RC beam with "broken line"

[greznik91]

English is not my 1st language.
What Im asking is what does it mean when beam has "a broken line" (i dont know a proper expression for this).
I compared a normal - straight line beam with a broke beam (distance A is small - lets say 300 mm) in FEM software and got the same results (bending moment, shear forces).
Is there anything special/different? Something to be careful about when reinforcing beam - especially at the point where line breaks? Shear reinforcement because a part that is perpendicular to other two lines transfer whole load from one to other line?

 

[TehMightyEngineer]

This exact question was asked a week or so ago, actually: [URL unfurl="true"]http://www.eng-tips.com/viewthread.cfm?qid=431674[/url]

Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

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[greznik91]

thanks for answer but i was thinking of horizontal offset not vertical offset...

 

[patswfc]

Torsion. Your beam with a crank on plan will experience torsion, thus you will need to design the rebar (both shear links and longitudinal steel for the effects of this.
What is the reason for the crank?

 

[hokie66]

Why not run the beam straight between the supports? Not everything has to be orthogonal.

 

[dik]

With a short crank, you may have difficulty developing rebar... Only good for light loading... unless the beam gets large. The center portion may be equal to the depth of the beam.

Dik

 

[GregLocock]

It would be fun to sketch out where your steel is in that design, assuming it's a pre or post tensioned steel reinforced concrete beam.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[KootK]

Seems pretty likely that this would be related to the other thread that you've got going at the moment. Assuming that to be the case, cantilevered beam four that ties into the jog ought to do an ample job of rectifying your torsion. The presence of the slab helps too, of course, but I'd be counting on beam four to do the lion's share of the work. After that, it's really all about the rebar detailing required to accomplish moment continuity across the offset. And that's not likely to be easy. You'll wind up with something that will be costly for you to design and express and costly to build. And the behavior will be more difficult to predict than is the case with more conventional framing.

As discussed in the other thread, I'd recommend something simpler like what hokie has suggested. If you do decide to go with this arrangement, I expect that you'll need a fair bit of overlap between beams in order to make a go of the detailing. It's not like HSS steel tubes where you can just CJP the miters and sleep easy.

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.