EXPERIMENTAL STUDY OF THE BENDING PERFORMANCE OF HOLLOW GLULAM BEAMS

摘要

Hollow glulam beam has some advantages that the traditional solid glulam beam does not have, such as the convenience for wiring construction and comparably light weight. Four-point bending tests of three solid glulam beams and 15 hollow glulam beams with various sizes of rectangular holes produced from small-diameter larch timber were conducted to investigate the influence of the hollow ratio and wall thickness on bending stiffness and load capacity. The midspan deflection, cross-section strain, and ultimate load were obtained from the tests, and the detailed failure modes and apparent MOE for all specimens are reported. Hollow glulam beams with the hollow ratio ranged from 25% to 40%, and the wall thickness greater than 20 mm after the assumption of plane section under bending moment. The apparent bending stiffness and ductility of hollow glulam beam were less than those of solid glulam beam, and the apparent MOE is 0.86 times the elastic modulus value calculated by theory of elasticity. In addition, a calculation formula for the ultimate bending moment is proposed.