Module 20
Computation for low-carbon structural design
Where the carbon actually is, why the grid moves it more than the material does, and whether a ranking survives the uncertainty in its own factors.
What this module covers
- Say where embodied carbon sits in a structure and when it is decided
- Compare scheme options on a rate basis at concept stage
- Show that span moves carbon more than scheme choice does
- Explain why mass alone does not determine environmental performance
- Test whether a ranking survives the uncertainty in the carbon factors
- Quote a carbon figure with the provenance it requires
Lessons
The awkward shape of the problem: the biggest lever is pulled at the stage with the least information.
Start lesson →Four schemes, five spans, and the comparison that shows which decision matters more.
Start lesson →The factors are uncertain. Test whether the conclusion depends on them — because that is the only result worth acting on.
Start lesson →
Module checkpoint
Check what you have taken in
3 questions
Question 1
Why can a lighter structural scheme have higher embodied carbon than a heavier one?
Question 2
A composite steel frame produces 562 tCO₂e at a 6 m grid and 1 028 tCO₂e at a 12 m grid. By what factor does doubling the span increase the carbon? Give the factor to two decimal places.
Question 3
A scheme uses 1 754 t of material and produces 447 tCO₂e. What is its carbon per tonne of material, in kg CO₂e per tonne, to the nearest whole number?