Prying Forces
Prying Forces
(OP)
does anyone know where i could get some good information on prying forces in bolted connections?
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RE: Prying Forces
RE: Prying Forces
http://www.beuth.de
Regards,
Cory
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RE: Prying Forces
RE: Prying Forces
found this paper on base plate design
I was trying to start my own thread, having a hard time finding out how to do that...???
RE: Prying Forces
Have a look at this site :-
htt
regards
desertfox
RE: Prying Forces
did I miss something? I didn't see anything about prying on that page.
RE: Prying Forces
Scroll down the page till you see the heading:-
Strength of bolt joints withstanding bending forces
Theres a bracket fastened to a wall with formula's for an offset horizontal or vertical loading putting the bolts under a moment loading.
regards
desertfox
RE: Prying Forces
RE: Prying Forces
That example only covers shear and tension combined. I still don't see any reference to prying. As kbarnett says, prying is when the tensile load that is transferred to the bolts is increased from that of the connecting element (usually a WT or angle) as a result of the lack of rigidity of that connecting member.
I do a ton of prying problems for Flexible Wind Moment Connections. AISC 13th edition page 9-10 is the best reference. There are many papers written also, but I have yet to find one that deals with anything other than a WT.
RE: Prying Forces
If you have a bracket fastened to say a vertical wall with
a horizontal projection say a foot or whatever, you then apply a vertical load to that projection either up or down.
The bracket will try to pivot at the wall on one edge.
If the bracket as a vertical line of bolts then the force
in each bolt will be different due to the levering effect and consquently the bolt furthest away from the pivot will see the greatest load in this case.
The link I have posted shows this situation of a line of bolts having to withstand an offset load on a bracket but assumes that the bracket base is rigid in which case all the load is transfered from the bracket to the bolt.
I can't post the diagram from the site I have tried but its under the previous heading I posted earlier.
Regards
desertfox
RE: Prying Forces
I understand your statement, but that is still NOT prying action. That is a resolution of the eccentric load into a direct shear and a moment. Then each bolt takes tension based on its distance from the NA.
Look at AISC 13th Edition page 9-10 for a discussion of prying.
RE: Prying Forces
Old Reference
RE: Prying Forces
Will study the reference you gave me in detail and comment later thanks!
regards
desertfox
RE: Prying Forces
I looked at the reference very kindly posted UcfSE (thankyou).
I agree having read this that prying is accounting for the
increased load due to deflection of mating parts which are bolted together and subject to forces offset from the bolt line.
When I read prying forces in the original post I merely thought of the bolts being levered out by a rigid based bracket as described in my earlier posts.
In addition to my original thinking I looked on the "The Bolt Science" Site which gave a definition of prying as:-
PRYING
The amplification of an external force acting on a bolt by a lever action which can occur when that force is an eccentric tensile load.
regards
desertfox