Throughout history, engineers have sought to understand how structures work and how the forces within a structure move from where the loads are applied to the supports and foundations. This is called structural optimisation – using exactly the amount of material needed in the locations required – a harmonisation between architecture and engineering.
The computer makes seemingly impossible quantities of calculations within minutes (or even seconds), and the opportunities for optimisation increase tremendously. Such advancement fuelled the need to start manufacturing these complex structures using techniques other than those traditionally available.
This is where 3D printing (additive manufacturing) of parts of the structure started being conceived, since this enables the fast production of several different shapes typically not possible through traditional construction. The process of additive manufacturing involves the building up of material layer by layer. It offers an unprecedented freedom of form, resulting in endless possibilities of customisation. The material is exactly where it needs to be to fulfil its function of carrying the loads.
A grid shell is a column-free structure that spans large areas and looks like a shell formed by a grid of structural elements. The connections of each of the structural members at various angles make its fabrication through 3D printing much more accessible. The Faculty for the Built Environment at the University of Malta is undertaking research of these connections, and optimising the intersections of these elements through a process known as topology optimisation.
The work and research mentioned so far is of a structure on a local scale. Structural engineering projects are usually on a large scale and require extensive labour. Recent advancements in 3D printing techniques have also enabled entire structures to be printed.
Concrete and steel 3D printing are also possible. Mobilisation of the 3D concrete may be done to enable printing on site, as has been done in Austin, Texas. A concrete house was made up of 24 concrete elements, printed layer by layer in a factory in Eindhoven. The elements were then transported to site and placed on a foundation. Another house known as the ‘3D Print Canal House’ completed in 2018, was a research design-and-build project to address new global housing solutions and market exploration in Amsterdam.
The time has come to boost the construction industry into the world of digitisation. From design to implementation, digitisation leads to sustainable and affordable structures which are tailor made to both the architects’ and the engineers’ wishes.
Jeanette M Muñoz Abela is a compassionate revolutionary designer.
Sound Bites
• Concrete 3D printing could be the future of construction on Earth and other planets. NASA is already looking at the possibility of 3D printing structures on the moon and Mars as part of the Artemis programme to build a 3D-printed habitat for deep space exploration. NASA is planning to put in place a lunar terrain vehicle, lunar RV or habitable mobility platform and surface habitat on the moon by the end of 2030.
https://www.youtube.com/watch?v=_MsOXrprYXs
https://www.nasa.gov/centers/marshall/news/releases/2020/nasa-looks-to-advance-3d-printing-construction-systems-for-the-moon.html
• Robots will help shape our future. In 3D printing of steel, MX3D utilises robotic arms for their system – they call it the robotic Wiring Arc Additive Manufacturing system (WAAM). They use a controller, a power source, and a wire arc welding machine. See how they do it by clicking on this link:
https://www.youtube.com/watch?v=STAHy6hTP14
For more science news, listen to Radio Mocha on www.fb.com/RadioMochaMalta/.
DID YOU KNOW?
• 3D printing has been around since 1984. Charles “Chuck” Hull was the first to successfully build a machine that could place layers of material on top of each other.
• Charles Hull’s 3D printing machine was called the stereolithography machine.
• Compared to traditional construction methods, printing concrete in 3D guarantees a shorter construction time, a safer working environment and higher freedom in shape.
• When 3D printing in concrete, the concrete mix needs to be carefully designed to suit the extrusion techniques used.
• For 3D printed steel, the material needs to be heated to 1,500 °C to make it malleable enough for printing.
• The 12-metre-long MX3D Bridge was built by four commercially available industrial six-axis robotic arms equipped with welding gear, and took six months to print.
For more trivia, see: www.um.edu.mt/think.