Design a connection 1

[lololol]

Hi
I want your help please . I want to design a connection in a blank page to join two grade 43 steel plates to carry a tensile load of 45kN. The plates are 80mm wide and 60mm thick.
I think i should find, first, the shear stress but i i must know the number of bolts i will use. My question is how do i find the number of bolts (i have the tables with diameters of bolts shank)
Thank you for understanding.

http://files.engineering.com/getfil...5-c80e-4ebc-8357-98efe397d93c&file=img024.jpg

http://files.engineering.com/getfil...0-253d-4def-954e-3b3928a9d4cd&file=img025.jpg

 

[Ron]

I'm going to give you the benefit of doubt and assume you are a practicing engineer and that you are not a student. The proposed design seems a bit academic, but nevertheless....

First of all, you are fastening two bars, not plates. Second, your load is not all that high, so to handle differential shear between the plates, you might only need one or two bolts, depending on the size bolt you select.

The tables you provided contemplate not only the bolt shear, but the bearing stress of the bolt on the bar material.

You do not state if your bolts must be in a dual configuration or a tandem configuration, relative to the load. Dual configurations are just additive. Tandem configurations can be simply additive, or you can consider that equal deformation of the bar material must occur for mobilization of equal shear on the bolts...fundamentally, the first deformation takes the first loading.

If my understanding of your issue is correct, your bolt will be in single shear. Your table does not mention whether the allowable loads are within the threaded section or in the plain shank....that makes a difference. Further, your table does not contemplate pre-load of the bolt to increase slip resistance by friction.

As simple as it might appear, there are numerous considerations you must make. The calculations are not rigorous, but the considerations require computing various parameters. You must also consider the edge distances of the bolt holes, both for material stress and for potential code compliance.

 

[hydtools]

Try this:

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

Ted

 

[TXStructural]

Steel design 101. Sounds like someone is working outside their expertise or is still in school. Seek a steel design manual. If you were US, I would recommend the AISC Manual of Steel Design, as it provides allowable values for bolts. Also you have block shear and various other failure modes/limit states to consider. You do not mention if this a factored load or service load, which makes a difference.

[The other day, I was looking for the statement in the "rules" for Eng-Tips which says "not for use by students", or did I imagine that, too?]

 

[MechEng2005]

TXStructural - Look in the area around the area where you type your posts.