Most embodied-carbon work in the last five years has gone at the material: lower-clinker cement, recycled steel, better EPDs. The CURE report goes somewhere else. It argues the code itself is specifying more material than the structure needs.
Phase 1 of Code Updates for Reduction of Embodied Carbon, funded by the Charles Pankow Foundation and led by the University of Colorado Boulder, names 11 priority code changes aimed at the next editions of ACI 318, AISC 360 and ASCE 7.
Two levers, not one
The proposals work through two mechanisms. The first reduces the total quantity of material, mainly by allowing smaller required section sizes. The second reduces the carbon intensity of what’s specified, for instance by letting designers use lower design-strength concrete where the structure doesn’t need the strength it’s currently required to have.
Certain proposals, according to the report, could cut a structure’s embodied carbon by as much as 12% against what current code requires. The authors also argue that reductions of 1 to 3% are worth chasing given the scale of the building stock, which is a framing argument rather than a finding.
Each prospective change comes with its estimated carbon impact, the next steps needed, and the roadblocks likely to stop it. That last column is the useful one. Code committees don’t move on carbon arguments alone.
The authors are explicit that safety isn’t the trade. The changes “represent a roadmap for future research and action that can lead to reduction in embodied carbon in the built environment without compromising safety, durability, or serviceability of structures,” and they say the topics are “achievable in the near-term through targeted, funded research.” They also put the responsibility squarely on one discipline: “Structural engineers should take the lead on innovations in embodied carbon reduction in building structures given their outsized impact on specifying materials and design requirements.”
Who paid, and what this isn’t
Phase 1 funding came through the Pankow Foundation from the ACI Foundation, AISC, the ASCE Structural Engineering Institute, the Magnusson Klemencic Associates Foundation and the NCSEA Foundation. Two of those bodies own the codes being targeted. That’s not disqualifying, but it belongs in any read of the 12% figure, which is a modelled estimate for specific cases rather than a measured, independently verified result.
And nothing here is code. These are recommendations to committees. ACI 318 and AISC 360 move on multi-year cycles with balloting that has defeated less contentious proposals than reducing prescribed section sizes.
The practical value in the meantime is that a structural engineer can read the 11 items and see which ones are already permissible through alternative-means provisions and engineering judgment. Projects chasing a carbon target, such as the net-zero designs going into the Barry Farm-Hillsdale redevelopment in Washington, are making these calls now, ahead of any code that endorses them.
Phase 2 is where the funded research either happens or doesn’t.
Source: Charles Pankow Foundation, CURE Phase 1 Final Report.