When do we NOT use Grade 50?

[EIT2]

I plan on attending a two-day course, at the University of Wisconsin, entitled "Structural Bracing for Lateral Loads and Stability". One of the "Key Topic Areas" to be discussed will be "When Not To Use Grade 50 Steel".

Can anyone furnish some "pre"-info or thoughts as to what might be discussed?

When do we NOT use grade 50?

Thank you!

 

[havesealwilltravel]

50 ksi yield is still not commonly or reliably available for angles, channels, pipe, or tube shapes yet.

Also some argue that for ductility during a seismic event you don't want the extra strength.

 

[dik]

I've got a project with a bit of a hiccup... the material was spec'd at grade 300 (45ksi) and the shop drawings indicate grade 350 (50ksi)... The members were proportioned using plastic design which requires a Class 1 section in Canada... the grade 350 members are now Class 2 and not suitable for plastic design...

 

[DTJ]

Another area where Grade 50 steel should not be used is with crane runwat girders. In most cases these members will need to meet stringent deflection criteria, so steel yield stress is no longer the controlling factor. Another reason is for ductility and fatigue conditions. There are several documents available for the design of industrial buildings that address these issues.

 

[Koz]

Dear EIT2

A good question regarding wide-flange shapes might be when can you even find these shapes that are true A36 anymore? Wide-flange shapes these days are all triple or quadruple certified as A36, A572 GR50, A992 and A709. If you want A36, some suppliers may white-out the other specs for you. Check your yield strengths! Strong column - weak beam is being defeated by the producing mills. Have fun

Koz