Availability and Grades of A441 Steel in 1965?

[Screwtape]

I've got a project with a combination of A36 and A441 steel for the primary roof framing. The A441 members are limited to a select few that experience higher loads (obviously). Unfortunately, the original structural plans only call out A441 and don't specify the grade. Per Table-1 in AISC 9th Ed., Fy for A441 steel could be 40, 42, 46, or 50 KSI.

Regardless, we are proceeding with a coupon test to confirm the steel grade, as the members are large and heavily-loaded who control the overall capacity. My opinion is we will find 50 KSI steel.

I'm just curious if any of the above grades could be possibly eliminated based on the building age. The building was constructed in 1965 in the southeast US. Any ideas or guesses?

 

[OldPaperMaker]

My copy of the AISC, 6th edition on a sheet labeled "Revised 3/66" indicates that A441-63T steel had 3 different yield strengths:
Group I: Fy=50 ksi which is for all shapes except those in Groups II & III
Group II: Fy=46 ksi which is for Wide Flange shapes 36x16-1/2, all weights, 33x15-3/4 all weights, 14x16 142 to 211, incl. and 12x12 120 to 190, incl.
Group III: Fy=42 ksi which is for WF shapes 14x16 with weights per foot from 219 to 426, incl.

I hope that this helps.

 

[dhengr]

Screwtape:
Look a little deeper. As I recall those strengths were primarily based on material thickness in that ASTM Designation; i.e. plate thickness or in your case ASTM groups for Structural Shapes. There were four Structural Shape groups, with the heavier shapes having the lower strengths. Basically, this was due to work strengthening (hardening) caused by the added rolling required for thinner shapes, and I believe it was Fy = 50ksi min. for thicknesses up to about .75" thickness.

 

[Screwtape]

Thanks for the info. I should have simply kept digging.

The 3 sizes in question are W14x109/111, W14x68, and W14x43. Looking in AISC 7th edition, The W14x43 falls under Group I, with the W14x109 and W14x68 falling under Group II -- both of which were only available as 50 KSI steel.

It's embarrassing when the answer you need is just a page turn away.

 

[OldPaperMaker]

Screwtape,
That's OK, I am glad to help.

I did notice that the price tag from my 6th edition is still attached to my copy. It cost a whopping $7.00 back in the mid 60's. I belive that the 13th edition's current cost is $350 (for non members).That's only a 50 times increase in 45 years.