Variation of Concrete strength - Columns&Walls
Variation of Concrete strength - Columns&Walls
(OP)
Dear All,
Is applicable in the practice if the variation of column concrete strength changes from 10 ksi to 5 ksi at a level?
Even this variation is safe to resist the internal moments & shears.
Your input will be appreciated.
Murai
Is applicable in the practice if the variation of column concrete strength changes from 10 ksi to 5 ksi at a level?
Even this variation is safe to resist the internal moments & shears.
Your input will be appreciated.
Murai





RE: Variation of Concrete strength - Columns&Walls
With a limit of 1.4 maximum between floor and column, you have to do some different design work to accommodate 10 ksi vs. 5 ksi in the columns....in other words, at least one of your two columns will most likely be more than 1.4 times the floor f'c. See 10.15 and the few sections that follow for the required actions.
RE: Variation of Concrete strength - Columns&Walls
Section ACI 10.15 is transmission of column loads through floor system. When the f'c of column is more than 1.4 times f'c of floor, either of 10.15.1 to 10.15.3 adopted.
Once i take care of the floor system as above, Is it allowed to change my concrete strength from 10 ksi to 5 ksi at a level from the design point of view alone.
Is there any limitation in the view of practice ?
Your input will always be appreciated.
RE: Variation of Concrete strength - Columns&Walls
RE: Variation of Concrete strength - Columns&Walls
The seismic provisions for "soft stories", etc. should be carefully looked at to verify whether or not you have created an irregular structure.
But other than that, I do not believe that there is any code/spec provision that would keep you from varying the f'c as you propose.
RE: Variation of Concrete strength - Columns&Walls
Thanks ishvaaag & JAE. In this structure the predominant lateral force is due to wind only. I understood that one can use this option once satisfying 10.15 provisions