Mixing a steel and wood framing in a RAM model

[Despy]

I have searched but not found any info on this.

I have a residential project that is being built on the side of a 30-45 degree slope. As a result the house will be built on a platform consisting of steel columns and steel x-braces. The house itself is large and unconventional and will require a special moment frame as well as other miscellany steel beams and columns. The majority of the house will be wood framed.

I would like to be able to use the RAM structural system to model the building to help with the lateral calculations and steel checks. Has anyone attempted to mix wood framing with steel in a RAM model? Are there any resources available for this?

Thanks.

 

[Lion06]

Just use material "other" for the wood in RAM. It won't design it for you, you'll have to do that by hand (or with another program).

 

[Den32]

Yes, PAStructural PE is correct, you can model wood as 'other' material in RAM. RAM will not design it though, but you can probably extract the forces.....be careful though, I would back-check a few locations since RAM is not really intended to model wood.

Be careful setting up the Material Properties and Sizes for the Wood, because RAM will distribute the Lateral Loads based on Stiffness (if you have steel and wood sharing loads on same levels)

Also, I assume the Wood Lateral System is Shearwalls - RAM will just model this as a 'solid' wall which is not really what you have (since sheathing resists lateral load). May want to run a quick calc to see an equivalent wall thickness vs. size/type sheathing you have.

As a sidenote, you may want to look into RAM Elements which you can better model this. I haven't used it, but have read about it.

 

[Despy]

Thanks for the responses. I had noticed the "other" material type and was going to use that. I just wanted to know if there were any strange quirks I should be aware of.

The majority of my reason for using RAM was to get the onerous steel checks done without tediously hand calcs.

 

[abusementpark]

If all you want to do is design the steel, then RAM Elements may be a better option. You'll have to trace loads to your steel members by hand, but that may be less burdensome than building the entire model just to design a few members.

Were you going to design the wood members by hand?

 

[rscassar]

I have used other FE packages and combine wood and steel in the same model. If you model the correct stiffness for the plywood sheathing and the vertical steel bracing and define the stiffness of the horizontal diaphragm correctly there should be no issues with the distribution of lateral force.

 

[abusementpark]

I have used other FE packages and combine wood and steel in the same model. If you model the correct stiffness for the plywood sheathing and the vertical steel bracing and define the stiffness of the horizontal diaphragm correctly there should be no issues with the distribution of lateral force.

It seems to me like using FE to define wood stud wall framing would be a bear.

 

[Lion06]

I assumed the lateral system was the special moment frame that was mentioned in the OP. If that is the case, then I think RAM SS is more helpful than RAM Elements. RAM SS is much easier to design steel with and is much, much easier for doing the lateral checks.

I use Elements as more of an analysis tool when I'm just pulling out forces and designing by hand (I know it has design capabilities, but they're not as good as RAM SS).

Also, you can model openings in shearwalls in RAM SS.