Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

Re: Bending Threaded Connection Design

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Mat-

I'll take a shot at it.......

Although I do not know the complete loading conditions (combined axial, shear & bending), for bending I would check to see if the connection was adequate to develop the moment capacity of the rod.

The maximum plastic moment of the rod must be able to be resisted by the threaded joint. For axial load only the 5/8" wall thickness would be inadequate (unless the plate was substantially higher strength than the rod).

However for a bending application the rather small engagement of the plate might be enough (again depending on the relative strengths of the plate & the rod).

I would look at it as follows......the top portion of the threads (say 10 o'clock to 2 o'clock) and the bottom portion of the threads (4 o'clock to 8 o'clock) as creating a resisting couple. Not unlike the steel and the concrete compression block in a RC section. These resisting portions (sectors of the complete rod circumference) are just gut level estimates.

Play around with the numbers and see if you can generate the required plastic moment for the rod with reasonable sector sizes which (hopefully) will result in reasonable plate thread stresses. I'm guessing that the plate is weaker than the rod. My gut says that although 5/8 plate is kind of thin to be accepting a 2" rod but a 2" rod doesn't have a huge bending capacity. The whole thing just might work out.

regards
Bob  Kazanjy, PE
Department of  Civil Engineering
UC Irvine

Mateusz Podskarbi wrote:

List,

The steel cantilever rod (2in OD) is screwed into the steel wall (0.625in
WT).
Does anybody know any basic reference for designing the threads between the
rod and the wall?
From the information I have found, it is quite straight forward, how to
design the threads when the bolt is under axial load.
Unfortunately, I have no luck with finding the answer, when bending is
included.

Any help will be greatly appreciated.

Regards,

Mat Podskarbi
2H Offshore Inc,
Houston, TX

******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
* * This email was sent to you via Structural Engineers * Association of Southern California (SEAOSC) server. To * subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
* Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you * send to the list is public domain and may be re-posted * without your permission. Make sure you visit our web * site at: http://www.seaint.org ******* ****** ****** ****** ******* ****** ****** ********
.




******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
* * This email was sent to you via Structural Engineers * Association of Southern California (SEAOSC) server. To * subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
* Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you * send to the list is public domain and may be re-posted * without your permission. Make sure you visit our web * site at: http://www.seaint.org ******* ****** ****** ****** ******* ****** ****** ********