Beam Properties in 1944 Building 1

[jimbojr]

Working on building renovation and I'm looking at drawing from 1944. The beam designation on the plans is 'B12 16.5', which to me indicates a 12' beam at 16.5 plf. However, when I look at steel manuals on-line, both before and during that time period, the beams designate with B12 are 8" deep beams....makes no sense right?
A site visit revealed the beams are 12" deep with 4' wide flange, and are shaped like WF beams. I do need to confirm the beam capacity.

Can someone provide clarification on the beam designation and/or properties? Is it safe to assume it is FY 36ksi steel and use the dimensions to calculate the allowable stresses?

 

[dik]

A 12B16.5 was a common section as late as the early 70s, and, may still be available. They were 12" approx deep and if I recall, had a 4" wide flange... I'll see if I can dig up some section properties. It is likely A36, but may have an Fy of 30 or 33 if memory serves (getting fuzzier).

Dik

 

[canwesteng]

Here's a CISC listing of some historical steels

https://www.google.ca/url?sa=t&rct=...alsteels.pdf&usg=AOvVaw3c-4m2_An2lh89T3ELCO98

You can range from 27 ksi to 36 ksi for something built in '44

 

[SlideRuleEra]

jimbojr - Go to this page of my website and download "Bethlehem Structural Shapes Catalog -1948" (near top of webpage).

Properties for 12B16.5 are on pages numbers 24 and 25.

Nominal yield strength of structural steel in 1944 was 33 ksi. If samples are tested, will likely be higher.
A36 steel was introduced c. 1963.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[JStephen]

In my old AISC book, that's shown under a separate category called "Light Beams" as one of several 12x4 sections with 16 1/2 lb/ft weight.
It shows Ixx = 105.3 in^4, Sxx = 17.5 in^3, rxx = 4.65", Iyy = 2.79 in^4, Syy = 1.39 in^3, ryy=0.76".
Depth as 12.00", flange as 4.00", 0.269" flange, 0.230" web, 4.86 in^2 area.
Under the foreword at the front, they show typical callout for Miscellaneous Light Beams as "6 B 12" = nominal depth, group symbol, and weight in lbs/ft.
I think those would be A7 in that AISC book, not sure when A36 kicked in, think that was early 60's.

 

[BridgeSmith]

The info we use for rolled shapes used as bridge girders agrees with SRE and JStephen - without documentation otherwise, 33ksi yield is assumed for steel produced between 1936 and 1963.

 

[StrucDesignPE]

A resource that I have used for beams in old buildings is the following link:

https://www.aisc.org/globalassets/aisc/publications/out-of-print/iron-and-steel-beams-1873-1952.pdf

I believe the information for the beam you are looking for is on page 90. It agrees with the info already posted by others and believe it is the same book JStephen refers to.