RC deflections

[Anonymous]

Can Robot determine the cracked moment of inertia( second moment of area) of a reinforced concrete section in particular a flat slab. Taking into account the reinforcement and tensile strength of the concrete

I appreciate that this would require several interations in order to produce the correct results.

Does it take into account tension stiffening?

[Artur.Kosakowski]

Pease check the stiffness update method (http://forums.autodesk.com/t5/Autodesk-Robot-Structural/elastic-and-nonelastic-slab-deflection-verif...

The number of iterations is limited to one. The values of the reduction of stifness (inertia) are shown both as maps or in the reinforcement table.

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[maciej.zielinski]

Dear Artur,

You confused the question which was being asked with a completely different subject.

I am now trying to compare long term deflections calculations between Robot and another program and I would also want to know if Robot takes under consideration the effect of tension stiffening - in plate and beam elements. In the other program I can either use, or disable this effect.

Tension stiffening is in short the consideration of help of pure concrete between the cracks in an element subjected to bending. Basically the concrete between cracks helps the steel rebars in bearing the tension forces. The resulting deflections of an element are hence smaller - would that effect not be considered.

At this point, I am pretty sure that Robot doesn't consider this effect at all, but I want to confirm it.

EDIT: grammar 🙂

[Artur.Kosakowski]

Hi @maciej.zielinski

This effect is disregarded in the RC design modules. It can be taken into account only at the static analysis of a model.

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