Search Results (341)

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 study investigates the potential of Eucalyptus benthamii wood from planted forests in southern Brazil for the production of cross-laminated timber (CLT) panels. The performance of E. benthamii CLT panels is compared to that of Pinus spp. panels and European commercial panels (KLH^®), using the finite element method applied to a two-story building model. Class 2 of the Brazilian standard ABNT NBR 7190-2 was adopted as the reference for the physical and mechanical properties of Pinus spp., while the European commercial specifications from KLH^® were used to represent European reference panels. The results indicate that E. benthamii wood exhibits superior mechanical properties, enabling reductions of 12.5% to 27.3% in panel thickness and a 20.7% decrease in wood volume when compared to Pinus spp., without compromising structural safety. Relative to the KLH^® and ETA 06/0138 standards, E. benthamii wood demonstrates higher stiffness (modulus of elasticity of 15,325 MPa vs. 12,000 MPa) and greater flexural strength (109.11 MPa vs. 24 MPa), allowing for the use of thinner panels. Stress and displacement analyses confirm that E. benthamii CLT slabs can withstand critical loads (wind and vertical) within normative limits, with maximum displacements of 18.5 mm. The reduction in material volume (22.8 m³ versus 28.7 m³ for Pinus spp.) suggests potential benefits in terms of environmental impact and logistical efficiency. It can be concluded that E. benthamii represents a sustainable and efficient alternative for CLT panels, combining high structural performance with resource optimization and contributing to the decarbonization of the construction industry. Full article

Cross-laminated timber (CLT) is a high-performance engineered timber that is very widely adopted. In several conditions, such as strength improvement at vulnerable connection points, local stress concentrations, existing structure retrofitting, and others, it is desirable to enhance the mechanical performance of CLT by applying additional reinforcement systems. This paper reports on an experimental campaign aimed at assessing the mechanical behavior of CLT panels reinforced with steel-reinforced polymers (SRPs). Twenty Sardinian Maritime Pine CLT panels, including unreinforced, SRP single- and double-layer reinforced panels, have been subjected to bending tests to determine the bending strength, stiffness, failure mechanism and enhancement of the reinforced panels compared to the unreinforced ones. In addition, an analytical model has been proposed to understand the mechanical behavior of SRP-reinforced CLT panels. The results show that SRP reinforcement significantly increases the strength and stiffness and influences the failure mechanism of CLT panels. The strength improvement induced by the reinforcement, however, is not proportional to its amount, since the increase due to the SRP double layer is only slightly higher than that due to the SRP single layer. The stiffness enhancement is less relevant, as expected. Attention has been paid to the possible shear failures of reinforced panels. Full article

Guomari fortress in eastern Qinghai Province exemplifies vernacular architecture shaped by multiethnic interaction, environmental adaptation, and localized defense strategies. Originally a Ming Dynasty military-agricultural outpost, it evolved into a Tu ethnic settlement. Fieldwork, including architectural surveys and spatial analysis, identified a three-tiered defensive system: (1) strategic use of terrain and rammed-earth walls; (2) labyrinthine alleys with L-, T-, and cross-shaped intersections; and (3) interconnected rooftops forming elevated circulation routes. Courtyards are categorized into single-line, L-shaped, U-shaped, and fully enclosed layouts, reflecting adaptations to terrain, ritual functions, and thermal needs. Architectural features such as thick loam-coated walls and flat roofs demonstrate climatic adaptation, while the integration of Han timber frameworks, Tibetan prayer halls, and Tu decorative elements reveals cultural convergence. Traditional craftsmanship, including carved wooden scripture blocks and tsampa-based murals, is embedded within domestic and ritual spaces. The fortress’s circulation patterns mirror Tibetan Buddhist cosmology, with mandala-like alleys and rooftop circumambulation routes. These findings offer insights into vernacular resilience and inform conservation strategies for multiethnic fortified settlements. Full article

In Germany, Pinus sylvestris is a dominant tree species, and many trees with large diameters are not utilised due to difficulties with processing. However, older pines have larger volumes of sapwood, and boards with a high sapwood content can be produced. The durability of boards from large-diameter (>50 cm) P. sylvestris trees, treated with furfurylation, acetylation, DMDHEU (1.3-dimethylol-4.5-dihydroxyethyleneurea), and SorCA (Sorbitol/Citric Acid), was assessed. The samples were taken from different sections along the longitudinal axis and the cross-section. The durability was tested against Coniophora puteana, Rhodonia placenta, and Trametes versicolor, according to the EN 113-2 standard. All treatments had a median mass loss < 5%, so classed as “highly durable” (Durability Class 1) against all fungi. DMDHEU had a large deviation in mass loss against Coniophora puteana and could potentially be classified as “moderately durable” (Durability Class 3), if based on the mean mass loss. The inner part of the end section had a higher mass loss, indicating that there was poorer retention of the treatment at this location. Overall, chemical modifications on large-diameter pine trees were effective at increasing durability. Utilising large-diameter pine trees can help to make use of regional resources and potentially reduce reliance on imported timber. With favourable mechanical properties and easy-to-treat sapwood, large-diameter P. sylvestris trees could be used for commercial treatments. Full article

The building sector significantly contributes to global energy consumption and carbon emissions, primarily due to the extensive use of carbon-intensive materials such as concrete and steel. Mass timber construction, particularly using cross-laminated timber (CLT), offers a promising low-carbon alternative. This study aims to calculate the embodied carbon emissions and biogenic carbon storage of a CLT-based affordable housing project, 340+ Dixwell in New Haven, Connecticut. This project was designed using a honeycomb structural system, where mass timber floors and roofs are supported by mass timber-bearing walls. The authors are not aware of a prior study that has evaluated the life cycle impacts of honeycomb mass timber construction while considering Timber Use Intensity (TUI). Unlike traditional post-and-beam systems, the honeycomb design uses nearly twice the amount of timber, resulting in higher carbon sequestration. This makes the study significant from a sustainability perspective. This study follows International Standard Organization (ISO) standards 14044, 21930, and 21931 and reports the results for both lifecycle stages A1–A3 and A1–A5. The analysis covers key building components, including the substructure, superstructure, and enclosure, with timber, concrete, metals, glass, and insulation as the materials assessed. Material quantities were extracted using Autodesk Revit^®, and the life cycle assessment (LCA) was evaluated using One Click LCA (2015)^®. The A1 to A3 stage results of this honeycomb building revealed that, compared to conventional mass timber housing structures such as Adohi Hall and Heartwood, it demonstrates the lowest embodiedf carbon emissions and the highest biogenic carbon storage per square foot. This outcome is largely influenced by its higher Timber Use Intensity (TUI). Similarly, the A1-A5 findings indicate that the embodied carbon emissions of this honeycomb construction are 40% lower than the median value for other multi-family residential buildings, as assessed using the Carbon Leadership Forum (CLF) Embodied Carbon Emissions Benchmark Study of various buildings. Moreover, the biogenic carbon storage per square foot of this building is 60% higher than the average biogenic carbon storage of reference mass timber construction types. Full article

Wood is often used as an interior surface finish in buildings, including exposed cross-laminated timber panels and other structural mass timber members. Building occupants generally have a positive reaction to visible wood elements used in building interiors due to the visual qualities associated with wood being a natural material. This study aims to identify any thermal comfort impacts of wood interior environments using subjective occupant-reported perceived thermal sensation during two experiments conducted in a climate chamber fitted with either white-painted gypsum wallboard or unfinished laminated Douglas Fir wall panels. In the first experiment, the thermal environment was continually varied while the visual stimulus of the wall type remained constant. Irrespective of wood or white wall treatment type, thermal history played a significant role in the perceived thermal comfort of participants under continually modulating temperatures. In the second experiment, a slightly warm steady-state thermal environment was maintained while one of the two wall treatments was revealed from behind a black curtain. While the shift in thermal sensation toward neutral was greater with wood walls than with white walls, the difference was not found to be statistically significant and appears to diminish after 15 min of exposure to the new visual surroundings. Full article

The construction industry is a major contributor to the global climate crisis, prompting increasing interest in minimising the embodied carbon of structures, whether through material production regulations or the optimisation of structural elements. While a wide body of literature addresses the reduction of embodied carbon in superstructures, limited attention has been devoted to the optimisation of foundations, particularly piles. This research introduces a hybrid genetic algorithm optimisation tool designed to minimise the embodied carbon of tension piles in different soil conditions. Six different pile types are analysed: solid and hollow concrete piles, steel pipes, universal column (UC) sections, and timber piles in both square and circular forms. The optimal design parameters for each pile type on undrained clay and loose sand are presented and compared. The results demonstrate the potential for reducing the embodied carbon of tension piles when utilising optimised designs. Finally, a case study involving an 8-metre-high cross-road signpost is presented, illustrating the practical application of the proposed optimisation algorithm for reducing embodied carbon in future designs. Full article

With the aim of reducing the environmental impact of buildings, the appropriate selection of building materials is essential, as a building is a complex system composed of various materials. With this background, a multi-criteria decision-making approach has recently gained traction. This study demonstrated the effect of building material selection on both environmental and economic parameters of a building in the context of Japan. A comparative analysis of five structural frame options was conducted utilizing a reference building model to assess the implication of material choices. The findings indicated that wooden frame options are advantageous in environmental aspects compared to non-wooden frames, provided that sustainable forestry practices and appropriate recycling scenarios are implemented. Conversely, it was found that a Cross Laminated Timber (CLT) frame is the most expensive option. This suggests that a hybrid approach, which combines various frame materials, could yield a more effective solution in terms of both environmental and economic sustainability. In addition, it was highlighted that building envelopes, such as foundation, exterior wall, and roof, should be prioritized to enhance the sustainability of a building from a material perspective. Furthermore, gypsum board, commonly used for sheathing building elements, should be selected with careful consideration of its environmental impact. Full article

This study investigates the structural performance of cellular cross-laminated timber (CCLT) through a nonlinear finite element model using Hill and Hashin damage criteria in Abaqus. This study evaluates these criteria in simulating CCLT’s mechanical behavior under bending and shear loading. Experimental validation included short-span and long-span bending tests, along with rolling shear tests. In bending simulations, the Hill criterion predicted maximum loads with a 7% error for long-span beams when modeling lumber as solid elements and the corrugated panel as shell elements. When the entire CCLT was modeled using shell elements, the error increased to 9%. For the short-span bending, the error remained at 8% regardless of element type. The Hashin model provided more accurate results, with deviations of 0.2% for long-span beams and 1% for short-span beams. Both models successfully predicted failure mechanisms, identifying tension failure in the lumber under long-span bending and shear failure in the corrugated core under short-span bending. In rolling shear tests, the Hill criterion underestimated the maximum shear load by 11%, while the Hashin criterion had a larger underestimation of 26%. Despite these discrepancies, both models effectively captured the nonlinear behavior of CCLT panels. These findings highlight the potential of Hill and Hashin criteria for modeling CCLT’s mechanical response, offering valuable insights into structural design applications. Full article

The Life Cycle Assessment (LCA) evaluates the environmental impacts of a product or service throughout its life cycle, from material extraction to end-of-life, considering factors such as global warming, acidification, and toxicity. However, despite its significant health effects, noise has not yet been incorporated into the LCA. This study integrates noise impact into the LCA to assess and compare alternative structural designs for Australian high-rise residential and commercial buildings. Three scenarios were analysed: (1) reinforced concrete frames, (2) hybrid timber designs using engineered wood (e.g., cross-laminated timber and Glulam), and (3) steel-frame structures. The system boundary spans cradle to grave, with a 100-year lifespan. Material quantities were extracted from BIM software 2024 (Revit Architecture) for accuracy. The ReCiPe 2016 method converted inventory data into impact indicators, while noise impact was assessed using Highly Annoyed People (HAP) and Highly Sleep-Deprived People (HSDP). The results show that commercial buildings have more significant environmental impacts than residential structures due to their higher material usage. Steel frames generally exhibit the highest environmental impact, while concrete structures contribute most to noise effects. The total noise-integrated impact ranks as steel > concrete > timber. Additionally, noise accounts for up to 33% of the total impact on densely populated areas but remains negligible in low-population regions. These findings highlight the importance of incorporating noise into the LCA for a more holistic assessment of sustainable building designs. Full article

In the case of load increases and the refurbishment of existing buildings, it is often necessary to carry out strengthening measures on existing timber beams. When timber concrete composite (TCC) ceilings cannot be used, it is possible to reinforce the undersides of the beams with structural steel or fiber composites (aramid or carbon-fiber-reinforced polymer). This work investigates how significant effects on the load-bearing and deformation behavior can be achieved with these materials in terms of construction practice. The article is intended to show structural engineers which reinforcement measures lead to which forces, deformations, etc., and how these are utilized. This should form the basis for the planning of reinforcement measures, as it is not clear from the beginning whether AFRP, CFRP, or steel is the most suitable material. For this purpose, a comparative parameter study was carried out under practical conditions and with a variable degree of reinforcement using the corresponding formulas. The internal forces in the timber and reinforcement cross-sections, the deflection behavior, and the failure loads at the strength and design levels were calculated. It was demonstrated that, particularly for steel and carbon-fiber-reinforced polymer (CFRP) reinforcements, significant increases in the ultimate load can be achieved and the often-important deformation behavior can be significantly improved. Especially the steel variant leads to high improvements in deflection and breaking load behavior, with the base material (wood) also being utilized more economically as a result. A comparative ecological study in the form of the global warming potential showed that reinforcement methods are also advantageous from the point of view of sustainability compared to renovations with timber concrete composite slabs or new concrete slabs. Full article

Traditional construction of timber houses in Tanzania has been prevalent for years; however, inhabiting these structures has been a challenge due to the instability of the buildings under various loadings. This instability, despite its lightweight, is mainly controlled by mechanical joints within timber members. Parametric Python scripts were developed in Abaqus (version 6.13) to have a reliable joint between timber volume modules and assess their response when subjected to wind forces. Two timber volume modules, each with a height of 3.0 m, were subjected to a horizontal displacement of 10 mm. Results show that the screwed fasteners between the modules result in high shear resistance due to the embedded fastener’s threads in timber members increasing the rope effect. Additionally, with weak fastener stiffness, the openings in the longitudinal wall had no effect on resisting shear compared to strong joints between modules. Longitudinal walls with doors and window openings showed a decrease in shear force to 21.95 kN, which is 44% less than the 39 kN of walls without openings. In addition, for a single door in the wall, the shear force decreased to 17.9%, indicating that major shear forces in the wall are affected by the window opening due to its large size and proximity to the point of load application. Furthermore, the stresses were concentrated in the corners of the openings, subjecting the structure to failure during its in-service life and demanding the use of cross-diagonal timber members between the corners to redistribute corner stresses. It is recommended that these types of houses be adopted due to less slip deformation (less than 10 mm) caused by wind speed of 24 km/h. Full article

In developing countries with high seismic activity, a need exists to construct resilient infrastructure and reduce the housing deficit. Industrialized timber construction and the implementation of seismic isolation interfaces may represent a good alternative to respond to these demands. This paper studies the feasibility of constructing cross-laminated timber (CLT) buildings equipped with frictional pendulum bearings in Chile or similar highly seismic regions. The first part of this study shows a first-order approach for modeling the highly nonlinear behavior of CLT walls using a Smooth Hysteretic Model (SHM). An equivalent model of a base-isolated building was developed using the SHM as well as a physical model of the Friction Pendulum System in order to assess the seismic performance of CLT buildings with frictional isolators. The second part of this research presents and discusses the results of a broad parametric analysis concerning the seismic performance of base-isolated CLT buildings. The seismic assessment was carried out by deriving fragility curves and including the uncertainty linked to the seismic input and the friction coefficient of the isolation system. Constructing lateral resistant systems based on CLT walls presents a feasible alternative for buildings in high seismic hazard areas. Excellent seismic performance is achieved if the superstructure’s is designed with a reduction factor of 1, or if the superstructure’s fundamental period ranges from 0.6 to 0.9 s and is designed with a reduction factor of 2 and ductility capacity of 6 or more. An excellent seismic performance can be obtained for larger reduction factor values if the superstructure has middle to high maximum ductility capacity. Full article

Cross-Laminated Timber (CLT) is ideal for tall timber structures but relies on environmentally concerning chemical adhesives. Nailed Cross-Laminated Timber (NCLT) offers a sustainable alternative by using densified wooden nails that form eco-friendly, adhesive-free bonds through lignin’s thermoplastic properties. However, significant uncertainties remain regarding the synergistic effects of multiple wooden nails. To address this, this study systematically analyzed the impact of the group effect on the mechanical performance of wooden nail joints. The results show that within the elastic range, the number of wooden nails has no significant effect on the elastic behavior of a structure. However, it is significantly positively correlated with both the joint yield load and yield displacement, enabling the accurate prediction of the structural yield point based on the number of wooden nails. With consistent nail arrangements, the group effect coefficient for the load-bearing capacity remains highly stable and shows no significant correlation with the number of nails. Additionally, an increase in the number of wooden nails significantly enhances the deformation resistance and structural stiffness, while having a minimal impact on ductility. This study reveals the linear additive nature of the group effect in wooden nails, providing important theoretical support for the design of NCLT. Full article