Space frame problem

[lavov]

Hello everybody
I m doing a model of 1-floor reinforced concrete space frame with concrete slab. I m using columns 100x100cm (C70/85), beams 45/90cm (C50/60) and 22cm thick slab (C35/45). I m doing elastic analysis for only selfwight load. Results along with my staad file are in attachments. Problem is that sagging (vertical deflection) on 4 corner edges of my model is to big -node displacement around 11mm and it sholud be around zero, because of the columns!
[Image: modeldisplacement.jpg]

http://img829.imageshack.us/i/modeldisplacement.jpg/

Can anyone tell me what is the problem? Static check is ok, forcess in columns seems ok too. I m using staad pro 2007. Its urgent. Thank you.

http://www.easy-share.com/1912136644/spa...

model.rar

 

[edward1]

Suggest use 4 support points at each corner of column instead of 1 at center of column. Also, beams should be modelled as member offset start and end from center of slab to center of beam.