Preffered Beam Detailing
Preffered Beam Detailing
(OP)
Hi All
We had a discussion in our office and I would like
to know you preffered method.
When to beams connect over a column:
1. Secondary beam top reinforcing is placed lower througout beam
under primary beam top reinforcing and designed with the reduced depth.
2. Secondary beam top reinforcing cranked and placed on
the same level as primary beam top reinforcing and design with reduced depth.
There are good arguments for both, so basically what is the preference.
Kind regards
We had a discussion in our office and I would like
to know you preffered method.
When to beams connect over a column:
1. Secondary beam top reinforcing is placed lower througout beam
under primary beam top reinforcing and designed with the reduced depth.
2. Secondary beam top reinforcing cranked and placed on
the same level as primary beam top reinforcing and design with reduced depth.
There are good arguments for both, so basically what is the preference.
Kind regards






RE: Preffered Beam Detailing
1) the cranks will tend to straighten out and spall the concrete over the primary bars. Stirrups in the vacinity of the crank will help with that but I'd rather not rely on that.
2) the cranks add a bit of field complexity.
3) With the cranks, I'd ague that the secondary beam flexural depth is stil the lower d value at the face of the support anyhow.
4) A nice feature of beams is that they are generally not too sensitive to minor changes in flexural depth. If the primary beam has multiple layers of top steel, I might try to plan things out such that the secondary beam steel can run beneath the top layer of primary beam steel.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Preffered Beam Detailing
Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries
www.americanconcrete.com
RE: Preffered Beam Detailing
RE: Preffered Beam Detailing
RE: Preffered Beam Detailing
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Preffered Beam Detailing
RE: Preffered Beam Detailing
We detailed it often in the old days of full detailing. But then we had to think of clashes at high points with PT and sort out these sorts of details and did the same for the reinforcing. And also at end connections with columns etc.
Unfortunately others in the PT industry used to detail tendons in both directions to the same top cover and leave it to be sorted out on site, which resulted in under strength as one direction ended up lower than it was designed. But they did not worry about that as their solution was cheaper, even if it was under designed! And that is one of my biggest gripes with engineers today!