Search Results (168)

Robotic timber joinery demands integrated, adaptive methods to compensate for the inherent dimensional variability of wood. We introduce a seamless robotic workflow to enhance the measurement accuracy of the Workpiece Coordinate System (WCS). The approach leverages a Zivid 3D camera mounted in an eye-in-hand configuration on a KUKA industrial robot. The proposed algorithm applies a geometric method that strategically crops the point cloud and fits planes to the workpiece surfaces to define a reference frame, calculate the corresponding transformation between coordinate systems, and measure the cross-section of the workpiece. This enables reliable toolpath generation by dynamically updating WCS and effectively accommodating real-world geometric deviations in timber components. The workflow includes camera-to-robot calibration, point cloud acquisition, robust detection of workpiece features, and precise alignment of the WCS. Experimental validation confirms that the proposed method is efficient and improves milling accuracy. By dynamically identifying the workpiece geometry, the system successfully addresses challenges posed by irregular timber shapes, resulting in higher accuracy for timber joints. This method contributes to advanced manufacturing strategies in robotic timber construction and supports the processing of diverse workpiece geometries, with potential applications in civil engineering for building construction through the precise fabrication of structural timber components. Full article

This paper presents an analysis of the ultimate strength of wooden joints of the structures of ancient wooden ships. The aim is to contribute to the discussion about how joining technology and types of joints contributed to the transition from ‘shell-first’ to ‘frame-first’ construction, of which the latter is still traditional Mediterranean wooden shipbuilding technology. Historically, ship construction has consisted of two main structural types of elements: planking and stiffening. Therefore, two characteristic carvel planking joints and two longitudinal keel joints were selected for analysis. For planking, the joint details of the ship Uluburun (14th c. BC) and the ship Kyrenia (4th c. BC) were chosen, while two different types of scarf joints belonging to the ship Jules-Verne 9 (6th c. BC) and the ship Toulon 2 (1st c. AD) were selected. The capacity, i.e., the ultimate strength of the joint, is compared to the strength of the structure as if there was no joint. The analysis simulates the independent joint loading of each of the six numerical models in bending, tension, and compression until collapse. The results are presented as load-end-shortening curves, and the calculation was performed as a nonlinear FE analysis on solid elements using the LSDYNA explicit solver. Since wood is an anisotropic material, a large number of parameters are needed to describe the wood’s behaviour as realistically as possible. To determine all the necessary mechanical properties of two types of wood structural material, pine and oak, a physical experiment was used where results were compared with numerical calculations. This way, the material models were calibrated and used on the presented joints’ ultimate strength analysis. Full article

We designed detachable steel sleeves to reinforce wooden joints and improve their integrity under earthquake action and investigated their mechanical properties. Monotonic bending tests were performed on a half-tenon pure wooden joint and a joint strengthened by a detachable steel sleeve. More obvious tenon pulling-out failure was observed in the pure wood joint; in comparison, only slight extrusion fracture of wooden beams and extrusion deformation of steel sleeves occurred in the wood joint reinforced by a detachable steel sleeve. Our test results showed that the initial rotational stiffness of the strengthened joint, JG1, was increased by 495.4% compared with that of the unstrengthened joint, JG0. The yield bending moment increased by 425.9%, and the ultimate bending moment increased by 627.5%, which indicated that the mechanical performance was significantly improved when the joint was reinforced by a detachable steel sleeve. Numerical simulations of different components were performed with finite element analysis software to analyze the mechanical performance of the reinforced joint. It was found that the stiffness and ultimate flexural performance of the joint could be increased by setting stiffeners on the steel sleeve and connecting the wooden column with self-tapping screws. The results of the tests were compared with those obtained through finite element analysis, and a high degree of accuracy was achieved, which could provide a theoretical basis for the reinforcement of timber structural buildings. Full article

The corrosion-induced strength degradation of steel nails poses a critical challenge to the structural integrity of timber connection joints, particularly in hygrothermal environments. Compressed wood nails exhibit hygroscopic expansion characteristics, demonstrating their potential as a sustainable alternative to steel nails in structural connections. However, systematic investigations on their shear performance under cyclic hygrothermal conditions remain limited. This study comparatively analyzed the shear behavior evolution of compressed wood nail and galvanized steel nail connections under wet-dry cycles. Distinct failure mechanisms were observed: wood nail connections exhibited characteristic brittle fracture patterns, whereas steel nail connections demonstrated ductile failure through pull-out deformation with nail bending. Notably, compressed wood nails displayed superior environmental stability, with significantly lower degradation rates in terms of load-bearing capacity (2.8% vs. 22.3%) and stiffness (16.3% vs. 38.0%) than their steel counterparts under identical hygrothermal exposure. These findings provide critical design references and data support for implementing wood-based fasteners in moisture-prone engineering applications. Full article

Dou-Gong brackets, the distinctive structural element in ancient Chinese architecture, fulfill critical roles in load transfer, span reduction, and decoration, making its preservation vital for safeguarding wooden heritage buildings. This study investigates the combustion performance and residual load-bearing capacity of key Dou-Gong bracket components—Zuo-dou, Zheng-xin-gua-gong, and Qiao—exposed to varying fire conditions. The results reveal that an increasing fire load elevates heating rates and peak temperatures of wood substrates, resulting in a significant degradation of structural integrity. At a fire load of 55 kW, the peak temperatures at the bottom, joint edge, and top of the Dou-Gong brackets reach 755.3 °C, 489.9 °C, and 620.7 °C, respectively, representing increases of 2%, 65%, and 38%, respectively, compared to those observed at a fire load of 20 kW. Moreover, the charring rate of Dou-Gong bracket increases from 0.22–0.26 mm/min at a fire load of 20 kW to 0.50–0.56 mm/min at a fire load of 55 kW, accompanied by an increase in mass loss rate from 28.5% to 36.9%. These findings highlight the significant impact of fire conditions on the fire characteristic and structural integrity of Dou-Gong brackets, providing the first quantitative evidence of their degradation under fire exposure. By addressing this vulnerability, the study contributes to the scientific preservation of ancient wooden architecture under contemporary fire risk scenarios. Full article

The worldwide energy crisis is causing people in most countries to reduce their energy use to prevent the next generation from being unable to fulfill their needs. The Osing people use sustainability values based on traditions passed down from generation to generation with appropriate technology to fit the needs of the people and their environment. This research employs a qualitative descriptive method with a literature review and data collection. Based on the framework used by Iwanmura, Osing house construction primarily focuses on the principles of low impact and health and amenity. This study reveals that the architectural design and construction process of an energy-efficient traditional building can be adapted to contemporary sustainable housing. The primary aim was to identify and analyze sustainability values in the construction process and techniques of traditional Osing houses in Kemiren Village, Banyuwangi, which can serve as a reference for modern sustainable architecture practices. The study reveals the uniqueness of traditional Osing construction using the local material Bendo wood, which can be dismantled from the foundation up to the roof joint systems, thus allowing the materials to be repaired and recycled down to the smallest parts and minimizing construction waste. The advantage of this building construction process is the use of traditional housing techniques to minimize the need for mechanical systems. This traditional construction method, using wood as the building material and considering climatic features, demonstrates how to achieve sustainable building values throughout all elements of a building that provides users with comfort and safety. Full article

Two types of reinforcing the half-tenon wood joints, one reinforced with an energy dissipation plate (SW-1) and the other by a steel sleeve with energy dissipation plate (SW-2), were designed. The pure wood beam–column joint specimen SW-0, specimen SW-1 and specimen SW-2 were experimented by the monotonic loading test, and the corresponding failure mode of joints and load–displacement curve were obtained. Based on the reliability of the verified finite element numerical model, the impact of thickness of the energy dissipation plate on the seismic performance of the SW-2 joint was analyzed. The research results show that the SW-0 and SW-1 joints exhibited significant tenon pulling phenomena, while the SW-2 joint did not show this phenomenon. The initial stiffness of the joints is significantly improved after reinforcement, and the initial stiffness of the SW-1 and SW-2 specimens is 2.64 and 7.24 times that of the SW-0 specimen, respectively. The ultimate loads of specimens SW-0, SW-1 and SW-2 are, respectively, 2.8 kN, 6.2 kN and 24.9 kN. The enclosed area of hysteresis loop and the slope of skeleton curve gradually increase as the thickness of the energy dissipation plate increases, resulting in a significant enhancement in energy dissipation capacity. The ultimate bearing capacity of the joint and the slope of skeleton curve exhibit negligible variation when the thickness of energy dissipation plate exceeds 2.0 mm, and the corresponding optimal thickness is obtained as 2 mm. Full article

Connection systems are a critical component of buildings constructed with engineered wood products (EWPs), influencing structural integrity, durability, and construction efficiency. This systematic review categorises connection types into mechanical, adhesive, and interlocking systems and evaluates their structural performance, adaptability in prefabrication, applicable design standards, and modelling approaches. The review synthesises recent trends in EWP connection research, highlighting key developments in digital fabrication, reversible joints, and sustainable construction. Findings emphasise the need for standardisation, performance validation, and hybrid systems to support the wider adoption of prefabricated timber structures in environmentally responsible building practices. Full article

The use of innovative insulating materials can contribute to an energy-efficient design by improving the thermal performance of building envelopes while also reducing the embodied energy of materials. Ultra-low carbon steel envelope solutions with bio-based insulations are aligned with this approach. However, fire safety aspects in general and smoldering issues in particular need to be considered when using bio-based insulations. Accordingly, this paper proposes a system-level assessment of the fire performance of steel envelopes with bio-based insulations, not only identifying potential smoldering issues of the core material but also defining and evaluating strategies that could address these concerns within the system design. For this purpose, the variables that could affect the fire performance of wood fiber insulation sandwich panels were identified while considering the different stages of the smoldering phenomena, such as the influence of the joint design or mounting provisions for the initiation, the existence of air cavities, oxygen entrances or physically continuous materials with a tendency to smolder for the continuation, or the inclusion of limiting elements or mitigation layers for spread limitation. Finally, strategies for fire-safe enclosures using bio-based insulations are proposed, assuming smoldering affections in wood-derived materials and analyzing possible mitigation elements at the system level. Full article

As part of the transition to low-carbon energy and for the sustainable utilisation of resources, it is necessary to seek a replacement for solid fossil fuels, but unfortunately, it is impossible to completely abandon them for various reasons at the moment, so only partial replacement with new, high-calorific, biomass-based fuels is possible. The purpose of this work is to determine the typical parameters of the co-combustion of carbonisate, coal and their mixtures, taking into account the synergetic effects influencing the combustion intensity of the mixture. Carbonisate was obtained in the process of the gasification of pinewood through the counter-blowing method at a temperature of 800–900 °C, while air was used as an oxidant. Basically, this method of gasification is used for coal in order to obtain high-calorific coke for the metallurgical industry. Also, in this study, for the first time, carbonisate was obtained from 50% pinewood and 50% lignite. The O/C and H/C ratios were determined for carbonisate. A technical and elemental analysis of the investigated fuels was carried out. A thermal analysis in oxidising medium was applied to determining the typical combustion parameters in the process of slow heating of the fuels under study. According to the results of this thermal analysis, typical heating parameters such as the ignition temperature, burnout temperature, maximum mass loss rate, combustion index, etc., were determined. It was noted that the calorific value of carbonised wood is two times higher than that of coal. The combustion index of carbonisates is 2.5–36% lower compared to that of coal. According to the results of the analysis of the interaction of the components among themselves (in the process of their joint combustion), the presence of synergetic interactions between the components was determined, which affected the change in the combustion intensity and heat release intensity. The results of this study may be useful for retrofitting coal-fired boilers to run on a mixture containing carbonisate and lignite. If carbonisate is produced from biomass, the resulting gas could be used as an energy fuel by burning it in a coal-fired boiler. Full article

The seismic performance assessment of timber structures and topology optimization have been widely researched in recent years. Furthermore, the use of wood as a construction material has increased due to new sustainability challenges. This research assesses the seismic performance of a topologically optimized timber building located in Concepcion, Chile. The structure is a five-story glulam braced frame, designed following current Chilean standards. The structural configuration was obtained through a topology optimization process using a variation of a soft-kill BESO algorithm implemented in MATLAB R2015a, obtaining topologies with low structural redundancy. For the analysis, a full 3D nonlinear model was prepared using OpenSees (Version 3.7.1), and the nonlinear behavior of the structure was only considered at joints using the backbone curves introduced in ASCE 41-13. Six different study cases were analyzed, varying joint strengths and ductility. The fragility curves were determined from a static pushover analysis (SPO) using SPO2FRAG (V1.1), considering the performance levels established in ASCE 41-13. The seismic hazard of the building’s site is estimated through a probabilistic seismic hazard analysis (PSHA), and the seismic performance of each case is determined by computing the probabilities of exceedance of the considered limit states. Analysis results show that wood braced-frame structures with low structural redundancy (and fewer main joints to dissipate energy), such as those obtained from topology optimization algorithms, exhibit a markedly brittle behavior with almost no displacement ductility. This undesirable behavior does not improve by providing more deformation capacity to this structure’s reduced number of main joints. Currently, the Chilean standard for seismic design requires a unique response modification factor R for wood structures. This research suggests that this requirement should be revisited, specifying different R values depending on the wood structure’s redundancy, considering that its displacement ductility comes almost exclusively from the nonlinear deformation capacity of joints. Full article

In modern engineering applications, the use of sustainable materials and eco-friendly methods has become increasingly important. Wood joints, especially those strengthened with bio-adhesive, have attracted considerable attention due to their inherent environmental benefits and desirable mechanical properties. Compared to traditional joining methods, adhesive joints offer unique advantages such as improved load distribution, reduced stress concentration, and enhanced aesthetic appeal. This study aims to enhance delamination resistance in wooden adhesive joints using a novel method involving reinforced high-toughness resin on surfaces. Additionally, a hybrid substrate approach applies a tough layer to outer plies and a densified wood core with greater fiber direction strength. Normal, toughened, and hybrid single-lap joint specimens were analyzed through both experimental and numerical methods under various loading conditions, including quasi-static and intermediate rates. The proposed method involved bio-adhesive penetration into the wood substrate, forming a reinforced surface zone. The experimentally validated results show a significant improvement in joint strength, exhibiting an approximate 2.8-fold increase for the toughened joints compared to the reference joints under intermediate-rate conditions. Furthermore, the absorbed energy of the toughened joints increased by a substantial factor of up to 4.5 times under the same conditions. The fracture surfaces analysis revealed that the toughening method changed the failure mechanism of the joints from delamination to fiber breakage, indicating that the strength of the substrate was lower than that of the joint under impact conditions. The viscoelastic behavior of the bio-adhesive also influenced the response of the joints to the changing displacement rate. The toughening method enhanced the resilience and load-bearing capacity of the wood joints, making them more suitable for dynamic applications. Full article

Chinese forests, particularly the coniferous forest ecosystems represented by pines, play a crucial role in the global carbon cycle, significantly contributing to mitigating climate change, regulating regional climates, and maintaining ecological balance. However, pine wilt disease (PWD), caused by the pine wood nematode (PWN), has become a major threat to forest carbon stocks in China. This study evaluates the impact of PWN invasion on forest carbon stocks in China using multi-source data and an optimized MaxEnt model, and the study analyzes this invasion’s spread trends and potential risk areas. The results show that the high-suitability area for PWN has expanded from 68,000 km² in 2002 to 184,000 km² in 2021, with the spread of PWN accelerating, especially under warm and humid climate conditions and due to human activities. China’s forest carbon stocks increased from 111.34 billion tons of carbon (tC) to 168.05 billion tC, but the carbon risk due to PWN invasion also increased from 87 million tC to 99 million tC, highlighting the ongoing threat to the carbon storage capacity. The study further reveals significant differences in tree species’ sensitivity to PWN, with highly sensitive species such as Masson’s pine and black pine mainly concentrated in the southeastern coastal regions, while less sensitive species such as white pine and larch show stronger resistance in the northern and southwestern areas. This finding highlights the vulnerability of high-sensitivity tree species to PWN, especially in high-risk areas such as Guangdong, Guangxi, and Guizhou, where urgent and effective control measures are needed to reduce carbon stock losses. To address this challenge, the study recommends strengthening monitoring in high-risk areas and proposes specific measures to improve forest management and policy interventions, including promoting cross-regional joint control, enhancing early warning systems, and utilizing biological control measures, while encouraging local governments and communities to actively participate. By strengthening collaboration and implementing control measures, the health and sustainable development of forest ecosystems can be ensured, safeguarding the forests’ important role in climate regulation and carbon sequestration and contributing to global climate change mitigation. Full article

The increasing use of large glass surfaces in modern architecture requires robust adhesive solutions that balance aesthetic appeal with structural resilience, particularly in timber–glass applications. This study examines the influence of primer treatments on the shear performance of timber–glass adhesive joints, employing a combination of experimental testing and simulation techniques. Double-lap shear tests with epoxy adhesives assess the impact of various surface treatments on joint stiffness, shear stress distribution, and deformation. Additionally, a finite element model is developed to simulate joint behavior, evaluate failure modes, and analyze displacement patterns. Results indicate that primer applications notably enhance structural integrity by reducing displacement and increasing joint stability, thereby supporting more durable timber–glass assemblies. These findings offer valuable insights for advancing adhesive technologies in architectural components, enabling a closer alignment between structural performance and design innovation in timber–glass systems. Full article

This study is based on a 10-day survey carried out at seven beaches in March 2023 in El Puerto de Santa María municipality (SW Spain). An amount of 5592 items were collected, with a combined weight of 26 kg. Fresh litter, which refers to litter transported to the shore by marine/coastal processes, accounted for 4634 items weighing 23 kg. The remaining 958 items, weighing 3 kg, were identified as litter deposited by beach visitors. The average total litter recorded during the sampling was 0.40 ± 0.07 items m⁻¹ with a density of 1.85 ± 0.69 g m⁻¹. Litter materials were relatively consistent regardless of whether they were stranded by marine processes or discharged by beachgoers. Plastic dominates fresh and deposited litter followed by metal and glass, with minimal contributions of chemicals, organic matter, clothing, rubber, wood, and paper. They were identified 115 items’ categories from the 184 listed in the EU Joint List: 107 for fresh and 75 for deposited litter. Food consumption-related items made up a significant portion of the total debris followed by personal hygiene and care-related and smoking-related litter. The obtained information is very useful to propose sound management actions that have to be especially devoted to raise beach users’ responsibility. Last, in order to have a year-round view of litter characteristics and behavior, further investigations should be carried out during winter, when the number of visitors is very low and waves’ energy is high, and summer, when opposite conditions are recorded. Full article