AWWA M23 Clarification

[workingweekends]

Hello,

Can anyone please confirm equation 4-35 in AWWA M23 (2nd ed)? I suspect that my copy may show the equation incorrectly, see attached. Besides the division line missing it seems that Fs and Rs should simply be added together within the denominator.

 

[HTURKAK]

The denominator is Fs + (1/2)Rs.

 

[workingweekends]

Thank you! Also, for eqn. 4-39 where N phi and Q are defined below the equation, the plus (or minus) symbol between 45° and phi/2 is not showing. Could you confirm as well?

 

[HTURKAK]

Apparently you are civil engineer and you are expected to be familiar with active and passive earth thrust.

The eqn. 4-39 is Rankine’s Passive Pressure formula.

NΦ = tan**2(45° + Φ/2) OR NΦ =( 1+ SINΦ )/( 1- SINΦ )

You may look to any soil mechanics handbook to remember the theory or nowadays famous to search the web , one of the pages,

https://slideplayer.com/slide/13802848/