Flat slabs limited "edge column" moment transfer

[SnapSpace]

Hi!
I have a question on this subject.
When calulating this problem by hand, you divide flat slab into 2 strips, one is the column strip and the second is the middle strip.
When calculating negative moments at the "edge column" we had a limitating moment trasfer to column that was expressed as Mt=0,18*b*d^2*fck. This expression limited the slab section of becoming over-reinforced.
Now, if I calculated this using quivalent frame method, I had an option of reducing negative edge moments by not more then 50%, if calculated moments where higher then this, but then I had to increase the postivive momets in the span by the same precentage..
Im now using structural analysis program that uses FEM.
My question is, should I also limit the values of Momet transfer to edge column, and also reduce -moment/increse +momets if necesary or not?
Thank you

 

[SnapSpace]

Flats slabs thicknes 20 cm, rectangular column array 6,00 m spans, column 40/40 cm and storey hight 3,00 m.
Loads where: self-weight and 10kN/m^2 on slab deck.
Heres the structure:

http://img206.imageshack.us/img206/3079/s12tp4.jpg

and the rusults:

http://img142.imageshack.us/img142/2566/s32tk6.jpg

 

[csd72]

There is definately something wrong with the way you have modelled the analysis, the external column moments should definately be less than the internal moments over the columns.

Also, I dont know the specifics of your analysis package, but I am sure that the slab dosnt stop half way across the column as shown. Model the slab edge as a cantilever to get out to the actual slab edge.

You should get advice from a more experienced person in your office. Dont be afraid to ask, we all have to learn.

 

[SnapSpace]

You mean like this...

http://img245.imageshack.us/img245/3011/dfkx5.jpg

 

[csd72]

Yes, if that is what it looks like.

Also, have you allowed for cladding loads along the slab edge? I would recommend you take a closer look at this before you finalise your slab design.

Good luck.

 

[SnapSpace]

What an cladding?
Sorry my english is kinnda limited :-(

 

[csd72]

external walls/windows e.t.c.

 

[SnapSpace]

aaaa yes, yes...