NCEES 2014 Civil Structural Sample Question 515

[rambox]

Hello~ I have a question for the subject sample question's correct answer.

Has anybody solved this question and agreed with the answer "B" given on the book?

My understanding is that the N-S direction is matched to the grid line A and B Elevation, not Grid 1 and 2 Elevation. Thus, Kns > Kew, that is, the correct answer seems to be "A", not, "B". Please advise me, if any.

Thank you!!!

 

[bflem]

Hey Rambox,

I actually looked at this problem last night. My understanding from AISC Tbl C-C2.2 was that K(e-w) was two( pinned at the bottom, fixed at the top, and K(n-s) was one ( pinned top and bottom). Leading me to believe "B" was correct. Thoughts?

 

[rambox]

Hi~ bflem

Thank you for your input!!!

I agree with that "K(e-w) was two( pinned at the bottom, fixed at the top, and K(n-s) was one ( pinned top and bottom)".

Thus, K(e-w) will be 0.7 and K(n-s) will be 1.0 theoretically. So, K(n-s) > K(e-w), but the solution of the NCEES says that K(e-w) > K(n-s). As you know, the buckling will control the column capacity in the bigger "K" direction, if other condition is same as like this question. So I still believe the correct answer is "A".

Please advise me, if any. Thank you.

 

[rambox]

Hi~ bflem

Thank you for your input!!!

I agree with that "K(e-w) was "pinned at the bottom, fixed at the top", and K(n-s) was "pinned top and bottom".

Thus, K(e-w) will be 0.7 and K(n-s) will be 1.0 theoretically on the basis of TBL C-C2.2. So, K(n-s) > K(e-w), but the solution of the NCEES says that K(e-w) > K(n-s). As you know, the buckling will control the column capacity in the bigger "K" direction, if other condition is same as like this question. So I still believe the correct answer is "A".

Please advise me, if any. Thank you.

 

[rambox]

Hi~ bflem

Thank you for your input!!!

Now, I understand clearly !!, thank you again!!