Steel Beam Supporting CMU Wall
Steel Beam Supporting CMU Wall
(OP)
I have a client that is desiring to support a 9' tall CMU wall with a steel beam below. This CMU wall is an exterior wall that is located over garage space below. We are in both high wind and seismic zone, so we have other load considerations on the beam other than gravity. This wall will be approximately 32' long, but the span of the supporting beam can be broken up into smaller spans with several columns. I am concerned with supporting an entire masonry wall on a steel beam. Deflection (resulting in cracks) and providing connection of cmu reinforcing to beam below are major concerns. Has anyone done anything like this with long-term success? What should my deflection limits be? How do I connect these two systems together? I'm thinking that a masonry beam (or precast) would be a beter solution, but my client is putting pressure on me to use steel beam.






RE: Steel Beam Supporting CMU Wall
Use control joints in the CMU at spacings about 24 ft to 30 ft. on center.
As far as connecting the steel beam to the CMU, what we've done is use 5/8" dia. deformed bar anchors welded to the top flange and extended up into grouted cells 32", lapping with vertical reinforcing and matching their spacing.
RE: Steel Beam Supporting CMU Wall
RE: Steel Beam Supporting CMU Wall
RE: Steel Beam Supporting CMU Wall
1. The L/600 seems to have been established for a "typical", simple-span lintel where the supported masonry is in compression as deflection increases.
2. A continuous beam with multiple supports will have several reversals of the deflection curve. This will cause some the masonry to be in compression, other masonry sections in tension.
3. The geometry of a continuous beam with multiple supports makes it much easier to minimize defection without going to a "ridiculously large" steel member.
www.SlideRuleEra.net![[idea] idea](https://www.tipmaster.com/images/idea.gif)
RE: Steel Beam Supporting CMU Wall
Also what stops the whole thing toppling over in the wind. i.e. lateral restraint of the beam. If you have doors under then this will need to support the top half of the doors.
To connect the ends you could replace a few blocks with concrete and put embedded plates in it (only if it is not exposed).
Regards
csd
RE: Steel Beam Supporting CMU Wall
RE: Steel Beam Supporting CMU Wall
RE: Steel Beam Supporting CMU Wall
Your original post asked for advice on only the gravity load condition, and stated that the other conditions were being addressed.
I think the most straightforward solution would be to design the 9' high masonry wall with adequate reinforcement and grout fill to span the opening itself, as the wall will be much stiffer than a steel beam designed for strength.
Build the wall on a steel beam to carry the weight during construction, or alternatively build it on temporary staging, but in either case, the wall will in the end carry itself.
RE: Steel Beam Supporting CMU Wall
thread507-176484: deflection limit for spandrel beams supporting brick?
If L/600 and 0.3" are applied to all self+dead+live loads then should certainly be conservative. The steel beam will act somewhat compositely with the cmu it is supporting if DBA's or threaded rods are extended up into the cells.
RE: Steel Beam Supporting CMU Wall