| 1. |
- Goto, Yutaka, 1984, et al.
(författare)
-
Legislative background of timber structures in Europe and Japan - Case study in structural design of light-frame timber structure
- 2021
-
Ingår i: World Conference on Timber Engineering 2021, WCTE 2021.
-
Konferensbidrag (refereegranskat)abstract
- Standards and design codes are necessary to guarantee the desired safety and performance of structures. With regard to timber structures, considerable differences exist in the standards and design codes between Europe and Japan. In this contribution the framework of design codes for timber structure in Europe and Japan is compared. The fundamental approach in the structural planning, application of load and associated fire regulation is explained. Furthermore, a case study of the structural design of a 3-storey residential building with light-frame timber structure is performed to highlight the differences in the structural calculation and design approaches in construction details. Finally, potential optimization of different standards is suggested.
|
|
| 2. |
|
|
| 3. |
- Jockwer, Robert, 1984, et al.
(författare)
-
Design for adaption - Making timber buildings ready for circular use and extended service life
- 2020
-
Ingår i: IOP Conference Series: Earth and Environmental Science. - : IOP Publishing. - 1755-1307 .- 1755-1315. ; 588:5
-
Konferensbidrag (refereegranskat)abstract
- The construction sector has a significant share of Green House Gas emission and raw material consumption globally. Among common construction materials, timber has a long tradition of numerous applications as a renewable material. The implementation of the concept of circularity in the process of the construction of timber buildings has a high potential sustainability impact. The concept of design for adaption is to extend the service life of timber building to the maximum in several life cycles. In this paper the demand regarding circularity is analysed from interviews with different stakeholders and their economic, social and environmental incentive. The possibility to assess the sustainability impact of design for adaption are evaluated. Different examples of existing practices and potential solutions for design for deconstruction and adaption are summarized.
|
|
| 4. |
- Jockwer, Robert, 1984, et al.
(författare)
-
Design for adaption - making timber buildings ready for circular use and extended service life
- 2021
-
Ingår i: World Conference on Timber Engineering 2021, WCTE 2021.
-
Konferensbidrag (refereegranskat)abstract
- The use of timber and the implementation of the concept of circularity in the process of the construction of buildings potentially has a high sustainability impact, both from the perspective of material and construction technique. The three most effective ways to ensure the benefit of the circularity in the building sector in general are (1) maintain the service life of structures and buildings materials as long as possible to avoid unnecessary emissions and costs for demolition and reconstruction (2) conserve the quality of materials as long as possible to avoid unnecessary emissions and costs for the replacement and processing of new materials and (3) recycle and repurpose only the parts and materials which cannot function any more for technical and/or socio-cultural reasons. In this paper an approach is discussed towards a more sustainable built environment by making buildings adaptable to the changes of demands and requirements to building functions and thus leading to an extended use of buildings in a maximum of life cycles. This design for adaption may enhance economic, social and environmental benefits to various stakeholders and key players related to the building process, i.e. developers, building owners, users, municipality and others.
|
|
| 5. |
- Jockwer, Robert, 1984, et al.
(författare)
-
TOWARDS ADAPTABILITY AND CIRCULARITY OF TIMBER BUILDINGS
- 2023
-
Ingår i: 13th World Conference on Timber Engineering, WCTE 2023. ; 3, s. 1497-1505
-
Konferensbidrag (refereegranskat)abstract
- The construction industry has been a major contributor to resource consumption and global greenhouse gas (GHG) emissions, owed to high demand for building construction and the rapid urbanization trend. Timber construction has gained traction globally due to environmental advantages, such as renewability and carbon sequestration. However, sustainably available wood resources are limited. Extension of service life of timber structures is key to prolong their carbon stock. This paper showcases research projects carried out in Australia and Sweden that aim to design adaptable timber buildings capable of accommodating functional and spatial changes over time, thereby extending the service life of buildings and their components, as well as optimising their life cycles through spatial variations and repair of local damages to structural elements. This approach, known as Design for Adaptation (DfA) is an important step of the roadmap towards circular design solutions for timber buildings, which provide many economic, social and environmental benefits to all stakeholders and key players related to the building process, including manufacturers, engineers, architects, end-users, municipalities, and others.
|
|
| 6. |
- Alam, Ashraful, et al.
(författare)
-
Sustainability Assessment of a Wooden Multi-Storey Building Compared with an Equivalent Reinforced Concrete Alternative Using ToSIA: Finnish Perspective
- 2022
-
Ingår i: Journal of Sustainability Research. - : Hapres. - 2632-6582. ; 4:4
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to conduct a sustainability impact assessment (SIA) on a wooden multi-storey building and compare this to an equivalent reinforced concrete building using ToSIA (Tool for Sustainability Impact Assessment). The SIA considered the material flows and processes along the respective supply chains in Finland and included environmental, economic, and social indicators. The greenhouse gas savings of various wood-based materials of the buildings were also compared with concrete elements. The boundary of the quantitative analysis was cradle-to-construction site and included the structural support system of the building. Primary data was collected from the material supply chain and manufacturing facilities and were used to develop the life cycle inventory database. Secondary data were also referenced for the selected indicators. The results indicated that the wood frame structure provided greater environmental benefits, being responsible for only one-third of the greenhouse gas emissions and two-thirds of the non-renewable energy consumption during building material sourcing to the construction site gate, compared to the reinforced concrete alternative. In terms of socio-economic sustainability, the reinforced concrete alternative had higher production costs, but a lower labour intensity than wood. It was also found that non-fatal accidents occurred more often in the concrete supply chain, especially at the manufacturing facility, indicating that work safety was higher in the wood-alternative. In addition, the avoided greenhouse gas emission calculation showed that 159 kgCO2 m–2 could be avoided and 101 kgCO2 m–2 could be stored by replacing concrete frame building with wood. Such information can be useful for constructors, designers, and public bodies in making informed choices during building design and future construction. Future studies may extend the system boundary and include end-of-life scenarios and the cascading use of wood to find further greenhouse gas emissions savings.
|
|
| 7. |
- Aljuhmani, Ahmad Ghazi, et al.
(författare)
-
DEVELOPMENT OF A NOVEL JOINT SYSTEM FOR MID-TO-HIGHRISE CLT WALL BUILDINGS IN SEISMIC REGIONS
- 2023
-
Ingår i: 13th World Conference on Timber Engineering, WCTE 2023. ; 2, s. 1183-1191
-
Konferensbidrag (refereegranskat)abstract
- In Japan, the possibility of multi-story timber buildings is not yet practiced at a large scale due to the complex structural design process and construction cost. In conventional CLT buildings in Japan, a high number of complex steel connections are required. In this practice, complex processing of CLTs panel is also required. The objective of this paper is to propose easy-to-apply and easy-to-design steel joints. The proposed joint is designed to resist both shear and tensile forces to reduce complex steel parts. Single-bolt element tension tests were conducted to investigate the effect of the fibre direction, bolt diameter, and bolt embedded length. Cyclic loading for single and coupled CLT walls with the proposed joints was also conducted. The failure characteristics and strength of single-bolt connections could be predicted by the ratio of bolt embedded length and diameter. The fibre direction was found to have a minor effect on the connection strength. The proposed joint system showed high strength and ductility as found by the cyclic loading. The lateral strength of a wall with two panels was double the single wall case, indicating the lack of interaction between the two panels.
|
|
| 8. |
- Aljuhmani, Ahmad Ghazi, et al.
(författare)
-
Development of Steel Plate-bolt Joint System for CLT Hybrid Structures: Structural Performance Evaluation and Component-level Experiment
- 2024
-
Ingår i: AIJ Journal of Technology and Design. - 1341-9463 .- 1881-8188. ; 30:74, s. 106-111
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, a bolt-type steel joint system for CLT-steel hybrid buildings is proposed. The proposed connection consists of insertion steel plates and steel bolts with a large diameter that connect two CLT walls to steel beams. Evaluation methods to predict the structural performance of the connection are proposed and validated with component-level one-bolt connection tests. It was found that the methods can be used to predict the structural performance of the connection with good accuracy. The proposed connection can utilize the high strength and stiffness of CLT wall panels while maintaining an acceptable level of ductility.
|
|
| 9. |
- Andersen, Julie Swartz, et al.
(författare)
-
Economic comparison of mass timber and concrete construction in the nordic region
- 2023
-
Ingår i: 13th World Conference on Timber Engineering, WCTE 2023. ; 7, s. 4360-4369
-
Konferensbidrag (refereegranskat)abstract
- The timber sector has been growing strongly in various regions of the world. Yet, the construction industry is still far from being sustainable. One barrier is the economic concern in planning and construction works of timber constructions. This study aims to provide insights on the cost performance of Cross Laminated Timber (CLT) constructions for stakeholders to make an informed decision. It analysed the production cost of multi-story residential buildings with CLT in comparison to concrete in Norway and Sweden. The production cost data of various construction projects with either CLT or concrete was collected and analysed. Interviews with stakeholders were conducted to complement the interpretation of the cost data. The result showed that each project had its individual conditions in the economic background and requirements by client, and thus it was difficult to formulate a general tendency on the cost performance. The variability of the cost was larger and the average production cost was higher in CLT cases. Yet, there are high incentives of contractors and clients for a more sustainable alternative in general. The incentive is also reinforced by the general experience of contractors that the construction cost is better optimized as the contractor gains more experiences.
|
|
| 10. |
- Goto, Yutaka, 1984, et al.
(författare)
-
Applicability of a vapor-open wooden building envelope for subtropical regions in global context
- 2014
-
Ingår i: World SB14, 28-30 Oct 2014, Barcelona.
-
Konferensbidrag (refereegranskat)abstract
- The subtropical regions are of interest of our time as it includes both developing anddeveloped regions. The applicability of a vapor-open wooden building envelope to those regions wasevaluated in terms of the longevity of the wood fiber insulation layer and its life time cost. Atlanta,New York City, Shanghai and Sydney were selected as representing cities with different economic setups.Transient heat and moisture transfer simulation and life time cost analysis of the envelope wascarried out. It was shown that regions with lower humidity load from exterior in the summer andhigher electricity price such as New York City have high potential to apply the system. In order toeven further promote such an envelope system in the regions with lower electricity price and higherhumidity load, it is required to employ materials with lower price and higher moisture sorptioncapacity.
|
|
| 11. |
|
|
| 12. |
- Goto, Yutaka, 1984, et al.
(författare)
-
Economic, ecological and building physical optimization of a wooden building envelope for subtropical regionas
- 2012
-
Ingår i: World Conference on Timber Engineering, 15 - 19 July 2012, Auckland, New Zealand. - 9781622763054 ; :Architectural Technical Issue 2, s. 287-296
-
Konferensbidrag (refereegranskat)abstract
- With regard to the resource depletion and the global climate change, the construction industry is important for the realization of a sustainable society. In this study, a wooden envelope system for subtropical regions was investigated in order to find the optimal wood fiber insulation thickness. The analyses were done by weighting the initial investment and the running cost form the ecological and economic viewpoint. The building physically minimum insulation thickness was also calculated by hygrothermal models. It was shown that the ecological optimum is more costly than the economical optimum. I was also shown that the building physical minimum is dependent on the local climatic conditions. By conducting the analyses in terms of the ecology, economy and the building physics, it was able to identify the regions that the envelope system works more sustainably.
|
|
| 13. |
- Goto, Yutaka, 1984, et al.
(författare)
-
Economic, ecological and thermo-hygric optimization of a vapor-open envelope for subtropical climates
- 2012
-
Ingår i: Energy and Buildings. - : Elsevier BV. - 0378-7788. ; 55:December 2012, s. 799-809
-
Tidskriftsartikel (refereegranskat)abstract
- With regard to resource depletion and global climate change, it is becoming important to take holistic measures comprising ecological, economic and social aspects of the construction industry. An optimization method that deals with the trade-off among those pillars is needed to approach the overall life span of constructions from a holistic viewpoint. In this study, the insulation thickness of a vapor-open envelope system for subtropical regions with social advantages was investigated by an economic and ecological optimization model, taking into account both initial and running costs under the conditions of 8 cities in Japan. The thermo-hygric minimum thickness was also determined in order to ensure the longevity of the buildings. The following main findings were made: (1) the ecological optimal thickness was larger than the economic optimal thickness, (2) the thermo-hygric minimum was within the economic optimal range in most of the cases, and (3) the interest rate of the currency and the electricity price increase have a significant influence on the result of the optimization analysis. With the aid of the optimization model, it was shown that application of the envelope system is feasible in Japan, especially in the central and southern regions.
|
|
| 14. |
- Goto, Yutaka, 1984, et al.
(författare)
-
Heat and moisture balance simulation of a building with vapor-open envelope system for subtropical regions
- 2012
-
Ingår i: Building Simulation. - : Springer Science and Business Media LLC. - 1996-8744 .- 1996-3599. ; 5:4, s. 301-314
-
Tidskriftsartikel (refereegranskat)abstract
- Global warming and the resource depletion induced discussions on sustainable developments within the construction sector. Also the rapid urbanization in subtropical regions is becoming one of the most important global issues. Appropriate measures must be taken in such developments to avoid further damage to the environment. In this study, the heat and moisture balance simulation of building with a sustainable building envelope system for subtropical climate was proposed. In the moisture balance simulation the moisture buffering by the interior materials was taken into account. The prediction of moisture buffer value (MBV) of the interior finishing materials was attempted and validated by measurements. Subsequently, the whole building calculation was carried out and the contribution of the moisture buffering to the indoor comfort and energy consumption was investigated. The MBVs of the mineral-based materials were predicted with high accuracy. However, that of wood-based composite was much higher than the experimental value. In order to create a more accurate model, nonlinear moisture conductance should be accounted when modeling wood-based materials. The heating and cooling demand of a test house was 9.4 kWh/m2 and 14.5 kWh/m2, respectively. It was concluded that the utilization of the building envelope system has a high potential to provide sustainable houses in subtropical regions. In order to enhance both energy efficiency and indoor comfort of buildings in subtropical regions, there still is a strong need to develop a holistic method to find the optimum building design considering not only moisture buffering but also all the relevant factors. The presented model will be validated by in-situ measurements in the near future.
|
|
| 15. |
- Goto, Yutaka, 1984, et al.
(författare)
-
Hygrothermal Design of a Prefabricated Wooden Facade Module for School Building Renovation in Sweden
- 2016
-
Ingår i: World Conference on Timber Engineering (WCTE 2016), August 22-25, Vienna (Austria). - 9783903039001
-
Konferensbidrag (refereegranskat)abstract
- Today it is widely recognized that the construction industry plays a key role in the rational use of resources and the realization of a more sustainable society. Concerning buildings and energy use, renovation of the existing building stock to the higher energy performance is crucial. Among the various existing buildings in Europe, school buildings are of importance among the publicly owned buildings. However, there has been little effort in Sweden to promote the school building renovation by prefabricated wooden modules, which should be highly advantageous due to the short refurbishment period and its light weight.The present study investigated the hygrothermal property of wooden refurbishment modules in combination with an existing brick wall under Gothernburg (Sweden) climate. The criterion for the moisture safety inside the wall after the refurbishment was at 75% relative humidity in order to comply with the Swedish building regulation while it was assumed that the surface of the wall was wet from the precipitation during the refurbishment period. Two-dimensional transient heat and moisture transfer simulation was applied to three different module configurations. It was shown it is important to design the module vapour permeable so the entire wall system after the refurbishment have sufficient drying potential.
|
|
| 16. |
- Goto, Yutaka, 1984, et al.
(författare)
-
Hygrothermal performance of a vapor-open envelope for subtropical climate, field test and model validation
- 2016
-
Ingår i: Building and Environment. - : Elsevier BV. - 0360-1323. ; 110, s. 55-64
-
Tidskriftsartikel (refereegranskat)abstract
- The construction industry is known to be a key contributor to manmade climate change. Amongst other nations, Japan has a building energy efficiency goal which does not yet emphasize the importance of the moisture safety design of well-insulated building envelopes considering its diverse climatic conditions. The authors developed a vapor-open wooden building envelope for the subtropical conditions of Japan and optimized a design method, which considers environmental, economic and hygrothermal aspects. As a case study, a detached residential building has been constructed in Ohmihachiman (central Japan). The building has been monitored using a large number of temperature and humidity sensors inside the walls and the roof. Results have been obtained from measurements over a period of one year. Furthermore, transient hygrothermal simulations using the measured exterior and interior climates have been carried out. It was shown that 1) the construction of the wall was successful with the desired level of air-tightness and 2) the simulation model by a commercial software is applicable for predicting the hygrothermal performance of the wall with the envelope system in the actual use condition.
|
|
| 17. |
- Goto, Yutaka, 1984, et al.
(författare)
-
Indoor Comfort Evaluation of a Sustainable Wooden House with a Novel Vapor-open Envelope System in Subtropical Climate
- 2015
-
Ingår i: CISBAT 2015 International Conference "Future Buildings and Districts - Sustainability from Nano to Urban Scale", Lausanne, Switzerland, September 9-11, 2015.
-
Konferensbidrag (refereegranskat)abstract
- Concerning the resource depletion and global warming, the realization of sustainable constructions is crucial because the building industry has a big impact on the greenhouse gas emission. Recently the interest in the buildings in subtropical regions has been growing due tothe high growth rate of their urbanized areas. From the view point of building physics, those regions are very challenging because they have both heating and cooling demand. Also the prediction of indoor air humidity is acquiring a greater interest concerning the envelopedurability, the comfort and the energy consumption, which is very relevant to such regions. Meanwhile, there is a need of developing a new construction system and its design method for subtropical regions since it is inappropriate to simply use the established construction systems for cold regions which have only heating demand.Based on the transient hydrothermal model of the envelope and the whole building heat and moisture balance model taking into account the moisture buffering by hygroscopic interior materials, the authors have developed an envelope system and its insulation optimization scheme which considers lifetime environmental impact, lifetime cost, durability, users’ behaviour and local climate. The envelope consists of natural materials such as wood and clay and thus allows the moderate transfer of the water vapour in both directions i.e. from exterior to interior and from interior to exterior. A detached house with this system was realized in Ohmihachiman (central Japan) in June 2013 and the indoor temperature and humidity havebeen monitored at several points. The measured indoor climate was analysed and it was revealed that 1. the indoor climate in summer has a certain improvement potential and 2. the indoor climate in winter is satisfying. As the monitoring of electricity generation by the photovoltaic panels and the electricityconsumption of the whole house has showed a positive balance (more generation than consumption), it is suggested to either use the cooling radiator more actively or install an active dehumidifier into the mechanical ventilation system to provide a more agreeable indoor climate in the summer. The former recommendation will be implemented in summer 2015 and its impact on the comfort and energy consumption will be further analysed.
|
|
| 18. |
- Goto, Yutaka, 1984, et al.
(författare)
-
Numerical and real-life assessment of the moisture safety of CLT structure with PIR insulation composite under the Swedish climate
- 2020
-
Ingår i: E3S Web of Conferences. - : EDP Sciences. - 2555-0403 .- 2267-1242. ; 172
-
Konferensbidrag (refereegranskat)abstract
- The building industry is a major contributor of CO2 emission. Wood construction is a good option for carbon storage among various construction alternatives. Considering the growing market of multi-story wooden building in Sweden, CLT (cross laminated timber) structure with an alternative insulation composite with PIR insulation and MgO board was proposed. In order to prove the applicability of this construction for moisture safety, the hygrothermal performance of the wall was measured in real life at HSB Living Lab (Gothenburg, Sweden) throughout 2019. Furthermore, a numerical model to analyse its performance by transient heat and moisture transfer analysis was created to predict the performance of the wall system. After the successful validation of the numerical model, a parameter study was carried out to investigate the moisture risk of the wall system in the case of extensive wetting of the CLT panel and in various areas in Sweden (Gothenburg, Stockholm, Lund, Karlstad and Lule). The study showed a low mould growth risk either in the test at the living lab or in the feasibility study. The development of the technology should further focus on the cost-effectiveness and design of all the construction details for the future market application.
|
|
| 19. |
- Goto, Yutaka, 1984, et al.
(författare)
-
Preliminary investigation of a vapor-open envelope tailored for subtropical climate
- 2011
-
Ingår i: Building and Environment. - : Elsevier BV. - 0360-1323. ; 46:3, s. 719-728
-
Tidskriftsartikel (refereegranskat)abstract
- Concerning global warming and resource depletion, the impact of buildings in subtropical regions is becoming even greater due to a high growth rate of urbanized areas. From the viewpoint of building physics, the main problem concerning subtropical climate is the high level of humidity in combination with high temperature. In this study, a flexible building envelope consisting of wood and clay components was developed so that the materials and the assemblies can be easily tailored to comply with local climatic conditions. The movement and accumulation of moisture in the wall was of prime concern. This has been investigated by means of testing full scale walls in a climate chamber and the corresponding one dimensional transient heat and transfer simulation. In order to achieve a consistency between calculation and measurement, the individual materials were tested for their hygric and thermal properties. Based on these findings attempts were made to calculate the behavior of an optimized wall assembly under real climatic conditions of central Japan. As a result, it was shown that the hygrothermal behavior of the envelope is predictable by means of the models and the simulation program used, and that no risk of interstitial condensation and mold growth was predicted under the real climatic conditions of Kyoto.
|
|
| 20. |
- Goto, Yutaka, 1984, et al.
(författare)
-
Study on heat and moisture balance of a sustainable building envelope for subtropical regions
- 2011
-
Ingår i: CISBAT 2011 "CleanTech for Sustainable Buildings – From Nano to Urban Scale", Sept. 14-16, 2011, EPFL, Lausanne, Switzerland. - 9782839909068
-
Konferensbidrag (refereegranskat)abstract
- Concerning the resource depletion and global warming, the realization of sustainable constructions is crucial because the building industry has a big impact on the greenhouse gas emission. Recently the interest in the buildings in subtropical regions has been growing due to the high growth rate of their urbanized areas. From the view point of building physics, those regions are challenging because they have both heating and cooling demands. Also the prediction of indoor air humidity is acquiring a greater interest concerning the envelope durability, the comfort and the energy consumption. Authors developed a new building envelope system for subtropical regions. This envelope is a vapor-open and sorption-active system which allows the moderate transfer of the water vapor in both directions i.e. from exterior to interior and from interior to exterior. It consists of hygroscopic materials such as wood and clay, and its design system enables the make-up of the envelope to be flexibly changed according to the individual design conditions such as local climate, preferred room temperature and humidity and so on. The wall make-up is optimized so that no occurrence of interstitial condensation is predicted by transient heat and moisture transfer simulations. The energy consumption and the comfort of the building with this system, which will be built in central Japan, was analyzed. The dynamic energy simulation on hourly basis of an example case was carried out by means of a simulation program in accordance with ISO 13790.Furthermore, based on the heat balance simulation, the indoor humidity of the living room was predicted by means of a simplified moisture balance equation. This equation included the ventilation rate, the internal moisture load, and the moisture buffering by the interior materials. The result of the heating and cooling energy need was 13.9 kWh/m2 and 9.8 kWh/m2 respectively. The moisture buffering by the interior finishing reduced the fluctuations of the humidity and the acceptability of the room air. As a result, it was concluded that the utilization of the building envelope system has a high potential to provide the low-energyconsuming and durable houses in subtropical regions. However, there still remains a need to improve the indoor comfort situation in summer. The model will be validated by the in-situ measurement in the test house in the near future.
|
|
| 21. |
|
|
| 22. |
- Goto, Yutaka, 1984, et al.
(författare)
-
Sustainable Buildings based on international know-how exchange and adaptation – technological approaches on building physical problems of building envelopes in terms of climate difference
- 2010
-
Ingår i: Annual meeting of Alliance of Global Sustainability, 17-19 March 2010, Tokyo.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- While the need to reduce energy consumption in buildings is well accepted, the exact measures to be taken to counter the resulting emissions are generally not agreed on. The general discussion is whether to focus on passive (the envelope), active measures (heating/ cooling system and the energy generation) or user behaviour to reduce energy consumption. This gets even more difficult when building concepts are to be transferred and adapted to other climates than where they originate from. As the demand in many countries for knowledge on how to most effectively reduce the emissions from the building stock is high, the need for a sound approach on this problem is likewise huge.The poster will introduce an ongoing cooperation between the University of Tokyo and ETH Zürich on developing sustainable buildings for Japan, using existing know-how, technology and experience values from Switzerland and/or Europe and tailoring them to Japanese culture and climate. In Japan, the low energy efficiency and the short life-span of buildings are the outstanding issues. Their poor insulation and ventilation plan are requiring huge energy consumption for heating and cooling. Furthermore, countermeasures against heat and moisture problems are so insufficient that dew condensation would cause mold growth resulting in biological deterioration of building elements and emission of poisonous substances. The main reason is that generally only several standardized construction methods are employed regardless of wide range of design conditions and engineers are lacking sound building physical knowledge.In this study, a flexible and sustainable building envelope whose wall make-up can be tailored easily to local climate and use behavior was developed. For social and ecological sustainability, this method allows the building elements to be free from condensation ensuring the longevity of buildings, inhabitants’ health and the energy efficiency because of the sufficient amount of insulation and its systematic ventilation. At the same time, the materials used as building components consist of wood and soil that have low environmental load for production and don’t contain toxic compounds. For economical sustainability, the well-organized insulation and ventilation system keep the running consumption low. As a unique potential steaming from the construction method, it can offer the industry to utilize a large amount of small-sized woods which come from forest improvement and are regarded as too weak to use as structural elements.For validating the feasibility of this building envelope, the hygrothermal property of the wall was examined. From the view point of building physics, the main problem concerning Japanese climate is high level of humidity in combination with high temperature in summer. Thus the moisture sorption characteristic of the wall is hereby of prime concern. For archiving a quality simulation, the individual materials’ hygrothermal properties were tested as well as full scale test walls using standard conditions. In parallel, transient heat and moisture simulation was also done. As a result, the simulation and the experiment corresponded each other with high accuracy. Consequently, it was shown that the envelope can eliminate the risk of dew condensation in comparison with conventional wall constructions.
|
|
| 23. |
- Goto, Yutaka, 1984, et al.
(författare)
-
Sustainable wooden envelope for subtropical regions - The realization and validation in Japan
- 2014
-
Ingår i: World Conference on Timber Engineering 2014, 10-14 August 2014, Quebec City.
-
Konferensbidrag (refereegranskat)abstract
- A vapor-open wooden building envelope for subtropical regions and its design optimization method, whichconsiders environmental, economic and thermo-hygric aspects, were developed by the authors. As a case study, a test house(a detached residential building) has been constructed in Ohmihachiman (central Japan) and a number oftemperature/humidity sensors were installed inside the walls as well as in the rooms. It was found that closecommunications among the designers, the constructors and the client is essential in order to realize a building with newfeatures as it is designed. The hygrothermal model of the building envelope was successfully validated.
|
|
| 24. |
- Goto, Yutaka, 1984, et al.
(författare)
-
Transfer of energy efficient building concepts to subtropical climate– The first MINERGIE P® based building in Japan
- 2014
-
Ingår i: 10th Nordic Symposium on Building Physics, 15-19 June 2014, Lund.
-
Konferensbidrag (refereegranskat)abstract
- While there are solid experience values for energy efficient buildings in moderate climate in Europe,the transfer of these concepts to differing climate and socio cultural conditions is a field ofexperimentation in building physics. Started as a cooperation project between Switzerland and Japanand now continued by including Sweden as a partner, the first Japanese residential building based onthe MINERGIE P® standard has recently be realized in central Japan.This presentation will offer a summary of the applied concept for the building envelope and housingservices. The focus will be on measures to deal with the high humidity loads in subtropicalindustrialized country with related demand for comfort conditions and regular earthquakes strainingthe construction and the measures to achieve the MINERGIE P® targets in Japanese climate.
|
|
| 25. |
|
|
| 26. |
- Hansted Andersen, Julie, et al.
(författare)
-
Construction cost of timber buildings
- 2022
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- There are increasing interests and practices in modern large timber constructions globally for the renewability and carbon storage function of wood. However, many stakeholders with limited knowledge and experience with timber still feel uncertain on how to carry out construction projects with timber. The common notion is that timber constructions would become more costly than a conventional alternative such as concrete. In order to inform wide spectrum of construction stakeholders in Scandinavia, this report presents a study on construction cost of cross laminated timber (CLT) buildings compared with concrete/steel buildings in Denmark, Norway and Sweden. The study investigated the actual cost of 9 recent multi-storey residential buildings, 5 constructed with a load-bearing system in primarily CLT and 4 constructed in primarily concrete in Norway and Sweden. Due to the nature of the chronological and geographical differences of market conditions, the cost data were evaluated separately for Norway and Sweden. In addition to the case building analysis, interviews were conducted with stakeholders from the case building projects as well as those from the industry with experiences with CLT buildings. The interviews contributed to a broader perspective of the cost analysis, with explanations of the projects and experiences of advantages and disadvantages for CLT building and concrete buildings. The results showed a tendency that the construction cost of the Norwegian CLT projects were higher than the Norwegian concrete projects. For the Swedish projects the concrete building had a higher cost compared to the CLT projects, however it can't be concluded as a tendency for the Swedish projects, since investigation only included one concrete project and two CLT projects. The results showed that often the material-related costs were higher for CLT buildings than concrete buildings. Such costs are for example the material cost itself and transportation cost for a long distance. Furthermore, the fire protection and measures for the finalized building according to fire safety resulted in a higher cost in the CLT cases. However, the construction time is often shorter for CLT buildings than concrete buildings, and CLT buildings are lighter and therefore the foundation can be dimensioned smaller. Although such observations were made, throughout the interviews it was stated that one should be careful comparing the cost of two buildings since the cost is very much depended on the specific project. Thus, the results shown in this report must be seen as tendencies and not as a forecast for specific cost difference between CLT building and concrete buildings. This study was an investigation of construction costs and advantages and disadvantages of CLT buildings in relation to the construction cost up till 2022. When there is a major change in the economy and legislations of the construction sector, the cost structure may be substantially affected. One of such factors may be the increasing focus on the reduction of greenhouse gas (GHG) emissions from the construction industry. The availability of resource might be also a key factor for the future cost development for both CLT and concrete.
|
|
| 27. |
- Kono, Jun, 1987, et al.
(författare)
-
Factors for Eco-Efficiency Improvement of Thermal Insulation Materials
- 2016
-
Ingår i: Key Engineering Materials. - 1013-9826 .- 1662-9795. ; 678, s. 1-13
-
Tidskriftsartikel (refereegranskat)abstract
- Thermal insulation material is an important component to reduce the environmental impact of buildings through the reduction of energy consumption in the operation phase. However, the material itself has embodied environmental impacts for the value it provides. Eco-efficiency is a method that quantifies relation between the environmental performance and the created value of a product system. This study investigated contributing factors of the eco-efficiency of thermal insulation materials to support decision making of material manufacturers. For the improvement of eco-efficiency, the assessment was made in two scopes: investigating the contributing factors of impact caused at production processes; and thermal performance through thermo-physical properties. For quantifying environmental impacts, cradle-to-grave life cycle assessment (LCA) of each materials were made. The life cycle impact assessment (LCIA) indicators used were ReCiPe H/A and global warming potential (GWP100a). For the assessment of production process, the inventories of the materials were assigned to six categories: heat, chemicals, electricity, transportation, raw materials and wastes. Among the assessed materials, contribution of electricity and heat within the production process was large for foam glass which had the highest potential to improve the eco-efficiency which was by factor 1.72. The analysis on relation between thermo-physical properties and eco-efficiency based on product data of the materials highlighted the importance of density as an indicator upon development and use. Although density often gains less attention, the finding suggested the effectiveness of improving the efficiency by having lower density without compensating the performance of the materials.
|
|
| 28. |
- Kono, Jun, 1987, et al.
(författare)
-
Utilization of Multi-Criteria Assessment on Building Thermal Insulation Materials
- 2015
-
Ingår i: The 5th International Conference on Green and Sustainable Innovation (ICGSI 2015) Towards Green Growth and Green Competitiveness". ; , s. O-65
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- IntroductionMulti-criteria assessment (MCA) is a methodology that supports making decisions by capturing multiple aspects. Building thermal insulation materials are products that have various properties including mechanical strength, fire resistance, acoustic performance, hygrothermal property and so on. In addition, Life Cycle Impact Assessment (LCIA) of the materials is gaining its importance with the growing interest on the design of sustainable buildings. However, there is limited number of studies which dealt with the selection of the material considering multiple aspects. This study applied MCA on common insulation materials (stone wool and expanded polystyrene (EPS)) to examine its effectiveness when selecting more environmentally friendly material.Experimental/Theoretical StudyAmong various MCA methods, the study applied analytical hierarchy process (AHP). AHP is one of the most common approaches for MCA that performs pair-wise comparison between different choices against each criterion[1]. AHP integrates the compared results into single normalized scale as an output. Upon integration, weighting which reflects the relative importance of the criteria can be made. The study applied AHP for thermal insulation materials to be used for vertical walls by taking technical and environmental criteria: thermal conductivity (TC), compression strength (CS), fire resistance (FR) and global warming potential (GWP) via LCIA of the materials. Case studies were made in five scenarios with weighting of each of three criteria as top priority and no weighting which is shown in Table 1.CasesPrioritiesResultCase 1GWP > TC = CS = FRSW > EPSCase 2TC > CS = FR = GWPSW > EPSCase 3CS > FR = GWP = TCEPS > SWCase 4FR > GWP = TC = CSSW > EPSCase 5GWP = TC = CS = FRSW > EPSTable 1. Summary of priority of seven cases and their resultsResults and DiscussionFor Case 3 where compression strength was top priority, EPS was superior to Stone wool. With all the other cases, stone wool was preferable over EPS. Moreover, stone wool outperformed EPS even without weighting. This suggests that in contrary to conventional design practice, the inclusion of LCIA results in AHP encourages users to select more environmentally friendly material between the two for the investigated value criteria. As the weighting showed its importance upon selection of sustainable insulation materials, further investigation on the weighting scheme is necessary. ConclusionThe study applied MCA for assessing two typical building thermal insulation materials that took environmental and technical aspects into account. The result showed the effectiveness and challenge of using AHP for including LCIA results upon choosing sustainable insulation materials. Moreover, further consideration for compression strength is also necessary as it may require restrictions such as threshold value depending on specific building details, codes etc. In order to allow this MCA fully applicable for building design, further improvements on the method is necessary.Reference[1] Huang, I.B., J. Keisler, and I. Linkov, Multi-criteria decision analysis in environmental sciences: ten years of applications and trends. Sci Total Environ, 409(19): p. 3578-94 (2011).
|
|
| 29. |
- Leyder, Claude, et al.
(författare)
-
Investigations on the Sustainable Resource Use of Swiss Timber
- 2021
-
Ingår i: Sustainability. - : MDPI AG. - 2071-1050. ; 13:3, s. 1-34
-
Tidskriftsartikel (refereegranskat)abstract
- In Switzerland, the advantages of timber buildings for the climate are broadly discussed. In the following paper, a comparative sustainability assessment of four building alternatives is presented. Especially the contribution of implementing Swiss timber versus the implementation of imported timber is highlighted. Additionally, the timber-hybrid building structures are compared to a pure reinforced concrete structure. The timber-hybrid structure, with Swiss timber, has clear ecological advantages with only half the greenhouse gas emissions and half the non-renewable energy consumption compared to the reinforced concrete alternative. Comparing the Swiss timber alternative to the imported timber alternative, there are clear ecological advantages, as well. In terms of economic and social sustainability assessment criteria, the reinforced concrete alternative has the lowest production costs and the lowest labor intensity (measured in terms of full-time equivalents). Additionally, the paper includes an analysis of biogenic CO2 emissions and CO2 storage within the timber building alternatives. Finally, an up-scaling to the national level is attempted, showcasing the ecological and economic advantages of promoting the use of locally produced timber.
|
|
| 30. |
- Piccardo, Chiara, et al.
(författare)
-
Challenge-based, interdisciplinary learning for sustainability in doctoral education
- 2022
-
Ingår i: International Journal of Sustainability in Higher Education. - 1467-6370. ; 23:7, s. 1482-1503
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: Doctoral candidates possess specialized knowledge that could support sustainability transitions. Doctoral education, however, often focusses on discipline-specific topics and working methods, making it difficult to “see the bigger picture”. This summer school on wood construction gathered doctoral candidates from different fields to explore how solutions to complex sustainability issues could be found by working together across disciplines and by engaging multiple stakeholders. The purpose of this study is to report the pedagogical approaches taken and to understand whether these fostered the candidates’ ability to develop systemic solutions and professional competency. Design/methodology/approach: Twenty doctoral candidates from various backgrounds participated in a two-week summer school organized by a consortium of four universities. Interdisciplinary groups worked on real-life challenges using a systemic approach to co-create tangible solutions. To support the creation of socio-technical innovations, stakeholders and experts from different fields were involved. The participants completed two questionnaires during the summer school to help elucidate their learning experiences. Findings: The doctoral candidates showed strong willingness to cooperate across disciplines, though they found it important to connect this learning experience to their research. The candidates reported that the experience enhanced their ability to work in a multidisciplinary capacity. The experience identified a solid basis for interdisciplinary learning principles that could be replicated. Originality/value: The summer school focussed on an innovative learning experience based on a systems thinking approach and the development of interdisciplinary capacity in the research-business ecosystem.
|
|
| 31. |
- Tsuda, Kazuki, et al.
(författare)
-
A Workability and sustainability assessment of multistorey earthquake-resistant timber building
- 2023
-
Ingår i: 13th World Conference on Timber Engineering, WCTE 2023. ; 7, s. 4286-4294
-
Konferensbidrag (refereegranskat)abstract
- Although two-Thirds of the area of Japan is covered with forests, the domestic wood resources are not widely used in the construction sector. Due to the complex design process, construction work and high precision needed, most of timber constructions are limited to one or two-storey buildings. This paper aims to clarify the efficiency of a proposed joint system for CLT walls-steel beams hybrid structure. In addition, the workability and the environmental impact of the proposed hybrid system in comparison to other structures were analysed. The proposed joint system showed higher workability and efficiency compared to other conventional joints in Japan. The construction process of a prototype of a module with the proposed system was studied and confirmed its easier and faster work than the conventional system. A 4-storey building was taken as a case study to evaluate the environmental impact of the proposed system. Although the proposed hybrid system showed higher carbon emissions than a conventional CLT alternative, advantage in terms of the environmental impact was confirmed in comparison to a reinforced concrete and a steel structure.
|
|
