A15 and A16 Steel Bar Areas
A15 and A16 Steel Bar Areas
(OP)
Analyzing a building built in 1929 with old A15 or A16 steel bars, probably twisted. Symbols look like square bar. Anyone have a table of bar areas for that time if the area is different than just the square of the bar size?
In other words, for a 5/8" square bar (#5 now), is the area .39 sq. inches, or something different? Makes a whale of a difference in the capacity.
In other words, for a 5/8" square bar (#5 now), is the area .39 sq. inches, or something different? Makes a whale of a difference in the capacity.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com






RE: A15 and A16 Steel Bar Areas
CRSI Evaluation Report #48 in Table 2 implies that no reduction was given for bar sizes due to the twisting or rounded edges. It also only lists square bar sizes for 1/2, 1", 1.125" and 1.25" bars. There are no area values for 3/8", 5/8", 3/4" or 7/8", implying that these sizes had to be round bars if used (much lower areas). I find that difficult to fathom logically speaking.
The area difference makes a difference in capacity of 20% or more. Anyone ever run into this before?
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: A15 and A16 Steel Bar Areas
Something you might want to watch out for is that placement of bars back then wasn't necessarily what we have now, particularly in regards to stirrups and shear reinforcing, if I'm remembering correctly from one particular beam I saw some years back.
On the other hand I know of a one lane bridge built back in the 1920's that had square reinforcing and it's still functioning fine after all these years and recently some heavy gravel trucks went over it with no ill effect.
RE: A15 and A16 Steel Bar Areas
1/4" d: .05
3/8" d: .11
1/2" d: .20
5/8" d: .31
3/4" d: .44
7/8" d: .60
1" d: .78
1" s: 1.02
1 1/8" s: 1.27
1 1/4" s: 1.56
The only one that surprises me is the 1" square one. I wonder why the area is 1.02 and not 1.00? For what it's worth...
RE: A15 and A16 Steel Bar Areas
Again, the insinuation from what I have read in the CRSI Publication I posted above from 1924 is that square bars were not available up to 1/2" and 1" or greater on a side, but not between 1/2" and 1". That seems funny since I am getting obvious square bar callouts on the plans I have from 1929.
Something doesn't add up here.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: A15 and A16 Steel Bar Areas