Steel moment frames in a wood structure 1

[dpa]

I am doing the structural calcs for a house that is extremely irregular in shape and has too many windows for my liking. I am considering recommending the use of steel columns and moment frames but I am totally unfamiliar with the details of combining wood and steel as far as connections and especially with regard to differential thermal expansion and contraction. The temperatures in this area can vary from -25F to upper the 90's. A good reference book would be a real help. Naturally the owner hired a contractor before getting any permits so time pressures are not just crucial but more like ridiculous.

Thanks,
DPA

 

[DaveAtkins]

I know of no textbooks on this specific topic, but I wouldn't worry about thermal issues too much, unless the dimensions of this house are unusually large, or the steel is not protected from large thermal changes. Otherwise, your most typical detail will probably involve bolting a 2X to the top of the beam, and fastening trusses, joists, etc. to the 2X.

DaveAtkins

 

[dpa]

Hi Dave,

Thanks for the help. By the way my name is Dave Adkins. Close.

Dave

 

[boo1]

I have built a few houses mixing steel and wood. The steel beams and columns were bolted like Dave indicated. In exterior applications consider using PT, due to the thermal bridge causing sweating in the wall cavity.

 

[AlohaBob]

I would be careful of deflections and keep the stiffness of the frames compatible with the glass. Or else detail some resilient isolation joints.

 

[Taro]

Another issue that may need to be addressed is shrinkage. When the wood shrinks and the steel doesn't, things tend to tear apart. Might not be a big issue for your residential design, but it could be a concern if it's multi-story construction.

 

[mkberry]

Don't forget about the limits of your diaphragm. When I've mixed steel moment frames with wood, I've always been surprised at how long my drag strut needs to be to develop my frame. Not to mention the hold-downs. Rarely does a residential contractor have experience with precise locations of anchor bolts and templates. (If you are going that route)

 

[mkberry]

My post above is more applied to a braced frame rather than a moment frame. Sorry

 

[dpa]

Thanks for all the help guys. This is a scary project and I appreciate all of your comments.


DPA