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deep beam - strut and tie model

deep beam - strut and tie model

deep beam - strut and tie model

(OP)
Im having some issues modeling a strut and tie model for following case.




Any suggestion?



RE: deep beam - strut and tie model

How much load is coming in from the uniform load at the top of the beam? Also, can you explain how it is that your point loads are applied at 0.8 m? The details tend to be important with this kind of thing.

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: deep beam - strut and tie model

MacGregor page 789 or just review all of chapter 18.

RE: deep beam - strut and tie model

(OP)
How much load is coming in from the uniform load at the top of the beam?
just self weight - aprx. 10 kN/m

Also, can you explain how it is that your point loads are applied at 0.8 m?
Timber beams via steel hangers are anchored there (roof). Concentrated loads F1 = F2 = 20 kN

RE: deep beam - strut and tie model

The sketch below would be my recommendation for STM. That said, I think that you'd want to think carefully about whether or not STM is the right tool for this particular job. Strut and tie kinda kicks in at the 11th hour when everything is already cracked up terribly. You may not want that for this element. You could, perhaps, replace the hanger ties that I've show below with a concrete anchorage check as we typically do with ACI 3118 Appendix D in north america. That would essentially just be another means of dragging the load up into the body of the wall/beam.

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: deep beam - strut and tie model

Any suggestion?

Nothing specific from me. Go with KootK's if it's a new design.

If it's an old wall and you don't know what reinforcement it has, start by looking at the scale of the loads. A 20kN load equates to 180MPa in a single 12mm bar, or 160MPa in a half-inch bar (KootK's hangers). Probably less than that for the main bottom bending moment reinforcement. It may not be worth considering any more than that except out of interest.

It might also be convenient to use a different strut-tie model for the two different loads since a single model doesn't seem to handle both of them very well. Superimpose the results.

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