How we can control bolt connection quality (tightening) after erection long time.

[ThomasNguyen]

Dear All,

I have one question stuck in my mind long time. And sometimes, Client or Consultant ask me also, When I go to explain about design.
When we install bolt connection at site, even pass all inspection about tightening already.(Actually, We don't inspect 100% and we already know the quality of work depend on worker at site a lot,...)

But how we can sure that, This nut still keep tight with thread (shank) bolt year by year,... beside that, Some type of connection we only use one nut (two nuts will be better than)

Some methods, our company already used for structural components support dymamic load (machine or crane,...). At this position we use spiral washer or point welding at site to make sure nut will not move. But normal cases are not. And some project, they also not allow to welding at site.

I want to find some study reports about this matter or evidence in Code to explain to them. I can not convince them by feeling explaination.

Thank you and waiting for your help and opinion

Regards,
Ai