End Plate Connections per AISC 358-16

How does ideCAD design End Plate Moment Connections according to AISC 360-16 & AISC 358-16?

Bolted Stiffened and Unstiffened End Plate Connections

End-plate connections consist of welding the beam to an end-plate and bolting the end-plate to a column flange.

If there is no axial load on the connection, total tensile and compressive forces are equal and opposite in both flanges, so that total force creates a force pair. It is accepted that the center of rotation is in the center of the compression flange.

Extended end-plate moment connections are prequalified for use in special moment frame (SMF) and intermediate moment frame (IMF) systems. Configurations of extended end-plate moment connections are given below.

• Four Bolts Unstiffened End Plate Connection

• Four Bolts Stiffened End Plate Connection

• Eight Bolts Stiffened End Plate Connection

The limit states of end-plate moment connections are listed below.

• Flexural yielding of the beam section

• Flexural yielding of the end-plates

• Yielding of the column panel zone

• Tension rupture of the end-plate bolts

• Shear rupture of the end-plate bolts

• Rupture of various welded joints.

The limit state checks listed above are applied automatically, and detailed explanations, references, and parameters used in the account are given in the connection report.

There are conditions that must be met in order to be used in 3 types of frames with special moment frames or intermediate moment frames. These conditions are given in AISC 358-16 6.3. ideCAD Structural automatically checks and reports these conditions.

Plastic hinges cause inelastic bending deformations in the joining beam and column panel area in the joints with end plate. Therefore, stronger column, stronger joint and acceptible weak beam design are considered as philosophy. For this reason, the length of the plastic hinge and its distance from the column flange are especially checked in the table below.

Also, it should be checked that:

1. The clear span-to-depth ratio of the beam is limited:
   (a) For SMF systems, 7 or greater.
   (b) For IMF systems, 5 or greater.

2. The protected zone is determined:
   (a) For unstiffened extended end-plate connections: the portion of beam between the face of the column and a distance equal to the depth of the beam or three times the width of the beam flange from the face of the column, whichever is less.
   (b) For stiffened extended end-plate connections: the portion of beam between the face of the column and a distance equal to the location of the end of the stiffener plus one-half the depth of the beam or three times the width of the beam flange, whichever is less.

3. The end-plate should be connected to the flange of the column.

4. Rolled shape column depth is limited to W36 (W920) maximum. The depth of built-up wide-flange columns is not exceed that for rolled shapes.

End Plate Connections Design Steps

• The strength of end plate connection is determined by the assumption that tensile force of the bolts in one flange is controlled by rupture limit state under compressive force.

• If there is no axial load on the joint, the total tensile and compressive forces are equal and opposite in both flanges, so that the total force creates a force pair.

• Flexural strength of end plate and column flange is determined by yield line analysis. The yield line method can be calculated by the energy or virtual work method.

• Strong column, strong joint and weak beam are used to calculate the forces on the bolt and to find the required bolt strength. According to this assumption, while the column, panel region and beam inelastic behavior, the joint and column show elastic behavior. For this reason, it is necessary to design suitable for the thick plate for end plate. In thick plate behavior, the force in the bolts is the static moment at the center of comprensive flange.

  • The equations used are as follows:

Boundary Situations to Check