Structural performance of I-beam fabricated from a fast-growing tree, Gmelina arborea

There is an increasing supply of fast-growing plantation species in Costa Rica. The main objective of this study was to assess the performance of I-beams fabricated from Gmelina arborea wood using lumber for the flanges and 12-mm plywood for the web. Three types of profiles were fabricated for static bending tests, i.e. 6.5 cm × 24.2 cm, 6.5 cm × 16.5 cm and 6.5 cm × 10 cm (width × depth) × 600 m (length). Modulus of rupture varied from 23 to 41 MPa while modulus of elasticity, 12 to 17 GPa. Static bending tests showed that it was necessary to classify the I-beams according to two qualities. Structural design values varied from 5.9 to 14.4 MPa in the bending test and from 4.0 to 8.9 MPa in the shear stress according to the Costa Rican structural standards.