Overstrength factor in wood shear wall holddown (flexible diaphragm)

[Prakhar421]

Hi, where can I find in code where it states that designing holddown for wood shearwall system doesn't need an overstrength factor to calculate the design load? Any suggestion is greatly appreaciated!

 

[JAE]

Which code? Which country?

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[Agent666]

I doubt you will find that stated in any code. By their very nature wood shear walls are designed to dissipate energy in a ductile manner, so the hold downs should therefore be designed for the overstrength of the system. Unless there is some get out of jail clause in your local code that allows you to design the wall in such a manner that it might remain elastic and hence overstrength actions on the holddowns do not develop.

 

[jdgengineer]

In general, I think it would be a better detail to design the holdowns for overstrength factor to allow the yielding of the wood shearwall to occur in the plywood nails rather than the holdown device. However, it's not commonly done and I'm not aware of anywhere in the IBC that would require it. I think the codes doesn't explicitly say it's not required, but rather doesn't specify that it is required anywhere.