4 story wood building with steel beams and columns at the first story
4 story wood building with steel beams and columns at the first story
(OP)
I am designing a large 4-story wood residential building with wood stud walls and wood truss floors. The half of the building at the first story is parking garage, framed with steel columns and beams which support the wood structure above. My question: is the steel frame needed to be braced by itself, such as using moment frame? Since the floor truss will sit on the top of the steel columns and beams, I am concerned that if the steel frame can be braced by the plywood floor diaphragm above. Any comments appreciated, thanks in advance!






RE: 4 story wood building with steel beams and columns at the first story
RE: 4 story wood building with steel beams and columns at the first story
Mike McCann
MMC Engineering
RE: 4 story wood building with steel beams and columns at the first story
RE: 4 story wood building with steel beams and columns at the first story
RE: 4 story wood building with steel beams and columns at the first story
RE: 4 story wood building with steel beams and columns at the first story
When in doubt, just take the next small step.
RE: 4 story wood building with steel beams and columns at the first story
RE: 4 story wood building with steel beams and columns at the first story
RE: 4 story wood building with steel beams and columns at the first story
However, if it is a decent-sized multi-family "residence", you should consider replacing the first floor framing with PT.
Whatever works though...
Mike McCann
MMC Engineering
RE: 4 story wood building with steel beams and columns at the first story
neffers
RE: 4 story wood building with steel beams and columns at the first story
RE: 4 story wood building with steel beams and columns at the first story
RE: 4 story wood building with steel beams and columns at the first story
If you have a viable load path from the steel framing to the timber shear walls I can't see that 'extra' bracing is required just for the steel frame.
Your local design codes may dictate otherwise, but I'm not familiar with those.
RE: 4 story wood building with steel beams and columns at the first story
RE: 4 story wood building with steel beams and columns at the first story
Depending on where you are, some jurisdictions limit the number of wood stories to anywhere from three to five stories.
If you have an eight story building then, it is common to have the parking levels in concrete (PT), and as many of the living floors as necessary to meet the maximum number of wood stories.
In some jurisdictions, the top of the PT or concrete level, commonly called the Podium Slab Level, is used as the seismic base, with none of the lateral forces in the PT having to be transmitted to the wood stories. This helps immensely where allowed, and it does work where the lateral stiffness of the concrete floor system is much greater than the wood floors. Generally, this difference in stiffness must be proven via calculations to be accepted and allowed. It is tedious, but doable.
Mike McCann
MMC Engineering
RE: 4 story wood building with steel beams and columns at the first story
however, i'm surprised that the first elevated level is not concrete. see if you can explore this option with your architect.
RE: 4 story wood building with steel beams and columns at the first story
RE: 4 story wood building with steel beams and columns at the first story