Moment in long direction is greater than moment in short direction ?!

[abduallahadi]

Hi everybody
can anyone tell me why the moment in the long direction is greater than the moment in the short direction ?
it should be the opposit !!
sloid slab with 40X50 edge beams

[abduallahadi]

the robot file

[Artur.Kosakowski]

You need to be careful in matching the selected result type with the direction on which you project it.

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.

[abduallahadi]

Thanks arther
recpect to what you said , but the same result apper
in structural behavior it is known that the force goes in the shortest direction
and by looking at the picture below , it shows a coefficient multiples by the moment depending on the length to width ratio
in my case let us say that the edges is pinned and the ratio is (5/10 =0.5) , then the short direction is multiple by 0.95 and the long direction by 0.05
which means the moment in the short dirction should be much larger thn in the long direction .

[Rafacascudo]

I think this table is for fully supported slab on its edges.Results get better if you model this in Robot

[abduallahadi]

WOW , i am amazed
nice result
but my slab is fully support by beams !
this is realy strang

[Anonymous]

It looks as if your longitudinal beams were not sufficiently stiff - that cause resultant moment distribution in the opposite direction

[Artur.Kosakowski · Accepted solution]

Opps - I'm sorry I entirely misunderstood the question  Luckily Rafacascudo explained the situation - thank you. Indeed you are comparing a slab suppoted on beams (which can deform) with situation where you have a slab supported on walls (which cannot deform). 

Mind that the distribution of forces is the function of rigidity of elements / deformation of a structure. The more rigid the side beams are the closer you are to the results you wanted to see.

[abduallahadi]

Ok , now i got it
it is all about the stiffness of the beams supporting the slab
thanks a lot artur , god bless you