Leveraging HyperWorks for Topology Optimization in Architectural Structures: A Case Study

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The Aarhus School of Architecture in Denmark was keen on exploring the potential of applying simulation-based topology optimization, a technique commonly used in the automotive, aeronautical, and naval industries, to architectural concrete structures. The challenge was to combine this with robotic fabrication of polystyrene formwork for concrete casting. The Unikabeton Prototype project was created for this purpose, involving collaboration among the eight largest institutions and corporations in the Danish building industry. However, the use of computerized optimization tools was largely foreign to the field of architecture. There was a reluctance to lose design control to the optimization software, and this conservatism in the architectural industry posed a significant challenge. The Unikabeton project was one of the first academic research projects to address the use of topology optimization in architectural design. The potential payoff was significant, considering that CO2 emissions from the production of concrete account for 5 percent of total global emissions.

The customer in this case study is the Aarhus School of Architecture in Denmark. The school was interested in exploring the potential of applying simulation-based topology optimization, a technique commonly used in the automotive, aeronautical, and naval industries, to architectural concrete structures. The school aimed to couple this with robotic fabrication of polystyrene formwork for concrete casting. The project was led by Per Dombernowsky, who served as project manager and engineer, and Asbjørn Søndergaard, who headed the project’s design and optimization aspects. The Unikabeton Prototype project was a collaborative effort involving the eight largest institutions and corporations in the Danish building industry.

The team chose Altair’s HyperWorks for their optimization experiments, particularly valuing the OptiStruct in the HyperWorks suite. They first carried out structural analysis and small-scale simulation of the digital fabrication process, comparing the effect of topology optimization with a series of familiar pre-fab and in-situ concrete members. The optimized structures produced a 60 to 70 percent reduction of material usage compared to standard equivalents while meeting normative structural requirements. The team then set out to optimize a non-uniform doubly curved concrete slab supported by three asymmetrically placed concrete columns. Topology optimization was carried out to meet the fabrication requirements of the CNC milling process for the structure’s EPS formwork. The forms were milled in polystyrene blocks, assembled at the site using traditional assembly techniques and scaffolding, and self-compacting concrete was cast into the formwork. The architect had to devise new strategies of design intervention, which took the form of “non-design spaces”—areas that were excluded during the optimization process.

• The successful optimization of the Unikabeton project demonstrated the significant value of simulation-generated topology optimization for architectural structures. The optimization offered the opportunity to mimic the morphology of biological structural systems, sharing with them the principle of maximum structural performance generated by the smallest possible mass. The subtraction of superfluous material from the design significantly reduced the environmental costs related to producing the structure, in terms of energy saved in concrete production and transportation. Moreover, the polystyrene used to create the formwork could be recycled and used for new formwork. The project marked a potential larger shift in architectural practices, enabling a shift from typological to topological design thinking. The team found HyperMesh to be a very strong FE-modeling component, meeting a critical aspect of creating advanced design space models. They also employed HyperView post-processing for analytical checking of displacement and stresses. The team anticipates a bright future for using HyperWorks in commercial architectural projects.

• 60 to 70 percent reduction of material usage compared to standard equivalents
• Significant reduction in CO2 emissions from the production of concrete, which account for 5 percent of total global emissions
• Significant reduction in design time