NCEES 16 Hour Structural Engineering Sample Exam Questions

[keiwong]

keiwong - you'd solve 137 in the same way.

• With a P*e=M and vertical equilibrium check, you have 2 unknowns: the distance of bearing and qmax.

• When e<L/6, you have a qmin and qmax.

• With a large e (>L/6)... just a 0 and qmax.

• You might be served well by actually deriving the formulas at the very beginning of the foundation chapter of the SERM. It's basic statics.

That would be true if it were a rectangular section. I do not think it will work the same way since the section is a flanged shape. The middle third thing works for all rectangular sections and sections that are symetric and can be composed of rectangular sections.

Lets think first of a pure rectangular footing; once the the load moves outside the middle third you will have zero load under the back end of the footing, however this new reduced area footing is still rectangular and you can assume that the load now is at the 1/3 point of this new smaller footing. The (P/BL)+(M/S) equation just becomes a rewritten form of (P/B)+(M/S'). However, if the footing was an I shape, the new reduced area footing is no longer symetric therefore the equations in the front of the SERM will not work any more.

 

[TehMightyEngineer]

hmmmm, as an educated guess; couldn't you use a similar approach? Let's see, it would be the equivalent of a T section then... Maybe some sort of iterative approch with a trial distance to the point of no stress?

 

[keiwong]

hmmmm, as an educated guess; couldn't you use a similar approach? Let's see, it would be the equivalent of a T section then... Maybe some sort of iterative approch with a trial distance to the point of no stress?

Perhapse, but I was wondering if there was a way to do it formula wise.

 

[McEngr]

Your question has to incorporate lots of assumptions with trial and error. I hope that you don't see anything like that on the test!!! If they did that to you, they'd have to throw out the problem unless they give you some assumptions to quickly solve it.

It is my understanding that they will give you obtainable 6-minute problems. Just relax and be confident guys!!