Modelling Deck in SAP2000

[Struct-007]

Hi,

I need to model a deck in SAP2000 such that it transfers the load in one direction only. The deck is supported on 4 beams (one at each side) and I want the load to be transferred in one direction to two parallel beams only.

In ETABS, there is an option to define a deck section and then assign an orientation for that deck. However, in SAP2000, I can't see this option.

Can anyone please help?

Thanks!!

 

[JoshPlumSE]

Can't you just convert that to distributed loads on the beams without modeling the deck or the deck load directly?

 

[centondollar]

You describe an orthotropic deck what can (in theory) be modelled by assigning orthotropic plate stiffness in the FE program. It's not necessarily realistic at all unless the slab is very long in one direction (span between slabs large), and what JoshPlumSE suggests is how this problem was solved in the old days.

If you are relying on the longitudinal beams (with, presumably, a concrete deck slab primarily for purpose of stiffening the beam) in a primary direction and the total system can reasonably be modelled as a uni-directional beam or as a series of uni-directional beams, that would probably yield as good a result as any fancy finite element calculation.

 

[JLNJ]

In RISA you can define the distributed load so that it resolves the load in the direction(s) you desire. This doesn't help model the deck, though, if that's of primary importance to you.

 

[271828]

Option 1 is to do as JoshPlumSE said.

Option 2 is to define an orthotropic shell. I would make the shell the same thickness as the deck. Then use a property modifier to make the slab much stiffer parallel to the ribs. If you need to model in-plane shear stiffness, then use another property modifier to give you the same G' as the deck/fastener combination. This is pretty easy, but you should run some easy cases with known results to make sure your approach is working.

 

[X4vier]

That option in SAP2000 is directly at the load definition. You use load areas to frames, it uses the first axis (red arrow) to define which border members bears.