Search Results (242)

This paper proposes the use of cross-laminated timber (CLT) panels in conjunction with back-to-back cold-formed steel (CFS) channel or angle sections in combination with laminated veneer lumber (LVL) beam, for composite CFS-timber beams. Under a hogging and sagging moment, part of the CLT panel will act compositely with CFS-LVL in order to resist compression, while the lower part of CFS-LVL web will be in tension. Whilst shear lag effects have been well-researched for concrete-steel composite beams, there has been little research on this for CLT panels working with CFS-LVL sections. In this paper, the finite element method (FEM) is used to determine the effective flange width (FFW) for CFS-timber beams. In conclusion, the obtained result has shown that the EFW increases with any changes that lead to an increase in the ratio of the transverse layer’s depth to the longitudinal layer’s depth. Moreover, combinations of CFS sections with LVL have significantly resulted in the depth-of-beam decrease. Full article

The EPBD 2024 recast sets the deadline for new Zero-Emission Building standards for all new publicly owned buildings to 2028 and to 2030 for all new buildings. In the scope of Life Cycle Assessment stages, all steps resulting in major emissions from buildings must be considered and presented. The research evaluates the life cycle greenhouse gas emissions of a single-family house, focusing on diverse construction types and the hourly method of the annual energy calculations for continental and coastal climate areas in Croatia under the upcoming standards. Embodied carbon of diverse construction types was compared mutually, and required steps to meet the operational zero-emission standards were analyzed. Embodied energy of a 137.0 m² family house built out of reinforced concrete results in up to 67 tons of CO₂eq emissions, while wood in cross-laminated timber structures absorbs more carbon than emitted for all other materials and construction processes—23 tons of CO₂eq. Regarding operational energy and accompanying emissions, in order to cost-effectively meet future ZEB standards in Croatia and offset the remaining operational emissions, photovoltaic systems of up to 2.5 kWp are required in continental areas and 1.6 kWp in coastal regions. Full article

The application of volumetric modular construction using Cross-Laminated Timber (CLT) has emerged as a sustainable and efficient alternative to traditional building methods, especially in residential and mid-rise structures. However, the widespread adoption of this technology remains limited due to the lack of standardized inter-modular connection systems. This paper presents a comprehensive state-of-the-art review of inter-modular connections used in volumetric CLT modular buildings. This review aims to evaluate the inter-modular connections by developing performance objectives and identifying gaps in knowledge of volumetric CLT inter-modular connections. It begins with an overview of global CLT modular construction trends, highlighting geographic distribution, structural demands, and environmental hazards such as seismic and wind exposure. Seven representative connection systems were identified from the literature and assessed using a multi-criteria framework comprising structural performance, manufacturing feasibility, on-site construction efficiency, and experimental and numerical evaluation. Each connection was scored according to defined evaluation metrics, and the results were provided to identify key strengths and limitations. The top-performing systems demonstrated superior resilience, modular adaptability, and validation through experimental testing and simulation. The paper identified critical research gaps, including limited performance data available for seismic applications, challenges in disassembly and reuse specifications, and the need for adaptable, damage-tolerant systems to enhance building structural performance. These findings provide a reference evaluation methodology for future development of inter-modular connections, to expand the applicability of volumetric CLT modular construction in moderate and high seismic and wind hazard regions. Full article

This article addresses the problem of insufficient bearing capacity and stiffness in laminated timber beams during use and proposes a reinforcement method by increasing the cross-section. Twenty glued laminated timber beams with dimensions of 2850 mm × 120 mm × 50 mm were produced using Pinus sylvestris var. mongolica as the raw material. Douglas fir with good tensile properties and new self-tapping screws were selected as reinforcement materials. Through adhesive bonding and adhesive–nail combination methods, an enlarged section reinforcement beam was formed. The influence of section height, bonding process, and the arrangement of self-tapping screws on the bending performance of three groups of six adhesive-reinforced specimens and three groups of fourteen adhesive–nail reinforced specimens was examined through bending performance tests. The results showed that compared with specimens reinforced with single-layer panels, the ultimate load of specimens reinforced with double-layer panels increased by 22.82 to 29.49%, and bending stiffness increased by 17.26 to 48.17%. Within the same group, the ultimate load of specimens reinforced with standard compressive stress adhesive increased by 3.88 to 5.71% under bending. Compared with adhesive reinforcement specimens, adhesive–nail combined reinforcement specimens showed an 8.91 to 11.36% increase in ultimate load. In specimens with the same screw insertion angle, the ultimate bearing capacity of beams reinforced with longer screws and smaller spacing was actually lower. Moreover, the ultimate load of specimens reinforced with self-tapping screws inserted at 90° was 4.2% higher than that of specimens with screws inserted at 45°. Full article

This study presents an integrated intervention strategy for the adaptive reuse of vernacular architecture in a state of ruin, focusing on the fortified village of Moya (Cuenca, Spain). The proposal is framed within a rural revitalization program aimed at educational and cultural tourism uses, with the goal of reactivating abandoned built fabric through the incorporation of new functions that generate social value and contribute to territorial development. The proposed methodology combines archival research, digital documentation, material characterization, and a constructive solution based on the insertion of a reversible, structurally autonomous timber volume within the existing stone masonry. Through material characterization, a differentiated consolidation protocol is developed to stabilize the ruins while maintaining historical legibility. The new architectural volume, built with prefabricated cross-laminated timber (CLT) and insulated with locally sourced expanded cork, is designed to meet contemporary standards of energy efficiency, reversibility, and environmental responsibility, while remaining fully independent from the original structure. The intervention offers a replicable model for sustainable rural regeneration, balancing conservation ethics with functional adaptation. Future lines of research include the dynamic simulation of the energy performance of the inserted dwelling, with the aim of assessing its contribution to climate neutrality and net-zero emissions targets. Full article

Due to their sustainability, lightweight qualities, and simplicity of installation, wood slab systems have gained increasing attention in the building industry. Cross-laminated timber (CLT), an engineered wood product (EWP), improves structural strength and stability, offering a good alternative to conventional reinforced concrete (RC) slab systems. Conventional CLT, however, contains adhesives that pose environmental and end-of-life (EOL) disposal challenges. Adhesive-free CLT (AFCLT) panels have recently been introduced as a sustainable option, but their environmental performance has not yet been thoroughly investigated. In this study, the environmental impacts of five slab systems are evaluated and compared using the life cycle assessment (LCA) methodology. The investigated slab systems include a standard CLT slab (SCLT), three different AFCLT slabs (AFCLT1, AFCLT2, and AFCLT3), and an RC slab. The assessment considered abiotic depletion potential (ADP), global warming potential (GWP), ozone layer depletion potential (ODP), human toxicity potential (HTP), freshwater aquatic ecotoxicity potential (FAETP), marine aquatic ecotoxicity potential (MAETP), terrestrial ecotoxicity potential (TETP), photochemical oxidation potential (POCP), acidification potential (AP), and eutrophication potential (EP), covering the entire life cycle from production to disposal, excluding part of the use stage (B2-B7). The results highlight the advantages and drawbacks of each slab system, providing insights into selecting sustainable slab solutions. AFCLT2 exhibited the lowest environmental impacts across the assessed categories. On the contrary, the RC slab showed the highest environmental impact among the studied products. For example, the RC slab had the highest GWP of 67.422 kg CO₂ eq, which was 1784.3% higher than that of AFCLT2 (3.779 kg CO₂ eq). Additionally, the simulation displayed that the analysis results vary depending on the electricity source, which is influenced by geographical location. Using the Norwegian electricity mix resulted in the most sustainable outcomes compared with Sweden, Finland, and Saudi Arabia. This study contributes to the advancement of low-carbon construction techniques and the development of building materials with reduced environmental impacts in the construction sector. Full article

As a green-material structure, cross-laminated timber (CLT) has attracted increasing attention and applications in construction. This study presents an analytical model for a CLT plate under the coupling effect of load and moisture content, where the moisture-induced deformation and moisture-dependent properties are both considered. In the analytical model, state-space equations for moisture variables and for stresses and displacements in the CLT plate are established based on moisture diffusion theory and three-dimensional elasticity theory, respectively. Using the transfer matrix method, the relationships of moisture variables, stresses, and displacements between any two layers of the CLT plates are formulated. The analytical solutions are then determined by the load and moisture conditions applied to the top and bottom surfaces. Comparative analysis indicates that the proposed solution surpasses finite element methods in both computational accuracy and efficiency. In addition, the stress and displacement patterns of CLT plates under pure load and pure moisture conditions, as well as their interrelations, are investigated through a decoupled analysis. An applicable modified superposition principle is then proposed. Finally, a detailed parametric study is conducted to examine the effects of moisture distribution and wood species. Full article

Cross-beam glued-laminated timber (glulam) floor systems offer material efficiency but pose a complex design challenge due to three-dimensional (3D) load interactions, and systematic optimization guidelines are lacking. This study implements a parametric optimization framework using a three-factor Design of Experiments (DOE) approach (beam spacing ratio, height-to-span ratio, width-to-height ratio). A total of 27 full-factorial finite element models (FEMs) were simulated in Dlubal RFEM. A second-order response surface methodology (RSM) model was developed to predict the load utilization factor (Y) in accordance with Eurocode 5. The predictive model demonstrated high statistical accuracy (R² > 0.98). A multi-criteria optimization using the Pareto frontier identified a balanced solution (x₁ = 0.250, x₂ = 0.042, x₃ = 0.5) that achieved 97.4% load utilization (Y = 0.974). This optimal configuration reduces the required timber volume by approximately 10% compared with other efficient designs and by over 60% compared with inefficient (Y ≈ 0.5) but safe designs within the experimental space. The resulting regression model provides a validated engineering tool for designing materially efficient glulam floor systems, allowing designers to balance structural safety with material economy. Full article

The Unbroken Rehabilitation Center in Lviv illustrates how architectural design can support recovery in post-conflict conditions. Drawing on concepts of healing environments, evidence-based design, and trauma-informed architecture, this study aimed to identify architectural strategies that enhance physical and psychological rehabilitation in war-affected populations. A mixed-method approach was applied, combining field observations, architectural analysis, and user surveys triangulated with interviews and documentation review. Results show that decentralised layouts, daylight access, barrier-free circulation, and cross-laminated timber (CLT)-based vertical expansion contribute to therapeutic effectiveness. Survey data from 45 respondents confirmed very high ratings for accessibility (9–10/10) and strong appreciation of group therapy rooms (9.0), art therapy (8.8), and music therapy (8.7). These findings highlight the value of sensory and symbolic elements, including natural materials and culturally embedded art. While the exploratory character and uneven respondent distribution limit generalisability, the triangulated methodology enhanced reliability and revealed clear user trends. The study demonstrates that architectural design can actively support resilience and rehabilitation in war-affected contexts, offering transferable insights for future post-conflict reconstruction. Full article

Engineered wood products have become key sustainable alternatives to conventional building materials, offering strong potential for reducing climate impacts in the construction sector. This review systematically assesses recent life cycle assessment studies on engineered wood products to compare their environmental performance and support low-carbon building practices. The peer-reviewed literature published over the past decade was analyzed for publication trends, geographic focus, and methodological approaches, including goal and scope definition, life cycle inventory, and life cycle impact assessment. Comparative analyses examined climate change impact and key parameters influencing environmental outcomes. Results indicate a steady growth of research in this field, led by China, the United States, and Europe. Volume-based functional units (e.g., 1 m³) are predominant in structural wood studies, while mass-based units are more common for composites. Cradle-to-gate boundaries are most frequently used, and data are primarily drawn from Ecoinvent, Environmental Product Declarations, and regional databases such as GaBi and CLCD. Common impact assessment methods include CML-IA, ReCiPe, and TRACI, with climate change identified as the core impact category. Cross-laminated timber and glue-laminated timber consistently show lower and more stable climate change impacts, while fiberboards exhibit higher and more variable results due to adhesive content and energy-intensive manufacturing. Key factors influencing environmental outcomes include service life, wood species, and material sourcing. The review highlights the need for standardized methodologies and further exploration of emerging products, such as nail-laminated and dowel-laminated timber and laminated bamboo, to improve comparability and inform sustainable design practices. Full article

Cross-laminated timber (CLT) panels, composed of orthogonally bonded layers, are often used in civil engineering and tall constructions owing to their sustainability, prefabrication advantages and favourable mechanical performance. However, their multilayered, anisotropic and shear-compliant nature presents significant challenges for accurate structural modelling and performance prediction. This study presents an advanced numerical approach to analysing the bending behaviour of CLT panels using the finite element method (FEM) in combination with the classical laminate theory. The proposed plate model was implemented in FlexPDE and validated through a series of three-point bending experiments on three-layer spruce panels. Further verification was conducted using commercial FEM software—Dlubal, incorporating both linear elastic and non-linear damage models, and Abaqus, where a three-dimensional solid model with a cohesive zone formulation captured progressive delamination and local failure in the glued layers. Comparison of the experimental data and numerical simulations revealed strong agreement in load–deflection behaviour, stiffness evolution and damage localisation. The framework we developed accurately reproduces both the global and the local mechanical responses of CLT panels while maintaining computational efficiency. Our results confirm the reliability of laminate theory-based FEM formulations in the design, optimisation and safety assessment of cross-laminated timber structures in building applications. Full article

The use of Cross-Laminated Timber (CLT) panels in buildings offers earthquake resistance with a low carbon footprint. However, significant seismic displacements can cause damage, raising concerns about the long-term embodied carbon balance obtained, particularly if significant interventions are required to restore the original functionality. This study embraces a systematic review of innovations considered for massive timber structures in seismic zones, focusing on embodied carbon emission reduction. The analysis undertaken is based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) using the Scopus and Web of Science database references published from 2010 to 2025. A total of 53 documents meeting the search criteria were identified and assessed, considering their degree of technological maturity (TRLs). The results highlight efforts toward innovation in the performance of connections and lateral stabilization to minimize damage and enhance reparability, revealing the need to link new practices and technologies to the structural and environmental results of the solution, particularly in terms of efficiency in the use of materials about their possible repair and reuse at different stages of the life cycle. The availability of innovations aimed at carbon footprint reduction, and which present a high degree of technological maturity is reviewed and the potential of these solutions is evidenced in places where seismic vulnerability greatly influences the design; combining performance with the aim of achieving a carbon-neutral economy. Full article

As an innovative advancement beyond cross-laminated timber (CLT), cross-laminated bamboo and timber (CLBT) combines sustainability with enhanced structural performance. This review critically assesses the current state of CLBT research, focusing on its failure mechanisms, mechanical properties, and predictive theoretical models. Key findings indicate that CLBT exhibits superior rolling shear strength, bending stiffness, and stability compared to conventional CLT, achieved through optimized hybrid layering and manufacturing techniques. The integration of bamboo not only improves mechanical performance but also promotes diversification of raw materials and more efficient use of regional biomass. This paper highlights the potential of CLBT as a high-performance, eco-friendly construction material and identifies key research gaps and future directions to facilitate its standardized application. Full article

This review article critically examines the fire performance of cross-laminated timber (CLT), a key structural material for sustainable construction, by synthesising recent advancements in both experimental and numerical research. It identifies a critical gap between experimental findings and numerical models, offering insights to refine future fire-safe design and research. The article assesses fire design strategies across major international standards and reviews experimental fire testing of CLT elements, highlighting how adhesives, protective cladding, layer thickness, load levels, and support conditions affect fire resistance. This article also summarises CLT compartment tests, focusing on how openings, ventilation size, and protective cladding affect fire dynamics and CLT degradation. A literature review of numerically modelled CLT specimens under fire load is compiled and evaluated based on several criteria, including material characterisation, mesh characteristics, and modelling procedures. Subsequently, the outcomes of two distinct approaches are evaluated, emphasising the disparities in the techniques employed and the difficulties inherent in performing more precise numerical simulations. The article will bridge and inform the gap between experimental tests and numerical analysis, focusing on identifying suitable approaches for such simulations. The study aims to provide a broader understanding of the topic and promote the development of fire-safe design and modelling of engineered timber construction using CLT. Full article

Timber structures and structural members have undergone rapid development in recent decades and are now fully competitive with traditional structures made of reinforced concrete or structural steel in many areas. Low self-weight, high durability, rapid construction assembly, and a favourable environmental footprint predispose timber structures for wider future use. A persisting drawback is the often-complicated joining of individual elements, especially when moment resistance is required. For CLT panels, this issue is more urgent due to their relatively small thickness and cross-laminated lay-up. This paper presents experimental research investigating parameters related to the actual behaviour of a moment-resisting embedded joint of CLT panels. The test programme consisted of four series (12 specimens) loaded in four-point bending to failure. The proposed and tested joint consists of high-strength steel rods glued into the two connected parts of the CLT panel. In addition to a detailed investigation of the resistance and stiffness of the joint, this research evaluates the effect of composite action with a reinforced-concrete slab on the performance of this type of joint. The experimental results and their detailed analysis are also extended to propose a framework concept for creating a theoretical (mechanical) model based on the component method. Full article