Beam Bears on Steel Bearing Seat with Knife Plate
Wood beam is connected to wood girder with a custom-fabricated steel connection consisting of bearing plates for both the beam and girder, and a beam knife plate (shown) or bucket connection to the beam. Beam bears on seat and is connected to steel knife plate with dowel-type fasteners. The connection is fastened to the girder with partially-threaded screws or lag bolts through the bearing plate.
Purpose: Transfer of vertical load from wood beam to wood girder.
- Knife plate instead of bucket connection is more commonly used for exposed connections.
- Bearing plate size is dependent on perpendicular-to-grain bearing.
- Designer must account for eccentricity between load and reaction.
- Dowel connector is for positive connection only.
- At top-bearing connections, designer should account for fit of material above. CLT is not typically notched to accommodate connections.
- May be desirable to extend bearing plate beyond knife plate to cover kerf in beam for knife plate.
- Top-mount connection is shown; face-mount connection is possible.
- See the 2018 NDS and AITC Technical Note 19 Guidelines for Evaluation of Holes and Notches in Structural Glued Laminated Timber Beams for notch sizing.
- Deck not shown for clarity. Beam may require bracing for lateral-torsional buckling.
- Table 10: Mass Timber Beam Support at Mass Timber Wall Panel, at top of panel or where bearing notch is provided
- Class 2
- Load High
- Cost $$
- Constructability Moderate
- Fire Rating III