Development of high-performance strand boards: engineering design and experimental investigations

Strand-based engineered wood products such as oriented strand boards enjoy great popularity in structural engineering and are widely used for a variety of applications. To strengthen their competitiveness and to enlarge their range of utilization particularly in the load-bearing sector, the mechanical properties of these products need to be improved. This motivated the research efforts to use large-area, slender veneer strands for the production of strand boards with increased stiffness and strength. Target-oriented development of these products requires comprehending the effects of the relevant (micro-)characteristics, such as wood quality, strand geometry, and strand orientation and compaction during the production process, as well as layer assembly and density profile, on the mechanical properties of the finished strand boards. Comprehensive test series, in which these effects on tension, bending and shear properties of the boards have been studied individually, are presented in this paper. The obtained results provided insight into the microstructural load-carrying mechanisms and, thus, yielded valuable knowledge for product optimization and further improvement of custom-designed strand-based engineered wood products.