Brick Spandrel Deflections and Applied Loads
Brick Spandrel Deflections and Applied Loads
(OP)
I searched out a thread here that came very close to answering this question, but not quite. I hope you can provide a little more comment to this question.
We often design composite steel floor systems (also sometimes concrete on bar-joist floors)that have brick veneer clading on spandrel panels as the exterior skin. These spandrel panels are supported by the perimeter beams/girders, thus subject to the deflection of these members.
When limiting the deflection to L/600 or better, we typically consider the deflection caused by superimposed loads that would be felt by the spandrel. This would be the weight of the spandrel and any supported wall elements above (like windows), floor tributary live load, and miscellaneous superimposed floor tributary dead loads.
We typically do not consider the weight of the floor slab and beams since these are in place before the spandrel construction begins, and do not effect the deflection of the spandrel.
However, the Code simply says l/600 total load, which we have had others interpret to mean ALL loads need to be considered, not just superimposed. This can result in the need for very big beams, especially along the load bearing sides.
What are your interpretations and practices for this condition?
Thanks!
We often design composite steel floor systems (also sometimes concrete on bar-joist floors)that have brick veneer clading on spandrel panels as the exterior skin. These spandrel panels are supported by the perimeter beams/girders, thus subject to the deflection of these members.
When limiting the deflection to L/600 or better, we typically consider the deflection caused by superimposed loads that would be felt by the spandrel. This would be the weight of the spandrel and any supported wall elements above (like windows), floor tributary live load, and miscellaneous superimposed floor tributary dead loads.
We typically do not consider the weight of the floor slab and beams since these are in place before the spandrel construction begins, and do not effect the deflection of the spandrel.
However, the Code simply says l/600 total load, which we have had others interpret to mean ALL loads need to be considered, not just superimposed. This can result in the need for very big beams, especially along the load bearing sides.
What are your interpretations and practices for this condition?
Thanks!






RE: Brick Spandrel Deflections and Applied Loads
The other question is whether to include the full weight of the veneer itself in the total load. As the mason builds the veneer, the supporting structure deflects downward. So technically, some of the stress and movement in the brick is partial as the wall is built (i.e. the lower courses will experience the deflections from the upper courses, but the upper courses will not feel the deflections from the lower ones.
RE: Brick Spandrel Deflections and Applied Loads
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Brick Spandrel Deflections and Applied Loads
Woody--I agree with your method. Normally I check deflection assuming total load, but in a pinch, I have used your method.
DaveAtkins
RE: Brick Spandrel Deflections and Applied Loads
RE: Brick Spandrel Deflections and Applied Loads
I'm glad that our approach seems to generally follow other's practices.
Although we also tend to be conservative in the loading we use for deflection control, sometimes the results of using ALL loads in this spandrel condition just don't seem realistic.
RE: Brick Spandrel Deflections and Applied Loads
I would design the beam to have L/600 for only the loads imposed AFTER the brick is laid (live load and superimposed dead load).
Whatever deflection is in the beam after the concrete hardens will still most likely be small enough (if you've properly sized the beam) for the masons to adjust to. Masons are typically very good at what they do.
RE: Brick Spandrel Deflections and Applied Loads
RE: Brick Spandrel Deflections and Applied Loads
RE: Brick Spandrel Deflections and Applied Loads
RE: Brick Spandrel Deflections and Applied Loads
Also, I have worked with architects who assured me that L/600 will result in cracks in the veneer.
RE: Brick Spandrel Deflections and Applied Loads
RE: Brick Spandrel Deflections and Applied Loads
RE: Brick Spandrel Deflections and Applied Loads
RE: Brick Spandrel Deflections and Applied Loads
If your beams are getting large you might also consider the arching effect of the masonry around the opening. The following resource has some guidelines: http://www
If the openings are wide arching may not work in your application.