Mixed Lateral System

[dgengineering]

Hello everyone,

I am working on a house that has two gables as shown on my sketch. One of them has large openings so I was thinking if I could use a mixed lateral system- steel OMF for the large openings and wood shear walls for the other part. The stiffer part, wood shear walls will attract more load (70 % based on my calcs) and the steel OMF, more flexible part will take less load. Is it going to work or should I try something different? I can overdesign the shear walls and make sure the deflection is right for the glass openings. Please advice. Thank you

 

[dgengineering]

I used the lower R value to get the force on that line. I think I have to make sure the 2 systems move together with appropriate connections such as straps collectors which should be checked

 

[HTURKAK]

I can overdesign the shear walls and make sure the deflection is right for the glass openings. Please advice.

OK.. Do it.
I would consider to design the OMF as gravity only frame and design the SW for the total load.

My opinion.

 

[SE2607]

To elaborate on what @HTURKAK said, distribute the forces proportional to the relative stiffnesses (a lot of work) in which you will find the shear walls will take most of the load. When you do this, you will likely end up with @HTURKAK recommends.

 

[human909]

Mixing and matching moment frames and shear walls within a residential build is pretty common in my part of the world. You need large moment frames to accommodate open plan living especially when there is plenty of glass around the open plan area. Normally however the moment frames wouldn't be in line with another shear wall though so any differential deflection would be taken up in the diaphragm.

Unlike the advice above I'd absolutely still design the frame as a moment frame. But don't skimp on you capacity. IMO if you don't you are asking for trouble as you need local stiffness around the windows. Trying to rely on shear walls halfway down the house to keep that large frame square is a headache both for you you the engineer and the builder.