Topologically Optimized Concrete Beam

Concrete is one of the most consumed products in the world, with more than ten billion tonnes being produced every year. Optimising the use of concrete in prefabricated components can have a global impact in reducing material costs and the carbon footprint of buildings and infrastructure. However, optimisation algorithms often result in highly complex geometries which cannot be traditionally fabricated in concrete.

Actually concrete has excellent potential of being moulded into any conceivable shape. However, this potentially unconstrained geometric freedom is limited by the ability of the necessary formworks present a significant fabrication challenge. With FDM 3D printed formworks we can unlock an entirely new vocabulary of shapes for concrete structures, previously unavailable with traditional formwork systems. Only a minimal amount of 3D printing is required to deliver a very thin, stable shell.

3D Printed Formwork
To prove our hypothesis that architectural elements could be fabricated with additive manufacturing, we designed concrete beam components with the aid of topology optimization algorithms and fabricated the components using 3D printing. We utilized 3D printed formworks to expand the possibilities of concrete in constructing free-form architecture. With fibre-reinforcement to maximize load-bearing capacity of the beams, the geometric freedom and construction flexibility of concrete components was retained.

With these 3D printed plastic formworks, complex topologies can be achieved in concrete elements. Such elements can optimize structural performance or improve functional aspects, as well as introduce a radically different aesthetic. The design research selected several critical aspects of this method, such as the interface between the discrete elements, the integration of post-tensioning and rigid reinforcement, the provision of functional voids etc.

Architecture Component
While large scale elements can be produced with FDM formwork, the specific investigation of design and fabrication strategies for long-span concrete structures based on discrete sections assembled through post-tensioning. Limiting the size of the concrete elements reduces the build-up of hydrostatic pressure during casting and ensures the elements can be transported, handled and assembled on-site with ease.

The project demonstrates a hybrid fabrication process in which a precious, smart fabrication process is used minimally, only where necessary, while the structural performance is provided by concrete, which is cast in a conventional manner. Digital fabrication is only used to produce a minor proportion of the final product but has a major impact on its performance and behaviour. 

Project Credits: ZongRu WU and Fernando Cena.
This project was developed during four weeks called Smart FDM Formwork in ETH Zürich.
Supervisors: Andrei Jipa and Matthias Leschok.
Photo Credits: Tom Mundy.