TRACE is a tool designed to help structural engineers estimate embodied carbon in their structural system. Often times, early in the lifecycle of a new development project, structural engineers must make a decision about what gravity and lateral system they want to use. At the same time, an owner/develop may have specified carbon goals they want to hit for LEED, SE2050, or related programs. This tool is intended to help these designers get an initial sense of the environmental impact of their building, specifically regarding embodied carbon.
Intended users
This tool will primarily be used by building designers (namely, structural engineers and architects) during early stages of design.
Need you’re trying to provide a solution or support for
Often times, especially in the case of new designers who may not have developed intuition gained over a long career, designers have no idea how much carbon a structural system actually contains. Most designers know that we want to minimizer embodied carbon, but the process of how that is actually achieved is unclear. Especially because these decisions can often go against intuition (sometimes a steel building might contain more embodied carbon than a concrete one, or maybe even a wood building is more carbon intense), a tool like this is valuable to supplement this decision logic.
A tool like this can be valuable because it allows designers to provide quick answers to owners or other designers (who, especially in the case of owners/developers, don’t really care how the building gets to a certain number required for LEED certification or tax credits - they just want the building to get there). Especially during early design when the layout of a building may be rapdily changing (story heights, bay sizes, building dimensions, etc), having the ability to change a slider or two and get instant answers saves valuable time.
Inputs
My inputs will be as follows:
- Bay size (X and Y span)
- Number of bays (X and Y)
- Number of floors
- Floor-to-floor height
- Structural system choice (gravity and lateral; steel moment frame, concrete flat plate, CLT, etc.)
Underlying logic of the model you’ll implement
Part of the logic for this model was inspired by my work in Module 7, where I explored the effect of varying member uniformity across a structure on cost, embodied carbon, and more. Here, I envision the model working like this:
- Estimate beam/column sizes from span rules of thumb (e.g. span/20 for beam depth)
- Estimate lateral system layout from rules of thumb and system choice
- Calculate member volumes from geometry
- Multiply by material density to get mass
- Multiply by published embodied carbon factors (kgCO₂e/kg), which come from standard databases like the Inventory of Carbon and Energy (ICE)
Outputs
Some key outputs:
- Total embodied carbon in kgCO₂e and which LEED/LBC level the building achieves
- Breakdown and quantification by element type (columns, beams, slabs)
- Comparison chart across material options
- Standardized metric like carbon per square foot to be able to compare across buildings