column bars splices - position ?
column bars splices - position ?
(OP)
Hi struct.engs
I would like to ask something about the position of the column bars splicing. Does the upper bars really need to start at the floor level or can the splicing be also done in the 1/3 of the column height?
See attached sketch
and the left, ref bar
we discussed it already one, if it is also possible to cover with long bars directly two floors instead of only one. So then the bars will be instead of 3500mm 7000mm. By such thick bars it shouldn't be really a problem I guess as well
BauTomTom
I would like to ask something about the position of the column bars splicing. Does the upper bars really need to start at the floor level or can the splicing be also done in the 1/3 of the column height?
See attached sketch
and the left, ref bar
we discussed it already one, if it is also possible to cover with long bars directly two floors instead of only one. So then the bars will be instead of 3500mm 7000mm. By such thick bars it shouldn't be really a problem I guess as well
BauTomTom






RE: column bars splices - position ?
Respect if you can have your main (thick) rebars through some floor, you as well can. You need in every case ascertain that moment transfer of the floor or its beams is properly managed; that must mean detailed observation of the hypotheses and then that the floor or beams' rebars themselves are bent to overlap with the column rebar instead than passing horizontally through the column; this obviously introduces new requirements of attention and design; for those cases in that such kind of overlap with the rebar in the column is required, it is normally understood that the required overlap of each bar is in accord with its own diameter.
RE: column bars splices - position ?
ANY FOOL CAN DESIGN A STRUCTURE. IT TAKES AN ENGINEER TO DESIGN A CONNECTION."
RE: column bars splices - position ?
RE: column bars splices - position ?
Splicing in "midheight between floors" even recommended? Ok then am glad. Ok it is true that you want to have them not spliced in the areas of maximum forces. This makes also sensse. Only that you see usually the splicing right in the bottom (floor level) ok it is also more practical and easier to handle.
For taking the rebars through two floors what is the recommended height (max length) for such column bars?
Only one thing I don't understand. What you mean with "...instead than passing horizontally through the column..." The beams are actually never connected "into" the column by using L-shape bars. They actually really just go through the column. Hhmm...
--- tp rowingenieur ---
Three floors? So you column bars maid be even 9m long? Can you really still handle it on the site?
About which diameter are you talking here in such an case?
Ok this weight issue and start at the floor makes senses
RE: column bars splices - position ?
Splicing in "midheight between floors" even recommended? Ok then am glad. Ok it is true that you want to have them not spliced in the areas of maximum forces. This makes also sensse. Only that you see usually the splicing right in the bottom (floor level) ok it is also more practical and easier to handle.
For taking the rebars through two floors what is the recommended height (max length) for such column bars?
Only one thing I don't understand. What you mean with "...instead than passing horizontally through the column..." The beams are actually never connected "into" the column by using L-shape bars. They actually really just go through the column. Hhmm...
--- to rowingenieur ---
Three floors? So you column bars maid be even 9m long? Can you really still handle it on the site?
About which diameter are you talking here in such an case?
Ok this weight issue and start at the floor makes senses
RE: column bars splices - position ?
ANY FOOL CAN DESIGN A STRUCTURE. IT TAKES AN ENGINEER TO DESIGN A CONNECTION."
RE: column bars splices - position ?
In the inner columns, proper splicing is also required; there are always things to look at in structures. For example, you might, even if it is unlikely, to have bottom rebar highly in compression and, cut inside the column you might end having something not able to take such rebar compression unto the concrete, or corresponding spliced rebar to the other side. Precisely because of it being an uncommon situation it also will be a condition rarely checked.
I am sure there is some text out there describing the multiplicity of cases of special problems at reinforced concrete joints, even if I don't remember now one. But it would be good to remind. Er... I had one 1 meter from me, it is easy to forget ...
Design of Beam-Column Joints for Seismic Resistance
ACI SP-123
or some another on detailing concrete, maybe
ACI SP-66 04 Detailing Manual
htt
Another nice find
http://www
RE: column bars splices - position ?
12 m even? And the contractors are not complaining that the reinforcement is difficult to handle?
I thing to take the bars through two floors should be good enough so basically in my case rebar length of around 7m
--- to ishvaaag ---
Sorry, but somehow I don't get really what you mean?
"....They are almost never bent unto the columns....." ?
Just to confirm that I got you all right. So the splicing can be really done in the middle height of the column? And is actually even recommended?
Please have a look on the attached sketch. So this is the perfect column reinforcement?
Why is it then actually never done this way?
RE: column bars splices - position ?
Respect the recommended position at midheight, it only appears in our codes (namely NCSE-94) as a device of ensured strength -ductility for that matter at the most solicited points under lateral loads, thought to be joints.
htt
See fig 4.9 of such code where the central part of columns was reserved in the high ductility columns for the longitudinal rebar splice in columns.
The standing seismic code is NCSE-02, in which such "high ductility column" detail has dissappeared; but we only expect earthquakes say up to 0.2g and maybe that has made the better support characteristics of splices at floor level stand.
Follows NCSE-02
h
RE: column bars splices - position ?
ANY FOOL CAN DESIGN A STRUCTURE. IT TAKES AN ENGINEER TO DESIGN A CONNECTION."