Why do we have Grade 75 and Grade 80 rebar?

[STrctPono]

ASTM A615 has both Grade 75 and Grade 80 rebar. ASTM A706 has grade 80. I understand that A706 provides greater ductility than A615 but why do we have both grade 75 and grade 80? With such a small difference in the strength there must be some other reason why you would use Grade 80 over Grade 75 and vice versa.

 

[BAretired]

https://www.structuremag.org/wp-content/uploads/2014/08/D-QAC-Schwinger-Aug111.pdf

BA

 

[dik]

The cost of the steel is almost the same and there is a 5%+/- increase in strength (15%+/- if compared to Grade 60)... This strength increase reduces the cost a little and allows for smaller area concrete columns to be used... realising that the area of a floor taken up by columns is non-usable space when it comes to renting the floor area. Small, but it's a 'win-win' situation.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik