Staad 1 floor-space frame model

[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. I m doing elastic analysis for only selfwight load. I m seinding these resultsalong with my file of model in my attachments. Problem is that sagging (vertical deflection) on 4 edges of my model is to big -node displacement around 11mm and it sholud be around zero, because of the columns! Can anyone tell me what is the problem? Static check is ok, forcess in columns seems ok too. I m usiog staad pro 2007. Its urgent. Thank you.

 

[ToadJones]

I don't do a lot of concrete modeling in STAAD, but it looks
like you might need to add a node in the plates where the columns attach.

 

[ToadJones]

Infact, it looks to me like the slab-perimeter beam interface is improperly modeled all the way around. They are not connected.

 

[ToadJones]

I ran your model....took a while with so many plates.

Go to post processing and greatly exaggerate the displacements (I hold "CTRL" in "mouse wheel" in and out).

Look at your perimeter beam deflections and the slab deflections at the same location (not just the corners).
They do not coincide because your plates are not connected to the beams. I think you need to model these similarly to how you modeled your interior beams and plates.

 

[lavov]

Thank you ToadJones. I will try to model meshing so it is connected to the beams, and not over beams.

 

[ToadJones]

lavov-

I do not see a need to use STAAD's meshing feature. It often causes more problems.

Simply make the plates over the spandrel beams into (2) plates instead of one and connection them to the beam.

At the corner, break the plate up into (4) plates and connect them to the same node as the column.