Our Newest Code For The Library

by Don Friedman on July 11, 2016

Our office library now has a copy of the 1956 concrete code, ACI 318-56:


First, as a fan of typography, I have to ask: could that cover be any more evocative of the 50s?

More important is the issue of legitimation. The ACI code has always been meant to be an adjunct to local (or state, or national) building codes, to be referenced by the building codes or otherwise incorporated into them. The front cover manages to say “ACI” twice, “American Concrete Institute”  once, and “Building Code” twice in fewer than twenty words. (I’ve excluded the written name of G. W. Bishop, presumably the first owner of this copy of the code.) The code not only has an ACI reference number, it has an ASA number (the 1950s version of ANSI), and a UDC number for easy library cataloging. The legitimation process continues on the title page:


Only here, it’s not clear whether the code is getting a reference from the ACI’s convention, committee 318, and journal, or whether the ACI’s various organs are getting a reference from being connected to the code. The back cover adds some more depth:


The capsule history of the ACI certainly is intended to make it, and therefore the code, sound vital to the field of reinforced concrete. The ACI code was actually not the first commonly-used concrete code in the United States. The first was the Joint Committee report, released in 1924, but with pre-release progress versions as early as 1909. The “Joint Committee” was the temporary union of a number of non-profit organizations interested in concrete, including the ACI, the ASCE, the ASTM,   the PCA, and the American Railway Engineering Association (now the AREMA). The ACI later developed its own code: ACI 318 first appeared under that name in 1936; a pervious version without the committee 318 name appeared in 1927. But in the context of the multiple authorities responsible for the Joint Committee report, it’s understandable that the ACI felt it necessary to emphasize the research that went into their solo code.

Now that we’ve established how important this code was in 1956, why should anyone care now? Sixty years is a long time and it’s not as if we’re going to use it for design. One reason, as we sometimes work on 1950s concrete-frame buildings, is that it’s always good to be able to reverse-design a building as a way of being sure you understand it. In short, we should be able to confirm the beam and column sizes and reinforcing we see on site by reusing the original design codes. More importantly is that we want to understand the mindset of the engineers who designed the old buildings. To use a simple example, shear reinforcing in beams used to take the form of open-top stirrups rather than closed ties because research on ductility and earthquake design hadn’t yet caught up with the code. This transition took a long time, and, when I first worked on concrete in the late 1980s, whether we used stirrups or ties depended on the use of the member and the location of the project. Ties are now, in 2016, used everywhere.

Ultimately, the answer to why this code is useful today is the same answer we give on most of our projects: if you want to work on old buildings, you’d best understand the past.

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