NCEES 2008 Book, Problem 516 Geo Depth, pg. 165

For problem 516 of the Geo Depth Problems, the NCEES 2008 book page 165 uses S factors such as Sc, Sq, and S(gamma) in computing the Qult.

What do these factors represent? Or can someone explain what the equation for Sq is? The book has Sq=(1+0.2(2)/5). Thanks.

maximus808 said:

For problem 516 of the Geo Depth Problems, the NCEES 2008 book page 165 uses S factors such as Sc, Sq, and S(gamma) in computing the Qult.
What do these factors represent? Or can someone explain what the equation for Sq is? The book has Sq=(1+0.2(2)/5). Thanks.

Click to expand...

shape factors.

maximus808 said:

For problem 516 of the Geo Depth Problems, the NCEES 2008 book page 165 uses S factors such as Sc, Sq, and S(gamma) in computing the Qult.
What do these factors represent? Or can someone explain what the equation for Sq is? The book has Sq=(1+0.2(2)/5). Thanks.

Click to expand...

Hi,

You should probably check out the errata for this problem from the NCEES ot PPI site. They have changed this problem, although i thought is was a good one, the answer was the same if you used their shape and depth factors or the ones in the CERM, and the answer was also (A) if you didn't use any factors (most nearly).

The Eqn for Sq = 1.0 + B/L tan (phi)= 1 + 5/5(tan 20) =1.36

I just want to add my 2 cents in case for future readers. I'll use A, B, C designation for simplification.

Maybe the errata correct it. I don't have access to the errata for this edition. qult = A + B + C, under the term B, the solution left out the depth factor dq

For a detailed explanation of qult refer to Foundation Design: Principles and Practices by Coduto, 2nd Edition, page 183-185

Dear All,

please advise why we use this factors rather than other factors, i meant there is terzagi with modified shape or genral equation and others why we go for one and leave other one .

the problem not telling which equations you have to use.

each equtions will give differnt number one give 2200 other give 2700 ,.......etc

they are shape factors

they are different because the research are done by different people and you can not expect 100% similarity in any of them as even the slight variation of soil properties, testing equipment etc... can affect these