Proper R value for wood knee brace
Proper R value for wood knee brace
(OP)
Hi
Considering the cost of the moment frames and cantilever columns, sometimes when the subject structure is not so big I try to utilize wood knee brace for lateral loads. For example right now I have a wood deck at second floor level added to an existing building. The deck is only 8.5'x16' and let me assure you that no homeowner will pay the cost of a cantilever column and grade-beam and footing and....
Questions:
1- Do you think utilizing the wood knee braces are proper solution for small tributary areas?
2- If the answer is yes, then what would be a proper R-value per new IBC-06?
Thanks
Considering the cost of the moment frames and cantilever columns, sometimes when the subject structure is not so big I try to utilize wood knee brace for lateral loads. For example right now I have a wood deck at second floor level added to an existing building. The deck is only 8.5'x16' and let me assure you that no homeowner will pay the cost of a cantilever column and grade-beam and footing and....
Questions:
1- Do you think utilizing the wood knee braces are proper solution for small tributary areas?
2- If the answer is yes, then what would be a proper R-value per new IBC-06?
Thanks






RE: Proper R value for wood knee brace
Never, but never question engineer's judgement
RE: Proper R value for wood knee brace
Thank you
RE: Proper R value for wood knee brace
RE: Proper R value for wood knee brace
RE: Proper R value for wood knee brace
I saw that but the problem is that it does not define clearly what is a timber frame. I mean what kind of connections, or general requirements. Probably ASCE does not want to recognize the knee brace system as an accepted lateral resiting system.
RE: Proper R value for wood knee brace
What I meant by "R"-value is "Response modification factor" in earthquake design. This value kind of represents the level of ductility of the lateral resisting system.
ASCE 7-05 table 12.2-1 gives a complete list of different systems with their R, omega and Cd factors. The problem is that the table does not give any value for knee braces which we use to laterally support a car port or a deck.
My question is that if anybody has any suggestion for a proper R value for wood knee brace.
Thanks for the responses
RE: Proper R value for wood knee brace
RE: Proper R value for wood knee brace
RE: Proper R value for wood knee brace
The more I think, the more I become convinced that R=1 is the answer because of it firm technical justification. I think it is a safe and defendable decision.
Therefore, Thank you for the valuable answers.
nickky
RE: Proper R value for wood knee brace
Since your knee braces will take a great deal of load compared with the other components of your frame, it is very unlikely that any overall flexural mechanism will occur.
R=1.0 for sure.
Cheers,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...