads tab:
  • V2 (beam) = 15.9 kips
  • Beam / Axial = 69 kip (stiffener required strength)

Set the Seismic Parameters option in the Connection Design Configuration dialog.

Select the Smart Connections/Smart MEP Extended both ways (DG4/Seismic) connection type.

The following data is input into the Connection Pad:

Members group:
  • Thickness for beam stiffener = 0.4375 in.
Connector group:
  • Four/eight bolts in tension = 8 tension bolts
  • Plate thickness, tp = 0.625 in.
Connector / Beam Side group:
  • Top flange weld type = fillet
  • Top beam flange weld = E70XX
  • Weld size to top beam flange (1/16s in), D1 = 7
  • Bottom flange weld type = fillet
  • Bottom beam flange weld = E70XX
  • Weld size to bottom beam flange (1/16s in), D3 = 7
  • Weld size to beam web (1/16s in), D2 = 4
Connector / Support Side group:
  • Bolts = 3/4"⌀ A325N
  • Gage (transverse center-to-center spacing), g = 4 in.
  • Vertical spacing between bolt rows, s = 3 in.
  • Vertical edge distance, Lev = 1.25 in.
  • Horizontal edge distance, Leh = 1.5 in.
  • Distance from first interior bolt centerline to the beam flange, pfi = 2 in.
  • Distance from the outer bolt centerline to the beam flange = 2 in.
Stiffeners / Transverse Stiffeners group:
  • Position = both
  • Full depth = Check (set the option)
  • Transverse stiffeners width, bs = 3 in.
  • Transverse stiffener thickness, ts = 0.50 in.
  • Material = A36
  • Welding electrode to support = E70XX
  • Weld size to support (1/16s in), D = 4