Diaphragm Deflection Calculations

[JoshPlumSE]

I'm trying to come up with a way of modifying the 3 term diaphragm deflection equation (from the NDS, not the 4 term one from the IBC) to account for variable nailing patterns.

I've seen methods for doing this based on the 4 term equation, but not based on the 3 term one.

I suppose that I can take a closer look at the 4 term equation method and then use the theory to derive a method for the 3 term equation. But, I don't want to work that hard! More accurately, I just don't want to spend a ton of time verifying that the two methods produce the same results.

So, if anyone has already done the work (or knows of a publication which has) can you please point me in that direction?

Keeping my lazy fingers crossed,

Josh

 

[JoshPlumSE]

If anyone was interested in this thread, I ended up answering my own question.

For what it's worth, the NDS gives a method of deriving the Ga value based on Gt and the en value.

Ga = v / [ v/(Gt) + 0.75*en ]

So, if you have all the information available to you, then you can use the 4 term adjustment method to scale up the en term in the definition of Ga. Therefore, that gives you an equivalent Ga.

Unfortunately, what I was hoping for was a method where I didn't have to use all the the old 4 term variables (Gt and en).

Maybe I'll can still come up with an approximate method that I can validate versus the formula above.

Josh