Linear interpolation and extrapolation in excel

[S4Tyler]

Hello,I am working on a spread sheet to quickly provide engineers with seismic Fa and Fv values based on given soil class values (A through E), given Sa(0.2) (a number) and a given Sa(1.0) (a number) based on the Canada building code seismic Fa and Fv charts.

The charts are in the attached spreadsheet.

An example of what I need the spreadsheet to do:
given: Soil class = A
S(0.2) = 0.625
S(1.0) = 0.25

Fa is a linear interpolation where:
Fa=0.7 when Sa(0.2)=0.5 and Fa=0.7 when Sa(0.2)=0.75
So: when Sa(0.2)=0.625
then by interpolation Fa=0.75

Fv is a linear interpolation where:
Fv=0.5 where Sa(1.0)=0.2 and Fv=0.5 where Sa(1.0)=0.3
So: when Sa(0.2)=0.25
then by interpolation Fv=0.5

As you can see, the process for finding Fa and Fv is quite simple but this is something that is done several times every day and I thought a tool to automate this step would be a time saver.

Thanks in advance for any help anyone can offer.

Tyler

 

[SkipVought]

What happend with the spreadsheet solution I posted yesterday?

Skip,
[sub]
Just traded in my old subtlety...
for a NUANCE![/sub]

 

[SkipVought]

...in thread68-1599459???


Skip,
[sub]
Just traded in my old subtlety...
for a NUANCE![/sub]

 

[S4Tyler]

I spent some time on it this morning and wasn't having any luck.

I must have misunderstood your suggestion.

Attached is a copy with the spreadsheet with my attempt at the spreadsheet solution.

Tyler

 

[SkipVought]

Your answers back in the original thread.

Skip,
[sub]
Just traded in my old subtlety...
for a NUANCE![/sub]