Composite Action

[Burgon87]

I have a composite deck and steel frame structure, I am trying make the slab and beam perform with composite action. Also I need the slab to act as lateral restrant to the beams as the beams are often failing in buckling.

Is there any way to create these two criteria?

Many Thanks.

[tony.ridley · Accepted solution]

• Create the beams and draw the slab over the top. 
• Don't offset the beams down, rather increase the Iy manually to account for the offset that exists in reality. 
• Choose shell type and use flexible diaphragm for the slab. 
• In the steel design check module, assign full lateral restraint to the top flange or your beams.

This should work OK

[Burgon87]

Thank you for the help.

The only problem I seem to have is actually restraining the top flange.....how do I go about doing this? Is there a tick box or method of doing this ?

[Artur.Kosakowski · Accepted solution]

The design parameters are to be defined in the member type label assigned to a bar.

[sariklakis.emm]

How do you increase the ly manually on a steel beam? Are you really going to get composite action between the beam and the slab?

I tried to model a composite beam by designing a section from section definition, introducing the steel section and the concrete section that is acting together.

I then place in the model and tried to design them from the stresses. The results seemed correct.

What do you think of that solution?

[tony.ridley]

I don't think you can pro-rata steel member stifness, but you could define the section using user defined values, and factor the Iy accordingly.  

Cheers,

Tony

[Tuctas]

  All these methods concern modeling used in analysis (personally, i prefer the way that sariklakis.emm suggested which can be used either if panels are modeled with F.Es or without F.Es but with diaphragm).

  As concerns design of composite sections, it is not currently available and any kind of "technique" is just an approximation that cannot reach the real action that take place (see attached).