Help to calculate forces acting on pins

[MahReda]

Dear Sirs


In attached picture i have two beams which has hing at their end and they are supposed to move upwards under effect of uniform distributed load

but their movement must be stopped using two sets (each set consist of two eye plates each plate is welded on a beam and pin going through those eye plates)

my problem is that i don't know how to predict bending moment and shear force acting on those pins to know the diameter of pins and thickness of eye plate

i calculated max bending moment that will act on these beams after stopping ( 500 kg.m )

your help is much appreciated

thanks in advance

best regards

 

[Ingenuity]

500 t.m? As in: 500 tonne.m or ∼4900 kN.m?

 

[KootK]

Divide your bending moment by the vertical distance between the two pinned connections. That will give you tension/compression values that will need to be resisted at each pin assembly. From there, you'll need to evaluate the load effects on the various parts of the pin connections.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[TLHS]

What are you trying to do? Using the type of connection you're talking about in the location you're talking about has a lot of practical problems.

There are theoretically ways you could detail this for specific applications, but I don't know why you would. The applications I can see it working for pretty much require that the beam be at a reasonably small percantage of it's ultimate moment capacity, or that you have some really weird detailing so that you can fit a really huge pin and eye plate in there. You'd also have to put some significant detailing effort in to minimize pin slip, or that joint is going to rotate before it starts resisting anything.

 

[MahReda]

@Ingenuity

Sorry for mistake

bending moment is 500 kg.m

 

[MahReda]

@KootK

my BM is 500 kg.m

so if the distance is 2 meters, tension is 250 kg on each pin ?

 

[MahReda]

@TLHS

thanks for help

what other solution do you advice me to use in stead of this one ?

all i need is to prevent these two beams from going up is same time i need this lock to be temporary so i can open it when i need to let the beams to move up

 

[KootK]

so if the distance is 2 meters, tension is 250 kg on each pin ?

Yeah. Is your beam really 2+ m deep? I'd provide capacity to deal with some shear at the connection too, even if your theoretical shear force at midspan is zero. Maybe 25% of the end reactions as a minimum.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[KootK]

what other solution do you advice me to use in stead of this one ?

Kinda depends on how quickly removable you need it to be. A conventional bolted moment connection would work too. It'd just be a harder to take apart. To help us help you:

- What is this thing?

- What is the source of the load?

- How often will it be opened?

- What kind of member are you using for the beam?



I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[MahReda]

Kinda depends on how quickly removable you need it to be. A conventional bolted moment connection would work too. It'd just be a harder to take apart. To help us help you:

- What is this thing?

- What is the source of the load?

- How often will it be opened?

- What kind of member are you using for the beam?

it's some thing like gate and the load comes from water current

it will open like two times a day

but it should be easy to remove lock so i can open in short time for emergencies

 

[KootK]

What kind of member is it? Plate girder? Tube section? Is it steel? How taxed is the member in flexure at the middle? 90%? 15%?

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[SnTMan]

I'd hazard a guess the pins will be bound up.

Regards,

MIke

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Ron]

This is the same concept as a bascule bridge. There are inherent problems with pin alignment as SnTMan notes. The eye plates are designed for shear on the bearing area of the pin. The pins are designed for both shear and bending, but separately since the shear is a derivative of the force couple from the moment.

 

[southard2]

No offense but you have in unstable structure here. Either it moves or it doesn't. You connection points won't really stress until it stops moving. And once it does stop moving you are asking those pins to do two things for you.

1) transfer the bending load (will put the plates into tension or compression) (will put the bolts into shear) and

2) transfer shear across the connection. (the shear will put shear into the plates and their welded connections and will put tension into the bolts)


If you loading is PERFECTLY uniform in theory you won't have shear across the joint and you will only have to design for item #1 which is pretty easy to do.

The bolts are also subjected to a prying force in the configuration you drew.

If these are steel beams than you might consider welding flat plates to the ends of each beam with holes that align. Have a small gap between the beams and use extra long bolts to connect them. The gap will cause the beams to swing a bit but then one edge of the plates will hit and bear on each other and the bolted side on the other end will go into tension. Any shear through the connection would have to go through the bolts on the end in tension.

It is really hard to help though since we have no idea what kinds of forces, spans, etc you are dealing with so this is for conceptual help only.

John Southard, M.S., P.E.

https://www.pdhlibrary.com/

 

[dhengr]

MahReda:
Given the verbal descriptions you have given (incomplete word pictures) and the sketchy (lack of any meaningful details, dimensions, loads, workings, etc. etc.) drawing that you have provided, you have a thousand things to iron out and start to think about, describe and develop before you will get any meaningful help on your problem. Everyone is guessing and fishing for ideas of what you might be doing and what you might be trying to accomplish. Those pins and eye plates (pin plates) will not likely work very well in single shear. The eye plates will probably not mesh at all well as the gates swing closed. Is your drawing a plan view of a vertical gate holding back water (a water current) of some depth; or an elevation of a horiz. gate preventing water from falling through a hole? How do the gates swing, what loads force them open, how did you figure your 500 kg-m bending moment, what force and mechanism push/pull the gates closed? What are the gates actually made up of, dimensions, prelim. sizes and structural details, etc. etc? Do some real meaningful sketches, several view and details, so we can see what you are doing. Then, we can begin to understand what you are trying to do and maybe be able to give you some help.