Eng-Tips is the largest engineering community on the Internet
Intelligent Work Forums for Engineering Professionals
-
Congratulations waross on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!
Prying Forces
- Thread starter jmg2000
- Start date
VDI 2230 Systematic Calculation of High Duty Bolted Joints, available from Beuth:
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
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...???
Hi jmg2000
Have a look at this site :-
regards
desertfox
Have a look at this site :-
regards
desertfox
Hi StructuralEIT
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
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
desertfox, it appears that the paper you cite includes bending in terms of moment on the connection. Prying is not stated as being covered. I'm assuming that the prying that jmc2000 is concerned with is the force caused by a connection plate that is thin enough to deform under load and therefore bends up on one side, causing more tension on one side under the bolt head.
desertfox-
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.
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.
Hi kbarnet
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
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
desertfox-
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.
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.
Hi StructuralEIT
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
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
- Status
Similar threads
- Locked
- Question