combining different R values
combining different R values
(OP)
Hi,
Basic question:
I have a two story wood duplex with shearwalls. Below the main floor, for various reasons, I would like to use a cantilivered wood column system. I'm not quite sure how to combine the loads to get the correct base shear. At the moment, I am using:
V = Cs*W(upper flrs) + Cs * W(main flr)
I am using R=6.5 for the upper floors to calculate Cs and R=1.5 at the lowest floor to calc it's Cs. This method puts more seismic load into my shearwalls. I had thought I would only be penalized at the lowest level. What is the best way to calculate this?
Basic question:
I have a two story wood duplex with shearwalls. Below the main floor, for various reasons, I would like to use a cantilivered wood column system. I'm not quite sure how to combine the loads to get the correct base shear. At the moment, I am using:
V = Cs*W(upper flrs) + Cs * W(main flr)
I am using R=6.5 for the upper floors to calculate Cs and R=1.5 at the lowest floor to calc it's Cs. This method puts more seismic load into my shearwalls. I had thought I would only be penalized at the lowest level. What is the best way to calculate this?






RE: combining different R values
I would seriously consider ordinary moment frames (w shape) at the lower story if you have to have the structure more open. These frames can be integrated into the wood scenario without too many structural problems.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: combining different R values
Garth Dreger PE
AZ Phoenix area
RE: combining different R values
Any more thoughts about how to calc base shear with different values of R above and below?
Thanks!
RE: combining different R values
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: combining different R values