making new opening in existing wall
making new opening in existing wall
(OP)
Lets say we have an existing wall and existing concrete slab on it. We want to make new opening in existing wall.
We have two options:
1. to make opening all the way up to the slab
2. to not make opening all the way up to the slab
Because we have existing slab on the wall, we have positive moments - tension in the upper zone of the slab, so there is reinforcement there.
If we make an opening as shown in figure 1 (see attached picture) we get tension in the lower part of the beam and compression in the upper part of the beam/slab.
My question - is that way existing reinforcement in the slab OK? I think there is no need to additional reinforcement because tension is in the concrete beam?
Id connect new beam with existing slab by drilling holes in the slab + epoxy + rebar. OK?
What about figure 2? We dont change static conditions for the slab that way either, so existing reinforcement in the slab is ok too? Am I right?
We have two options:
1. to make opening all the way up to the slab
2. to not make opening all the way up to the slab
Because we have existing slab on the wall, we have positive moments - tension in the upper zone of the slab, so there is reinforcement there.
If we make an opening as shown in figure 1 (see attached picture) we get tension in the lower part of the beam and compression in the upper part of the beam/slab.
My question - is that way existing reinforcement in the slab OK? I think there is no need to additional reinforcement because tension is in the concrete beam?
Id connect new beam with existing slab by drilling holes in the slab + epoxy + rebar. OK?
What about figure 2? We dont change static conditions for the slab that way either, so existing reinforcement in the slab is ok too? Am I right?






RE: making new opening in existing wall
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: making new opening in existing wall
RE: making new opening in existing wall
get away without the beam. If the beam is still required and you dowel your
stirrups in the slab, roughen the slab soffit and use your wet-to-dry epoxy
you will be A for OK in opinion.
RE: making new opening in existing wall
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: making new opening in existing wall
Also, make sure you're not cutting a hole in shear wall first.
RE: making new opening in existing wall
I've heard some say, well openings less than 4' or 5' or 6' will be "fine" and for the most part they're probably right as I've seen even larger openings with no consideration for out-of-plane forces. Besides running a full on FEA of the wall I'm not sure the best way to approach these situations. One somewhat reasonable suggestion is to assume some sort of "effective jamb width".
I've stuck with the following:
EIT
www.HowToEngineer.com
RE: making new opening in existing wall
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: making new opening in existing wall