Flange Plate Column Cap Plate Moment Connection

RISAConnection includes the ability to design Column to Beam Column Cap Flange Plate Moment Connections according to AISC 360. This widely requested feature allows users to define the beam as a wide flange and the column as either a wide flange, tapered wide flange or HSS tube. To begin, choose the connection type from the Moment > Flange Plates connection category.

The basic theory behind flange plate moment connections (including the ones that already exist in RISAConnection) is that the moment developed within the beam is transferred as a force couple through the beam flanges into flange plates. These flange plates, in turn, transfer this force into the column through welds to the column flanges.

In the Flange Plate Column Cap Plate Moment Connection, the force transfer is essentially the same however the top flange plate extends over the top of the column. The force developed within the top flange plate will be then be transferred directly into the column through welds at the top of the column. The force developed within the bottom flange plate will be transferred into the column in the same manner as an ordinary flange plate moment connection.

In this configuration, the following assumptions are made:

• the cap plate acts as a transverse stiffener

• the flange force is applied normal to the column flanges

• the cap plate will be designed for the full flange force and not the unbalanced force

• design of the bottom flange plate will follow the current flange plate moment connection implementation

Finally, integrations with RISAFloor and RISA-3D for the Flange Plate Column Cap Plate Moment Connection is slated to be available in the next version and can be completed by assigning the connection type to the beam as long as the beam and column utilize the proper member shapes (wide flange or tapered wide flange for beams and wide flange, tapered wide flange or HSS tubes for columns).