Flat Slab - required reinforcement and provided reinforcement

[Wioletta_F]

Hello.

Can you please help me to understand the fallowing:

I'have calculated the long term deflection and required reinforcement for a flat slab. The results are: 33mm deflection and ~1277mm2 of required bottom reinforcement. I then defined reinforcement zones with almost twice as much reinforcement and re-run calculations. The outcome is a message 'to little bottom reinforcement area' as well as bigger deflection.

I'm confused.

[Wioletta_F]

Hi!

I've got a similar problem. Please find attached a print screen. This a 200thick slab on 200x500 columns on 7.2x5.5m grid. also, a long term defelction based on min required reinforcement seems to be ok, but when defining my own panel reinforcement I get a very long list of errors with no results.

Can you please advise.

Thank you.

[Wioletta_F]

The attached is a reinforcement map automatically created (before I adjusted zones manually). At column position there is something like 5000mm2 reinforcement for tension.

Any sugestions please?

[Artur.Kosakowski]

I'have calculated the long term deflection and required reinforcement for a flat slab. The results are: 33mm deflection and ~1277mm2 of required bottom reinforcement. I then defined reinforcement zones with almost twice as much reinforcement and re-run calculations. The outcome is a message 'to little bottom reinforcement area' as well as bigger deflection.

I'm confused.

Most likely what you did was not what you assumed you did 

[Artur.Kosakowski]

---

The attached is a reinforcement map automatically created (before I adjusted zones manually). At column position there is something like 5000mm2 reinforcement for tension.

Any sugestions please?

 Try to use the reduction over support option calculating the required reinforcement.

[Wioletta_F]

Probably... So what  did I  do?

[Wioletta_F]

I did use reduction...

[Artur.Kosakowski]

Try to compare the value of required area of reinforcement in this location with the value of area of provided reinforcement you declared (or proposed by Robot) for the zone (should be visible in its top right corner or in the table on the ) rather than the value from the map in the provided reinforcement.

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.

[Wioletta_F]

The proposed area of bottom reinforcement is ~ 5000cm2 above column (see pdf). I don't think it's correct but don't know what went wrong.

Please help.

[Artur.Kosakowski]

I will need the rtd file and the number of the panel to look at.

[Wioletta_F]

Artur,

Thank you very much for your reply.

In the meantime I've lost all results for this project. (The same thing happend with my last job). The pdf's I sent last night were based on results I was getting yesterday. I saved the file as always - with results. And today - no results... I mean bending maps were there, required reinforcement as well but not the provided zones (defined by me or creted by Robot). So I re-run analysis and the results are ok. No problems. What I'm worried about is that I will loose the results again and that actually I can never be confident that what I'm getting is correct.

Should I speak to our IT guys? I actually did, but they don't know...

Thanks for time.

[Artur.Kosakowski]

Perhaps you should consider making the copy of the original file before you start editing the provided reinforcement?