Analysis of wood laminated beams reinforced by natural fibres

This paper presents an analysis on the viability of the use of natural fibres, in particular sisal fibres, as a reinforcing material in wood laminate structures. The use of natural fibres associated with the manufacturing of beams, with wood from reforestation, is in accordance with current economic interests and ecological appeal. Sisal fibres have attracted attention for presenting adequate mechanical characteristics for such applications. The laminated beams used in this research were constituted by Pinus sp and were reinforced by sisal strips with a thickness of 2 nun glued by Epoxy adhesive on the bottom of the beam on the tensile region. Each lamina had the following dimensions: a width of 50 mm, a height of 20 mm and a length of 1.5 m. For the theoretical analysis of wood laminate beams three models are carried out: stress functions, classical lamination theory and the transformed section method. It was noted that the average differences between the theoretical results and experimental data are given by: 11% and 2 % for normal and shear stresses respectively, and around 8%, for displacements. In conclusion, the strengthening of wood laminate beams with sisal fibres is effective in wood structural elements, in which the elastic modulus is at maximum equal to these fibres and also prevents brittle failure on critical tensile regions.