Analytical Investigation of the Potential of Hollowcore Mass Timber Panels for Long Span Floor Systems

Abstract

AbstractMass timber products have shown tremendous potential as sustainable structural components in large building systems. However, challenges occur when open floor plan structures are desired due to conventional flat slab floor systems having difficulties achieving the longer floor span expectations (i.e., exceeding 9 m). This paper investigates the potential of an all-wood solution, namely, hollowcore mass timber (HMT) panels, in meeting the demands of longer spans while also minimizing the use of wood material when compared to a solid slab. A 400 mm deep, 9 m long HMT panel composed of 3-layer cross-laminated timber (CLT) panels as flanges, and glulam beams as webs, is compared to the maximum commonly available CLT and dowel-laminated timber (DLT) alternatives. Two analytical methods and a finite element model are used to determine the effective bending stiffness of the HMT panel, while CSA O86 design procedures are used for the CLT and DLT panels. The effective bending stiffness of the HMT panel between the finite element model and analytical methods ranged from 1.71–1.94 and 1.14–1.29 times greater, despite being 18% and 24% lighter, than the CLT and DLT panels, respectively. Although slightly deeper, the HMT section provided a more efficient use of materials when compared to the solid slab options. The vibration-controlled span limit of the HMT panel was on average 9.8 m, which was 1.8 m and 0.9 m longer than the CLT and DLT panels, respectively. Further areas of study were also identified and will be investigated as part of future work in the broader HMT panel research program.