Final answer:
The statement is false because glued laminated beams have different allowable stresses when loaded parallel or perpendicular to the lamination faces, due to the inherent directional properties of the wood and the variation in the beam's response to tensile, compressive, and shear stresses.
Step-by-step explanation:
The statement that the allowable stresses for a glued laminated beam are the same whether the beam is loaded parallel or perpendicular to the wide faces of the laminations is false. Wood and wood composites, such as glued laminated beams, often have different strength properties depending on the direction of the load relative to the grain. When loaded parallel to the laminations (along the grain), the beam has different stress limits compared to when it is loaded perpendicular to the laminations (across the grain).
The shear modulus, denoted as S, is an important material property in determining how a material will deform under shear stress, which is a force applied parallel to the cross-sectional area and perpendicular to the length, Lo, as shown in figures referencing a siderways stress or shearing force. The shear deformation is influenced by factors such as the cross-sectional area and the material's inherent properties, such as the shear modulus.
Bending stress, on the other hand, combines both tensile stress on one side of the beam and compressive stress on the other, as reflected in the example of a shelf sagging under the weight of heavy books. Therefore, the allowable stresses for bending (which includes considerations for both tension and compression) are different from the allowable shear stresses.