Stirrups placement in cantilvered beams
Stirrups placement in cantilvered beams
(OP)
As per attached sketch, please suggest the best arrangement and orientation of rebars and stirrups in cantilver beam. Beam is also supporting a secondary beam at the tip of cantilver (Not shown in sketch).
Appreciate for guidance.
Appreciate for guidance.






RE: Stirrups placement in cantilvered beams
Mike McCann
MMC Engineering
RE: Stirrups placement in cantilvered beams
RE: Stirrups placement in cantilvered beams
Top bars; obviously anchorage into the column is crucial and use laps as far away from the column as possible.
RE: Stirrups placement in cantilvered beams
RE: Stirrups placement in cantilvered beams
is that the same for a flat cantilevered beam with a tapered soffit?
RE: Stirrups placement in cantilvered beams
RE: Stirrups placement in cantilvered beams
RE: Stirrups placement in cantilvered beams
Your column/beam connection is critical here. I would make the cog a large hook, and have well anchored bars running perpendicular to the crack that will form at the internal angle.
RE: Stirrups placement in cantilvered beams
Is there any reference material for beam reinforcement in tapered sloped cantilver beams.
I have to use arrangement "A", type "Y" for varying stirrup sizes, otherwise each stirrup have to be made different. Two stirrup legs should have development length to act as one.
RE: Stirrups placement in cantilvered beams
RE: Stirrups placement in cantilvered beams
See Canadian code recommendations regarding stirrup lapping.
RE: Stirrups placement in cantilvered beams
RE: Stirrups placement in cantilvered beams
RE: Stirrups placement in cantilvered beams
RE: Stirrups placement in cantilvered beams
And that rule is disappearing in AS3600-2009 which should be available in the next month or so.
Yes AS3600 says no lap splices for stirrups, but I cannot understand why as long as proper development calculations are done allowing for lapping 100% of bars in a full tension zone.
RE: Stirrups placement in cantilvered beams
The varying beam depth can be accommodated by inclining the stirrups as the beam depth decreases, but inclining in the opposite direction to Option 'C'.
45 deg maximum inclination is typically allowed.
RE: Stirrups placement in cantilvered beams
RE: Stirrups placement in cantilvered beams
RE: Stirrups placement in cantilvered beams
The Australian code had incorporated a 20% additional reduction factor when the shear reinforcement cog is in a tensile zone because it does not achieve the same development as it would in a compression zone (micro-cracking I assume). The need for the reduction factor was discussed in the AS/NZS codes forum not so long ago and it is the only code that has this requirement. As Rapt has just informed us the new issue of AS3600 will not have this provision, after I just had all spreadsheets in our office updated to include this 0.8 factor.
RE: Stirrups placement in cantilvered beams
Appreciate if you can give a sketch for your idea.
RE: Stirrups placement in cantilvered beams
RE: Stirrups placement in cantilvered beams
BA
RE: Stirrups placement in cantilvered beams
Just wondering, is it easy to control that spacing pattern on site. Any limitations expected for placement, which would be dangerous, i mean any arrangement which cannot be monitored on site easily.
RE: Stirrups placement in cantilvered beams
Otherwise, determine the spacing you need at mid-height, then calculate what that means the spacing should be at the top of beam. You can check that with a tape measure before pouring.
Personally, I think I would make life easier for the guys on site by varying the height of each stirrup. It is not too difficult for the fabrication shop to do that.
BA
RE: Stirrups placement in cantilvered beams
I agree. This is the simplest way.
RE: Stirrups placement in cantilvered beams
RE: Stirrups placement in cantilvered beams
BA
RE: Stirrups placement in cantilvered beams
RE: Stirrups placement in cantilvered beams
I also agree that varying each stirrup length is probably preferable.