Zero-waste fabrication methodology for structurally optimized mass timber beams

Abstract

Mass timber construction has the potential to reduce the embodied carbon of new constructions and store carbon in the building stock. However, due to current design and manufacturing practices of engineered wood products, mass timber building can be more expensive than other structural material systems, making up to 30% of the total building cost.Optimized shaped beams can reduce material need by up to 70% in structures but are not easily manufactured with subtractive manufacturing or 3-dimensional milling methods, Manufacturing waste of these methods weakens the sustainability and material saving potential and challenges the adoption of these materially efficient shapes.We developed a zero-waste fabrication technique for shaped timber beams, by mixing subtractive and additive manufacturing techniques. The shape optimization is constrained by the requirements of the fabrication technique, to ensure that every result can be made.The paper covers the zero-waste fabrication methodology and its implementation in a constrained optimization for structurally optimized shaped timber beams. The beams are made from individual layers, cut from sheet material in a zero-waste pattern resulting from structural logic. The layers are then reassembled into a solid layered beam close to the optimal shape for minimal material use. The methodology is demonstrated in a small-scale load test. Material savings of around 20-30% on average and up to 40.1% can be achieved on simply supported beams with constant height.