Existing 1941 drawing Concrete beam reinforcement Schedule Interpretation

[Rocks1]

Is anyone able to help me decipher the the reinforcement and stirrup call outs in the beam schedule in the uploaded pdf?

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1548442980/tips/12-201_pxy5dd.pdf[/url]

 

[JAE]

What exactly don't you understand?
The schedule provides the width and depth of the beam.
It also provides longitudinal rebar - combination of straight bars and "bent" bars which were typically bars that started on top at the ends, diagonally drop to bottom bars near the center of the span, and then turn back up diagonally to top bars at the other end.

The bars are given in diameter (vs. bar number). Stirrups are shown for total number of stirrups in the span, and then a sequence spacing from each end.

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[structSU10]

they tell you the bar diameter for bent bars, straight bottom bars, and straight top bars. for stirrups they tell you the total number, and its diameter, then the number at specific spacing. they might be another sheet showing a typical beam elevation that would tell you more about the bent bars.

It all looks fairly straight forward.

 

[fel3]

Here's what I think, based on "Beam Schedule for Mezzanine Flr. Framing at Pump Room" (lower left). This table is clear, the other tables are hard to read.

Beam No. 201 - 12 stirrups total, 6 at each end: starting from the end, 1 @ 6", then 5 @ 12"
Beam No. 202 - 16 stirrups total, 8 at each end: starting from the end, 1 @ 6", then 7 @ 12"
Beam No. 203 - 14 stirrups total, 7 at each end: starting from the end, 1 @ 5", then 6 at 10"
Beam No. 204 - 14 stirrups total, 7 at each end: starting from the end, 1 @ 5", then 2 @ 10", then 2 @ 12", then 2 @ 18"
....and so on.

Please note that beams are not my area of expertise. I do RC design from time to time, but for non-building structures (e.g. cast-in-place vaults, concrete head walls for drainage structures, retaining walls, etc.), and I haven't designed a RC beam in about 30 years. Still, I think my interpretation is reasonable.

==========
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--Winston S. Churchill

 

[JAE]

Also this:

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[Agent666]

I'm guessing you mean for example what the '1/5,3/10,4/16' means on beam 102 for example?

If so I deduced it to mean the number over the spacing, with the arrangement being symmetric from each end of the beam. So 16 total 1/2" stirrups with 1st at 5" spacing, followed by 3 at 10", followed by 4 at 16", then repeated in reverse.

Not sure what the 2.1 with a small square means in this example beam.


EDIT.... looks like I'm too slow figuring it out!

 

[BAretired]

Agent 666,

It's not 2.1 with a small square. It means 2-1" square bars. Square bars were sometimes used in those days. Square bars were not deformed in the usual sense; the cross section was continuously twisted throughout the length to improve bond with the concrete.

BA

 

[Ron247]

I think BA is correct on the two 1" square bars. One reference I saw said they were from 1957 to 1963 but I think it is incorrect. I have seen pictures showing square twisted rebar from the late 1800s and 1920s. 1/2" square and 1" square were common sizes I think and were used simultaneously with round bars. I know I have seen them actually in a structure where I live that was reportedly built during WWII. Geez, now I feel old. Let me go measure something with my tape measure that is laid out in cubits.

 

[hokie66]

Twisting bars not only makes the bond better, it increases the yield strength by work hardening. In Australia, twisted bars were used until a few years ago, but they were round deformed bars.

 

[Rocks1]

Thanks Guys - Big help

 

[JLNJ]

Those old square bars are why the cross sectional areas of modern #9, #10, and #11 bars are not 9/8 diameter, 10/8 diameter, and 11/8 diameter round shapes. They are 1" square, 1.125" square, and 1.25" square bars equivalents respectively.

 

[robyengIT]

old rebars historical doc