Structural Plastic Trusses

Engineers at the Massachusetts Institute of Technology (MIT) have developed a new way to turn discarded plastic into lightweight, high-strength building components using large-scale 3D printing.

Using recycled PET plastic reinforced with glass fibers, the team produced floor trusses that withstood 4,000 pounds of weight in testing—twice the load required by U.S. federal housing standards. The trusses were manufactured at MIT’s Bates Research and Engineering Center using an industrial, room-sized 3D printer capable of producing up to 80 pounds of material per hour. This process enables the rapid conversion of raw plastic pellets into construction-ready parts.

To demonstrate real-world viability, the researchers assembled a full floor frame using four 8-foot trusses topped with plywood. Each truss weighed just 13 pounds, making them significantly lighter than traditional wood alternatives while delivering comparable strength. Additionally, computer modeling enabled optimization of the truss design to maximize stiffness and minimize sag.

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