Overview
TRACE is a structural engineering design tool intended to help consulting design engineers estimate total embodied carbon in the gravity system of their building and compare it to project benchmarks as well as industry standards.
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 guide these designers through the decision-making process and lead them to making a data-driven decision about the smartest choice for their building.
How it works
The tool operates by taking a specified set of user inputs, described below, and conducts preliminary beam sizing based on industry-standard logic and rules-of-thumb, and then calculates embodied carbon based on standard metrics. It then compares the totals to benchmarks. The tool also constructs a visual representation of the building to aid in schematic design.
In specific, the underlying logic behind the design is as follows:
- 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)
Primary Inputs (Design Variables)
The tool takes several inputs:
- Bay size in feet (X and Y span)
- Number of bays (X and Y)
- Number of floors
- Floor-to-floor height
- Mechanical, typical floor, and typical roof loads (PSF)
- Structural system choice (from structural steel, reinforced concrete, and cross-laminated timber (CLT))
Primary Outputs
- 3D representation of structure designed
- Total embodied carbon in kgCO₂e
- Embodied carbon on a per-square-foot basis (kgCO₂e/sqft)
- 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
System Requirements
- Mac/Windows machine running Rhino 8
- Local Python 3 environment
- No additional requirements!
How to Use
- Open Rhino, and run the Grasshopper command to open a separate window. It is highly recommended to split screen both programs so that the user can see the visual feedback of their parameter adjustment in real time.
- Open TRACE.gh. The sample structure will automatically generate in the Rhino window.
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.