Experimental and numerical investigation of lateral torsional buckling of wood I-joists

This paper investigates the elastic lateral torsional buckling capacity of wood I-joists. A sensitivity analysis determined that the orthotropic material properties that affect the critical buckling load of wood I-joists are the longitudinal modulus of elasticity, the transverse shear modulus of the flanges, and the elastic modulus of the web. A 3D finite element (FE) model was developed using experimentally determined material properties and initial imperfections. The study found that FE linear predictions provided reasonable agreement with the experimental buckling loads. The FE geometric nonlinear analysis was able to replicate the experimental nonlinear behavior that was observed during the test. Comparison with contemporary North American design standards showed significant conservatism in the design approach.