Multi-storey Timber Buildings Research Articles

Multi-scalar robotic fabrication system for on-site press gluing in multi-storey timber buildings

The amount of timber construction has increased significantly in recent decades due to the development of digital processing technologies in prefabrication. However, on site, timber components are still commonly assembled manually and connected with low performance joint types. This paper presents a multi-storey timber building system with a co-designed heterogeneous multi-scalar robotic construction system, consisting of a clamping device, an industrial robotic arm, and an automated crane, for the automation of on-site timber construction. By integrating construction features into the building material, the different robotic entities can work together to assemble a point-supported quasi-monolithic timber panel of theoretically unlimited dimensions with high precision.

Parametric Analysis of Moment-Resisting Timber Frames Combined with Cross Laminated Timber Walls and Prediction Models Using Nonlinear Regression and Artificial Neural Networks

The light weight and moderate stiffness of multistorey timber buildings make them susceptible to increased lateral displacements and accelerations under service-level wind loading. Therefore, the fulfilment of serviceability requirements is a major challenge. In this study, linear elastic finite element analysis was used to perform a parametric study of moment-resisting timber frames combined with cross laminated timber walls. In the parametric study, various mechanical and geometrical parameters were varied within practical ranges. The results of the parametric study were used to derive simplified analytical expressions and to train artificial neural networks which can be used to estimate fundamental frequency, mode shape, top floor displacement, maximum inter-storey drift, and wind-induced acceleration. The analytical expressions and the artificial neural networks can be used for the preliminary assessment of serviceability performance of moment-resisting timber frames with and without cross laminated timber walls, under service-level wind loading.

Modelling of Multi-Storey Cross-Laminated Timber Buildings for Vibration Serviceability

In this study, the vibration serviceability of multi-storey timber buildings is addressed. The core of this study pertains to the preparation of a comprehensive finite element model to predict modal properties for an accurate vibration serviceability checking. To that end, findings obtained from studying three multi-storey timber buildings are summarized and discussed. Two of the buildings (of seven and eight storeys) consist entirely of cross-laminated timber (CLT), while the third is a five-storey hybrid CLT-concrete building. Thanks to the detailed finite element models and modal testing results, one has the capability to conduct sensitivity analyses, classical and Bayesian model updating, and uncertainty quantifications. With these methodologies, influential modelling parameters as well as the sources of modelling error were identified. This allowed for conclusions to be drawn about the in-plane shear stiffness of the constructed walls (whose higher value causes the natural frequencies to increase by up to 25%), the soil deformability (which may cause the natural frequencies to drop by up to 20%), and the perpendicular-to-the-grain deformation of floor slabs (which may lead to an overestimation of a fundamental frequency by up to 8%).

LOAD-BEARING TIMBER DSF ELEMENTS INFLUENCE ON RACKING STABILITY OF MULTI-STOREY PREFABRICATED TIMBER BUILDINGS

Application of double-skin façade (DSF) elements is an important approach in a designing process of contemporary multi-storey timber buildings. A double-skin facade is an envelope wall element that consists of two glass components separated by a cavity and can essentially improve building-physics properties of building envelope. In a sense to reduce global warming potential (GWP) an ecological solution with a timber frame is presented in this paper. Recently, many studies have analyzed thermal and acoustic performance of DSF elements, but practically none in a sense of structural behavior, especially in determination of racking resistance of such wall elements. Because costs of experiments performed on such full-scale DSF elements are very high and such experiments are also very time-consuming, a special mathematical model using a Finite Element Method (FEM) for analyzing the racking resistance and stiffness was further developed. Finally, a specially selected four-storey timber-framed building is subjected to a seismic analysis comparing the influence of the developed timber DSF elements on the overall racking behavior of that structure with non-resisting DSF function. It is demonstrated in the presented study on the selected case that the racking resistance (R) and a consequent seismic resistance of a whole building can be essentially improved if DSF elements are considered as lateral load-bearing wall elements. Consequently, such an approach by using DSF elements as additional bracing wall elements can essentially further increase a potential of designing also high-rise timber buildings with asymmetric position of transparent areas.

Co-Design Methods for Non-Standard Multi-Storey Timber Buildings

To meet climate change goals and respond to increased global urbanisation, the building industry needs to improve both its building technology and its design methods. Constrained urban environments and building stock extensions are challenges for standard timber construction. Co-design promises to better integrate disciplines and processes, promising smaller feedback loops for design iteration and building verification. This article describes the integrated design, fabrication, and construction processes of a timber building prototype as a case study for the application of co-design methods. Emphasis is placed on the development of design and engineering methods, fabrication and construction processes, and materials and building systems. The development of the building prototype builds on previous research in robotic fabrication (including prefabrication, task distribution, and augmented reality integration), agent-based modelling (ABM) for the design and optimisation of structural components, and the systematisation of timber buildings and their components. The results presented in this article include a functional example of co-design from which best practises may be extrapolated as part of an inductive approach to design research. The prototype, with its co-designed process and resultant flat ceilings, integrated services, wide spans, and design adaptability for irregular column locations, has the potential to expand the design potential of multi-storey timber buildings.

Advanced Timber Construction Industry: A Quantitative Review of 646 Global Design and Construction Stakeholders

There has been a multi-storey timber construction boom since the start of the millennium. While there is now a body of research on trends, benefits, and disadvantages of timber construction, there is not yet literature on the wider market or the impact of stakeholders on it. This research investigates the (i) architects, (ii) engineers, and (iii) manufacturers involved in the realization of 300 contemporary multi-storey timber buildings from an existing survey. The analysis is based on data sourced from stakeholder websites and the building survey. It evaluates the perceived level of timber expertise of stakeholders based on service categorization and stakeholder type and relates them to the buildings they worked on. The research uses quantitative methods to answer qualitative questions on the connection between architectural variety in timber construction and the stakeholders involved. Interconnectivity between stakeholders and projects is visualized in an interactive network graph. The study shows a segmented mass timber market with relatively few impactful design and construction stakeholders, mostly located in central and northern Europe. It also identifies fabricators as the largest group of innovators advancing the industry and enabling the construction of more complex projects. It reveals the importance of collaboration and knowledge sharing for the industry’s growth.

A new concept for column-to-column connections for multi-storey timber buildings—Numerical and experimental investigations

A new jointing concept for the vertical load transfer between glued laminated timber (GLT) columns in multi-storey timber buildings has been developed. The basic components of the connection are two stepped, pyramid-shaped inserts made from block-glued laminated veneer lumber (LVL), which are bonded oppositely into corresponding cavities of the jointed GLTs. The load transfer between the mating columns relies on an intermediate LVL pin, fitting into pyramid-type cavities. Beech LVL was chosen for both, insert and pin, due to its 2.2 times higher characteristic compressive strength as compared to the employed high-strength softwood GLT (GL32h). The form fit of the stepped components which are bonded together relies on high precision robotic milling and a gap-filling two-component polyurethane adhesive. Manufacturing and mechanical performance of the scalable connection was investigated with full-sized specimens, achieving up to 90% of the characteristic GLT compressive capacity of 1040kN for a cross-section of 180mm×180mm. A parametric model based on the finite element method (FEM) showed a good agreement with empiric strain distributions and provided a stress-spread angle of 35° for the concentrated vertical load for an analytical design approach. The location and magnitude of tensile stresses perpendicular to the grain causing splitting failure was identified by FEM. Reinforcement by self-tapping screws proved a significant load-capacity enhancement. The mean experimental axial compressive load capacity exceeded the analytical prediction by 19%. First investigations on the rotational stiffness delivered a value of 240kNm/rad. The column utilization due to additional directly supported floor slabs was assessed exclusively by FEM. The calculation results predict a significant reduction of the tensile stresses perpendicular to the grain to be verified experimentally.

Investigation of Wood‐Steel Composite Shear Walls Behavioural Parameters

AbstractOver the last few years, hybrid steel‐timber components and systems are enjoying increasing popularity in the construction sector, particularly in the case of multistorey timber buildings where significant benefits arise due to faster and safer on‐site erection, improved structural and seismic performance combined with minimized environmental impact. Most of these studies focus on steel frames with Cross‐laminated Timber (CLT) infills and hybrid steel‐timber joints. However, it may only sometime to be possible to satisfy the maximum drift limit prescribed by building codes only with CLT shear walls and hybrid steel‐timber joints. Some promising improvements have been proposed in the literature for improving buckling stability and avoiding excess building drifts. Among these, is a new type of shear wall called the Wood‐Steel Composite Shear Wall, which has much higher stiffness and can drastically reduce the overall building drifts due to the employment of Steel Plate Shear Walls. Regarding the above considerations, this paper assesses the structural behaviour of Wood‐Steel Composite Shear Wall systems via the finite element method. In the developed Wood‐Steel Composite Shear Wal system, glue connects a thin gauge steel web plate to the boundary Laminated Strand Lumber frame. Based on previous experimental studies, finite element modelling was performed to investigate the effects of behavioural parameters on the response of the Wood‐Steel Composite Shear Wall system. It was found that the plate wall thickness has a significant effect on the initial stiffness and the peak capacity of this system, while changing that parameter may not change the failure mode of the system.

Innovative Structural Systems for Timber Buildings: A Comprehensive Review of Contemporary Solutions

The remarkable development of timber construction technologies in recent decades has led to an increase in the number of timber buildings worldwide, including multi-storey buildings. The design of timber buildings, especially those of greater height, is relatively demanding and, even in the context of architectural expression, has certain constraints due to the specific structural and physical properties of this material. Thus, it is important for designers to have an overview of existing timber structural systems and their specificities to be able to make the right design decisions during the design process. Unfortunately, there is a lack of scientific literature that systematically addresses the essential features of contemporary timber structural systems. Within the aims of this paper to provide the systematic review of contemporary structural systems, both the scientific and professional literature are comprehensively reviewed. This paper presents a systematic classification and description of the following structural systems of timber buildings: all-timber and hybrid timber structural systems with an additional description of constituent structural elements, while examples of completed multi-storey timber buildings are also given for each structural system. The findings provide a broader view of the knowledge of contemporary solutions of timber structural systems and their application, thus representing a novelty in the field of timber construction review.

Identification and Trend Analysis of Multistorey Timber Buildings in the SUDOE Region

The construction sector has one of the most polluting economic activities. In this context, several policies are being launched by the European Union to promote the transition to a sustainable economy, and timber construction is a safe way to contribute to it. Due to the recent development of multistorey timber buildings, the architectural and structural typologies have not been widely studied yet and with not many studies from Southern Europe. In this context, the main objective of this research is to identify and analyse the trends in the use of wood as a structural material in multistorey timber buildings (≥4 floors) in the SUDOE region, i.e., Spain, Portugal, and Southwest France. The methodology involved identifying 28 timber buildings in the SUDOE region and 101 worldwide, most of them in Europe, and sending online information request forms to different actors involved in their design and construction, collecting plans and BIM models, and performing technical study visits to the identified reference buildings. The collected information was included in open-access technical datasheets, and different indicators in terms of building uses, structural system, wood species, and wood volume, among others, were defined. The results showed that there is a tendency to construct taller timber buildings in the SUDOE region with a predominant use of local softwood species, with ratios of wood volume per built area varying between 0.3 and 0.4 m3/m2. The mass timber typology using cross-laminated timber (CLT) is mainly used for residential buildings, while post and beam are used for educational and offices buildings. In addition, a potential embodied CO2 equivalent depending on the building typology and use was also analysed.

Fire Spread in Multi-Storey Timber Building, a CFD Study

The purpose of this paper is to investigate the fire performance in a multi-storey cross-laminated timber (CLT) structure by the computational fluid dynamics (CFD) technique using the Fire Dynamics Simulator (FDS v.6.7). The study investigates fire temperature, heat release rate (HRR), and gas concentration (O2, CO2). The importance of this research is to ensure that the fire performance of timber buildings is adequate for occupant safety and property protection. Moreover, the proposed technique provides safety measures in advance for engineers when designing buildings with sufficient fire protection by predicting the fire temperature, time to flashover and fire behaviour. The present numerical modelling is designed to represent a 10-storey CLT residential building where each floor has an apartment with 9.14 m length by 9.14 width dimensions. The pyrolysis model was performed with thermal and kinetic parameters where the furniture, wood cribs and CLT were allowed to burn by themselves in simulation. This research is based on a full-scale experiment of a two-storey CLT building. The present results were validated by comparing them with the experimental data. Numerical simulation of CLT building models show a very close accuracy to the experiment performed in the benchmark paper. The results show that the CFD tools such as FDS can be used for predicting fire scenarios in multi-storey CLT buildings.

Effect of protective cladding on the fire performance of vertically loaded cross-laminated timber (CLT) wall panels

ABSTRACT Cross-laminated timber (CLT) is a sustainable engineered wood product which is utilised in modern multi-storey timber buildings. The fire behaviour of timber structures is often a concern due to their combustible nature. In this paper, experimental fire testing of CLT panels made of Irish spruce was performed. This series of tests consisted of four vertically loaded CLT wall panels which were tested under Standard fire curves in the Structural Laboratory of Munster Technological University, Cork (MTU). To improve the fire performance of CLT panels, different types of protective claddings were used. The effectiveness of each system of protection has been stated particularly in terms of the delay in the start of charring of the CLT panels. The location of joints in the protective cladding was also analysed and was found to be a key factor in the fall-off time of the protective claddings. The results show that protective claddings made with Fireline gypsum plasterboard and a combination of plywood and Fireline gypsum plasterboard delayed the charring of CLT panels by as much as 30 and 44 min respectively. This paper analyses the detailed results of experimental fire testing and measures the charring rate and temperature distribution across the panels.

Barriers, Opportunities and Recommendations to Enhance the Adoption of Timber within Multi-Storey Buildings in Austria

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.

From Trees to Skyscrapers: Holistic Review of the Advances and Limitations of Multi-Storey Timber Buildings

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.

Structural development of a novel punctually supported timber building system for multi-storey construction

Though capable of allowing multi-directional spans, timber products such as cross-laminated timber are primarily utilized uni-directionally using linear supports like walls or beam elements. Recent building designs increasingly show punctual supports but with narrow column grid layouts. Support beams and narrow grids limit the design space for multi-storey timber buildings. To overcome these design limits, an integrative design concept for punctually supported timber slabs is being developed that allows for large spans and irregular column layouts. Therefore, engineering methods are integrated in the architectural design of the building components, such as plates, columns, and their connections. The developed slab system combines hardwood and softwood materials in a sandwich construction. The plates have a tailored internal topology considering the force flow in the slab. A plate-to-plate connection design is evaluated through mechanical tests, which also serve as calibration for the global structural model. The research findings are validated through the design and construction of a large scale demonstrator: the ITECH Campus Lab.

Mechanical behaviour of multi-panel cross laminated timber shear-walls with stiff connectors

Multi-panel Cross Laminated Timber shear-walls with stiff vertical joints may represent a valuable structural solution for multi-storey timber buildings in low seismic prone areas. In this study, the opportunity of using shear-key connectors in the assemblage of stiff vertical joints as an alternative to short-spacing traditional dowel-type mechanical fasteners is evaluated. The mechanical behaviour of two types of stiff shear-key connectors is investigated through an experimental campaign conducted at joint and wall level. Shear tests were firstly carried out to determine the mechanical properties of panel-to-panel joints assembled with the shear-key connectors. The results are compared with those obtained from shear tests on joints with screwed connections (half-lap and spline joints). Full-scale shear-wall tests were then performed to determine the mechanical performances of the connectors at wall level. Joints with a single shear-key connector showed values of stiffness and strength comparable to those that would be obtained for vertical spline joints with approximately thirteen couples of 6 mm screws. The failure modes on the joints with shear-key connector were characterized by either a localized crushing in the wood or the shear failure in outer lamination of the CLT panels with no plastic deformation of the connectors.

Advanced Timber Construction Industry: A Review of 350 Multi-Storey Timber Projects from 2000–2021

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.

Embodied energy and GHG emissions of residential multi-storey timber buildings by height – A case with structural connectors and mechanical fasteners

In recent years, interest in the construction of multi-storey timber buildings in the urban context has increased. The stability of any timber building depends on the structural connections that transfer and anchor the loads acting on the building, such as horizontal forces (wind, earthquake), which increase significantly with the building height. However, they are generally neglected in studies assessing their environmental performance. For this reason, the present study investigates the embodied energy and greenhouse gas (GHG) emissions of a residential multi-storey timber building with an increase in height by performing a life cycle assessment (LCA) with an integrated approach that considers structural behaviour and includes connectors and fasteners. The results presented as relative and absolute contributions of different building elements show that the embodied impacts per floor decrease as the building height increases, However, relative and absolute contributions of different building elements change with the variation in the number of storeys. While the building envelope is recognised as a critical element when considering GHG emissions, the load-bearing timber structure is a critical element when considering cumulative energy demand (CED). The results further revealed the importance of connectors and fasteners, as they account for up to 4.80% of the non-renewable CED at the building level, and up to 25.66% when assessing the load-bearing timber structure. Considering a significant contribution, it is suggested that their impact should be evaluated in the environmental impact assessments of timber buildings. In addition, the study highlights the relevance of certain design parameters regarding the embodied impact to achieve a more environmentally efficient building design.

Sustainability Assessment of Modern High-Rise Timber Buildings

As woodworking and construction technologies improve, the construction of multi-storey timber buildings is gaining popularity worldwide. There is a need to look at the design of existing buildings and assess their sustainability. The aim of the present study is to assess the sustainability of modern high-rise timber buildings using multi-criteria assessment methods. The paper presents a hierarchical system of sustainability indicators and an assessment framework, developed by the authors. Based on this framework, the tallest timber buildings in different countries, i.e., Mjøstårnet in Norway, Brock Commons in Canada, Treet in Norway, Forte in Australia, Strandparken in Sweden and Stadthaus in UK, were compared across the three dimensions of sustainability (environmental, economic/technological, and social). Research has revealed that none of the buildings is leading in all dimensions of sustainability. However, each building is unique and has its own strengths. Overall multi-criteria assessment of the buildings revealed that the Brock Commons building in Canada has received the highest rank in all dimensions of sustainability. The paper contributes to the theory and practice of sustainability assessment and extends the knowledge about high-rise timber buildings. The proposed sustainability assessment framework can be used by both academics and practitioners for assessment of high-rise timber buildings.

A Review of Architectural and Structural Design Typologies of Multi-Storey Timber Buildings in Europe

Numerous countries across the globe have witnessed the recent decades’ trend of multi-storey timber buildings on the rise, owing to advances in engineering sciences and timber construction technologies. Despite the growth and numerous advantages of timber construction, the global scale of multi-storey timber construction is still relatively low compared to reinforced concrete and steel construction. One of the reasons for a lower share of high-rise timber buildings lies in the complexity of their design, where the architectural design, the selection of a suitable structural system, and the energy efficiency concept strongly depend on the specific features of the location, particularly climate conditions, wind exposure, and seismic hazard. The aforementioned shows the need for a comprehensive study on existing multi-storey timber buildings, which correspond to the boundary conditions in a certain environment, to determine the suitability of such a construction in view of its adjustment to local contexts. Apart from exposing the problems and advantages of such construction, the current paper provides a brief overview of high-rise timber buildings in Europe. Moreover, it addresses the complexity of the design approach to multi-storey timber buildings in general. The second part of the paper highlights the importance of synthesising the architectural, energy, and structural solutions through a detailed analysis of three selected case studies. The findings of the paper provide an expanded view of knowledge of the design of tall timber buildings, which can significantly contribute to a greater and better exploitation of the potential of timber construction in Europe and elsewhere.