IBC 2006 Equation 18-3

[nongamer12]

Sorry for the simple question, but you need a break every once in a while... Equation 18-3 of the 2006 IBC is:
d^2=4.25*(Mg/(S3*b))
Is S3 evaluated at a trial depth "d", so that it's an iterative solution? I'm just making sure. Thanks in advance for the reassurance.

 

[akastud]

Yes it's iterative and it's a pain.

 

[msquared48]

I agree, not to be iterative here.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[apsix]

Iterative, also known as irritative.

 

[CTSeng]

dust off the old cubic root solution equations?

yeah, I iterate too.

 

[akastud]

I wrote an excel macro to solve it, not too hard.

 

[MiketheEngineer]

Yes - I agree

Engineering International sells a spreadsheet for this. I think it is about $40.00. Seems to work well

 

[nongamer12]

Thanks so far everyone. I too wrote an excel program to do it for me. Now my question is about Equation 18-1, and specifically "d" and "S1" within.

"d" is limited to 12' for purpose of computing lateral pressure. "S1" is the allowable lateral bearing pressure at 1/3 of the depth "d".

Once again, we have an iterative process (or excel), but I'm confused: is "S1" limited to a maximum value at 4' deep (= 1/3 * 12')? This seems silly, but I can't figure out what the intent of the verbage is about. Can you all help me out with the intent and why it's written the way it is?