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The creep of bamboo scrimber is an important factor to be considered in engineering applications. Simply using the creep test method not only consumes a lot of time and money, but also cannot be extended to the full stress level. Therefore, in this paper, the short-term creep tests of bamboo scrimber under different stress levels (30% and 40%) and ambient temperatures (30°C–70°C) were carried out. The multicomponent Kelvin-Voigt model and generalized Maxwell shear relaxation model of bamboo scrimber were established. The Maxwell-3 shear relaxation model was used as the constitutive model of bamboo scrimber, and the creep finite-element model of bamboo scrimber under parallel-to-grain compression was established, which verified the creep constitutive model of bamboo scrimber. The results showed that the shear relaxation modulus exhibited a significant decrease during the unstable creep stage, reaching a maximum reduction of 62.0%. It showed nonlinear for the effect of ambient temperature on the compression creep of bamboo scrimber, and the creep rate near the glass transition temperature was significantly higher than that at other temperatures. The fitting coefficients, R -square of creep compliance models, were sorted as KV-4 and KV-5>KV-3>Burgers>KV-2. The fitting coefficients, R -square of the generalized Maxwell model of shear relaxation modulus, were sorted as Maxwell-4 and Maxwell-3>Maxwell-2>Maxwell-1. The simulated creep displacement error of the two specimens was 2.8% and 0.1%, respectively, which verified the accuracy of the numerical simulation method. The paper proposed creep behavior and a constitutive model for bamboo scrimber under parallel-to-grain compression, which holds significant theoretical implications for its widespread application. [ABSTRACT FROM AUTHOR]

In the past decade, bamboo scrimber has developed rapidly in the field of building materials due to its excellent mechanical properties, such as high toughness and high tensile strength. However, when the applied stress exceeds the ultimate strength limit of bamboo scrimber, cracks occur, which affects the performance of bamboo scrimber in structural applications. Due to the propensity of cracks to propagate, it reduces the load-bearing capacity of the bamboo scrimber material. Therefore, research on the fracture toughness of bamboo scrimber contributes to determining the material's load-bearing capacity and failure mechanisms, enabling its widespread application in engineering failure analysis. The fracture toughness of bamboo scrimber was studied via the single-edge notched beam (SENB) experiment and compact compression (CC) method. Nine groups of longitudinal and transverse samples were selected for experimental investigation. The fracture toughness of longitudinal bamboo scrimber under tensile and compressive loadings was 3.59 MPa·m1/2 and 2.39 MPa·m1/2, respectively. In addition, the fracture toughness of transverse bamboo scrimber under tensile and compressive conditions was 0.38 MPa·m1/2 and 1.79 MPa·m1/2, respectively. The results show that, for this material, there was a significant distinction between longitudinal and transverse. Subsequently, three-point bending tests and simulations were studied. The results show that the failure mode and the force–displacement curve of the numerical simulation were highly consistent compared with the experimental results. It could verify the correctness of the test parameters. Finally, the flexural strength of bamboo scrimber was calculated to be as high as 143.16 MPa. This paper provides data accumulation for the numerical simulation of bamboo scrimber, which can further promote the development of bamboo scrimber parameters in all aspects of the application. [ABSTRACT FROM AUTHOR]

Purpose: Bamboo scrimber is a new natural fiber-reinforced composite material in the modern industry. In this paper, the strength characteristics of this material were chosen as the object of study. Design/methodology/approach: First, axial tensile fracture experiments were conducted on different test specimens to determine the corresponding strength data. Then three commonly used distribution models were applied to analyze the relationship between the strength and survival rate. Findings: The results show that the tensile data demonstrate obvious dispersion. In addition, the three-parameter Weibull model fits the data best and may be used as the fundamental model for future analysis. Originality/value: Special statistical analysis research of the bamboo material experimental results has rarely been discovered. This paper provides a solid foundation for better understanding the mechanism of the bamboo scrimber strength phenomenon. [ABSTRACT FROM AUTHOR]

This paper studies the rotational behavior of beam-to-column bolted connections in bamboo scrimber structures. Three types of beam-to-column connections, including bolted connections with outer-clamping steel plates, bolted connections encased with T-shaped steel plates, and bolted connections encased with double L-shaped steel plates, were designed and tested under monotonic or reversed cyclic loads. The influence of bolt arrangement on the mechanical properties was also studied. Failure of the connections was mainly caused by cracking of the adhesive interface near the bolt at the tensile side of the beam, which was a weak point that needs further attention. The elastic stiffness, capacities, ductility coefficient, and energy dissipation capacity of the T-steel connections improved compared with the I-steel connections. The load-carrying capacities of the connections were calculated according to common standards. Results showed that for the I-, T-, and double L-steel connections, the different standards had different safety margins. [ABSTRACT FROM AUTHOR]

Bolted steel-bamboo scrimber-steel (SBSS) connections are commonly employed in composite bamboo structures, but their equivalent stiffness in the elastic phase is difficult to determine. This study develops a novel theoretical formula for estimating the equivalent stiffness in the elastic phase of single-bolted SBSS shear connections considering various failure modes. Specifically, the method focuses on calculating the contact stiffness between the bolt and the pre-drilled hole wall, as well as the shear load applied to the bolt end by the steel plate. The method uses the double-shear yield mode, which is included by European Yield Modes (EYM), and the beam on elastic foundation theory (BEFT), and considers the bamboo scrimber embedment stiffness, bolt diameter and steel plate strength class. The method is tested by conducting experiments on single-bolted SBSS connections with varying load and fiber direction (LFD) angles, bolt diameters, steel plate thicknesses and strength grades. The results show that the connection stiffness increases with bolt diameter and steel plate strength grade, decreases with LFD angle, and is not affected by steel plate thickness. The parameter μ , which is important in the theoretical equations, is also calibrated based on the experimental data. The proposed method is validated by comparing it with existing test results of single-bolted SBSS connections. This paper provides a simple and reliable model for predicting the equivalent stiffness in the elastic phase of bolted SBSS connections in bamboo scrimber structures and offers useful insights for their design. • We proposed a method to calculate the elastic stiffness of bolted steel-bamboo scrimber-steel (SBSS) connections. • The elastic stiffness of connections with Q235 steel plate is considerably lower than that of connections with higher-strength steel plates. • The elastic stiffness of bolted SBSS connections that fail in any possible mode can be estimated by using the elastic stiffness for yield mode III. [ABSTRACT FROM AUTHOR]

• The study examines the flexural behavior of bamboo scrimber-aluminum plate composite beams. • Aluminum plate thickness significantly improves flexural stiffness and capacity in the service limit state. • Increasing the depth-width ratio and shear span ratio improve flexural stiffness and capacity. • The shear strength of adhesive has a significant impact on flexural capacity. • Modified calculation formulae are proposed to predict the flexural capacity of composite beams. This paper presents a study on the flexural behavior of twelve bamboo scrimber-aluminum plate composite beam specimens. The research investigates the effects of aluminum plate thickness and shape on specimen failure mode, flexural moment–curvature relations, and flexural capacity. Finite element (FE) analysis is used to benchmark test results. The study also includes parametric studies that explore the impact of various factors such as aluminum yield strength, plate thickness, adhesive shear strength, shear span ratio, and depth to width ratio on the flexural capacity of the specimens. The results indicate that while increasing the yield strength of aluminum plate has little effect on flexural stiffness and capacity, increasing plate thickness significantly improves these characteristics in the service limit state. Additionally, increasing the depth-width ratio and shear span ratio correspondingly improves flexural stiffness and capacity. The shear strength of adhesive has a significant impact on flexural capacity, but only a minor effect on flexural stiffness during the elastic stage. Based on the parametric study, modified calculation formulae are proposed to predict the flexural capacity of composite beams with and without inter-layer slip. [ABSTRACT FROM AUTHOR]

This paper presents a pilot experimental study aimed at evaluating the performance of engineered bamboo beams exposed to and following exposure to three-sided standard fire conditions. Nine tests were carried out including two constant applied load fire tests and seven flexural tests of engineered bamboo beams following exposure to fire. Test parameters include load ratio in fire tests, fire exposure duration, beam geometry and engineered bamboo type. Two engineered bamboo products: laminated bamboo and bamboo scrimber, commonly used in construction were considered. In all cases, regardless of fire exposure, the failure mode was flexural failure associated with tensile fracture of the extreme tension fibre. The stiffness and ultimate loads of engineered bamboo beams were observed to decrease with increased fire time and the strain distribution at the mid-span cross-section remained linear after exposure to the standard fire. The fire resistance of laminated bamboo beams decreased with increased applied load. Charring depth was measured for all beams after tests and equivalent charring rate was calculated. Result shows that laminated bamboo beams had a higher charring rate than the denser bamboo scrimber beams. Both sectional analysis and simplified methods based on the reduced cross-section method are used to determine the fire resistance and ultimate load capacity of the engineered bamboo beams following exposure to fire. • Performance of engineered bamboo beams exposed to fire were experimentally studied. • Performance of engineered bamboo beams after fire were experimentally studied. • Charring depth was measured after tests and equivalent charring rate was calculated. • Simplified methods based on the reduced cross-section method were developed. [ABSTRACT FROM AUTHOR]

• Eight bamboo scrimber I-beam-to-box-column connections with two types of detailing were tested under static loads. • Shear and moment resistances of beam-column connections were obtained from experimental tests. • Design methods were evaluated for shear and moment resistances of I-beam-to-box-column connections. As an eco-friendly construction material, bamboo scrimber has been increasingly investigated recently in terms of mechanical properties and member behaviour. However, limited test data about connection behaviour are available in published literature. This paper addresses the behaviour of bamboo scrimber I-beam-box-column connections under static loads. Two types of bamboo scrimber beam-column connections were tested, and the number of bolts connecting the beam flange and steel angles or T-stubs was also varied in the experimental programme. The moment resistance, failure mode and deformation capacity were obtained for connections. The shear strength and distortion of panel zones were quantified from experimental data. Comparisons were also made between the calculated shear strengths of panel zones and bamboo scrimbers. Finally, design methods were used to calculate the shear and moment resistances of bamboo scrimber I-beam-box-column connections subjected to static loads. Comparisons between experimental and calculated results suggest that the design methods could evaluate the shear and moment resistance of beams with good accuracy. [ABSTRACT FROM AUTHOR]

• The bamboo scrimber had higher rolling shear properties than those of SPF. • The most of CLTB specimens had higher bending properties than those of SPF CLT. • The main failure modes of CLTB specimens were different from those of SPF CLT. • There were good agreement of apparent bending stiffness of CLTB in various methods. Using bamboo and timber to manufacture cross-laminated timber-bamboo (CLTB) composites could utilize the advantages of two material to improve the mechanical properties and expand the raw material source of cross-laminated timber (CLT). To explore the feasibility of using engineered bamboo as CLT lamination, the rolling shear properties of two bamboo scrimbers and one bamboo plywood were evaluated. Two types of CLTB specimens, using bamboo scrimber as transverse layer or as both transverse layer and the outermost longitudinal layer, were developed in this study. The bending properties of CLTB and generic Spruce-pine-fir (SPF) CLT specimens were evaluated by dynamic tests and third-point bending tests, respectively. The shear analogy method was employed to calculate the apparent bending stiffness of CLT/CLTB specimen. The results indicated that the rolling shear modulus and strength of bamboo scrimber (group RB(F)-4.5) were 92.81% and 98.64% higher than those of bamboo plywood, respectively, and were 330.19% and 121.13% higher than those of SPF dimension lumber, respectively. The CLTB specimens, group BWBWB, had 23.69% and 60.50% higher apparent bending modulus and peak load than those of generic SPF CLT specimens. Most of the CLTB bending specimens had main failure mode of tensile failure in the bottom layer which replaced rolling shear failure in transverse bamboo scrimber layer. The apparent bending stiffness values of CLT/CLTB specimens obtained from dynamic test and shear analogy method were in good agreement with the static experimental values. The results presented in this paper can provide fundamental basis for supporting the potential engineering application of CLT panel products fabricated with bamboo scrimber. [ABSTRACT FROM AUTHOR]

Bamboo fiber composite (BFC) is a unidirectional and continuous bamboo fiber composite manufactured by consolidation and gluing of flattened, partially separated bamboo culm strips into thick and dense panels. The composite mechanical properties are primarily influenced by panel density, its variation and uniformity. This paper characterized the horizontal density distribution (HDD) within BFC panels and its controlling factors. It revealed that HDD follows a normal distribution, with its standard deviation (SD) strongly affected by sampling specimen size, panel thickness and panel locations. SD was lowest in the thickest (40 mm) panel and largest-size (150 × 150-mm2) specimens. There was also a systematic variation along the length of the BFC due to the tapering effect of bamboo culm thickness. Density was higher along panel edges due to restraint from the mold edges during hot pressing. The manual BFC mat forming process is presented and found to effectively minimize the density variation compared to machine-formed wood composites. This study provides a basic understanding of and a quality control guide to the formation uniformity of BFC products. [ABSTRACT FROM AUTHOR]

Bamboo scrimber is a new type of bamboo-based panel that is prone to be affected by biological and service environments under outdoor conditions. In this paper, the physical and mechanical performance and the microchemical and surface properties of untreated and hot-oil-treated bamboo scrimber were analyzed to illustrate the processing mechanism of scrimber. Methyl silicone oil treatment was carried out at 120, 140, and 160 °C for 2, 4, and 6 h. The density, mechanical properties, air-dried moisture content, surface morphology, chemical structure, swelling properties, color, and contact angle of the bamboo scrimber were analyzed to evaluate the treatment effectiveness. Observation of the environmental-scanning electron microscope indicated that the glue layer of the bamboo scrimber was not significantly damaged after hot oil treatment. At low temperatures, the mechanical properties did not change significantly. Infrared-spectrum analysis showed a significant decrease in mechanical properties at higher temperatures and longer treatment time for the degradation of hemicellulose. The contact angle test and swelling properties test showed that the hot oil treatment improved the dimensional stability and reduced the wettability on the surface of the bamboo scrimber. The above analysis results show that the treatment at 140 °C for 2 h is most effective. [ABSTRACT FROM AUTHOR]

• A-state-of-art review was conducted on novel engineered wood and bamboo composites. • Attentions were paid to their manufacturing technologies, modeling approaches, and mechanical properties. • Mechanical properties of the engineered wood and those of the engineered bamboo were compared. • Several structural application cases of these engineered wood/bamboo composites were illustrated. Both wood and bamboo are renewable anisotropic materials with a long application history in human society. Engineered wood or bamboo aiming to mitigate the variability of the natural material can provide better material properties and structural performance, compared to original sawn lumber or raw bamboo. In this paper, a state-of-the-art review was conducted on three types of novel engineered wood composites, namely fiber reinforced polymer (FRP) reinforced glulam, cross-laminated timber (CLT), and wood scrimber, as well as three types of novel engineered bamboo composites, namely laminated bamboo lumber (LBL), glued-laminated bamboo (glubam), and bamboo scrimber, with particular attentions to their manufacturing technologies, modeling approaches, and mechanical properties. Then, for these novel engineered wood/bamboo composites, a comprehensive comparison was conducted on their mechanical properties and on their densities. Finally, several cases of structural applications were respectively illustrated, in which these aforementioned engineered wood/bamboo composites were adopted as main building materials. Potentials of applying these engineered wood/bamboo composites for structures were confirmed, and their possible existing drawbacks were also discussed. [ABSTRACT FROM AUTHOR]