Bolt and Nut with Vertical Axis Connecting Beam to Column 2

[McDermott1711]

Hi everyone,
I should be grateful if someone guide me to a reference(e.g. AISC manual) which requires bolts being "over" nuts in bolted connections in order to prevent from falling in case of loosening due to vibration. I think assembling of bolt and nut in opposite (similar to the below picture is wrong.

Nothing is more fairly distributed than common sense: no one thinks he needs more of it than he already has. Rene Descartes

 

[Tmoose]

When I'm concerned about loss of a fastener I use a prevailing torque locknut or a cotter pin.

When I'm concerned about the fastener loosening in the first place, I get serious about joint prep, fastener quality and installation torque. Some will correctly point out that torque as method of establishing fastener preload has "limitations." The more sophisticated methods of preloading fasteners can certainly be more accurate, but torque has its place.

 

[McDermott1711]

Thanks Tmoose for your reply. As I got you, you do not have any reference for bolt-above-nut assembling and you do not believe that it's necessary. Am I right?

Nothing is more fairly distributed than common sense: no one thinks he needs more of it than he already has. Rene Descartes

 

[SnTMan]

Well, I can't tell from your picture, but I would put the bolt thru from the top, nut on bottom. In the event the bolt & nut part company, gravity will still keep the bolt in the holes.

This may be written somewhere, I don't know. I want to say it's just common sense.

Regards,

Mike




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

 

[SceneryDriver]

Does it really matter? Either way, you'll have hardware falling on someone if the joint loosens. Followed very shortly thereafter by the piece of beam that the bolts and nuts were holding in the air. Design the joint properly, and assemble it properly, and nothing should fall out of the air.


SceneryDriver

 

[racookpe1978]

During installation, there is a little bit of caution and construction logic that would indicate the bolt coming into a vertical hole from above would not fall out before the nut is turned on by hand, but thereafter, there should be no loosening in service - if the bolted assembly is torqued properly.

But, the first bolt going through a assembly of many bolts is going to depend more on the convenience of the steelworkers trying to wedge the joint together and getting it aligned while the steel is still on the hook and everything is "mobile, agile, and hostile." We don't know where the scaffolding was, where the steel was supported, where the man was, what was in the way, etc.

 

[MintJulep]

You will find no such standard.

Because once the nut has loosened the joint has failed and attempting to standardize the performance of a failed connection is not useful.