NCEES Sample Question & Solutions: Civil - Geotechnical

[bulllgator]

Can someone familiar with bearing capacity help me out here? The NCEES sample questions and solutions for the Civil - Geotechnical section consistently leaves out the depth of footing (Df) term in their solutions. Specifically in question 526 regarding a 7 ft deep mat footing, the solution disregards the Df term. Any ideas why? Haven't seen this in any other practice problems or solutions. THANKS!

 

[Badger]

Well i don't have that particular problem set, but depending what are supposed find, you may not need it.

You are given the Depth of ooting (df), and If you given the dimiensions of the mat, B, & L, and some soil parameters gamma, c, φ, you can determine the the ultimate bearing capacity.

Generally you would determine the B and L dimensions requred for the loads on the footing before you determine the depth of the footing, as those dimensions are required for thecalculation of effective depth. Determining efffective depth and D is more of a structural problem. I think chapter 55 in the CERM has problems that are good examples.

 

[Badger]

oops the next was clearer what you asked.