How to go about plate pry for beam bolted under another beam? (Monorail)
How to go about plate pry for beam bolted under another beam? (Monorail)
(OP)
Analyzing monorail for installation in an industrial facility. What is the best practice for checking plate pry on the 2 bolts shown on this connection (Picture attached). There are 4 bolts total, but just checking prying action on the outer 2.
Would you treat it like an angle connection with the weight pulling down at the flange edge of the top beam?
Would you treat it like an angle connection with the weight pulling down at the flange edge of the top beam?
RE: How to go about plate pry for beam bolted under another beam? (Monorail)
RE: How to go about plate pry for beam bolted under another beam? (Monorail)
There are also 2 more bolts on the back side of the beam web you just can't see from this angle.
RE: How to go about plate pry for beam bolted under another beam? (Monorail)
RE: How to go about plate pry for beam bolted under another beam? (Monorail)
RE: How to go about plate pry for beam bolted under another beam? (Monorail)
RE: How to go about plate pry for beam bolted under another beam? (Monorail)
Note that I know of nothing published that says that there is anything at all wrong with the original scheme in such an application.
RE: How to go about plate pry for beam bolted under another beam? (Monorail)
RE: How to go about plate pry for beam bolted under another beam? (Monorail)
If I was going to be concerned about fatigue surely the welds would be a greater concern? (EG in the cleat shown in your first image.) Though in this case I'm not particularly concerned with fatigue, though maybe I am naive and I should be.
(Some bending of a plate in my mind isn't a terrible fatigue issue. A many moment connection light posts and similar such connections regularly have such bending plate loads.)
RE: How to go about plate pry for beam bolted under another beam? (Monorail)
I don't have a good enough feel for the numbers here to be able to comment on that with much confidence I'm afraid. My point was really that:
1) I consider it to be a fundamental tenet of good steel detailing that loads should be moved around in plate shear rather than plate flexure whenever possible.
2) When there is prying, there tends to be uncertainty about the amount of flexural stress generated within the connection. And that means uncertainty in establishing the stress ranges at play for fatigue evaluation.
So, if I'm going to use a mechanically poorer detail when mechanically better ones are available to me, I would want a good reason for that. Possible options:
3) Cost if the basic four bolt setup with it's associated, welded stiffeners that OP mentioned is significantly cheaper.
4) Perhaps your are correct and my bolts and welds arrangement is indeed worse than OP's bolts and welds arrangement for fatigue.
As is often the case, I really enjoy kicking around alternate detailing options and discuss their merits. That's the crux of what I've done above.
OP's solution also has structurally active welds on the stiffeners proposed.
Granted. But, then, I would say that those choices are dictated by the practical necessity of mass construction economics rather than by what is most structurally awesome. Additionally, pole bases usually sit on grout or are gapped. In both cases, you do have plate bending but you do not have prying and its associated uncertainty.
RE: How to go about plate pry for beam bolted under another beam? (Monorail)
RE: How to go about plate pry for beam bolted under another beam? (Monorail)
I really do not have any serious concern with you detail. I simply thought that I might be able to improve upon it.
A couple of other things, completely unrelated to this thread.
1) Can you come say hi over here. I feel that you may be able to help me with something that is of great interest to me. Really just my sketch at the end.
2) Are you a member of the Pub forum here? I've got some structural bicycle stuff that I'd like to get your input on.
RE: How to go about plate pry for beam bolted under another beam? (Monorail)
1. I think you had that one covered yourself. But I've added my 2cents. I hope it made sense.
2. I haven't stuck my head into the Pub forum until your comment today. I couldn't see anything relating to bicycles so I presume this is a future post?
RE: How to go about plate pry for beam bolted under another beam? (Monorail)
It will be a future post. Two actually:
1) What causes fork shudder with cantilever brakes in general and;
2) What causes / solves speed wobble / shimmy on road bikes (my road bike).
I've decided to attempt to place these threads in the structural forum rather than the pub and see if that gets me into trouble. The conversations will be centered around structural behavior and I'm obviously a real structural engineer. The only oddities are that the questions not pertain to paid work and there's little chance of anyone making use of the threads in the future.
Unfortunately, if I put my threads anywhere other than here, I likely won't hear anything from my favorite/trusted people. Sometimes it is better to ask for forgiveness than permission...
RE: How to go about plate pry for beam bolted under another beam? (Monorail)
RE: How to go about plate pry for beam bolted under another beam? (Monorail)