Strength of Steel

US researchers, in collaboration with SHoP Architects, have developed a potential alternative to steel and concrete floor structures: recyclable panels made from bioplastic and wood flour. These prefabricated panels were created using 3D printing technology by teams from Oak Ridge National Laboratory (ORNL) and the University of Maine (UMaine) as part of the SM2ART public-private partnership.

The new material, called the SM2ART Nfloor cassette panel, is environmentally friendly and faster to produce than traditional steel-and-concrete components, which are commonly used in multi-story buildings. The idea for these bio-based panels was prompted by SHoP Architects, who challenged the researchers to explore sustainable materials and advanced manufacturing techniques for mass production of floor systems.

SHoP principal John Cerone explained that they drew inspiration from the aerospace industry, where new technologies are first introduced in small components and then gradually expanded to larger systems. They applied this same approach to building systems by focusing on one specific product: a light-gauge steel floor cassette assembly.

Working with an existing supply-chain partner, they used this steel assembly as a benchmark to replace it with a single, 3D-printed bio-based part made from solid-state materials. This process allowed them to explore the use of sustainable materials while ensuring the new product could be integrated smoothly into current manufacturing practices.

Strength of combined materials

ORNL and UMaine researchers created the recyclable floor panels using polylactic acid (PLA), a bioplastic made from corn residue, mixed with wood flour, a byproduct from lumber processing. This combination of materials gives the panel its strength and stiffness. According to ORNL researcher Katie Copenhaver, adding wood flour to PLA increases its stiffness significantly, which is critical to the panel's performance.

The panel's strength also comes from its geometric design, which evenly distributes weight to the outer edges, where it connects to a building's steel framework. Copenhaver explained that while PLA alone might not be as strong as steel, the structural design compensates for the material's properties. The result is a panel with the same strength as a traditional steel-concrete floor system.

Additionally, the panel is biodegradable, comfortable to walk on, and easier to produce. Unlike conventional steel floor cassettes made from 31 parts and three materials, this new panel is a single-piece construction, making it faster to manufacture and easier to recycle.

The manufacturing process for the new bioplastic-wood floor panels allows channels for wiring, plumbing, and ductwork to be built directly into the panel during 3D printing. This eliminates the need to cut these channels after assembly, saving both time and money. The entire printing process for the panel takes about 30 hours and is estimated to reduce labor costs by around 33%.

SHoP principal John Cerone emphasized that, unlike typical 3D printing, which focuses on aesthetics, this process is centered on improving performance. The use of bio-based materials like PLA (polylactic acid) and wood flour not only helps reduce carbon emissions but also allows for efficient structural material placement and integration of mechanical systems, all in one step.

Although still in the early development stages, the team believes that this technology holds great potential for advancing construction, especially for modular multiresidential buildings. The PLA and wood flour blend can be used for producing a variety of large-scale 3D-printed components, offering new possibilities for efficiency and performance in construction.

SHoP founding principal Christopher Sharples highlighted that this innovation could revolutionize construction by industrializing the process itself, making it more efficient and adaptable to various building types and scales. The researchers are now working to further refine the design, aiming to reduce print time, use less material, and add more functionalities.

Did you like this post? Interested in more? Feel free to like and/or share with your network.