Circular argument ASCE 7 Section 12.14

[JLSE]

Section 12.14.8.1 specifies Fa=1.4 for soil sites, but also allows Fa to be determined by Section 11.4.4 which requires Fa to be a minimum of 1.2 and references back to 12.14.8.1.

As a designer, Ive never used the Simplified approach... as a plan reviewer, I'd like to get clarification.

Any insight?

 

[JStephen]

My take just reading this- I would reword 11.4.4 to say "When the simplified procedure is used, the value of Fa MAY be determined", etc.
Check if the commentary clarifies.
I'm looking in ASCE 7-16, so I'd check if the newer one is any more clear also.

 

[andrews2]

This does seem like a circular argument, but I think the intent is to use the higher Fa value when using the less refined simplified method of 12.14. I'm not very familiar with the simplified method, but I think if I were using it I would use the 1.4 value given in 12.14.8.1.

The issue is even worse in the newer code. Fa and Fv have been removed from Chapter 11 entirely, but 12.14.8.1 still says you can use 11.4.4 to determine Fa even though it's not there anymore. I'm getting the idea that not much time is spent refining this simplified method..