higher reinforcement in flat RC slab

[Anonymous]

I wonder why Robot give me a higher reinforecemnt (required area) than what it suppose to be.

for example in my slab I have a maximum moment at the span 320 kn.m/m

I am expexting no more than 3000 mm2 /m , however the reinforcement given by robot is double that. even if u remove the option that increase reinforcement for crack and deflection.

any answer?

2- when reinforcing the support area shall I reduce the force around columns? if I dont do that I would get a massive force.

Regards

[Artur.Kosakowski]

1. As far as I can see the moment is larger and the reinforcement is not that much bigger than what you expected for smaller bending.

2. Yes, I think you should . 

[Anonymous]

can u see the attached picture please..

why do I need 6196 mm 2 for this area according to a 315 kn.m/m? 

my calcs shows half of this value. 

[Artur.Kosakowski]

Have you included in your calculations the stress limit which is checked when you enter SLS combination in the list?

See: http://forums.autodesk.com/t5/robot-structural-analysis/minimum-reinforcement-in-slabs-again/m-p/549...

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[Anonymous]

BASED ON what I can understand from reading .. I need to disable SLS  whic is ok and replace the 280 fy by 500 how can I do that?

[Artur.Kosakowski · Accepted solution]

You need to enter combinations in ULS field only (see the picture I attached to my first answer) and you already set fy 500 MPa.

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.