Welcome Updates to the ACI 318 Structural Concrete Code

After decades of near-unintelligiblity, the ACI- 318, the guide for structural concrete used in design and construction, has been revised and reorganized to make it more useable for building code enforcement in the construction industry. Many see the current update as the most dramatic changes since 1971. Whereas the entire industry had previously seen ACI-318 as a ponderous document that was tedious to read and difficult to understand, the current edit, which streamlines several chapters, rearranges key information, and simplifies the language being used, is a welcome change.

The changes to the code have come about in response to the improved knowledge of innovation in concrete materials, of how structural concrete behaves, and of increased sophistication in structural concrete technology. The latest changes, however, give a new, clearer, context for that information. According to award-winning structural engineer Cary Kopczynski, the current revisions “revolve mainly around the organization of the code requirements, shifting the focus from a “force-based” to “element-based” format.” For example, instead of organizing the document according to the different forces that affect concrete such as shear and flexure, the new code addresses how concrete performs when it is used in particular building elements such as slabs, columns, and beams.

In older versions of the code, builders had to flip back and forth madly between chapters, piecing together the code for a given structure. In the newly updated code, the structure being built has everything you need to know about the proper code compiled cleanly together in a single chapter. In cases where a complex design incorporating multiple elements is being built, take rebar bends, for example, the information will be published in a “toolbox chapter” that will avoid needlessly repeating information by referencing the previous chapters.

It was clear to the committee that further updates are needed as soon as possible, but the need to both update and reorganize the information was a daunting and time-consuming task. Many vital updates have been postponed until the 2017 update. The current edition isn’t a simpler or condensed version of the structural concrete building code, but it is a clearer and more user-friendly one that designers and builders will be very happy to see.

The building code committee of the American Concrete Institute updates ACI-318 every three years. The ACI standardization procedure mandates that the draft of these changes be made available for public review for a period for 45 days before the update is submitted to the International Code Council. To review the new code, visit the ICC website.

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