Slab carrying a slab using hangers/ties !

[Mohammed_Ata]

Dear, All

As a problem of unsafe slab section (20 cm), constructed 5 years ago. A solution is to link it with a n upper slab that will be implemented soon. The links are two tie columns 25 cm*25 cm ! 

My model is to make the 2 columns as truss bar/tension only members to have the correct behavior.

I already make this but no results on the ties, i mean Fx as tension force ! Am i true? or there is teething forgotten !

As shown in pic(1), the definition of tension behavior. Pic (2)  shows the results where are no bar results ! Why?

The file is attached below.

Pic(1) 

Pic (2)

[HoshangMustafa]

Hi

Add a beam between the two columns and it gives the results

Please find the attached file

[Mohammed_Ata]

Your interest is appreciable Hoshang but, i already got results while not assigning truss bar attributes! 

When i assign it as a truss bar / tension, it gives no results ! May it be a hanger or a post (tension or compression) bar. Is it a bug! 

Defining a beam is not the real model! It affects the slab results and overall weight is i have a 3D model.

[Refaat · Accepted solution]

Dear  Mohammed

Greetings

 IMHO in order to get an axial tension force in the ties (using tie bars as tension bar).

You should have more rigidity at upper ties nodes such as increasing the slab thickness more than lower one.

In the attach picture I have increased the upper slab thickness to (400mm).

Hope it helps

Best Regards

Refaat

[Mohammed_Ata · Accepted solution]

Great Thanks, Refaat.

I already model the slab with its thickness but, i increased the inertia of the upper slab! 

[HoshangMustafa]

Hi

1- You can add beams parallel to the global (x axis) in the upper floor and get the Results.

or

2- You can add a beam between columns 9 and 10 parallel to the global (y axis) in the upper floor and get the Results.

[Mohammed_Ata]

Dear, Hoshang.

The system of the upper slab doesn't include any beams. It is just the slab carrying the lower slab through ties.