BEETLE², (Built Environment Efficiency Tool for Low Environmental Externalities) is a tool aimed at promoting an efficient and effective use of resources in the built environment. Beetles can be found anywhere in the world and so do buildings. Beetles are also a virtuous example of the effective and efficient use of resources. They hardly produce any waste; in fact some species use waste from other sources for their purposes. Such a virtuous behaviour has inspired us to aim to achieve the same efficiency and effectiveness in our built environment.
At this first stage, the tool is able to quantify the embodied carbon (EC) of steel frame building structures. It requires a small set of input parameters to run and it is ideally suited for use at concept and early design stages, making very easy to explore how variations of the frame geometry (span lengths, number of floors etc.) and magnitude of applied (wind and floor) loading would affect the overall structural steel mass and EC intensity.
Extensive research, conducted so far about the environmental impact of buildings, has produced a range of EC coefficients to provide a measure of embodied CO2e emissions per unit mass of building material. Knowing the overall mass of a building structure is therefore a sufficient prerequisite to estimate the corresponding amount of embodied carbon. Nonetheless, a neat figure of the overall structural mass becomes available when the design is well beyond the conceptual stage, at which point, the room for design variations is very limited, and looking back to alternative frame geometries is not a feasible option any longer.
Conversely, BEETLE² enables to estimate the structural mass of regular steel frames at concept design stage. Several structural designs, of geometrically different steel frames, can be automatically generate in few seconds. Structural analyses are performed via Direct Stiffness Method for various load combinations accounting for the frame self-weight, permanent and imposed floor loads and eight wind-load cases evenly oriented at increments of 45 degree angles. Based on the analyses results, optimised cross-sections of minimum area are iteratively computed for each beam, column and cross-bracing, according to Eurocode 3 requirements and limited to commercially available section profiles.
The conversion from mass to embodied carbon is based on Monte Carlo simulation. This choice is due to the significant uncertainty around the EC coefficients, which should be ideally representative of the specific steel being used in the project. For this reason a probability distribution of EC coefficients has been developed from primary data collected and published studies. This is then combined with another element of uncertainty related to the exact total mass of steel being used. The two are then combined randomly 5’000 times through Monte Carlo simulation to produce the final results which are presented to the user in the form of a probability density function. If using BEETLE² for research purpose, please refer to our paper:
B. D'Amico and F. Pomponi, Accuracy and reliability: a computational tool to minimise steel mass and carbon emissions at early-stage structural design, Energy and buildings, 168 (2018) 236–250.
To solve the systems of linear equations, involved with the structural analyses, the BEETLE² relies on Math.NET Numerics libraries to run. A folder called “MathNet.Numerics” has been included in the Zip file for download. Place the folder to the following directory before loading the plug-in in Rhino:
- “C:/Program Files (x86)/Rhinoceros 5/Plug-ins/MathNet.Numerics”
Regardless of whether you are a student, a researcher or a design practitioner, if you’ve got an interest for collaborations on further development of this tool, or you’ve got comments or feedback to share, please do get in touch. We are looking forward to hear from you!
Bernardino D’Amico, Francesco Pomponi
Category: Structural Engineering, Life Cycle Analysis, Parametric Design, Steel Frames, Optimization
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