Weak Storey
Weak Storey
(OP)
I am working on a 6 storey reinforced concrete building where the first floor height will be almost three times that of the other floors.
I am worried about having a weak storey especially given the fact that a lot of my bottom storey walls will have major openings (excluding the core shear walls at the elevator.)
What is the best way to compensate for this loss of stiffness? Would flanging my elevator core walls really give me that much of a boost in stiffness? Increasing column sizes? I am trying to come up with a reasonable solution for the architect.
I guess the best way is for me to run a couple of trial runs on my analysis software and compare lateral deflections. Before I do that, I am curious as to how you folks usually compensate for stiffness when you come across something like this.
I am worried about having a weak storey especially given the fact that a lot of my bottom storey walls will have major openings (excluding the core shear walls at the elevator.)
What is the best way to compensate for this loss of stiffness? Would flanging my elevator core walls really give me that much of a boost in stiffness? Increasing column sizes? I am trying to come up with a reasonable solution for the architect.
I guess the best way is for me to run a couple of trial runs on my analysis software and compare lateral deflections. Before I do that, I am curious as to how you folks usually compensate for stiffness when you come across something like this.
Clansman
If a builder has built a house for a man and has not made his work sound, and the house which he has built has fallen down and so caused the death of the householder, that builder shall be put to death." Code of Hammurabi, c.2040 B.C.






RE: Weak Storey
RE: Weak Storey
RE: Weak Storey
I agree. I think this would really help. I won't be able to run my trial runs until Monday though.
Clansman
If a builder has built a house for a man and has not made his work sound, and the house which he has built has fallen down and so caused the death of the householder, that builder shall be put to death." Code of Hammurabi, c.2040 B.C.
RE: Weak Storey
BA
RE: Weak Storey
RE: Weak Storey
Also, remember to increase the buckling lengths of your columns between ground and 1st-can significantly increase the column size.
RE: Weak Storey
The Architect will love this... DO IT!
Mike McCann
MMC Engineering
RE: Weak Storey
Like BA says, You will need some hefty columns to be able to participate in the lateral stiffness. Otherwise, small columns will only end up "going for the ride" with the core walls.
If you are in a seismic zone, you may incur more of a penalty due to the soft story effect.
RE: Weak Storey
After unending negotiations with the architect, we settled with using a few deep beams and flanging some of my walls to achieve my target stiffness.
Thanks again for your help folks.
Clansman
If a builder has built a house for a man and has not made his work sound, and the house which he has built has fallen down and so caused the death of the householder, that builder shall be put to death." Code of Hammurabi, c.2040 B.C.
RE: Weak Storey