The seismic behaviour of wood buildings is often one of their best features. However, despite this inherent advantage, seismic design must be based on the most recent data and
techniques; otherwise, substantial structural damage could occur during powerful earthquakes. The considerable losses sustained during recent large earthquakes have shifted the philosophy of seismic design towards so-called “resilient” or “low damage” structural systems. These innovative systems aim to reduce structural damage, while providing occupants with the same or even a higher degree of safety. This session will serve as an opportunity to present the work accomplished, share the results and build on recent knowledge and experience.
Moderators : Marjan Popovski (FPInnovations, Canada) & Thomas Catterou (FCBA, France)
Speaker: Marjan Popovski (FPInnovations, Canada)
High strength-to-weight ratio, ease of assembly, and good environmental performance have allowed the greater use of mass timber products in residential and non-residential construction around the world. FPInnovations has initiated a number of research projects to accelerate the intake of mass timber in structural systems in non-residential applications in moderate and high seismic zones in Canada. This presentation will provide a brief overview of up-to date results from these projects regarding the seismic performance of Balloon Mass Timber Walls, Braced Timber Frames, and Post-Tensioned “Pres-Lam” Walls as Seismic Force Resisting Systems (SFRS). The presentation will also provide an update on the code acceptance of Mass Timber SFRS in Canada.
Seismic Performance of Timber Structures in Japan
Speaker: Hiroshi Isoda, Kyoto University, Japan
Japan is located on the boundaries of four tectonic plates; consequently, severe earthquakes occur frequently. The 1995 Kobe earthquake destroyed 104,906 buildings. In 2011, the most powerful earthquake ever recorded in Japan struck in the Tohoku region, triggering a tsunami that caused nearly 16,000 deaths and destroyed 127,290 buildings. In 2016, the Kumamoto earthquake destroyed many timber houses, including newly built houses that followed current standard building laws. As a result of the severe damage to timber structures caused by earthquakes, much seismic research including real-sized shaking table tests have been conducted, and seismic design procedures and guidelines have been modified. In this presentation, current seismic design requirements for timber structures are outlined and the research background is explained. Research performed on mass timber buildings—one of the main topics among timber researchers—will also be presented.
State-of-the-Art Seismic Dampers for Resilient Timber Structures: Characteristics and Applications
Speaker: Pierre Quenneville
In light of the recent earthquakes in New Zealand that resulted in significant economic loss and loss of life, it is becoming more pressing to provide seismic design solutions that offer resilience to buildings and infrastructure. Timber structures, although known for their ability to withstand greater earthquake events because of their lower mass, can also suffer irreversible damage as the ductility of the entire system is provided through crushing of the wood fibres and connector yielding at the connections.
Presented with this problem, a resilient friction damper was developed. The damper configuration is such that its load-deformation behaviour is the desired flag-shape response, i.e., the damper will be forced to its initial position following the decrease in earthquake load demand. This is highly desirable given that any residual drift following an earthquake event could result in a decision to demolish the building. Its characteristics can be tailored to any load and displacement demands, fitting the requirements of the different lateral load resisting systems.
The developed resilient slip friction damper is presented, along with its characteristics, advantages, and applications in the different lateral load resisting systems. Finally, its application in different timber structures in New Zealand is described.
Developed primarily for timber structures, the damper gives an advantage to the timber construction industry by providing a structural solution that will make the timber building stock resilient.
Seismically Resilient Tall Wood Buildings: From Concept to Full-Scale Validation
Speaker: Shiling Pei, École des mines du Colorado, États-Unis
With the newly passed International Building Code (IBC) provisions to enable the building of mass timber structures up to 18 stories, mass timber is beginning to get serious consideration for tall building applications in the United States. In seismic regions, it is desirable to mitigate earthquake damage by designing new construction to be low-damage and resilient. Specifically, post-tensioned mass timber rocking walls have shown great potential to enable multi-storey wood building designs that can remain undamaged under design-level earthquakes. This presentation summarizes the latest outcomes from the NHERI Tall Wood Project, which is a collaborative research effort involving researchers and engineers from the United States, Canada, and New Zealand to develop a resilience-based seismic design methodology for tall wood buildings. The focus of this project is tall wood buildings, with open, flexible floor plans, that utilize post-tensioned rocking wall lateral systems. Results from ongoing experimental and analytical investigations as part of this project will be discussed, including shake table tests of a two-story mass timber building conducted in 2017, and the plan to test a full-scale 10-storey wood building at the world’s largest outdoor shake table at UC San Diego in 2021.
Marjan Popovski is Principal Scientist in the Building Systems Group at FPInnovations. He is also an Adjunct Professor at the Department of Wood Science, at the University of British Columbia (UBC), and at the Centre for Integrated Wood Design, at the University of Northern British Columbia. He has 30 years of research and technical experience in the seismic performance of buildings, and is one of the leading researchers in the area of seismic performance of wood structures. He is an author and co-author of over 180 scientific and technical publications, including textbooks chapters, the Canadian Technical Guide for the Design of Tall Wood Buildings, the Canadian and the U.S. CLT Handbooks, and the Canadian Technical Guide for Mid-rise Wood Frame Construction. Mr. Popovski is part of the technical team that is developing the Seismic Design Factors for platform-type CLT buildings in Canada and the U.S. He is a member of the Technical Committee of the Canadian Standard for Engineering Design in Wood (CSAO86) and various Canadian, U.S. and ISO Subcommittees and Task Groups. He also served as a member of the National Building Code of Canada, Standing Committee on Earthquake Design (2009–2014).
Thomas Catterou studied civil engineering at the Ecole Normale Supérieure de Cachan and holds a master’s degree in structural dynamics from the Ecole Centrale Paris. His Ph.D., completed at CEA (French Alternative Energies and Atomic Energy Commission), dealt with nonlinear numerical modelling of reactor core elements subjected to dynamical loadings during earthquakes or transport.
Thomas Catterou joined FCBA, the French Institute of Technology for Forest-based and Furniture Sectors, in January 2019 as a research engineer. He is working on different subjects related to structural dynamics: floor vibration and comfort; similitude laws for wooden buildings; and seismic testing.
Dr. Hiroshi Isoda received his PhD at the Faculty of Engineering of the University of Tokyo in 1997. From 1992 to 1997, he was an Assistant Professor in Architecture and Civil Engineering at Shinshu University where he taught in the area of structural engineering. In 1997, he moved to the Building Research Institute (BRI), National Institute of Japan, as a Senior Researcher, where he was involved in the revision of Japanese Building Standard Law. In 2000-2001, he was also Visiting Researcher in the Department of Structural Engineering at the University of California, San Diego, where he analyzed the seismic response of four index wood buildings. In 2006, he was a Visiting Researcher in the Department of Civil, Structural, and Environmental Engineering at the State University of New York at Buffalo, and involved in the shaking table tests of the NEESWood Project. He became an Associate Professor at Shinshu University in 2006 and was elevated to a Professor in 2011. He moved to Kyoto University in 2013. Dr. Isoda is now a Professor in the Laboratory of Structural Function at Research Institute for Sustainable Humanosphere of Kyoto University and a Visiting Researcher at BRI.
His research topics are:
Estimation and analyses of mechanical properties of various wooden structural components.
Structure development of high-performance houses and mid-rise/ large-scale buildings by utilizing wooden and wood-based composite materials.
Evaluation of the bio-deterioration factor on the structural performance of timber buildings.
Pierre Quenneville is a structural engineer by education and has been involved in timber research since 1988. He obtained his PhD in 1992 and his research interests are in timber structures, specifically connections. He is recognized for his research on bolted timber connections and their brittle failure modes. He has served on the Canadian O86 Wood Design standard for timber structures since 1993 and continues to be actively involved in its ongoing development. He has consulted on numerous timber projects in Canada and overseas since 1999. Mr. Quenneville moved to Auckland, New Zealand in July 2007 to take on the position of the chair of timber design at the University of Auckland. He served as Head of the Civil and Environmental Engineering Department in Auckland between February 2011 and June 2017. His main research direction is to develop design rules for connections in timber structures. Between 2008 and 2013, he participated in the STIC research consortium and more recently began to co-lead research on resilient seismic connections and their significance for structures design.
Dr. Shiling Pei received his Ph.D. in civil engineering from Colorado State University in December 2007 and is currently an associate professor in civil and environmental engineering at Colorado School of Mines. His research focused on multi-hazard mitigation through performance-based engineering, numerical modelling of structural dynamic behaviour, traditional and innovative timber systems, and large-scale dynamic testing. Dr. Pei received the 2012 ASCE Raymond C. Reese Research Prize for his work on seismic performance of mid-rise wood frame buildings (NEESWood). He is the author of the Seismic Analysis Package for Woodframe Structures (SAPWood). Dr. Pei is currently leading an NSF-funded six-university collaboration effort to develop a seismic design methodology for resilient, tall cross-laminated timber (CLT) buildings. This project involves shake table testing of a 10-storey full-scale tall wood building at the NHERI@UCSD outdoor shake table planned in 2021. Dr. Pei served as the chair of the ASCE Wood Technical Administrative Committee and is a registered professional engineer in California.