Is this bolted joint appropriate? 2

[JM_10]

Hello,

We are designing an steel curved structure with a rectangular opened section, please see images.

It needs to be able to be opened for maintenance purposes. So, the joining of the different sheets which form the curved beam have to be bolted.

My question is how big can be the hole, so the sheet is not taking any risk due to its thickness (20 mm)
Please, see images which are more explanatory:

https://imgur.com/a/5Dpag

Where can I find some rule for this situation?
Thank you in advance

 

[desertfox]

Hi JM 10

What loads are on this structure?
You need to give us more information about what this thing does, as it stands I wouldn't go above the 10mm hole size

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[JM_10]

Hello, thank you for your response

Of course,

The idea is to create a steel support (blue) in a ring shape, containing lead blocks (grey) inside:

https://imgur.com/a/tJCNU

Total lead weight estimated is 14 Tons, while the ring middle radious is 1,125 m

Several analysis returns that the structure is ok to support this static load. But it was considered as a whole geometry, not taking joints into account

 

[desertfox]

Hi

Thanks for the next picture, it seems to me that the structure takes all the weight and the screw you are referring to merely holds the covers together or have I missed something.

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[JM_10]

Right, that is why I did not show in the first time

Basically my concern is about making the holes in a "so thin" sheet. I am not aware about "how big" can it be with no compromising the material

 

[desertfox]

Hi jom 10

Thanks for the response.
A rule of thumb for bolted joints is that whatever the bolt Siamese is multiply by 1.5 and that's the dimension you need from any plate edge to the hole centre, this ensures that the joint doesn't fail by the joint material failing between the bolt and plate edge.
I appreciate that you did know the bolt wasn't taking much load but reading you're original post I didn't know that.

Desertfox

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[JM_10]

Ok, thank you very much for the advice

By "siamese" you mean diameter?

Also, do you know any reference where I can check the rule? (not that I do not trust you, it´s because it will be documented If possible)

Thank you!!

 

[desertfox]

hi
Yes I

http://www.eng-tips.com/meant

diameter, have a look at this link the rule of thumb is related to the fastener shearing out through the plate edge. I haven't a specific reference but it might be in some mechanics books dealing with riveted joints.

http://www.roymech.co.uk/Useful_Tables/Screws/Bolted_Joint.html

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[JM_10]

You have been so helpful, I will note about this. Thank you very much

 

[desertfox]

Hi JM10

You're very welcome

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[desertfox]

Hi JM10

Here is a reference that states the 1.5 x bolt diameter for minimum edge distance of a rivet which can also be used for bolts.

http://nptel.ac.in/courses/112105125/pdf/mod10les2.pdf

Scroll down till you come to "tearing of plate at edge"

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[JM_10]

Hello @desertfox

That´s great. Thank you very much! It will be so helpful