lintel bearing

huangyhg

lintel bearing
the approach that i see engineers take seems to vary and i have often wonder about this:
how many engineers extend bottom plates to the end of beam lintels?
how many engineers require that the bottom plates extend only to the face of the opening and lintels shall be welded down to bearing plates at each end? if yes, is this because you are designing buildings in a seismic zone or high wind area?
is your approach the same on both interior and exterior lintels?
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hi, jike,
i generally assume the plate is just the width of the opening, and does not extend into the support.  of course, the torsion at the end of the lintel (if any) must be resisted, either by welding to a bearing plate, or without a bearing plate, if there is enough dead load coming down from above the end of the lintel.
daveatkins
i usually extend the plate the full length of the beam.  an exception might be if there are steel columns on either side of the opening, in which case the bottom plate could stop at the edge of the opening.  but i like for the plate to have full bearing to help provide torsional resistance.  at some point you need to transition from the beam and plate bearing with no anchorage to requiring welding to an anchored bearing plate.  i usually do this for lintels greater than 10' unless there are horizontal and vertical bars above and beside the opening to "tie" the wall.
i also use a full length plate and no bearing plates. i like the simplicity of fabrication and installation. i try not to have torsion on a lintel.
our projects are in a non-seismic part of the country. if i was working in a seismic area, i probably would weld them down as dave atkins does.
if i do have significant torsion, i am somewhat skeptical that the masonry backup (usually 8" cmu) can actually resist the torsion. i would prefer to attach the torsion resisting lintel to a steel column at each end if necessary.
i typically follow mike's method.  however, i never weld the lintel to the bearing plate.  i always bolt.  during construction i have had times where a welded lintel will bust out the face of the wall due to thermal expansion.  (even when wall is grouted solid.)  the bolts allow enough "play" so the beam can expand and contract without causing damage to the block.