To improve the performance and utilization of low grade pine lumber, southern pine (SP) laminated planks (184 mm 9 320 mm 9 4.29 m) were fabricated and evaluated for construction mats application. The laminated planks were made from No. 3 grade SP lumber and face-laminated with waterproof polyurethane adhesive. Modulus of rupture (MOR, 33.1 MPa), characteristic design value of fiber bending stress (F b , 12.6 MPa), and modulus of elasticity (MOE, 7040 MPa) were obtained from four-point static bending tests. The comparison results demonstrated that the product of this research has applicability as a member stock for construction mats application.
This study investigates the effect that specimen depth has on the torsional shear strength of full-size Eastern Species Laminated Veneer Lumber (LVL). Characterization of this effect is valuable for structural design purposes as well as for use in constitutive modeling when predicting member strength of one depth based on member strength of a different depth derived from testing. To this end, torsion tests were carried out on three depths (140, 184, and 235 mm) of 1.98 m long by 44 mm thick 1.9E Eastern Species LVL. The shear strength of each depth was determined based on homogeneous, orthotropic theory for beams of rectangular cross-section. Despite a perceptible trend of slightly decreasing shear strength with increasing depth, an analysis of variance test indicated that no statistically significant depth effect exists as it relates to torsional shear strength. Further, a three dimensional finite element model of the 44 mm by 140 mm specimen indicated that stresses are uniform within the shear span of 2 times the depth plus the grip distance away from each end of the specimen. The predicted average maximum shear stress in this region compared well to the maximum shear stresses obtained experimentally.
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