Extended End Plate Moment Connection

An extended end plate moment connection transfers both shear and moment from a beam to a column. The plate is shop-welded to the beam end (CJP or fillet welds at flanges and web) and field-bolted to the column flange. The plate extends beyond both beam flanges, placing tension bolts in the extended portions.

AISC Design Guide 4 covers three standard configurations:

Design checks include: bolt tension (with prying), end plate flexural yielding (yield line method), column flange flexural yielding, column web local yielding, column web local crippling, column web compression buckling, panel zone shear, and weld design.

The tension force per bolt row is determined from the applied moment. For an 8ES configuration with 4 bolt rows (2 above top flange, 2 below bottom flange), DG4 uses a simplified model where each bolt row carries a tributary share of the flange force T_f = M_u / d_eff.

Prying action amplifies the bolt tension. DG4 provides a yield line model for the end plate that gives the no-prying bolt force limit and the plate thickness required to preclude prying. When t_p ≥ t_p,req (no-prying condition), the bolt design force equals T_f/n_{bolts per row}.

The end plate is designed using a yield line model (DG4 §3.2). The virtual work method gives the required plate thickness based on the plastic moment capacity per unit length m_p = F_y t_p² / 4. Each configuration has a specific yield line pattern that accounts for the bolt positions (p_f, g, p_b) and plate width b_p.

The column must be checked for the concentrated flange force T_f delivered by the beam top/bottom flanges through the plate. Limit states per AISC 360-22:

Doubler plates and/or continuity plates are required when column capacity is exceeded.