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Cross-laminated timber (CLT) is increasingly being utilized in Europe, North America and elsewhere due to its superior mechanical properties and environmental-friendly performance. Considering regions and countries, such as China, those are scarce in structural wood resource but rich in bamboo forest, an idea of introducing bamboo into CLT system has been proposed to form a novel composite material, named as cross-laminated bamboo and timber (CLBT). This paper focuses on the comparison of thermal insulation performance of CLBT and CLT panels. The thermal resistance and transmittance of CLT and CLBT wall specimens were measured by the Guarded Hot Box test. A calculation method provided by ISO standard and a finite element (FE) model were also used to evaluate the thermal resistance of CLT and CLBT panels. Based on the proposed FE model, some parametric analysis was performed through 11 CLBT panels with different compositions, including the layer number of glubam and timber, the thickness of extruded polystyrene and the use of gypsum board and screws. Moreover, the feasibilities of these CLBT panels were evaluated for the application in different climate regions of China and the United States in accordance with the corresponding Chinese and American building energy efficiency standards, respectively. It can be finally concluded that, the development and application of CLBT contributes to achieving the low carbon sustainable features of structures, which is due to the good carbon sequestration ability of its component materials (i.e., timber and bamboo) as well as the good insulation performance of CLBT panels. [ABSTRACT FROM AUTHOR]

• CLBT exhibited superior compressive strength, outperforming CLT by 65 % for 3.0 m high wall panels and by 40 % for 6.0 m high wall panels. • For specimens showing buckling instability, CLBT exhibited more concentrated failure in end regions, while CLT failed primarily in central region. • Theoretical calculations and FE simulations of ultimate bearing capacity in compression showed good agreement with experimental results. This paper investigates the in-plane compressive behavior of 5-layer cross-laminated bamboo and timber (CLBT) wall elements with variable heights. Five different heights of CLBT specimens, ranging 400 mm – 3800 mm, were designed for the experiment, with conventional 5-layer cross-laminated timber (CLT) specimens used as controls. Theoretical calculations based on timber structure design codes were employed to analyze the ultimate bearing capacity in compression, complemented by finite element simulations based on Abaqus that also explored the failure characteristics. The results indicated that CLBT wall panels had significantly better compressive performance compared to those of CLT wall panels. For wall panels of around 3.0 m and 6.0 m in height, the compressive strength of the CLBT was approximately 65 % and 40 % higher than that of the CLT, respectively. For specimens showing buckling instability, CLBT demonstrated more concentrated failure in the end regions, contrasting with CLT, which failed primarily in the central region. The outcomes of this study clearly delineate the superiority of CLBT over CLT when used as wall panels, providing valuable references for their potential engineering applications. [ABSTRACT FROM AUTHOR]

In this paper, the bending properties of a 3-ply cross-laminated bamboo and timber (CLBT), prefabricated with the bamboo mat-curtain panel and hem-fir lumber, were examined in the major and minor strength directions, and a 3-ply hem-fir cross-laminated timber (CLT) was taken as a control group. The analytical model for the sum of the orthogonal apparent bending moduli with the two types of layer classifications were proposed, and the two kinds of contribution models were developed to analyze the apparent bending modulus variation behavior of the CLBT and CLT panels in the major and minor strength directions. The experimental results showed that since the CLBT group had more internal orthogonal structures, its difference in the bending properties between the major and minor strength directions was lower than that of the CLT group. Furthermore, the proposed contribution models quantitatively analyzed the relationship between the apparent bending moduli of the CLBT and CLT panels and the corresponding composition layer characteristics. The contribution model to characterize the apparent bending modulus in major and minor strength directions demonstrated good agreement with the test results. Based on this model interpreted by three-dimensional figures, the contribution variation characteristics in the major and minor strength directions were revealed.

Given the exceptional mechanical properties of cross-laminated bamboo and timber (CLBT) and its ability to efficiently utilize bamboo and timber resources, CLBT holds considerable potential for applications in modern sustainable timber and bamboo structures. CLBT panels, when used as floors or roofs, typically experience out-of-plane loads. This study investigates the out-of-plane bending and shear characteristics of 5-layer CLBT and cross-laminated timber (CLT) specimens using the variable span three-point loading test method. The results indicated that the developed CLBT exhibited superior mechanical properties compared to CLT, offering a preliminary demonstration of its value in engineering applications. In addition, factors such as the span and outermost lamination influenced the failure modes, vertical deflections, strain distributions, ductility indices, and energy absorption characteristics of CLBT and CLT specimens. This study provides a foundational reference for using CLBT as floor and roof panels subjected to out-of-plane loads and lays the foundation for further research. • A CLBT with outermost bamboo scrimber laminations and inner SPF laminations was proposed. • The out-of-plane performance of CLBT was higher than that of CLT. • Compared with CLT, the outermost laminations of CLBT did not fail easily. • The loading responses of specimens were influenced by the span and outermost lamination type. [ABSTRACT FROM AUTHOR]

This study investigated the post-yield behavior of 5-layer cross-laminated bamboo and timber (CLBT) short wall specimens under in-plane compressive loading, and cross-laminated timber (CLT) specimens were used as the control. Compared to CLT, the replacement of the outermost spruce-pine-fir layers in CLBT with bamboo scrimber layers led to a 90% increase in compressive strength and a 20% increase in compressive modulus in the major strength direction. A quantitative evaluation employing absolute and relative error indicators demonstrated that the Richard-Abbott model adequately predicted the tested stress–strain relationships. In contrast to CLT, CLBT exhibited a more extended strain hardening stage after yielding and a shorter strain softening stage after the maximum point, particularly in the major strength direction. The ductility and toughness indices of CLBT, calculated based on the yield and failure points, were higher than those of CLT in the major and minor strength directions. The energy absorption provided a better representation of toughness characteristics for CLBT and CLT compared to the toughness index. This study provides a technical database and guidelines for the application of mass hybrid bamboo and wood products in the construction industry. • The in-plane compressive strength and modulus of CLBT are significantly higher than those of CLT. • Compared with CLT, CLBT exhibits a longer strain hardening stage and a shorter strain softening stage. • Replacing the outermost SPF layers with bamboo scrimber layers enhances ductility and toughness. • The Richard-Abbott model accurately describes the measured stress–strain relationship. [ABSTRACT FROM AUTHOR]

• Outermost bamboo scrimber layers enhance CLBT stiffness and bearing capacity. • Embedded steel dowels limit delamination between bamboo scrimber and SPF layers. • Steel dowels enhance the ductility and energy absorption of CLBT. Cross-laminated bamboo and timber (CLBT) products exemplify the efficient utilization of bamboo and timber resources, demonstrating excellent potential in sustainable structural engineering. The significant difference in mechanical properties between high-density engineered bamboo and low-density timber laminations leads to premature in-plane delamination failure and loss of ductility and energy absorption for CLBT members subjected to out-of-plane loading. This study demonstrated that vertically-driven steel dowels significantly enhanced the layer combination efficiency and addressed the above problems of CLBT. A comparison of measured critical mechanical performance parameters was presented, systematically characterizing the structural behavior of CLBT beams with steel dowels. Steel dowels in CLBT were more effective than those in cross-laminated timber at resisting high in-plane shear stress and exhibiting the progressive failure phenomenon. Although steel dowels slightly reduced the bending stiffness in some specimens, they increased the ductility and energy absorption performance, particularly in CLBT. This study provides a potential solution for improving the structural behavior of CLBT members subjected to out-of-plane loads under high in-plane shear stress conditions. [ABSTRACT FROM AUTHOR]