Timber buildings can now stand very tall using new products. As timber materials are expected to be easily ignitable, the fire hazard of timber is a concern. Charring of the timber surface would maintain structural stability, but would also be accompanied by smoke. Although treating timber products with fire retardants would delay the ignition time under low radiative heat flux, toxic combustion products and unburnt fuel would be emitted immediately upon burning. More smoke and higher toxic gas concentrations such as carbon monoxide would be given off upon burning some fire retardants under high flashover heat fluxes. Due to the fast upward movement of smoke under stack effect, spreading of toxic smoke in tall timber buildings would lead to a hazardous environment. Engineered timber consists of derivative timber products. New engineered timber products are manufactured with advanced technology and design, including cross-laminated-timber (CLT), laminated veneer lumber (LVL) and glue-laminated timber (Glulam). The fire behaviour of timber products has been studied for several decades. However, the smoke hazards of using new timber products in building construction should be monitored. The objective of this study is to inspire stakeholders in fire safety of timber buildings, inter alia smoke hazards, to use new timber products to build tall buildings.
The rapid growth of the urban population and associated environmental concerns are challenging city planners and developers to consider sustainable and cost-efficient building systems. Timber-based buildings, such as sustainable systems, are increasingly used. The timber buildings, however, being lighter and flexible, can be vulnerable to earthquakes and wind loads. This paper gives a state-of-the-art review on performance-based design (PBD) considerations and future direction for timber and timber-based hybrid buildings. The PBD review covered both earthquake and wind loads and multi-hazard design considerations. The review also provided 1) current practice and future direction in consideration of hazard, response, and loss assessment within the multi-hazard PBD, 2) damping and energy dissipation devices, 3) optimization under uncertainty, and 4) future of surrogate and multi-fidelity modeling in PBD.
From record-breaking timber towers to innovative examples of adaptive reuse, mass timber construction is on the rise. Stay current with Think Wood and WoodWorks’ newly updated, must-have Volume 2 of the popular Mass Timber Design Manual.
Volume 2 features updated free and interactive resources to guide architects, developers, engineers, and anyone working on a mass timber project.
This manual is helpful for experts and novices alike. Whether you’re new to mass timber or an early adopter you’ll benefit from its comprehensive summary of the most up to date resources on topics from mass timber products and applications to tall wood construction and sustainability.
The manual’s content includes WoodWorks technical papers, Think Wood continuing education articles, case studies, expert Q&As, technical guides and other helpful tools. Click through to view each individual resource or download the master resource folder for all files in one handy location. For your convenience, this book will be updated regularly as mass timber product development and the market are quickly evolving.
Currently, there is limited knowledge of the dynamic response of taller glue laminated (glulam) timber buildings due to ambient vibrations. Based on previous studies, glulam frame connections, as well as non-structural elements (external timber walls and internal plasterboard partitions) can have a significant impact on the global stiffness properties, and there is a lack of knowledge in modeling and investigation of their impact on the serviceability level building dynamics. In this paper, a numerical modeling approach with the use of “connection-zones” suitable for analyzing the taller glulam timber frame buildings serviceability level response is presented. The “connection-zones” are generalized beam and shell elements, whose geometry and properties depend on the structural elements that are being connected. By introducing “connection-zones”, the stiffness in the connections can be estimated as modified stiffness with respect to the connected structural elements. This approach allows for the assessment of the impact of both glulam connection stiffness and non-structural element stiffness on the dynamic building response due to service loading. The results of ambient vibration measurements of an 18-storey glulam timber frame building, currently the tallest timber building in the world, are reported and used for validation of the developed numerical model with “connection-zones”. Based on model updating, the stiffness values for glulam connections are presented and the impact of non-structural elements is assessed. The updating procedure showed that the axial stiffness of diagonal connections is the governing parameter, while the rotational stiffness of the beam connections does not have a considerable impact on the dynamic response of the glulam frame type of building. Based on modal updating, connections exhibit a semi-rigid behavior. The impact of non-structural elements on the mode shapes of the building is observed. The obtained values can serve as a practical reference for engineers in their prediction models of taller glulam timber frame buildings serviceability level response.
The rise of wood buildings in the skylines of cities forces structural dynamic and timber experts to team up to solve one of the new civil-engineering challenges, namely comfort at the higher levels, in light weight buildings, with respect to wind-induced vibrations. Large laminated timber structures with mechanical joints are exposed to turbulent horizontal excitation with most of the wind energy blowing around the lowest resonance frequencies of 50 to 150 m tall buildings. Good knowledge of the spatial distribution of mass, stiffness and damping is needed to predict and mitigate the sway in lighter, flexible buildings. This paper presents vibration tests and reductions of a detailed FE-model of a truss with dowel-type connections leading to models that will be useful for structural engineers. The models also enable further investigations about the parameters of the slotted-in steel plates and dowels connections governing the dynamical response of timber trusses.
The construction industry represents one of the greatest contributors to atmospheric emissions of CO2 and anthropogenic climate change, largely resulting from the production of commonly used building materials such as steel and concrete. It is well understood that the extraction and manufacture of these products generates significant volumes of greenhouse gases and, therefore, this industry represents an important target for reducing emissions. One possibility is to replace emissions-intensive, non-renewable materials with more environmentally friendly alternatives that minimise resource depletion and lower emissions. Although timber has not been widely used in mid- to high-rise buildings since the industrial revolution, recent advances in manufacturing have reintroduced wood as a viable product for larger and more complex structures. One of the main advantages of the resurgence of wood is its environmental performance; however, there is still uncertainty about how mass timber works and its suitability relative to key performance criteria for construction material selection. Consequently, the aim of this study is to help guide decision making in the construction sector by providing a comprehensive review of the research on mass timber. Key performance criteria for mass timber are reviewed, using existing literature, and compared with those for typical concrete construction. The review concludes that mass timber is superior to concrete and steel when taking into consideration all performance factors, and posits that the construction industry should, where appropriate, transition to mass timber as the low-carbon, high performance building material of the future.
Since the publication of the first edition of this guide, substantial regulatory changes have been implemented in the 2020 edition of the National Building Code of Canada: the addition of encapsulated mass timber construction up to 12 storeys, and the early adoption of the related provisions by several provinces are the most notable ones. The 2022 edition of this guide brings together, under one cover, the experience gained from recently built tall wood projects, highlights from the most recent building codes and standards, and research findings to help achieve the best environmental, structural, fire, and durability performance of mass timber products and systems, including their health benefits. The approaches to maximizing the benefits of prefabrication and building information modelling, which collectively result in fast, clean, and quiet project delivery, are discussed. Methods for addressing limitations controlled by fire requirements (through an Alternative Solution) or seismic requirements (through a hybrid solution using an Acceptable Solution in steel or concrete) are included. How best to build with mass timber to meet the higher performance requirements of the Energy Step Codes is also discussed. What makes building in wood a positive contribution toward tackling climate change is discussed so that design teams, in collaboration with building owners, can take the steps necessary to meet either regulatory or market requirements.
Robustness research has become popular, however very little is known on its explicit quantification. This paper summarises a quantification method previously published by the main author and proceeds in demonstrating its step-by-step application with a case study tall timber building. A hypothetical 15-storey post-and-beam timber building with a central core is designed for normal loads, and four improved options are designed to account for abnormal loads in order to increase the building’s robustness. A detailed, nonlinear, dynamic Finite Element model is set up in Abaqus® to model three ground floor column removal scenarios, and a Random Forest classifier is set up to propagate uncertainties, to efficiently estimate the probability of certain collapse classes occurring, and to calculate the importance of each input parameter. The results show how design improvements at the whole building scale (e.g., strong floors) have a higher impact on robustness performance than just improving the strength and ductility of some selected connections, although these results are exclusive to the building studied. The case study reinforces the importance of a sound conceptual design for achieving robustness in tall 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.
In this paper, an adaptable and architecturally flexible lateral stiffening system for tall timber buildings between 50 and 147 m is developed and investigated. The system is based on a tube-in-tube concept. The internal tube consists of a braced timber core, and the external tube consists of a frame structure with semi-rigid beam-column joints in the façade. Based on a finite element framework, more than 500 000 simulations with different configurations are carried out to assess the performance of the lateral stiffening system subjected to wind loading. The resulting data is used to assess the feasibility of the tube-in-tube system and stiffness requirements for the beam-column joints.