Best Reinforcement Detail by stepped column?
Best Reinforcement Detail by stepped column?
(OP)
Hi Struct.Engs.
I would like to ask you for your advice, which reinforcement arrangement did you make best experience?
The case is: A column changes the Dimensions from 450x800mm to 450x450mm
what is the best way to stop the reinforcement now?
i prepared some sketches for you, it would be nice if you could have a look and report back.
Regards
BauTomTom
I would like to ask you for your advice, which reinforcement arrangement did you make best experience?
The case is: A column changes the Dimensions from 450x800mm to 450x450mm
what is the best way to stop the reinforcement now?
i prepared some sketches for you, it would be nice if you could have a look and report back.
Regards
BauTomTom






RE: Best Reinforcement Detail by stepped column?
RE: Best Reinforcement Detail by stepped column?
BauTomTom
RE: Best Reinforcement Detail by stepped column?
RE: Best Reinforcement Detail by stepped column?
- the 90 deg bends should be 30 deg
- additional confinement/shear reinf should be provided
- I would keep the tapered laps out of the beam column joint to minimize congestion
RE: Best Reinforcement Detail by stepped column?
RE: Best Reinforcement Detail by stepped column?
BA
RE: Best Reinforcement Detail by stepped column?
Usually I would simply terminate the lower, larger column bars, just under the floor. I'd then add dowel bars that matched the upper column bars. These dowel bars would lap splice with the upper column bars and extend down from the top of floor into the lower column to develop/splice down there.
If the floor is too narrow and the dowel bars would have to be extended below the bottom of the floor, then I might either extend them further to help with placement or go to hooks.
RE: Best Reinforcement Detail by stepped column?
As a general rule, if a location of a column face changes more than 3 inches (75 mm), do not try to offset the bars thru the slab/beam region. Discontinue bars and dowel the reinforcement into the lower column as dowels with one development length above and below the cold joint/top of slab (easy, essentially as shown in sketch #1.)
Where the reinforcement in the lower column must be developed at the top of column, bars should be hooked or anchored with headed reinforcing bars, as appropriate. Similar to your #5. Where you can get enough moment using the dowels or continuing certain bars into the upper column, that is preferred due to construction and rebar fabrication issues.
#2 is very complicated to construct, #3 even more so.
#6 does not work with such a sharp offset.
RE: Best Reinforcement Detail by stepped column?
Dik
RE: Best Reinforcement Detail by stepped column?
As for the splicing into the base column where the upper to lower column dimension difference is more than 6", doweling in to the lower column will not meet ACI 12.14.2.3.
RE: Best Reinforcement Detail by stepped column?
RE: Best Reinforcement Detail by stepped column?