Seismic Design, R Coeff. Question
Seismic Design, R Coeff. Question
(OP)
I'm designing a 15 ft high single story addition in SDC D, SUG-II, with log columns, glulam beams, and log "K-braces" for lateral force resistance. The roof will be 3x6 T&G. In ASCE 7-02, Table 9.5.2.2 I'm trying to determine what R coefficient to use and I don't see any that look applicable. They all seem to apply to steel, concrete, masonry, or wood shear panels. Does anyone have any experience with this?






RE: Seismic Design, R Coeff. Question
You are talking about a timber frame, in essence. Agree that the chart isn't much use for that particular lateral force resisting system. There doesn't seem to be a lot out there about timber FRAME design.
However fyi some research results on timber frame lateral design at the following link:
scholar.lib.vt.edu/theses/available/etd-08142002-232925/
Good resource for timber connection designs is timber framers guild, www.tfguild.org. They have several useful publications about joint design. (Joint design will probably be critical for your building).
Please post if you find any opinions about what R values are recommended. Good luck.
RE: Seismic Design, R Coeff. Question
RE: Seismic Design, R Coeff. Question
Thanks. It was there in the 1997 UBC, in Table 16N. R=5.6 for Building Frame System - Heavy Timber.
RE: Seismic Design, R Coeff. Question
RE: Seismic Design, R Coeff. Question
RE: Seismic Design, R Coeff. Question
I should have added chapter 16 on my previous post. I am glad you found it.
RE: Seismic Design, R Coeff. Question
RE: Seismic Design, R Coeff. Question
If your building can be considered conventionally light framed, and you abide by the detailing required in chapter 2308, you will not have to perform a seismic analysis.