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Hole in existing slab 3
- Thread starter Jandra11
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1
- #4
racookpe1978
Nuclear
Yes.
The requirements are:
1. Make a new hole big enough to serve the new purpose - whatever that new purpose may be.
2. Do not create a failure by creating a hole in the slab/floor/concrete/existing reinforcement/existing building/existing stress and settlement situation.
Seems simple, doesn't it?
ANALYZE the specific situation for ALL known and ALL unknown loads that "might" occur now, in the past due to operator error or original design or construction error or future operator error!
This is NOT "quote the book" so-called design.
It IS REAL engineering!
The requirements are:
1. Make a new hole big enough to serve the new purpose - whatever that new purpose may be.
2. Do not create a failure by creating a hole in the slab/floor/concrete/existing reinforcement/existing building/existing stress and settlement situation.
Seems simple, doesn't it?
ANALYZE the specific situation for ALL known and ALL unknown loads that "might" occur now, in the past due to operator error or original design or construction error or future operator error!
This is NOT "quote the book" so-called design.
It IS REAL engineering!
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- #5
In general, you will be checking the following questions:
1. How much flexural steel (if any) will I be interrupting from this opening and can the rest of the steel take care of it?
2. What effect on shear does this have? Specifically, will this opening cut back on my punching shear area at the column? (It can affect one-way shear as well but that seldom controls.)
3. [If any moment is transferred at the column...] How much unbalance in the moment is created? You will have to think about a pattern load with this and the possible increase in shear from a unbalanced/transfer moment.
4. What kind of coating system will I need to protect the exposed re-bar and concrete from the environment?
ACI 352.1 R-89 is a good resource on openings:
1. How much flexural steel (if any) will I be interrupting from this opening and can the rest of the steel take care of it?
2. What effect on shear does this have? Specifically, will this opening cut back on my punching shear area at the column? (It can affect one-way shear as well but that seldom controls.)
3. [If any moment is transferred at the column...] How much unbalance in the moment is created? You will have to think about a pattern load with this and the possible increase in shear from a unbalanced/transfer moment.
4. What kind of coating system will I need to protect the exposed re-bar and concrete from the environment?
ACI 352.1 R-89 is a good resource on openings:
- Thread starter
- #6
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1
- #7
Here is a great resource.
the bottom line: know what you are doing before you start blowing holes through slabs! Its the wild west as far as I'm concerned, and you want to be experience in gun slinging if you're venturing down that road.
the bottom line: know what you are doing before you start blowing holes through slabs! Its the wild west as far as I'm concerned, and you want to be experience in gun slinging if you're venturing down that road.
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