ThesisPDF Available

Multi-Storey Timber-Based Buildings: An International Survey of Case-Studies with Five or More Storeys Over the Last Twenty Years

Authors:

Abstract

Since the early 2000s, there has been a steady and heterogeneous proliferation throughout several western countries of multi-story timber-based buildings. This thesis confirms that since the first five-storey building was realised in 2004, at least 196 others were built until 2019. With many of these case-studies having been researched for the first time, the goal of this dissertation is to categorize the different international approaches and to define what are the drivers which had an effect on the design. Because the research topic is a recent development in academia, this thesis defines what multi-storey timber-based buildings actually are, and, after the discussion of existing literature, proceeds with the selection of the case-studies according to defined height and structural criteria. With the complete list of the buildings, the thesis first analyses the design characteristics of all case-studies, in order to research how these projects were built. The analysis includes thirty-two structural categories in which each case-study is classified and described. The analysis was able to show that there are many design differences between the countries involved. Some clusters of solutions can also be identified. The purpose of the second step was to understand by who and why these buildings have been built. In order to answer these questions, the thesis proceeds with each country's contextual analysis. Regulatory framework in place at the time of the project are described, but the focus is given on the stakeholders and R&D concepts involved in the realisation of the selected case-studies. Furthermore, the declared reasons for choosing a timber structure, along with the public and private typology of the commission were also researched. The contextual analysis shows, as the literature confirms, that the legal framework often sets the necessary rules for building multi-story timber-based buildings. However, the role played by the stakeholders is not secondary, and there are clear patterns of interdependence between many case-studies and the professionals involved in their construction. While private clients are often the actual drivers behind the majority of the cases, there are several countries in which the leading role is played by public initiatives. In some cases, the intrinsic properties of timber played a decisive role in the choice of the clients. This dissertation adds further valuable information regarding the constructive and contextual characteristics of multi-story timber-based buildings built over the last fifteen years, in order to show the differences and commonalities between each country involved. Multi-storey timber-based buildings are a complex phenomenon, which really depend on the nation in which they were built. At the same time, it was possible to identify international trends in their design, and major players which considerably influenced the design solutions and realisations of these buildings.
A preview of the PDF is not available
... Thus, the advances that relate to environmental sustainability and economic sustainability were strongly linked to the energy savings generated by multi-storey timber buildings compared to traditional construction methods and materials, while the use of CLT to achieve greener buildings at a competitive cost was next in importance. These findings were consistently based on studies carried out in different countries such as the United States, Canada, Italy, Australia, Sweden, Slovenia, and Finland; however, it would be interesting to validate these results in areas such as Asia and Latin America, where there are abundant forest resources but with a still incipient construction of multi-storey timber buildings [268,275]. ...
... The environmental, social, and economic sustainability of multi-storey timber buildings is a research trend currently focused on Australia, Canada, the United States, and European countries. Due to the fact of this, it is seen as a potential line of research to validate these results in Asian and Latin American countries, where there are important forest resources but the construction of multi-storey timber buildings is still incipient [268,275]. ...
... In terms of the advances related to engineering and construction sciences, they are very well documented, being consistent, robust, and marking a clear trend in the seismic analysis of multi-storey timber buildings as the main research line. This is also supported by different review articles focused on the seismic design of multi-storey timber buildings, covering topics such as cross-laminated timber (CLT) design, hybrid structures, and seismic protection technologies [10,15,[30][31][32][33]; and also supported by publications that have documented the current practice of the world industry in the development of high-rise timber buildings [268,275]. ...
Full-text available
Article
Products derived from trees have been used by mankind for thousands of years, where timber has a long tradition as an ecological construction material. There is currently an increasing trend in multi-storey timber buildings, because of the projected growth in the demand for housing in urban areas between now and 2050, along with the urgent need for a more sustainable and productive construction industry. The construction of these buildings is now possible thanks to the new advances in architecture, engineering, and construction (AEC) and the new technological developments around timber construction. Its industrialization requirements imply a paradigm shift for the construction industry, which requires, among other aspects, the early and collaborative integration of stakeholders in its design and construction process. According to this, the objective of this review article is to determine the main advances and limitations related to the design and construction of multi-storey timber buildings, categorizing them in aspects such as sustainability, engineering and construction sciences, and collaborative design. The methodology of this article was based on the review of 266 articles published in Web of Science (WoS), as indexed scientific journals, between 2017 and mid-2022, performing a comparative and cooccurrence analysis of the contents. The results evidenced that 73% of the articles showed advances and limitations corresponding to the engineering and construction sciences category, 23% to sustainability, and the remaining 4% to collaborative design. The main advances in the development of multi-storey timber buildings are related to seismic analysis, connections design, fire performance, and fire design. While the main limitations are related to social sustainability, the results are not conclusive due to the low number of publications that support them.
... The 14-story Treet was built in Bergen in 2014, then Brock Common in Vancouver, with 18 floors, opened in 2017 and Mjøstårnet, also with 18 floors, opened in 2019 in Norway, see Figure 12 (left). Eventually, the hotel tower at Sara Cultural Center in Skellefteå (Sweden), see Figure 12 (right), made of Cross-Laminated Timber (CLT), is 20-story tall and the top of the construction was reached by the end of 2020, Salvadori (2021) and Safarik et al. (2022). Now, in 2022, the pace might increase even more if we believe the wooden projects under construction and planned in several big cities according to Dezeen.com: ...
... The CTBUH is keeping track of all types of tall buildings around the earth and now also on high-rise timber buildings above seven stories, or 25 m in height, on new propositions, and pushes innovation for timber and hybrid solutions Safarik et al. (2022). Together with several recent other surveys on multi-story timber buildings, they pointed out interesting technical facts from built projects and new trends, Salvadori (2021) and Svatoš-Ražnjević et al. (2022): ...
... Glued-in rods are often used for GLT column connections. In tall CLT-based buildings, screws with diameters from 6 to 12 mm are widely used, and sometimes in combination with steel brackets and plates with thicknesses varying between 2 and 8 mm, Salvadori (2021). ...
Full-text available
Thesis
Climate change and densification of cities are two major global challenges. In the building and construction industry, there are great expectations that tall timber buildings will constitute one of the most sustainable solutions. First, vertical urban growth is energy and resource-efficient. Second, forest-based products store carbon and have one of the highest mechanical strength to den-sity ratios. If the structural substitution of concrete and steel with wood in high-rise buildings awakens fears of fire safety issues, engineers and research-ers are particularly worried about the dynamic response of the trendy tall tim-ber buildings. Indeed, due to the low density of wood, they are lighter, and for the same height, they might be more sensitive to wind-induced vibrations than traditional buildings. To satisfy people’s comfort on the top floors, the ser-viceability design of tall timber buildings must consider wind-induced vibra-tions carefully. Architects and structural engineers need accurate and verified calculation methods, useful numerical models and good knowledge of the dynamical properties of tall timber buildings. Firstly, the research work presented hereby attempts to increase the under-standing of the dynamical phenomena of wind-induced vibration in tall build-ings and evaluate the accuracy of the semi-empirical models available to esti-mate along-wind accelerations in buildings. Secondly, it aims at, experimen-tally and numerically, studying the impact of structural parameters – masses, stiffnesses and damping – on the dynamics of timber structures. Finally, it suggests how tall timber buildings can be modeled to correctly predict modal properties and wind-induced responses. This research thesis confirms the concerns that timber buildings above 15-20 stories are more sensitive to wind excitation than traditional buildings with concrete and steel structures, and solutions are proposed to mitigate this vibra-tion issue. Regarding the comparison of models from different standards to estimate wind-induced accelerations, the spread of the results is found to be very large. From vibration tests on a large glulam truss, the connection stiff-nesses are found to be valuable for predicting modal properties, and numerical reductions with simple spring models yield fair results. Concerning the struc-tural models of conceptual and real tall timber buildings, numerical case stud-ies emphasize the importance of accurately distributed masses and stiffnesses of structural elements, connections and non-structural building parts, and the need for accurate damping values.
... In recent years, there has been a growing number of design-related studies on the topic of multi-storey timber construction and its international adoption since the changes in building code in the early 2000s [19]. Pioneering 'Nordic Wood Program' with light frame timer residential projects in Sweden, as well as cross laminated timber (CLT)-based projects in Austria and Bavaria, starting in the 1990s set the foundation of the technologies these studies have built upon [19]. ...
... In recent years, there has been a growing number of design-related studies on the topic of multi-storey timber construction and its international adoption since the changes in building code in the early 2000s [19]. Pioneering 'Nordic Wood Program' with light frame timer residential projects in Sweden, as well as cross laminated timber (CLT)-based projects in Austria and Bavaria, starting in the 1990s set the foundation of the technologies these studies have built upon [19]. Most existing scientific literature on multi-storey timber buildings discusses technical, acoustic [20][21][22], structural [23][24][25][26][27], or energy [28] and sustainability scopes [29,30]. ...
... As Figure 2 shows, the data sources comprise: academic papers and grey literature sources such as government and institutional reports, master and doctoral theses, published timber construction books, magazines, websites, and online project databases. Out of 350 projects, 141 match with the latest Salvadori's 2021 survey [19,40]. In most cases, multiple sources were used to gather necessary quantitative and qualitative information on the projects. ...
Full-text available
Article
Throughout the last two decades the timber building sector has experienced a steady growth in multi-storey construction. Although there has been a growing number of research focused on trends, benefits, and disadvantages in timber construction from various technical perspectives, so far there is no extensive literature on the trajectory of emerging architectural typologies. This paper presents an examination of architectural variety and spatial possibilities in current serial and modular multi-storey timber construction. It aims to draw a parallel between architectural characteristics and their relation to structural systems in timber. The research draws from a collection of 350 contemporary multi-storey timber building projects between 2000 and 2021. It consists of 300 built projects, 12 projects currently in construction, and 38 design proposals. The survey consists of quantitative and qualitative project data, as well as classification of the structural system, material, program, massing, and spatial organization of the projects. It then compares the different structural and design aspects to achieve a comprehensive overview of possibilities in timber construction. The outcome is an identification of the range of morphologies and a better understanding of the design space in current serial and modular multi-storey mass timber construction.
... Interviewed experts underlined that the existence of fire protection strategies such as fire-retardant paints is critical for the realization of taller wooden buildings today. Similarly, many studies on tall wooden buildings in the literature have drawn attention to the vital importance of fire protection for these towers [68,[92][93][94][95][96]. Furthermore, the increase in demands for fire protection applications in wood was among the key issues that the experts addressed. ...
Full-text available
Article
This paper examined wood preservation practices and outlook considering climate change from the perspective of Finnish experts through interviews. Key findings highlighted that: (1) pressure impregnated wood will continually evolve and secure its market, and it seems worthy of developing modified wood products, especially with the increasing attention to recyclability and lifecycle concepts; (2) demand for highly processed surface treatment products is high; (3) opportunities for more sustainable and environmentally friendly wood preservation methods, and thus production volume will increase in the future; (4) increasing mold problems in Finland due to climate change make surface treatment more important than ever; (5) demands for fire protection treatments are increasing, but fire testing fees and processes have slowed product development; (6) although the possibility of the spread of termites triggered by global warming to Finland seems to be a future scenario, this issue needs to be considered in products exported to hot countries; and (7) preservatives have become more critical to protect untreated wood from the adverse effects of climate change. It is believed that this study will help accelerate the transition of innovative and environmentally friendly wood treatments on the Finnish market, thereby promoting the use of wood in the building construction industry.
... CO 2 has been a game-changer since 1970, sparking a revolution in the way buildings are built. With the successful implementation of issues such as efficiency and passive standards in just a few years, there has been an increased emphasis on sustainability during and after the construction site [10]. Furthermore, today, the construction industry accounts for approximately 40% of annual greenhouse gas emissions, 40% of global resource consumption, 40% of energy use, and 50% of global waste, timber is a valuable alternative material [11,12]. ...
Full-text available
Chapter
Since the end of the twentieth century, the question of how to deal with the increasing scarcity of resources has been at the center and the need for renewable materials has come to the fore, especially in the construction sector. A possible solution to these environmental challenges is represented by the development of engineered timber products, which allowed the realization of tall timber structures. Their main drivers are decarbonization, forest management, and timber life cycle, urbanization, and densification, productivity in the construction industry, and the benefits of using timber indoors. In this context, this chapter will analyze data from the 10 tallest timber building cases to enhance the understanding of contemporary trends. Data are collected through literature surveys and case studies to analyze the main architectural and structural design concerns to contribute to the knowledge about the growing tall timber structures around the world. By revealing up-to-date features of the tallest timber towers, it is thought that this chapter will contribute to aiding and directing key construction professionals such as architects, structural engineers, and contractors, in the design and construction of future tall timber building developments.
... In line with the government policy mentioned above, by focusing on the impact of business activities, for example, building construction industry, on climate and natural sources, ecological awareness has increased significantly in the last two decades and environmental degradation has been defined as a global problem (e.g., [56][57][58]). This important global rising awareness has led to the development of new and more environmentally friendly timber-based solutions, especially in the Finnish wood construction industry as the future vision. ...
Full-text available
Chapter
Finland has a long history of massive wood construction such that the log construction technique has been used as a traditional method of Finnish residential construction for thousands of years, and the entire history of Finnish architecture is based on this technique. Today, almost all leisure buildings, for example, cottages in Finland are made of wood and mostly log construction. Also, today 90% of Finland's detached houses have timber frames, and a quarter of them are made from industrial glue logs. Apartment buildings began to be made of wood, especially cross-laminated timber (CLT) and laminated veneer lumber (LVL). The most common way of constructing wooden apartments is to use volumetric elements as compared to load-bearing large elements and post-beam systems. The increase in environmental awareness in Finland, as in many European countries today, strengthens the popularity of wood construction, and this brings the search for innovative and environmentally friendly engineered wood product solutions (e.g., dovetail massive wood board elements) as a future vision. The chapter aims to identify, combine, and consolidate information about massive wood construction in Finland from past, present, and future perspectives. This study will assist and guide Finnish key professionals in the design and implementation of timber buildings.
Full-text available
Article
Timber construction is considered a main strategy towards a more sustainable built environment. Industrialized manufacturing methods have advanced the realization of multi-storey timber buildings generating enthusiasm about their implementation in urban areas, and the expectation of their further completion. These are still pilot projects, so there is a lack of specific literature and guidelines, including common understanding, standard procedures and holistic considerations. This paper aims to assess the current situation of design and construction processes of timber buildings in Austria, highlighting barriers and opportunities and formulating recommendations for its further adoption. The methodology used is based on an extended literature review and a qualitative analysis from expert interviews. Different disciplines were involved to approach the topic holistically. Interviews were recorded, transcribed and inductive coded within several iterative rounds. Excerpts were organized into codes, sub-codes and categories to identify and classify themes and patterns and build the case. The findings are structured into the categories of Acquisition, Design and Production and Assembly, and further identified as Barriers and Opportunities. Upon the analysis of results, a selective range of recommendations are formulated and summarized in a catalogue, serving as a guide for further research and actions to widespread the adoption of timber.
Full-text available
Article
Although buildings produce a third of greenhouse gas emissions, it has been suggested that they might be one of the most cost-effective climate change mitigation solutions. Among building materials, wood not only produces fewer emissions according to life-cycle assessment but can also store carbon. This study aims to estimate the carbon storage potential of new European buildings between 2020 and 2040. While studies on this issue exist, they mainly present rough estimations or are based on a small number of case studies. To ensure a reliable estimation, 50 different case buildings were selected and reviewed. The carbon storage per m ² of each case building was calculated and three types of wooden buildings were identified based on their carbon storage capacity. Finally, four European construction scenarios were generated based on the percentage of buildings constructed from wood and the type of wooden buildings. The annual captured CO 2 varied between 1 and 55 Mt, which is equivalent to between 1% and 47% of CO 2 emissions from the cement industry in Europe. This study finds that the carbon storage capacity of buildings is not significantly influenced by the type of building, the type of wood or the size of the building but rather by the number and the volume of wooden elements used in the structural and non-structural components of the building. It is recommended that policymakers aiming for carbon-neutral construction focus on the number of wooden elements in buildings rather than more general indicators, such as the amount of wood construction, or even detailed indirect indicators, such as building type, wood type or building size. A practical scenario is proposed for use by European decision-makers, and the role of wood in green building certification is discussed.
Full-text available
Article
In this paper an LCA is carried out on a concrete and steel apartment building and a cross laminated timber apartment building to compare the greenhouse gas (GHG) emissions from the two buildings. The buildings are built by Veidekke Entreprenør AS and they are almost identical except for the structural system and the number of floors. They are connected by an underground car park of reinforced concrete. The product stage (A1-A3), transport to the building site (A4) and operational energy use (B6) is examined. Results show that the cross laminated timber building has 25% lower GHG emission compared to the concrete and steel building when looking at the production stage, and 13% lower emissions when looking at all stages. The results also show that the material that contributes to the most GHG emissions is reinforced concrete, and that the underground car park has a high GHG emission because it consists of a lot of concrete. What is new in this paper is that there are two real buildings close together that can be compared to find out which has the lowest environmental impact. The paper is valuable for people designing environmentally friendly buildings with a low carbon footprint.
Full-text available
Article
Many studies have shown that wooden buildings in general have a lower climate impact than buildings built of conventional materials such as concrete and steel. In Sweden, however, only about 10% of the multi-dwelling buildings are built with timber frames. The goal of this empirical study is to provide a broad picture of the views of Swedish actors regarding the use of wood products in multi-storey residential buildings and suggest measures for an increased use. A questionnaire concerning the use of wood products in construction was sent out to Swedish developers, main contractors, and architects and 100 answers were received. The study shows that the views of the groups of actors differ in some respects and factors that may either facilitate or be obstacles to an increased use of wood products were identified and discussed.
Full-text available
Technical Report
The use of wood in the construction of multi-storey buildings has increased since the middle of the 1990’s and is still expected to grow in the future. 1994 the Swedish building rules changed. From material based, the rules became functional based. Before this year, the use of wood in houses with more than two storeys were prohibited for fire safety reasons. Now that wooden multi-storey buildings have been built for almost a quarter of a century, this report presents and explains the current technical requirements that multi-storey residential buildings must achieve: • Safety in case of fire, • Safe and comfortable structure, • Healthy indoor climate and frugal heating, • Good acoustic. Environmental aspects and construction praxis are also shortly developed. Even thought, the list of requirements does not pretend to be exhaustively studied hereby. The choice is also related to the timber structures specificities. Five reference projects from 6 to 8 floors and built between 2006 and 2015 are presented briefly and used as examples along the report. Different wood building systems and technical solutions were used and illustrate the architectural and technical variability in the timber building industry as well as the evolution of the building regulations. The appendices to this report contain further information, drawings and pictures of these reference buildings. This report aims to bring some knowledge and practical ideas to people planning, designing or producing taller timber buildings in Sweden. It should be mention that the second part on safety in case of fire and the fifth part on acoustic require that the reader has some basic knowledge on this technical fields.
Full-text available
Article
Do experiences with nature – from wilderness backpacking to plants in a preschool, to a wetland lesson on frogs—promote learning? Until recently, claims outstripped evidence on this question. But the field has matured, not only substantiating previously unwarranted claims but deepening our understanding of the cause-and-effect relationship between nature and learning. Hundreds of studies now bear on this question, and converging evidence strongly suggests that experiences of nature boost academic learning, personal development, and environmental stewardship. This brief integrative review summarizes recent advances and the current state of our understanding. The research on personal development and environmental stewardship is compelling although not quantitative. Report after report – from independent observers as well as participants themselves – indicate shifts in perseverance, problem solving, critical thinking, leadership, teamwork, and resilience. Similarly, over fifty studies point to nature playing a key role in the development of pro-environmental behavior, particularly by fostering an emotional connection to nature. In academic contexts, nature-based instruction outperforms traditional instruction. The evidence here is particularly strong, including experimental evidence; evidence across a wide range of samples and instructional approaches; outcomes such as standardized test scores and graduation rates; and evidence for specific explanatory mechanisms and active ingredients. Nature may promote learning by improving learners’ attention, levels of stress, self-discipline, interest and enjoyment in learning, and physical activity and fitness. Nature also appears to provide a calmer, quieter, safer context for learning; a warmer, more cooperative context for learning; and a combination of “loose parts” and autonomy that fosters developmentally beneficial forms of play. It is time to take nature seriously as a resource for learning – particularly for students not effectively reached by traditional instruction.
Conference Paper
Lighthouse Joensuu is a 14-story construction, it will be almost 48 meters tall being by then the highest wood building in Finland. The structure is being built mainly using wood elements. It is located at city of Joensuu at eastern part of Finland. It will provide 117 apartments for local students to live in. The builder of Lighthouse Joensuu is Student housing Company Joensuun Elli. Principal designer was Samuli Sallinen from Arcadia Oy Arkkitehtitoimisto and head of structural design was A-Insinöörit, Tomi Rautiainen. The building is expected to be completed in autumn of 2019. The first option was to use large machine shop parts like in modular buildings. After discussions with designers and the crew at the building site it became obvious that having steel parts weighting more than 30 kilograms and being almost one meter in diameter is not going to ease the smoothness of work. The forces that were accumulated at the base levels of the building were then too big for traditional hold-down systems to be reasonable size or the amount of connections would be too large. So, it was time to move on in search of a more functional tie-down system. The seemingly small weight of the wood building elements caused therefore large overturning moments induced by lateral loads, wind load mainly. And this in the other hand caused uplift forces to the individual LVL-X wall panels. The uplift forces needed then to be transferred directly from multiple levels to the foundation. The concrete base must also have mass and strength to resist these overturning forces. This led to usage of tension piles at the corner areas of the building and to a thicker concrete floor at first floor level. In other words, the first reinforced concrete floor acts as a stiff cube that provides the upper floor mass and stability. After some brainstorming with the structural designers, worksite crew and structure designs external inspector it became obvious that tension rod system might be our best hope to make this building work for the sake of design and construction. Rebublished at: NEW ZEALAND TIMBER DESIGN » JOURNAL VOL 27· ISSUE 2 (https://www.timberdesign.org.nz/journal/case-studies/use-of-tension-rods-in-wood-construction-14-storeys-with-laminated-veneer-lumber-as-shear-walls-lighthouse-joensuu/)
Article
In the urbanizing society faced with the climate change challenge, wood has major potential as a low-carbon and renewable construction material. Yet, Wooden Multi-storey Construction (WMC) remains a niche even in countries with rich forest resources. This paper compares the institutional and policy setting and assesses the WMC growth prospects in Austria and Finland, based on expert interviews, Delphi surveys, and the review of secondary materials. Clear differences were detected in the policy frameworks and institutional settings between the two countries. The Austrian fairly informal and largely private sector driven approaches to promote the growth of the WMC sector seem to have had a rather similar effect on the markets, as the formal policy measures, typically driven by the public sector in Finland. In both countries, the interviewed experts suggested additional, but partly different, policy measures and institutional changes to accelerate WMC market diffusion. In spite of the increase in WMC activity within the past ten years, the WMC market share is likely to remain rather low by 2030 in both countries, as the institutional frameworks are not expected to change abruptly. However, the future market prospects appear to be somewhat more positive in Finland compared with Austria.
Conference Paper
A research project was carried out by first time in Chile to determine the Lateral-Force-Resisting-System for a prefabricated modular 6-story wood light-frame building, to be able to withstand the Chilean seismic solicitations and the high regulations demands regard the stiffness required to accomplish the admissible inter-story displacements provision on the NCh433 code. Through cyclic testing of wall elements combined with computational models using the test results as input to develop the mathematical models, it was possible to determine the needed structural feasibility, and thus the first 6-story wood light-frame building is currently being built in a Chilean mining company.