sharp reduction in beam moment capacity diagram near support

[patkson]

Hi All,

I have noticed a very sharp reduction in Moment capacity near the support for Beams using the provided reinforcement design module, And I find this very disturbing especially when I get this error feed back suggesting there is hogging moment capacity failure at the support.

But when I check the hogging moment capacity of the beam diagram some where at the middle it gives a value that exceed the those applied support moments.  And for whatever reasons the moment capacity is reduced near the support regions??? and i don't know why??

I have even tried extending the hogging bars beyond the support but to no avail. It only affected the capacity moment marginally. 

Could any please help me understand this. Is there a reference or some kind an engineering literature for this??

Regards,

Patrick

[Artur.Kosakowski]

As far as I can see you defined 90 deg hooks with the straight part equal to 0.431m. As Robot checks the stress limit in concrete at the location of the bent it considers only the length of 0.192m in reinforcement anchorage capacity calculations as otherwise concrete in this location would nor withstand the pressure. The possible solution for considering longer part of the hook in calculations is to increase the bend diameter of the hook but such option is not currently available in Robot.

See also: http://forums.autodesk.com/t5/robot-structural-analysis/anchorage-length-based-on-eurocode-rc-beams-...

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

[patkson]

ok Thanks Aurthur, But I guess the conclusion still remains

as in the other discussion which I'm trusting that your crew are working on as we speak and

hopefully there should be some improvments going forward.