Steel Design - Pinned Connection

[Anonymous]

Hi,

I have a project where there are no horizontal solicitations to the structure (I have no walls, just a isolated roof). 

The question I have is: since I do not have horizontal solicitations I wanted to have pinned connection to all the connections between columns and foundation (see attached image 1). 

In your opinion can I say that a pinned connection (see attached image 2) constrain Mxx (since my Mxx reactions are 0)?

Thanks in advance,

Alexandre

[ALEXTHAINESE]

Well the right term to be used is restraint not constraint .

which brings to the answer : yes a pinned  base connection restraints Mxx  and also other moments Myy and Mzz. 

[Anonymous]

If it's pinned, at least, in one direction you have a rotational degree of freedom... What I am asking is that if in the other direction the rotation is restrained?

[EduardoMeruvia · Accepted solution]

Hi aafm92, 

Looking at your previously attached image2 I would say that connection provides a Mxx (torsional) restrain ONLY and free to rotate in the other two directions.

Technically speaking however, your base connection might provide SOME elastic restrain in rotation in the direction of the bolt line, but this is not a full rigid restrain and it is usually ignored for simplicity and assumed to be free to rotate. Note that if the base plate is thick and rigid enough in conjunction with the hold down bolts then this connection can be 'MADE' to restrained rotation. 

[Anonymous]

Eduardo Meruvia, that is the answer I was looking for.

Thank you!