samdamon
Structural
- Jan 4, 2002
- 274
I am designing a replacement parapet as a 4' vertical cantilever. Architect wants us to use solid clay masonry two wythes thick with hor joint reinforcement. I need to provide vertical rebar reinforcement, centered in the parapet, to resist wind etc. Have heard several different ways to provide the needed grout space for the vert bars. (They will be #4's):
1. Increase the width of the collar joint between the two wythes to about an inch, which provides a continuous grout space, fill it with fine grout. This option assumes the two wythes will act compositely due to the grout.
2. Keep collar joint at 3/8"+- wide, notch a triangular area on the interior faces of both the front and rear wythe to form a vertical grout space and chase for the vert bars, fill it solid with fine grout.
3. Keep collar joint at 3/8" +- wide, on one interior face of one wythe, sawcut a partial depth rectangle from the bricks to form a vertical grout space. (The vert reinforcement bar will need to be offset slightly from center to provide enough grout space around the bar.)
4. Increase the wall thickness to three wythes and periodically omit part of the center wythe to provide a grout space.
This detail will be applied for several hundred feet of parapet. (The architect will be specifying vert joints in the parapet to break it up thermally). Option 1 seems to be the most attractive and simplest to me. My previous experience has been to do option 2, but only in a very limited area. Option 3 was described to me by the architect based on another engineer's input on another project, but I am dubious about it- I am not sure how practical it will be to cut brick as described. Option 4 has architectural implications, and the effects of the weight of the extra wythe would need to be checked of course. It will probably be more expensive than the other options.
My question, given the scope of this project, is which option is most practical to build? Anyone have experience with this issue? The construction is going to go to the lowest bidder. Thanks in advance.
1. Increase the width of the collar joint between the two wythes to about an inch, which provides a continuous grout space, fill it with fine grout. This option assumes the two wythes will act compositely due to the grout.
2. Keep collar joint at 3/8"+- wide, notch a triangular area on the interior faces of both the front and rear wythe to form a vertical grout space and chase for the vert bars, fill it solid with fine grout.
3. Keep collar joint at 3/8" +- wide, on one interior face of one wythe, sawcut a partial depth rectangle from the bricks to form a vertical grout space. (The vert reinforcement bar will need to be offset slightly from center to provide enough grout space around the bar.)
4. Increase the wall thickness to three wythes and periodically omit part of the center wythe to provide a grout space.
This detail will be applied for several hundred feet of parapet. (The architect will be specifying vert joints in the parapet to break it up thermally). Option 1 seems to be the most attractive and simplest to me. My previous experience has been to do option 2, but only in a very limited area. Option 3 was described to me by the architect based on another engineer's input on another project, but I am dubious about it- I am not sure how practical it will be to cut brick as described. Option 4 has architectural implications, and the effects of the weight of the extra wythe would need to be checked of course. It will probably be more expensive than the other options.
My question, given the scope of this project, is which option is most practical to build? Anyone have experience with this issue? The construction is going to go to the lowest bidder. Thanks in advance.
