Wood Frame Building, MWFRS or Componet? 2

[jheidt2543]

Under the IBC2000 (or ASCE-7), for a rectangular, single story, wood frame building with a manufactured wood truss roof, I maintain that the wood studs and the wood trusses are the Main WindForce Resisting System. They should be evaluated using the Wind Loads for MWFRS, not Components.

When evaluating, siding, roof sheathing, door and window headers or jambs for wind loads, they would be evaluated using the Wind Loads for Components.

Do you forum members agree or disagree and why?

 

[UcfSE]

If a member is part of a system that provides lateral load resistance for the building it is MWFRS. Keep in mind that a member may be designed with both C&C and MWFRS depending on the load. Wood trusses are not MW. They hold up a couple feet of roof, they do not provide stability or lateral resistance to the building as a whole. The same goes for wood studs loaded out-of-plane for bending.

Sheathing is C&C for out-of-plane loads and MW when it acts in-plane as part of a shearwall or roof diaphragm. The same goes for masonry rebar: same concept different material. Steel deck is like sheathing, C&C out of plane, MW in plane as a diaphragm. Moment frames supporting a diapragm are MW. Headers, jambs, C&C. Footings are also important. Shearwall footings and Moment or braced frame footings are probably MWFRS. Otherwise, they are C&C depending on tributary area.

If a member has a very large tributary area the MWFRS loads may be appropriate.

There is another similar thread in Struct. Eng. Other topics called "Components and Cladding Wind loads", currently page 2. Check it out for more stuff. These are my opinions as I understand them based on my judgment and talking to some other engineers around my area. I hope some of it helps!

 

[jheidt2543]

UcfSE:

Thanks for the noting the other thread, it actually states the question better than I did. I'll follow up there.