Search Results (92)

This study employed multiple machine learning and hyperparameter optimization techniques to analyze and predict the mechanical properties of self-drilling screw connections in thin-walled steel–ply–bamboo shear walls, leveraging the renewable and eco-friendly nature of bamboo to enhance structural sustainability and reduce environmental impact. The dataset, which included 249 sets of measurement data, was derived from 51 disparate connection specimens fabricated with engineered bamboo—a renewable and low-carbon construction material. Utilizing factor analysis, a ranking table recording the comprehensive score of each connection specimen was established to select the optimal connection type. Eight machine learning models were employed to analyze and predict the mechanical performance of these connection specimens. Through comparison, the most efficient model was selected, and five hyperparameter optimization algorithms were implemented to further enhance its prediction accuracy. The analysis results revealed that the Random Forest (RF) model demonstrated superior classification performance, prediction accuracy, and generalization ability, achieving approximately 61% accuracy on the test set (the highest among all models). In hyperparameter optimization, the RF model processed through Bayesian Optimization (BO) further improved its predictive accuracy to about 67%, outperforming both its non-optimized version and models optimized using the other algorithms. Considering the mechanical performance of connections within TWS composite structures, applying the BO algorithm to the RF model significantly improved the predictive accuracy. This approach enables the identification of the most suitable specimen type based on newly provided mechanical performance parameter sets, providing a data-driven pathway for sustainable bamboo–steel composite structure design. Full article

The standardization of physical and mechanical properties is critical for the large-scale application of engineered bamboo products. In this study, the distribution characteristics of density and modulus of elasticity (MOE) were systematically examined in a large sample of flattened bamboo boards. The density and MOE ranged from 0.46 to 1.12 g/cm³ and 5.60 to 22.18 GPa, respectively. Both exhibited a decreasing trend with increasing board thickness. Based on interquartile analysis, four density grades and five MOE grades were established. A strong positive correlation was identified between density and MOE, indicating that density—closely linked to fiber volume fraction—is the primary factor influencing mechanical performance. Notably, the graded bamboo boards demonstrated significantly higher modulus values than conventional wood veneers such as hemlock and poplar, highlighting their potential for high-performance structural applications. This study proposes a practical grading framework that contributes to the standardization and broader engineering utilization of flattened bamboo boards. Full article

Pile–raft foundations are widely used in soft soil engineering due to their good integrity and high stiffness. However, traditional design methods independently design pile–raft foundations and superstructures, ignoring their interaction. This leads to significant deviations from actual conditions when the superstructure height increases, resulting in excessive costs and adverse effects on building stability. This study experimentally investigates the interaction characteristics of pile–raft foundations and superstructures in soft soil under different working conditions using a 1:10 geometric similarity model. The superstructure is a cast-in-place frame structure (beams, columns, and slabs) with bamboo skeletons with the same cross-sectional area as the piles and rafts, cast with concrete. The piles in the foundation use rectangular bamboo strips (side length ~0.2 cm) instead of steel bars, with M1.5 mortar replacing C30 concrete. The raft is also made of similar materials. The results show that the soil settlement significantly increases under the combined action of the pile–raft and superstructure with increasing load. The superstructure stiffness constrains foundation deformation, enhances bearing capacity, and controls differential settlement. The pile top reaction force exhibits a logarithmic relationship with the number of floors, coordinating the pile bearing performance. Designers should consider the superstructure’s constraint of the foundation deformation and strengthen the flexural capacity of inner pile tops and bottom columns for safety and economy. Full article

Engineered bamboo has been considered a viable replacement for traditional wood and steel for structural and architectural purposes due to its renewable nature, high strength, and compatibility with different processing techniques. This systematic review analyzed the literature on the mechanical properties and processing techniques of engineered bamboo products, which include bamboo scrimber and laminated bamboo. The literature included in this systematic review was extracted from the Engineering Village platform. The studies retrieved from this platform were filtered to only have been published in top journals (Q1/Q2) related to engineering materials, materials science, and the construction industry. Using this methodology, from the initial 191 identified records, 51 studies that were the most relevant were chosen. The review revealed that bamboo scrimber has better performance for specific mechanical properties, which include its compressive, tensile, and bending strength. Laminated products had higher variability, which was often caused by the type of adhesive, orientation, and quality of adhesion. This study also identified the details of manufacturing processes, such as the adhesive systems, pre-treatment methods, and pressing conditions used. Moreover, the literature exhibited considerable inconsistencies in testing standards, reporting practices, and long-term durability evaluations. This review highlights these challenges and provides recommendations for future research to resolve these issues. Full article

Engineered laminated bamboo frame structures have seen notable advancements in China, driven by their potential in sustainable construction. However, accurately predicting their seismic performance remains a pivotal challenge. Structural and non-structural damage caused by earthquakes can severely compromise building operability, lead to substantial economic losses, and disrupt safe evacuation processes, collectively exacerbating disaster impacts. To address this, three laminated bamboo frame models (3-, 4-, and 5-story) were developed, integrating energy-dissipating T-shaped steel plate beam–column connections. Two engineering demand parameters—peak inter-story drift ratio (PIDR) and peak floor acceleration (PFA)—were selected to quantify seismic responses under near-field and far-field ground motions. The study systematically evaluates suitable intensity measures for these parameters, emphasizing efficiency and sufficiency criteria. Regarding efficiency, the applicable intensity measures for PFA differ from those for PIDR. The measures for PFA tend to focus more on acceleration amplitude-related measures such as peak ground accelerations (PGA), sustained maximum acceleration (SMA), effective design acceleration (EDA), and A₉₅ (the acceleration at 95% Arias intensity), while the measures for PIDR are primarily based on spectral acceleration-related measures such as S_a(T₁) (spectral acceleration at fundamental period), etc. Concerning sufficiency, significant differences exist in the applicable measures for PFA and PIDR, and they are greatly influenced by ground motion characteristics. Full article

Bamboo, as a sustainable and renewable biomass resource, possesses significant application prospects along with underutilized potential. However, challenges such as mildew infestation, insect damage, and discoloration during processing and utilization negatively impact its service life and economic value. This study proposes a simplified hydrogen peroxide bleaching method for bamboo processing, resulting in bleached materials with uniform coloration and improved mildew resistance. The scanning electron microscopy (SEM) analysis of bleached bamboo showed significantly reduced starch and protein inclusions, expanded intercellular spacing, partial fiber detachment, and localized structural deformation in treated bamboo. The X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analyses revealed substantial lignin degradation in hydrogen peroxide-treated samples. The color difference (ΔE) was measured at 13.65 between treated and untreated samples, confirming effective bleaching efficacy. The mercury intrusion porosimetry (MIP) analysis revealed enhanced porosity accompanied by diameter enlargement in treated bamboo. Antifungal assessments indicated that hydrogen peroxide bleaching delayed the onset of mold colonization and significantly enhanced the mildew resistance of bamboo substrates. Full article

Bamboo scrimber (BS) has been emerging as a promising construction material prepared from natural bamboo due to its high mechanical strength. However, the variability of the properties of bamboo scrimber is large, which limits the reliability assessment of bamboo scrimber in engineering applications. In this study, the variability of mechanical properties and dimensional stability of bamboo scrimber prepared by units pretreated at different temperatures (denoted as BS-150 and BS-200 for 150 °C and 200 °C, respectively) were compared and probabilistically analyzed using normal, lognormal, and Weibull distribution models. The results showed that BS-200 had a significantly lower thickness swelling rate (TSR), modulus of rupture (MOR) and shear strength (SS), with the modulus of elasticity (MOE) remaining essentially unchanged compared to BS-150. Probabilistic analysis revealed that the MOR, MOE, and TSR of BS-150 followed a lognormally distribution, and the shear strength was normally distributed. In contrast, the MOR, MOE, SS, and TSR of BS-200 all exhibited lognormal distributions. Meanwhile, the variability in TSR and SS for BS-200 was significantly reduced. The results provide a data base for the engineering application of bamboo scrimber and a new research idea for the evaluation of properties of forest biomass-based materials based on probabilistic analysis. Full article

Hydrogen energy as a sustainable alternative to fossil fuels necessitates the development of cost-effective and efficient electrocatalysts for the hydrogen evolution reaction (HER). While transition metal sulfides have shown promise, their practical application is hindered by insufficient active sites, poor conductivity, and suboptimal hydrogen adsorption kinetics. Herein, we present a heterointerface engineering strategy to construct Co₉S₈/FeCoS₂ heterojunctions anchored on bamboo fiber-derived nitrogen-doped porous carbon (Co₉S₈/FeCoS₂/BFPC) through hydrothermal synthesis and subsequent carbonization. BFPC carbon quasi-aerogel support not only offers a high surface area and conductive pathways but also enables uniform dispersion of active sites through nitrogen doping, which simultaneously optimizes electron transfer and mass transport. Experimental results demonstrate exceptional HER performance in alkaline media, achieving a low overpotential of 86.6 mV at 10 mA cm⁻², a Tafel slope of 68.87 mV dec⁻¹, and remarkable stability over 73 h of continuous operation. This work highlights the dual advantages of heterointerface design and carbon substrate functionalization, providing a scalable template for developing noble metal-free electrocatalysts for energy conversion technologies. Full article

Surface mining activities cause severe disruption to ecosystems, resulting in the substantial destruction of surface vegetation, the loss of soil organic carbon stocks, and a decrease in the ecosystem’s ability to sequester carbon. The ecological restoration of mining areas has been found to significantly enhance the carbon storage capacity of ecosystems. This study evaluated ecological restoration strategies in Chongqing’s Tongluo Mountain mining area by integrating GF-6 satellite multispectral data (2 m panchromatic/8 m multispectral resolution) with ground surveys across 45 quadrats to develop a quadratic regression model based on vegetation indices and the field-measured biomass. The methodology quantified carbon storage variations among engineered restoration (ER), natural recovery (NR), and unmanaged sites (CWR) while identifying optimal vegetation configurations for karst ecosystems. The methodology combined the high-spatial-resolution satellite imagery for large-scale vegetation mapping with field-measured biomass calibration to enhance the quantitative accuracy, enabling an efficient carbon storage assessment across heterogeneous landscapes. This hybrid approach overcame the limitations of traditional plot-based methods by providing spatially explicit, cost-effective monitoring solutions for mining ecosystems. The results demonstrate that engineered restoration significantly enhances carbon sequestration, with the aboveground vegetation biomass reaching 5.07 ± 1.05 tC/ha, a value 21% higher than in natural recovery areas (4.18 ± 0.23 tC/ha) and 189% greater than at unmanaged sites (1.75 ± 1.03 tC/ha). In areas subjected to engineered restoration, both the vegetation and soil carbon storage showed an upward trend, with soil carbon sequestration being the primary form, contributing to 81% of the total carbon storage, and with engineered restoration areas exceeding natural recovery and unmanaged zones by 17.6% and 106%, respectively, in terms of their soil carbon density (40.41 ± 9.99 tC/ha). Significant variations in the carbon sequestration capacity were observed across vegetation types. Bamboo forests exhibited the highest carbon density (25.8 tC/ha), followed by tree forests (2.54 ± 0.53 tC/ha), while grasslands showed the lowest values (0.88 ± 0.52 tC/ha). For future restoration initiatives, it is advisable to select suitable vegetation types based on the local dominant species for a comprehensive approach. Full article

Bamboo is a green, renewable material with high strength and low cost, but raw bamboo has limited application in residential buildings due to its irregular shape and dry cracking. In this regard, this work proposed a novel ecological sandwich panel to explore the potential combination of engineered bamboo and raw bamboo culms. Face sheets made of glued laminated bamboo panels were bonded to the bamboo culm core via epoxy resin and mortise–tenon joints. Two groups of specimens with height-to-thickness ratios of 4.63 and 5.37 were tested through edgewise compression to investigate the failure modes, strength and rigidity. The results revealed that the specimens had no overall stability problem under axial loading, but exhibited delamination and local bulging to the face sheets. When the height-to-thickness ratio increased from 4.63 to 5.37, but still belonged to the short member range, the area of the adhesive interface increased by 16.13%, and the edgewise compressive strength and rigidity increased by 17.57% and 35.04%, respectively. This indicated that the capacity and rigidity were mainly determined by the connection strength, which was obviously affected by the manufacturing and assembly errors. Accordingly, increasing the connection strength could be helpful for improving the load-carrying capacity and ductility of such panels. Full article

Bamboo’s perceived potential in livelihood development has led to development interventions that aim to strengthen the bamboo industry via activities such as training participants in bamboo management, strengthening institutions, and raising awareness. Using the Campaign for Environmental Evidence’s guidelines, we systematically map the available evidence of the impact of these interventions. The evidence is scattered across peer-reviewed and grey literature, with no universal reporting standards. Search sources for this systematic evidence map include a bibliographic database, CABdirect (now known as CABI Digital Library); a search platform for peer-reviewed literature, the Web of Science Core Collection; a bibliographic database for academic literature on agriculture and related fields, SEARCH by the USDA National Agricultural Library; a public search engine for scholarly literature, Google Scholar; a general search engine, Google; and the websites of 37 organizations, with both proprietary search engines and Google used to search for pdf files. Overall, 36 documents are included in the final review, describing 28 unique interventions from 13 countries. Most evidence is found outside the peer-reviewed literature. Outcomes including income changes, increased participation and engagement, and policy changes are reported, with economic impacts dominating the evidence base. Very little evidence of negative outcomes is found, likely constrained by reporting bias. Reporting on evidence of these interventions is limited, with many interventions being excluded from the database due to a lack of identifiable evidence of outcomes or impact. Full article

To reduce the cast in place work of concrete and realize the industrial production of a bamboo–concrete composite (BCC), innovative connection systems composed of an assembled bamboo–lightweight concrete composite (ABLCC) structure featuring perforated steel plate connectors are presented for use in engineering structures. This study examined the shear performance of connection systems composed of an assembled BCC structure featuring perforated steel plate connectors based on the design and fabrication of three groups of shear connectors with nine different parameters using bamboo scrimber, lightweight concrete, perforated steel plates, and grout. Push-out tests were conducted on these shear connectors. A linear variable differential transformer (LVDT) and digital image correlation (DIC) were utilized for measurements. The test parameters comprised fabrication techniques (assembled and cast-in-place/CIP) and connector size (steel plate thickness). This study investigated mechanical performance indicators, including the failure mode, load–slip relationship, shear stiffness, and shear capacity of the shear connectors. The experimental results showed that the shear connector failure modes involved concrete spalling near the connectors and deformation of the perforated steel plates. The load–slip curves generally included three stages: high slope linear increase, low slope nonlinear increase, and rapid decrease. The shear capacity and stiffness of the assembled shear connectors were 0.84 times and 2.46 times those of the CIP connectors, respectively. The stiffness of the 4 mm steel plate connectors increased by 42% compared to the 2 mm steel plate connectors. Analysis showed that the shear capacity of the BBC primarily consisted of four aspects: the end bearing force of the steel plate, contact friction, and forces due to the influence of tenon columns and the reinforcing impact of through-rebars. This study proposes a simple and suitable formula for obtaining the shear capacity of perforated steel plate connectors in the BCC structure, with the analytical values being in good agreement with the test results. Full article

The challenges highlighted at the 29th Conference of the Parties (COP29) emphasize the importance of using renewable resources in the architecture, engineering, and construction (AEC) industry. The building and construction sector is a major contributor to environmental pollution, with most emissions stemming from the extraction, transportation, production, and disposal of construction materials. As a result, developing renewable building materials is essential. In the past decade, bamboo has gained significant attention from researchers due to its strength, sustainability, high yield, and rapid growth. Bamboo in its original form has been used in construction for centuries, and recent innovations have led to the creation of engineered bamboo materials designed for more versatile applications. Researchers have been focused on understanding the physical and mechanical properties of engineered bamboo to assess its potential as a sustainable alternative to traditional building materials. However, modern practitioners are still unfamiliar with engineered bamboo materials, their types, and where they can be used. This article highlights the most widely researched engineered bamboo materials that have been used in the construction of small architectural forms and bigger structures. It provides an overview of common engineered bamboo building materials, namely laminated bamboo lumber, laminated bamboo sheets, parallel strand bamboo, bamboo mat boards, and bamboo particleboards, and their manufacturing processes and applications, offering valuable information for current practitioners and future research. Full article

A double-layer core–shell photocatalytic coating was engineered on carbon fibers (CFb) derived from bamboo pulp precursors, employing a sequential process involving seed pre-loading, solvothermal treatment, and impregnation. XRD, SEM, and SEM-EDS analyses revealed that g-C₃N₄ and Bi₂O₃ nanosheets were co-assembled on the carbon fiber skeleton, and 50 nm MoS₂ particles were successfully loaded, resulting in the fabrication of MoS₂/g-C₃N₄/Bi₂O₃/CFb photocatalytic fibers. UV–vis spectroscopy, transient photocurrent response, and EIS tests demonstrated that the introduction of narrow-bandgap visible-light photocatalysts (g-C₃N₄ and MoS₂) enhanced light absorption and improved the separation and migration efficiency of photogenerated electron hole pairs. Photocatalytic degradation experiments of MB showed that MoS₂/g-C₃N₄/Bi₂O₃/CFb significantly outperformed g-C₃N₄/Bi₂O₃/CFb and Bi₂O₃/CFb, achieving a degradation efficiency of 92% within 60 min. Band structure calculations and analysis confirmed the formation of Z-scheme heterojunctions between g-C₃N₄ and Bi₂O₃, as well as between MoS₂ and Bi₂O₃. This dual Z-scheme heterojunction endowed MoS₂/g-C₃N₄/Bi₂O₃/CFb with enhanced redox capabilities, providing a novel strategy for developing efficient photocatalytic materials. Full article

The synergistic application of ultra-high-performance concrete (UHPC) and bamboo scrimber provides innovative solutions for sustainable structural engineering. In this study, the structural response mechanism of the combined beams under the steel plate–screw composite connection system was systematically investigated by designing three shear connection gradient specimens (TS200/300/400) to address the key scientific issues of the mechanical behavior of the bamboo–UHPC interface. Based on the unidirectional compression tests of bamboo–UHPC composite shear connections and four-point bending tests of composite beams, the damage modes, load-mid-span deflection relationship, bending stiffness, bamboo–UHPC slip and normal lift were evaluated for all the composite beams with the shear connection gradient as a parameter. The results showed that the flexural performance of the composite beams went through three stages: elastic behavior, damage development and final damage. The interfacial slip and interfacial lift-off have more obvious asymmetric spatial distribution characteristics, and increasing the shear joint degree can delay the separation between the UHPC and the bamboo layer, thus enhancing the structural integrity. Typical features of the final damage are the bending damage of ultra-high-performance concrete and bamboo fiber damage. This study highlights the potential of UHPC–bamboo composite beams for sustainable construction and emphasizes the importance of optimizing shear connection for improved performance. Full article