Evaluation of Wood Composite I-Joist with Sinusoidal Web

This study presents a combined experimental and finite element analysis of composite wood I-joists under torsion, cantilever buckling, and four-point bending. Wood I-joists are long, slender structural members designed for long-span joist and rafter applications. Theses members are composed of thin-walled webs with relatively low stiffness and relatively thick flanges. Due to the nature of the web, these beams will likely fail in buckling before ultimate load is reached. Recently at West Virginia University, a new structural wood composite panel has been developed using discarded veneer-mill residues (McGraw 2009). This unidirectional composite panel was manufactured with two specific geometries, a flat and a sinusoidal configuration with equivalent volumes, to be used as web material in prefabricated wood I-joists. The web panels were joined in length using a finger joining technique and a tongue-and-groove joint was used connect the web to the laminated veneer lumber (LVL) flanges. These beams were evaluated at two different depths, each with flat and sinusoidal webs. Three tests were performed to evaluate specific properties of these joists. First, these beams were tested in torsion to evaluate their stiffness and torsional response, following the procedure outlined in Davalos et al. (2009). An evaluation of the flexural-torsional buckling response was performed using a cantilever test as presented in Qiao et al. (2003). Finally, a four-point bending test was performed to determine the elastic moduli of the beams. A finite element analysis was performed for each of the different tests, showing good correlations.