•Spruce and beech wood dovetail joints bonded with PVAc and PUR adhesive were tested.•Joint stiffness was analyzed by both, experimental and numerical methods.•Numerical model provided information on ...stress distribution in the joints.•Numerical and experimental results are well aligned, with exception of tension load in beech wood.
This study investigates the stiffness of dovetail joints by both numerical and experimental methods. Test specimens were made of Spruce (Picea abies L) and Beech (Fagus Silvatica L) wood, which were bonded with polyurethane (PUR) and polyvinyl acetate (PVAc) adhesives into dovetail joints. To determine the mechanical behavior, the joints were loaded according to grain direction under compressive and tensile load. The results of the experiment indicated that, under compression load, beech wood bonded with polyvinyl acetate (PVAc) adhesive had maximum elastic stiffness. Based on the experimental results, a numerical model using the finite element method (FEM) was developed by the Abaqus program to predict the stiffness of dovetail joints under compressive and tensile load. For numerical analysis, the assumption was made that arm deflection was caused by a displacement in the supports. The value of deflection corresponds to the limit of linear elasticity and the value of the force reduced stresses, which was determined on the basis of deflections. A cohesive zone was developed, which shows stress behavior under compressive and tensile load. A positive correlation was found between the numerical model and experimental study.
Passive controlled shear wall for wooden construction with high damping rubber to prevent degradation of seismic performance during repeated severe earthquakes is proposed in this study. In this ...paper, shear wall tests and shaking table tests of the full scale two-story wooden structure composed of proposed shear walls were described. As the result of tests, it is confirmed that the proposed shear wall is effective to reduce the degradation of seismic performance to repeated earthquakes in comparison with plywood conventional shear wall.
•Three building designs with increasing biobased material content were modelled and analysed using LCA.•Dynamic LCA was applied to account for biogenic carbon sequestration, storage and ...emissions.•Increasing biobased content reduces climate impact even if biogenic exchanges are assessed.•Time horizon, timing of forest growth and end-of-life recycling are key assumptions.•Time horizons lower than 100years are not enough to capture properly climate impacts from buildings.
Whenever Life Cycle Assessment (LCA) is used to assess the climate impact of buildings, those with high content of biobased materials result with the lowest impact. Traditional approaches to LCA fail to capture aspects such as biogenic carbon exchanges, their timing and the effects from carbon storage. This paper explores a prospective increase of biobased materials in Swedish buildings, using traditional and dynamic LCA to assess the climate impact effects of this increase. Three alternative designs are analysed; one without biobased material content, a CLT building and an alternative timber design with “increased bio”. Different scenario setups explore the sensitivity to key assumptions such as the building’s service life, end-of-life scenario, setting of forest sequestration before (growth) or after (regrowth) harvesting and time horizon of the dynamic LCA. Results show that increasing the biobased material content in a building reduces its climate impact when biogenic sequestration and emissions are accounted for using traditional or dynamic LCA in all the scenarios explored. The extent of these reductions is significantly sensitive to the end-of-life scenario assumed, the timing of the forest growth or regrowth and the time horizon of the integrated global warming impact in a dynamic LCA. A time horizon longer than one hundred years is necessary if biogenic flows from forest carbon sequestration and the building’s life cycle are accounted for. Further climate impact reductions can be obtained by keeping the biogenic carbon dioxide stored after end-of-life or by extending the building’s service life, but the time horizon and impact allocation among different life cycles must be properly addressed.
This study proposes a structural system and analysis model of passive controlled shear wall for mid-rise wooden construction with high damping rubber damper and cross laminated timber using drift-pin ...joint. In this paper, to verify the validity of the proposed analysis model and the effectiveness of the shear wall, cyclic loading tests of high damping rubber damper and full scaled shear wall specimens ware conducted. Test results ware simulated by analysis model using elastic-plastic pushover analysis. Calculation results simulated by proposed analysis model showed that the analysis results reproduced the experimental results accurately.
•It is feasable to use traditional hewing methods to produce beams for the structural repair of cultural heritage buildings.•It takes approximately 45 min per meter to hew squared beams 18 × 22 cm in ...cross section from spruce logs of suitable diameter by means of the low-work hewing method.•The time required for hewing spruce logs can be reduced by up to one-third by soaking the logs in water for several months after felling.•The costs and time required for producing hand-hewn versus machined structural elements are comparable, but there is an incomparable difference in ecological footprint and the effects on preservation of the carpentry craft.
The hand-hewing of timber has been a fundamental skill for carpenters throughout history. Inevitably though, the majority of wood used in construction at the present time is processed with the use of machines. Repairing heritage objects with machined wood however, as opposed to working replacement timber using similar craft methods and tools as those used in the original, is often in conflict with the principles set forth in the Venice Charter for the Conservation and Restoration of Monuments and Sites. Ultimately, relying on mechanization is a missed opportunity to contribute to the preservation of valued intangible cultural heritage.
Whereas the sustainability of traditional woodworking techniques and technologies can be promoted by applying them in the conservation of historical wooden buildings, the labor-intensive and time-consuming nature of manual woodworking makes feasibility questionable. In order to provide valuable insight for planners and monument care workers, the paper presents a study on the time demands associated with processing hand-hewn beams intended for use in the structural repair of wooden heritage objects.
A series of experiments was conducted wherein a total of 94 beams 18×22 cm in profile and 2.5 m in length were hewn from spruce logs of various diameters. The relationship between initial log diameter and required processing time is presented as a linear function. The relative proportions of the individual steps to the hewing process as a whole were also documented and showed a clear dependency on the total amount of material removal required. The overall processing time was significantly reduced in the case of timber that was soaked for several months before being hewn into beams, and the low-work hewing technique was shown to be more efficient in comparison to high work on trestles.
This paper has been published in memory of Petr Růžička, the great pioneer of forgotten carpentry techniques whose work opened a window to our past for future generations.
Brazilian timber housing producers were evaluated through a survey, which was based on face-to-face interviewing supported by a semi-structured questionnaire. Derived from expansive research, this ...paper aimed to identify labor size and to characterize economic size from this production sector. The sampling process evaluated 50.95% (n = 107) of all producers (n = 210) whose performance was considered close to ideal. This sector is mostly concentrated in micro and small-scale companies, though a small portion of medium-sized companies owned by sole proprietors, families, or small groups of entrepreneurs does exist. Due to compact sizing, no producer was classified as an industry or a large corporation. The main contrast was indicated by the number of direct jobs, whose estimation was about 3,700 workers for the whole studied sector, representing 1% of the overall Brazilian timber industry. Around 95% of timber housing producers are considered micro or small from a labor perspective. Unprecedented information could support discussions for the creation of assertive public policies.
Although not a new concept, modular construction has been the target of increasing interest and investment in recent years. Modular wood construction systems have economic and environmental ...advantages, as wood is a natural and locally available raw material with interesting thermal properties. In this context, the BlueWoodenHouse Project, a closed cooperation project between academy and industry, aims to improve the actual knowledge of modular wood construction in Portugal. Among other objectives, the project aims to characterize the solutions, systems, and materials used in wooden modular construction, specifically in a modular wooden, single-family house in full use. Afterward, the house was monitored for 1 year (temperature, relative humidity, and CO2) and the data collected were analyzed and the interior thermal comfort was evaluated. The results of CO2 concentration monitoring indicate adequate air renewal rates, except for some periods in the bedroom, during the night. Additionally, application of the adaptive comfort model proposed by the EN 16798-2 standard resulted in a percentage of time in discomfort due to overcooling ranging between 31.3% and 38.6%. However, most of these periods may correspond to times when there is no occupancy of these spaces.
Life cycle assessment (LCA) has been widely used to investigate the environmental performance of building developments. However, LCA studies on the construction stage emissions are limited due to its ...relatively minor impacts in a building life cycle. In view of the continual advancement in energy efficiency and building services, reducing carbon emissions from the construction activities will become more important. Such emission reduction is particularly crucial for wooden construction because reductions in these anthropogenic carbon emissions can enhance the utility of biogenic carbon sequestration and reduce the distance to carbon flux neutrality. This study applies LCA to a wooden construction to evaluate the anthropogenic carbon emissions from the material extraction, production, transportation, and particularly the construction stage. LCA data disaggregation is adopted to identify the unnoticed emission hotspots, contexts of the occurrence, and countermeasures against the underperformance for individual processes. The findings highlight that concrete foundation works of wooden constructions can contribute significantly to not only embodied carbon but also construction carbon emissions, and suggest courses of action for wooden constructions to reduce the anthropogenic carbon emissions. Future research should enrich the disaggregated LCA data for inter-referencing sustainable strategies to reduce the anthropogenic carbon emissions throughout the building life cycle.
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