Shear vs. Moment for wind resistance
For structural steel framing connections, I am confused about what connection type is better for resisting lateral wind forces.
My study materials suggest that for wind resistance, more ductile connections are better and it is important to allow a beam to rotate, which leads me to conclude a 'simple' shear or rotation-free pinned connection would be better than a stiff rigid moment frame connection.
Also, when it comes to shear walls vs. braced framed lateral force resisting systems, it is unclear to me which would be better suited to specifically resist wind loads.
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Wind is one kind of lateral forces. For lateral forces like wind and earthquake, a rigid connection is typically better.
A hinged connection has little value in resisting lateral forces.
Gang Chen, Author, AIA, LEED AP BD+C (GreenExamEducation.com)
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Let's then answer your question with a question. . .
For seismic events, which strategy best protects buildings?
Ductile structure
Heavy structure
Moment forces
Shear connections
. . . scroll down for the answer. . .
A: Ductile structure
Explanation
And for seismic (but not necessarily wind) ductility (steel) outperforms brittle (unreinforced masonry). Click <<here>>Light wood stick construction, like steel, has a bend-but-don’t-break nature that makes it also perform well in an earthquake.
Concrete, like masonry, is brittle and performs poorly in an earthquake (click <<here>>). . . unless there’s enough steel rebar in the concrete to make it relatively ductile (click <<here>>).
Again, the names are, admittedly, confusing…..try not to relate “shear wall” or “moment connection” to shear force and moment force. (They do relate from a physics point of view but not intuitively for most of us)
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For starters, a 'shear wall' isn't going to be a structural steel wall with a lot of connections.
A shear wall is going to be a solid masonry (concrete) wall. Think monolithic.
A structural steel wall can be a braced frame or moment frame. A moment frame has 2-way rigid connections, web & flange.
All the above can resist lateral forces. Shear walls can resist the most, then braced frames, and moment connections resist the least.
Hope this helps!
Rebekka O'Melia, Registered Architect, NCARB, B. Arch, M. Ed, Step UP, Step UP ARE 5.0 Courses
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A shear wall can be a reinforced masonry wall, a metal stud wall with plywood or OSB, a wood stud wall with plywood or OSB, a reinforced concrete wall, or walls made from many other materials…
See the definition of a shear wall here:
https://en.wikipedia.org/wiki/Shear_wall
Gang Chen, Author, AIA, LEED AP BD+C (GreenExamEducation.com)
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You're welcome Zachary!
Rebekka O'Melia, Registered Architect, NCARB, B. Arch, M. Ed, Step UP, Step UP ARE 5.0 Courses
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