Wood Construction Research Articles

Propensity of Sawmills to Produce Structural Sawn Wood in Chile

Abstract The goals of Chile’s forest policy regarding the use of wood in construction are far from being achieved. Chile is the ninth-largest global producer of sawn softwood and has an industry with numerous sawmills; however, structural sawn wood (SSW) represents less than 1 percent of the industry’s total production, which is insufficient to address large-scale construction programs with wood. Therefore, policy instruments are needed to lead to an increase in the volume of SSW production. This research aimed to design a typology of sawmills that facilitates the definition and implementation of these policy instruments to ensure attainment of the 2035 goal of the forest policy. Multiple linear regression and multiple logistic regression were used to assess the impact of various variables on SSW production; variable selection was done using stepwise regression. The number of clusters was determined using the gap method, and sawmill clusters were determined using k means. The result is a typology with five categories of sawmills based on their propensity to produce SSW. The most significant variable was the quality of the supply, so it is suggested to prioritize the management of Pinus radiata plantations. With this result, a map for the application of policy instruments was created, proposing an intervention pathway. The proposed typology will stimulate decisions to provide direct support to the sawmill industry, thereby increasing SSW production.

SUSTAINABLE PRODUCTION AND MANAGEMENT OF AN INDUSTRIALIZED HOUSE

The PRO.CRE.AR. Bicentenario (Argentine Bicentennial Single-Family Housing Credit Program) implemented between 2012 and 2015 approximately, included a model of wooden houses, thus enhancing in Argentina the opportunity to have a house built with industrialized wooden elements. The paper compares at a conceptual level the construction of the same house (similar to the prototype named “Maderera”) as a traditional building, i.e., with brick masonry and reinforced concrete, and instead with industrialized wood construction as funded by the PRO.CRE.AR program: the comparison focuses on the amount of CO2 incorporated in the two constructive solutions. Alongside this assessment, conducted on the basis of estimated quantities of materials and data found in the literature, the paper examines the amount of CO2 not produced over the lifetime of the house when photovoltaic elements and solar panels are possibly adopted for local energy production and then discusses the positive impact of any energy storage systems. The results regarding the building energy demand and the CO2 saved support the choice of building industrialization for the wood supply chain, propose additional options for the deployment of wood construction, and evaluate the impact of home PV & solar panels for sustainability and integration into the technological system.

The carbon footprint of future engineered wood construction in Montreal

Engineered wood (EW) has the potential to reduce global carbon emissions from the building sector by substituting carbon-intensive concrete and steel for carbon-sequestering wood. However, studies accounting for material use and embodied carbon in buildings rarely analyse the city-scale or capture connections between the city and supplying hinterlands. This limits our knowledge of the effectiveness of decarbonising cities using EW and its potential adverse effects, such as deforestation. We address this gap by combining bottom-up material accounting of construction materials with life cycle assessment to analyse the carbon emissions and land occupation from future residential construction in Montreal, Canada. We compare material demand and environmental impacts of recent construction using concrete and steel to future construction using EW at the neighbourhood, urban scales under high- and low-density growth scenarios. We estimate that baseline embodied carbon per capita across the Agglomeration of Montreal is 3.2 tonnes per carbon dioxide equivalents (CO2eq.), but this ranges from 8.2 tonnes CO2eq. per capita in areas with large single-family housing to 2.0 tonnes CO2eq. per capita where smaller homes predominate. A Montreal-wide transition to EW may increase carbon footprint by up to 25% under certain scenarios, but this varies widely across the city and is tempered through urban densification. Likewise, a transition to EW results in less than 0.1% land transformation across Quebec’s timbershed. Moreover, sustainable logging practices that sequester carbon can actually produce a carbon-negative building stock in the future if carbon in the wood is not re-emitted when buildings are demolished or repurposed. To decarbonise future residential construction, Montreal should enact policies to simultaneously promote EW and denser settlement patterns in future construction and work with construction firms to ensure they source timber sustainably.

Experimental, finite element and analytical characterization of hysteretic response of ductile connections with nailed angle brackets for mass timber structures

Engineered wood products along with advanced processing and fabrication are pushing the limits of modern wood construction. Innovative concepts and applications facilitate the development of a new generation of structural systems. However, capacities of such systems are often governed by capabilities of the connections. This paper presents the experimental results with numerical and analytical models of angle brackets for prediction of load bearing capacity, stiffness, and ductility. Three types of metal brackets in beam-column connections have been investigated and their performance has been studied in various loading arrangements. Detailed finite-element models of each connection have been developed to gain insights into their behavior. An analytical approach is also adopted to represent the connections. Comparison with test data suggests that the models can reproduce results with good accuracy. The findings confirm feasibility of implementing ductile connections in practical mass timber structures.

A Wooden Pin Reinforcement of Ancient Chinese Wooden Temple: A Case of Daxiong Hall

Post and lintel frame is a prominent architectural structure in Chinese temple architecture, characterized by its wooden construction. Mortise–tenon joints (MTJs) serve as the primary connection method for these wooden structures, employing straight mortise nodes (SMNs) and through-mortise joints (TMNs). This study presents a method that utilizes wooden pins to reinforce MTJs, enhancing the seismic performance of timber frame structures. Finite element (FE) simulation verifies the effectiveness of wooden pins in reinforcing both SMNs and TMNs, leading to improved load-bearing capacity and ductility of the MTJs. Additionally, the study confirms that reinforced nodes help to restrict the displacement changes within the wooden frame. The paper also investigates the optimal distribution of MTJs reinforced by the wooden pins throughout the structure, with the aim of enhancing the wood frame’s seismic performance. The results show the bearing capacity of MJT reinforced with wooden pins is approximately 11.3% higher compared to that of MTJ without reinforcement. The reinforcement of wood pins effectively controls the horizontal displacement of the overall structure of the wooden frame, which is reduced by about 50%–62% compared with the unreinforced wooden frame. The locating the wooden pin-reinforced MTJs in the outer columns and middle layer columns reduces the structural displacement, which is 31.53% in X direction, 5% in Y direction, and 25.86% in Z direction.

Flexible Polyurethane Adhesives: Predictive Numerical Model Calibration through Experimental Testing at Elevated Temperature

The thermo-mechanical behavior of polyurethane adhesive joints in wood structures is a crucial aspect that needs to be understood to ensure the durability and safety of timber structures, especially in seismic regions. As mass timber, particularly cross-laminated timber, continues to gain popularity as a building material, it is important to pay special attention to the behavior of connections between the timber elements. The use of flexible polyurethane adhesives presents a promising alternative to conventional mechanical connections in seismic-resistant timber structures. This research highlights the potential of polyurethane-based joints at elevated service temperature, offers a promising alternative to traditional wood joints, and suggests viability for post-fire restoration of wood structures. The response at the interface between wood and polyurethane under flexural stresses is also evaluated, underscoring the broader application possibilities of flexible adhesives in wood construction for mechanical and physical improvements.

Legacy of last millennium timber use on plant cover in Central Europe: Insights from tree rings and pollen

Throughout history, humans have relied on wood for constructions, tool production or as an energy source. How and to what extent these human activities have impacted plant abundance and composition over a long-term perspective is, however, not well known. To address this knowledge gap, we combined 44,239 precisely dated tree-ring samples from economically and ecologically important tree species (spruce, fir, pine, oak) from historical buildings, and pollen-based plant cover estimates using the REVEALS model from 169 records for a total of 34 1° × 1° grid cells for Central Europe. Building activity and REVEALS estimates were compared for the entire study region (4–15°E, 46–51°N), and for low (<500 m asl) and mid/high elevations (≥500 m asl) in 100-year time windows over the period 1150–1850. Spruce and oak were more widely used in wooden constructions, amounting to 35 % and 32 %, respectively, compared to pine and fir. Besides wood properties and species abundance, tree diameters of harvested individuals, being similar for all four species, were found to be the most crucial criterion for timber selection throughout the last millennium. Regarding land use changes, from the 1150–1250's onwards, forest cover generally decreased due to deforestation until 1850, especially at lower elevations, resulting in a more heterogeneous landscape. The period 1650–1750 marks a distinct change in the environmental history of Central Europe; increasing agriculture and intense forest management practices were introduced to meet the high demands of an increasing population and intensifying industrialization, causing a decrease in palynological diversity, especially at low elevations. Likely the characteristic vegetation structure and composition of contemporary landscapes originated from that period. We further show that land use has impacted vegetation composition and diversity at an increasing speed leading to a general homogenization of landscapes through time, highlighting the limited environmental benefits of even-aged plantation forestry.

Implementation of Building Information Modeling Technologies in Wood Construction: A Review of the State of the Art from a Multidisciplinary Approach

This research raises questions about the possibilities and options of using the BIM methodology associated with software for the wood design and construction of structure modeling along an asset’s cycle life. Likewise, several academic and research initiatives are reviewed. In this sense, this paper aims to establish an appropriate link between two agendas that the architecture, engineering, and construction (AEC) industry, academia, and governments normally handle separately. By conducting several literature reviews (book, journals, and congresses) and extensive software tests (BIM software: Revit v2023, Archicad v27, Tekla, and wood plug-ins: AGACAD, Archiframe, Timber Framing 2015, WoodStud Frame, etc.), the state-of-the-art was assessed in both fields, and several cases linking BIM and wood are shown in detail and discussed. Various theoretical samples are modelled and shown, and the advantages and disadvantages of each technique and stage are explained. On the other hand, although wood construction has been most common for hundreds of years, this is not the case of BIM software developments associated with this materiality. Furthermore, since the appearance of materials such as steel and reinforced concrete, all software developments have focused on these materials, leaving aside the possibility of developing applications for use in wood projects. According to that previously discussed, it can be concluded that BIM for wood has been used more frequently in academia, that both fields have several common processes, and, in many cases, that only a few BIM-wood tools have been used, thus disregarding the high potential and high level of benefits that result with the application of these methodologies for the complete building life cycle (design, construction, and operation).

Architectural Perspectives on Wood Reuse within Circular Construction: A South–Central European Study

This study explores the perspectives and practices of architects regarding the reuse of wood in construction across five South–Central European countries: Slovenia, Serbia, North Macedonia, Bosnia and Herzegovina (BiH), and Montenegro. Based on a survey of architectural professionals, this research explores their attitudes, challenges, and motivations for using reclaimed wood, with a focus on circular construction principles. Key findings reveal unanimous agreement among respondents that both their profession and government entities inadequately support or promote wood reuse within the context of circular construction. While architects value reclaimed wood, there are country-specific variations. Environmental benefits, unique aesthetics, historical value, and sustainability are cited as primary motivators for reclaimed wood use. Additionally, respondents emphasize the ecological aspect as the most important consideration in wood product reuse, followed by economic and technological factors. Common concerns revolve around the long-term quality and maintenance of wood products. This research provides insights into the challenges and opportunities surrounding reclaimed wood use in South–Central Europe, highlighting the need for support mechanisms and increased awareness to advance circular construction practices in the region. These findings can have implications for architects and investors by identifying market opportunities, promoting eco-friendly practices, and providing valuable insights for future building designs with a focus on reclaimed wood elements within circular construction.

Improving the Methodology for Determining the Biomass/Coal Co-Combustion Ratio: Predictive Modeling of the 14C Activity of Pure Biomass

Sampling and 14C detection of biomass are now essential steps to ensure the accuracy of the 14C method, but they require additional time and economic investment. When there are multiple types of biomass fuels, it is not possible to guarantee the uniformity of sampling. The 14C activity of biomass fuels exhibits variability, and this value significantly impacts the precision of the 14C method. Therefore, this study aims to investigate the influencing factors of 14C activity in biomass fuels. It also provides predicted values of 14C activity for different types of biomass fuels for each year from 2020 to 2030. Additionally, this study discusses the potential blending ratio measurement errors that may arise due to the uncertainties of the predicted values. The reduction in the 14C activity of biomass fuels can occur due to the utilization of fossil fuels, human activities, and the photosynthesis mode of C3 plants. This study presents a prediction method for determining the reduction factor. The other component of the prediction methodology involves determining the original 14C activity of biomass fuels. The 14C activity of the annual biomass is equal to the 14CO2 activity (the 14C activity of CO2) of the surrounding environment, and it experiences a decline of 0.355 pMC/year. The 14C activity has ranges of five types of perennial biomass fuels, including wood chips and branches, bark, leaves, wasted furniture, and abandoned building wood, for the time period between 2020 and 2030, are 97.34~102.84, 96.35~106.27, 96.35~102.64, 111.00~118.60, and 111.32~129.47 pMC, respectively. Based on these, this study introduces a new formula for calculating blending ratios, which enhances the current methodology. The calculation errors of blending ratios caused by the uncertainties of the predicted values are generally negligible, with the exception of wasted furniture and construction wood. The annual decrease in the blending ratio calculation error, caused by the uncertainty associated with the predicted value, can be observed. This study aims to reduce the implementation time and economic cost of the 14C method while ensuring the accuracy of biomass blending ratio detection.

Flexural behavior of LVL made from Australian radiata pine

As a commonly used engineering wood in modern timber constructions, laminated veneer lumber (LVL), produced from small-diameter wood, short-dimension wood, or fast-growing wood, significantly enhances material properties to meet the mechanical and physical requirements in structural engineering. This study aims to investigate the feasibility of utilizing fast-growing Australian radiata pine to produce structural LVL, providing essential theoretical support for its application in civil engineering. The investigation focuses specifically on Australian radiata pine LVL (RP-LVL) and involves a systematic experimental study to assess the bending performance of RP-LVL under various bending directions and specimen sizes. The findings reveal that the edgewise bending strength of RP-LVL is comparatively lower than its flatwise bending strength. Nevertheless, RP-LVL exhibits superior bending strength compared to conventional glulam and dimensional lumber, rendering it an attractive and suitable building material for achieving enhanced bending performance in flexure members. Moreover, the study identifies significant influences of height and width on the bending strength of RP-LVL. Consequently, prediction method is proposed to calculate the bending strength of RP-LVL, considering these size influences. Importantly, the size influences on bending strength are quantified to provide a comprehensive evaluation of the bending capacity of RP-LVL flexure members.

Environmental consequences of shifting to timber construction: The case of Denmark

Many life cycle assessments (LCA) studies on wooden buildings show potential to decarbonise the building industry, though often neglecting to consider the systemic changes of such a shift at the building stock scale. This study applies a consequential LCA to evaluate the transition from conventional construction to increased wood-based construction in Denmark from 2022 to 2050. The assessment models a material flow analysis of the two construction scenarios, incorporating an area forecast and case buildings. By that, we assessed suppliers' capacity to likely meet the demand for wood, steel, and concrete, employed an input-output model to enhance completeness and country representativeness for other materials' markets, and considered the competition for land by indirect land use change. We implemented a dynamic IPCC-based assessment of GHG-emissions concurrently with a carbon forest model to anticipate the relationship between the delayed carbon storage resulting from using wood in buildings and forest regrowth management. The findings indicate wood construction is the most climate-friendly option for multifamily houses. In contrast, single-family houses (SFH) and office buildings (OB) exhibit the lowest climate impacts in the conventional scenario. The SFH result could be credible due to the sizable GWP impact gap between construction scenarios despite uncertainties related to the weight proportion of sedum roofs. The less conclusive OB findings relate to the substantial steel quantities in the wood case buildings, requiring further investigation. Generally, metals, cement-based- and biobased materials demonstrate the largest climate impact among the material categories. Across all three building typologies, the change to timber construction increased the impact on nature occupation (biodiversity). In conclusion, this study emphasises the need for further research on forest management model inputs, land use change approaches, potential steel suppliers' impact, and a broader array of case studies. It is because these are influential factors in facilitating informed decision-making of the increased implementation of wood in buildings. As the first study to integrate these modelling characteristics, it contributes to the research gap concerning geographical circumstances, forestry, and markets relevant to decision support for increased wood utilisation in Europe's building industry.

TOWARDS AUTOMATIC DEFECTS ANALYSES FOR 3D STRUCTURAL MONITORING OF HISTORIC TIMBER

Abstract. Stability of historic wooden constructions is changing with time and should be inspected appropriately for risk assessment and prevention. The stability or strength values of built-in historic timber are difficult or even impossible to be derived without invasive investigation, but this is particularly problematic for the monitoring of heritage objects. Luckily there are some visible timber surface features, like knots and cracks, which can act as individual evidence to estimate the wood strength as well as to adjust its grade class indicator. In the final project, we aim to compare different approaches for 3D digital documentation of historic wood timbers and focus on automatic knot detection using AI techniques. A first feasibility study reported here provides a scientific baseline for the development of an automated method to analyse historic timber stability using 3D surveying and recognised surface features. First results about texture and resolution properties are discussed here.

The survival of multi-drug resistant bacteria on raw Douglas fir material

In today’s age of ecological transition, the use of materials such as renewable wood in construction is particularly relevant, but also a challenge in the healthcare sector where the hygiene dimension also comes into play. In this study we have investigated the survival of multi-resistant bacteria commonly responsible for healthcare-associated infections (HAIs) (ESBL-positive Klebsiella pneumoniae and glycopeptide-resistant Enterococcus faecalis) on two different types of wood (Douglas fir : Pseudotsuga menziesii and Maritime Pine : Pinus pinaster) compared to other materials (smooth: stainless steel and rough: pumice stone) and the effect of a disinfection protocol on the bacterial survival on Pseudotsuga menziesii. Approximately 108 bacteria were inoculated on each material and bacterial survival was observed over several days (D0, D1, D2, D3, D6, D7 and D15). Each analysis was performed in triplicate for each time and material. The results show an important reduction of the bacterial inoculum for Klebsiella pneumoniae and Enterococcus faecalis on Douglas fir, in contrast with the results obtained on maritime pine, stainless steel and pumice stone. No bacterial survival was detected on Douglas fir after application of a hospital disinfection protocol. These different results show that wood may have a place in the future of healthcare construction. Further studies would be interesting to better understand the different properties of wood.

The Creation of “Sacred Place” through the “Sense of Place” of the Daci’en Wooden Buddhist Temple, Xi’an, China

After the Industrial Revolution, new technologies and architectural forms gradually replaced China’s wooden construction system, which had lasted for thousands of years. The architectural narrative also turned a new page. As pieces of architectural and cultural heritage and as the residence of “gods”, wooden Buddhist temples carry the indelible imprints of history and religion and have become a healing place or spiritual home for people living in urban areas. In order to preserve the local cultural context and explore the creation of a spiritual “sacred place”, this study traces the spiritual and cultural value of Xi’an’s wooden Buddhist temple through ethnographic qualitative methods of text analysis, observation and interviews. The case study examines the metaphorical symbolism of the architecture’s “sense of place” and religion in terms of architectural structure and components, and the advantages of creating a “sacred place” are examined based on the characteristics of wooden materials. The results show that the design elements of wooden Buddhist temples connect cultural identity and collective memory, which are inseparable from religion, and because of the material properties of wood, they sublimate the sacred atmosphere of religion. Moreover, identifying the “sense of place” and the atmosphere of sacred spaces through the structure, components, and material characteristics of wooden temple architecture offers a new perspective that focuses on architectural emotions and creates a new topic of “sacred places”. Such temples have the potential to enhance human spiritual health and well-being.

Project-based business models in the construction industry – key success factors for sustainable timber extension projects

Building construction has significant negative impacts on the environment. However, various measures can mitigate these impacts, including using wood as a building material and improving the building and construction process. The need to renovate and extend existing buildings increases with urbanization and a growing population. Wood is an attractive option for adding new floors to existing structures because of its superior strength-to-weight ratio, allowing for the potential to “build on top” of existing buildings. In order to achieve higher levels of sustainability in wood extension building projects, this study aimed to highlight the benefits of adopting a project-based business model approach by studying the technical, economic, social, and environmental attributes associated with timber building extension projects. Unlike the common firm-level business model approach, a project-based business model allows for a comprehensive view of the value creation, delivery, proposition, and capture of all the key actors involved in a construction project. The study results emphasize the success factors of an extension building project and conclude with critical factors related to the business model’s resources, activities, and actors, which would enhance the outcomes of a wood extension project. Such factors relate to knowledge and experience derived from wood construction, and to a holistic perspective on planning, and involvement of all relevant actors from the design phase to project completion.

Exploring the socio-economic impacts of community based rehabilitated watersheds: an experience from Wera district, Ethiopia

ABSTRACT In developing countries, research evidence on the socio-economic impact is a crucial issue in motivating and encouraging community-based restoration of degraded watershed ecosystems. This paper focuses on exploring the socio-economic impacts of rehabilitating a watershed area in two villages (kebeles) using two independently pooled cross-sectional data sets. 240 households were selected at random to provide the data. Half of the households (120) were randomly chosen from the records of the rural land and agricultural development office in 2007 and the other half (120) were randomly selected and interviewed in 2022 using semi-structured questionnaires. Our results show that the contribution of the restored area to the economy of the local communities dramatically increased between 2007 and 2022. The main economic activities encountered in the restored area are fuelwood collection, the harvesting of construction wood, collecting grasses, and harvesting fodder, which are practiced by 75%, 68%, 59% and 41% of sampled households in 2022, respectively, while the same activities were practiced by 5%, 0%, 0%, and 2.5% households in 2007, respectively. Rehabilitation intervention also created job opportunities, and strengthened social networking among local households. These findings can help government and non-government stakeholders those implement ecosystem restoration by enhancing community-based rehabilitation of watersheds.

Prediction of withdrawal resistance of self-tapping screws in softwood structural lumber

The withdrawal resistance of self-tapping screws (STS) in Korean structural softwood in the vertical fiber direction was examined. Four representative softwood species were selected based on their specific gravity. Three STS fastener diameters were used for an STS penetration depth of 50 mm. The withdrawal capacity tended to increase with the specific gravity of the specimens and as the diameter of the STS increased. Primarily, the difference in strength was maximized as the STS diameter increased from 8 to 10 mm. Predictive experimental equations were proposed based on the experimental values of the relationship between the specific gravity of the structural material and the withdrawal resistance according to the diameter of the STS. The values were compared with the predicted values calculated using fastener and screw prediction equations proposed by the National Design Specification for Wood Construction (NDS) and European Standards (EN). The results calculated using the NDS prediction equations yielded a peak difference of 43% compared with the experimental withdrawal capacity, whereas the EN prediction equations yielded a difference of 0.7 to 1.14 times the experimental values. The ratios between the withdrawal capacity predicted by the proposed prediction equations and the experimental withdrawal capacity were the most similar, ranging from 0.80 to 1.15.

Attractiveness of wood-frame multi-storey buildings in seven European countries: consumer segmentation and the effect of fire safety information

Wooden construction has the potential to contribute to climate change mitigation, and it is being promoted by the EU and national governments. However, several market barriers to wood-frame multi-storey building (WMSB), have been recognized, including obstacles in national building codes, lack of expertise in wood construction, and material durability concerns among end-users as well as other technical aspects. Given that increased wood construction is a target, understanding consumer perceptions of WMSB is crucial. In this study, consumer attitudes on WMSB were studied through consumer segmentation relying on demographic attributes. Further, the effect of providing fire safety information was explored. To this end, an online survey was deployed in seven European countries, with 7007 responses. The results show that in general, the awareness and attractiveness of WMSB is low amongst European consumers. Out of all respondents, 46% had not heard of WMSB before and only 12% stated that they are interested in the subject and know something about it, showing a clear lack of information and awareness within the general public. Significant differences in the perceived attractiveness of wooden multi-storey construction between consumer segments exist, with younger consumers and urban consumers being more attracted to living in WMSB than older or rural consumers. Fire safety was an important attribute affecting overall attractiveness, yet updated information regarding fire safety and control in WMSBs had a small but statistically significant negative effect on the perceived attractiveness. The results indicate that targeted marketing efforts are needed to inform potential consumers of WMSB and aspects related to fire safety effectively.

The role of board interlocks in increasing the use of wood in Norwegian construction

This paper studies the existence of board interlocks between wood-based firms in the Norwegian construction supply chain and firms in other industries, and their role in enabling increased use of wood in construction. Wood-based construction remains a niche market globally. The literature highlights two main barriers to wood-based construction: 1) lack of expertise with the material, and 2) lack of coordination and collaboration across the supply chain. As a form of interfirm governance structure, board interlocks may promote innovation in construction, such as applying new materials, products and processes, by fostering strategic collaborations. Drawing on resource dependence theory (RDT) and the theory of dynamic capabilities, we explore this through analysis of registry data, interviews and case studies. It was found that the majority of wood-based firms have board interlocks and that a majority of the firms they are interlocked with belong to industries within the construction supply chain. It was also found that the role of these board interlocks is primarily to secure access to immaterial resources, such as knowledge, expertise and skills, which enables the wood-based firms to engage in processes (sensing, seizing, and reconfiguration) that are important for their dynamic capabilities and therefore closely related to their ability to innovate.