Experimental Study on the Flexural Behavior of I-Shaped Laminated Bamboo Composite Beam as Sustainable Structural Element

Abstract

Laminated bamboo (LB) is considered a promising environmentally friendly material due to its notable strength and advantageous lightweight properties, making it suitable for use in construction applications. LB I-beams are a prevalent component in bamboo structures due to their ability to fully utilize their material properties and enhance efficiency when compared to beams with rectangular solid sections, while the characteristics of connections should be further studied. This paper presents an experimental investigation of the flexural behavior of I-shaped LB beams that are connected using self-tapping screws and LB dowels. Compared with glued beams of the same size, the findings of the study reveal that the primary failure modes observed in those two types of components were characterized by the separation of the component and web tensile fracture. The screw beam and dowel beam exhibited a reduced ultimate capacity of 43.54% and 30.03%, respectively, compared to the glued beam. Additionally, the ultimate deflections of the screw beam and dowel beam were 34.38% and 50.36% larger than those of the glued beam, respectively. These variations in performance can be attributed to the early breakdown of connectors. Based on design codes, it can be observed that the serviceability limits were in close proximity, whereas the ultimate strains of the top and bottom flanges were significantly lower than the ultimate stresses experienced under uniaxial loading conditions. As a result of the slip and early failure of connectors, the effective bending stiffness estimated by the Gamma method achieved better agreements before elastic proportional limit. Therefore, in future investigations, it would be beneficial to enhance the connector and fortify the flange as a means of enhancing the bending characteristics of an I-shaped beam.