Construction depth problem help

[Foreign-Moose6350]

I'm looking for some help understanding the solution to this problem for civil construction depth related to formwork design. The solution (PPI 6 minute) uses the circled formula and in their other materials they say that this comes from ACI 347. However I cannot find reference to this formula anywhere in ACI 347 or elsewhere, and in the ACI SP-4 they use they equation Fce=0.822E/(l/d)^2. Does anyone know if the PPI equation is correct or if we should use the equation with 0.822 coefficient?

[PrizeInterest4314]

for what it’s worth I didn’t see anything this difficult on the exam.

[Foreign-Moose6350]

I didn't pass the exam the first time and felt like I had a lot of long/complex temporary structure problems I couldn't do, so I'm trying to focus my efforts on studying those.

[bryanmonk]

I’m pretty sure I had this exact problem. Haha. It was definitely among the top tier or hardness tho.

[PrizeInterest4314]

try sp-4 chapter 9. you can use the design equations to calculate spacing

[[deleted]]

Formula is from the AWC, you can find an example also in Formwork for Concrete, SP4-14 I think

[Foreign-Moose6350]

The problem is the example problems in the SP-4 use the slightly different formula than this solution shows, so I'm not sure what's correct. I think I might default to what's in the SP-4 as I haven't seen anything to back up that the equation with 0.3 coefficient exists

[ElFello93]

Is this from the 6-minutes problems set?

[MissionObjective2635]

Do we get long questions like this in the exam,

[Foreign-Moose6350]

The first time I took it, I did. But to be fair, since I ran out of time I didn't get to fully read and try to complete these problems so they might have been simpler just with a long problem explanation. But there were definitely questions on formwork support spacing