Masonry Wall Moment Connection
Masonry Wall Moment Connection
(OP)
I have some very long (approximately 80' with no perpendicular walls framing in to support) 2 story corridor walls. The floor to floor height is 16'-0'' for the 2nd floor and roof. The second floor will have a composite slab spanning over steel beam that frame into the cmu wall, and metal deck spanning the 10' from corridor wall to corridor wall at the roof.
My approach is to design the masonry wall with a moment connection and the second level and cantilever beyond the second level. (reinforcing ends up being #5 @ 16 which I can live with)
My question has to do with the attached detail and trying to avoid a construction sequence delay. Below is the construction sequence as the detail is shown.
1) Build the wall up to the top of concrete
2) place the steel beam in cmu pocket
3) deck and composite slab to be placed to secure dowel bar into cmu wall below.
4) Finish building of block.
The problem I have with the is the masons must wait on the steel beam, deck, and concrete to be placed in order to finish building the wall.
Thanks in advance for any suggestions.






RE: Masonry Wall Moment Connection
RE: Masonry Wall Moment Connection
1) You'll never manage a detail that convincingly accomplishes that and;
2) You should be able to get whatever moment capacity you need from the segments of wall on either side of the beams.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Masonry Wall Moment Connection
I don't quite understand why you need a moment connection here. As mike states, it is usual for the decking the brace the tops of the walls. From your detail, I can't tell if you have this or not (the floor will certainly brace the wall in your detail).
RE: Masonry Wall Moment Connection
See attached section of the corridor, hope this clarifies. These corridors go for a long ways (approximately 80') the connection shown is for the second level to create a frame with the wide flange. I don't thing the metal deck at the roof will to much to resist bending of the cmu wall. I think it will go along for the ride as there is a simple 4x4 angle the roof deck will be supported on.
I guess my main concern is the dowels that go into the composite deck at the beam AND between the beam connection. In my mind the dowel bars keeps the "moment connection" continuous between the wide flange members spaced at 10'.
If I eliminated the dowels that would the phasing, but the dowels seem like they are an essential part of the system to me.
RE: Masonry Wall Moment Connection
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Masonry Wall Moment Connection
RE: Masonry Wall Moment Connection
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Masonry Wall Moment Connection
RE: Masonry Wall Moment Connection
RE: Masonry Wall Moment Connection
I am not in love with idea of having the CMU walls and steel beams acting as a moment frame, but that is besides the point. If construction sequencing is important, have you considered embed plates designed to fit in the wall and have the beams attached to the embeds with a bolted or welded moment connection. The embed plates could have perpendicular plates inside the wall welded to reinforcing.
Have you considered using 10" or 12" CMU walls that cantilever from the foundation.
RE: Masonry Wall Moment Connection
You got a love architects Ugh. Don't get me started at this point
I am not in love with idea of having the CMU walls and steel beams acting as a moment frame, but that is besides the point. (agreed, not sure I have any other options at this point besides going to this wall as suggest below.) If construction sequencing is important, have you considered embed plates designed to fit in the wall and have the beams attached to the embeds with a bolted or welded moment connection. The embed plates could have perpendicular plates inside the wall welded to reinforcing.
I do like this idea, I will try and draw this concept and see how it works itself out. Will keep you posted
Have you considered using 10" or 12" CMU walls that cantilever from the foundation. I am afraid this is not an option at this point due to likely increased cost, I think I can get the concept to work and have a very stable system, just trying to avoid construction phasing issues.
RE: Masonry Wall Moment Connection
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Masonry Wall Moment Connection
Is this interior and are you looking at seismic?
I vote adding steel columns cut into the masonry, if it's interior why can't they be built in same plane as the wall? I'd take the smallest steel column they make over this.
RE: Masonry Wall Moment Connection
The architect can still have masonry control joints in the 80' length, but your truss would have to be continuous.
BA