PI: Dr. Tony Yang, University of British Columbia                                           HQP: Amir Ghahremani, Kilian Krauss

There are currently no design guidelines for balloon MT walls as a system in CSA O86 (CSA 2019) and the NBCC (NRC 2020), and this regulatory gap inhibits the implementation of such systems. The main objective of this research project is to quantify the system performance, and to develop the technical information necessary for the wide-accepted design, of individual balloon MT walls and cores in mid-rise and high-rise buildings. Specifically, design guidelines for such systems will be developed and force modification factors will be derived for future implementation of the system in the NBCC.

PI: Alexander Salenikovich, Laval University                                                    HQP:  Kiavash Gholamizoj

Braced timber frames (BTFs) are one of the most efficient structural systems in terms of lateral load resistance. The main objective of this sub-project is to generate technical information related to the performance of different types of innovative BTFs for mass timber and hybrid construction. Based on modelling and analysis, innovative braced frame system suitable for high-performance (low damage) and self-centering capability (Gauron et al. 2015) will be developed.

PI: Thomas Tannert, University of Northern British Columbia                     HQP: Houman Ganjali

A preferred floor design in CLT structures is a flat-plate system where the CLT panels rest directly on walls or columns without a beam framing system. This sub-project will investigate the structural performance of flat-plate floor systems in mass timber construction. Design guidelines for such a floor system in mass timber construction will be developed.

PI: Jeffery Erochko, Carleton University                                                            HQP: Anthony Zimmer

There has been limited research into their behaviour in MT panel floor diaphragms (D’Arsenzo et al. 2019), and no design guidelines currently exist. The main goal of this sub-project is to develop guidelines for the design of MT diaphragms that take into consideration their flexibility and the flow of forces through the diaphragm to the lateral force resisting system (LFRS) underneath. The design of panel-to-panel shear connections, collector elements, chord reinforcements, and connections to boundary elements will also be covered in the guidelines to be developed.

PI: Ghasan Doudak, University of Ottawa                                                           HQP: Pooya Domirani

The NBCC (NRC 2020) provides an empirical formula to estimate the natural periods of buildings based on its building height, but it has not been calibrated to timber buildings (Hafeez et al. 2018). The main goal of this sub-project is to develop a database of in-situ measurements of natural frequencies and Next Generation Wood Construction Page 10 of 34 Chui, Y. H. (18138) internal damping of timber buildings. This database will form the basis to derive appropriate predictive models.

 PI: Ying Hei Chui, University of Alberta                                                              HQP: Tao Gui

Stiffness properties are required for both serviceability limit state and ultimate limit state designs, and it is critical that reliable stiffness properties of common timber connections be provided to designers so that competitive, serviceable, and safe structural timber systems can be designed and constructed. Moreover, given that timber connections are often the main source of energy dissipation and deformation of timber systems, reliable connection stiffness information is a pre-requisite for adoption of advanced seismic and performance-based design methodologies. This sub-project aims to develop reliable predictive models for the stiffness properties of connections with threaded and smooth shank fasteners.

 PI: Hossein Daneshvar, University of Alberta                                                    HQP: Ali Yazdi Moghaddam

This project aims to enhance the seismic performance of Timber Moment Resisting Frames (TMRFs) by developing and validating connection details that meet moderate and limited ductility levels as specified in the 2020 National Building Code of Canada. With a focus on sustainable construction materials, this research will address the current lack of design guidelines for TMRFs, which limits their adoption despite their potential benefits. The project involves two phases: developing moment connection details through experimental testing and evaluating system performance through nonlinear dynamic analyses. The outcomes will contribute to establishing TMRFs as a viable and safe option for seismic force resisting systems and ensure their continued inclusion in the CSA O86 standards.

PI: Dr. Matiyas Bezabeh, McGill University                                                          HQP: Kalkidan Tesfaye

This project aims to create seismic design guidelines for wood-frame on podium buildings (WFPBs). These mid-rise structures combine concrete podiums with wooden upper stories. The existing seismic design methods are limited in addressing vertical irregularities, impacting structural performance. The study will assess current criteria, develop new empirical standards, and establish a comprehensive design guide. It involves archetype development, numerical modeling, ground motion selection, performance assessment, and collaboration with experts. The project will train a graduate student and work closely with industry partners and external advisors, contributing to Canada’s sustainable construction goals and informing building codes.

PI: Lina Zhou, University of Victoria                                                                     HQP: Ruite Qiang

Novel construction practices, such as large openings, longer spans, and concrete toppings, have created additional demand for lateral load resistance in light wood frame buildings. This has made it difficult for designers to use existing design solutions for the construction of mid-rise wood frame buildings in moderate and high seismic zones. To remedy this issue, a high-capacity shear wall system with multiple ows of nails along the sheathing panel edges will be developed. The results of this sub-project will support future code implementation of these high-capacity shear walls.

PI: Solomon Tesfamariam, University of British Columbia                             HQP: Biniam Tekle Teweldebrhan, Gidewon Tekeste

There is a growing need to develop more resilient and better-performing timber seismic force resisting systems (SFRS) that can be used in high-rise buildings. This sub-project aims to develop an aesthetically appealing SFRS that meets structural and architectural requirements while also sustaining limited post-earthquake damage. To this end, innovative MT systems with rocking CLT core (Wu and Yang 2017), glulam exoskeleton, and innovative energy dissipation connectors will be developed, along with a resilience-based design framework. This sub-project will provide design engineers with a new timber SFRS that is highly resilient and that can be implemented in high-rise structures.

PI: Frank Lam, University of British Columbia                                                  HQP: Jianan Chen

Reliability-based design procedures in CSA O86 (CSA 2019) are based on single member analysis for sawn lumber (Foschi et al. 1990) and glulam column (Lam and Oh 2018). Research on reliability analysis on connection and system behaviour of MT structures is almost non-existent. In this study, a framework to quantify the performance of MT structures will be developed. The research outcomes will form the basic framework needed to quantify the level of safety for a given MT system using the applied design method. This information can be benchmarked against safety levels of known systems to guide future changes in CSA O86.

PI: Cristiano Loss, University of British Columbia                                     HQP: Christopher Leong

Next Generation Wood Construction Page 11 of 34 Chui, Y. H. (18138) Performance-based seismic design (PBSD) guidelines for new and existing buildings have evolved over the last two decades and PBSD procedures for wood systems to-date have focused primarily on wood-frame construction up to six-storeys (Pang et al. 2010, Pang and Rosowski 2007, van de Lindt et al. 2010). This sub-project aims to develop innovative design strategies and reliable procedures for PBSD of larger and taller MT buildings that could be used to support the potential implementation of PBSD method in NBCC for wood-based systems.

PI: Ying Hei Chui, University of Alberta                                                      HQP: Dac Hoang Nguyen

Designers increasingly use computer models to analyze and design timber structures, driven by the need for improved cost-effectiveness and safety. Despite the success of FPInnovations’ 2022 Modelling Guide for Timber Structures, reliable input data for timber members and connections, particularly connections, remains incomplete in existing publications. This project addresses this gap by developing a comprehensive database of mechanical properties for timber products and connections. Supported by FPInnovations, BC-FII, and CWC, the project will involve reviewing and analyzing existing data, defining key properties, and creating a database to assist designers and researchers in utilizing accurate and reliable model inputs.

PI: Janhui Zhou, University of Northern British Columbia                        HQP: Chenyue Guo

The current vibration serviceability design method in CSA O86 (CSA 2019) is based on indirect performance criteria that correlate the performance of the floor with its subjective rating scores based on a large database of wood joisted floors (Hu et al. 2001). However, this simple and reliable design method is limited to traditional wood floor systems. Since timber floor construction has become more complex with a wide range of available engineered wood products, design engineers and product producers are advocating for a generalized floor vibration design method that can be used for a broad range of timber floor systems and configurations. The development of such a design method is the goal of this sub-project.

PI: Sylvain Ménard, University of Quebec at Chicoutimi                              HQP: Ibrahim Jaber

The basic acoustic property required for room acoustic design is the absorption coefficient of the construction materials. However, no such information is available for the materials and assemblies used in MT buildings (Zhou et al. 2019), and acoustic performance information is even missing for some of the solutions currently in use. To address these information gaps, this sub-project will establish a database of the acoustic performance properties of various construction materials that could be used in wood buildings. The database, which will be developed based on a literature survey, and laboratory and field testing, ultimately will support acoustic design and material selection toward providing satisfactory acoustic performance in wood buildings.

PI: Hua Ge, Concordia University and Cynthia Cruickshank, Carleton University    HQP: Sina Akhavan Shams, TBD

Hygrothermal modelling of 2D and 3D for wood-based assemblies, especially for MT, poses several challenges, such as the lack of proper material properties (Glass and Zelinka 2010), and reduced accuracy at high moisture levels (Wads 1994). Construction moisture is another major concern as it may affect long-term durability (McClung et al. 2014; Schmidt et al. 2019). This sub-project will tackle these issues and the expected outcomes are (1) a comprehensive material property database for wood products; (2) guidelines for hygrothermal modelling based on a stochastic approach that takes into account uncertainties in directional material properties, moisture loads and climatic conditions in MT timber buildings during construction and operation.

PI: Yuxiang Chen, University of Alberta and Hua Ge, Concordia University              HQP: Mengqi Jing and Himanshu Sharma

Effective thermal energy storage (thermal mass) can greatly improve thermal and energy performance of buildings and increase utilization of renewable energy (ASHRAE 2019, Heier et al. 2015). Studies have shown that the use of MT can improve energy efficiency compared to light-wood frame construction (Khavari et al. 2016; Glass and Zelinka 2010), while performing comparably to concrete structures in terms of mitigating overheating risk (Jensen et al. 2020). This sub-project aims to quantify the thermal mass effect of a MT envelope on a building’s thermal and energy performance, including the capacity to regulate indoor thermal and moisture conditions by using an outdoor test hut in Edmonton. The expected Next Generation Wood Construction Page 14 of 34 Chui, Y. H. (18138) outcome is a quantified assessment of the potential of using MT for thermal storage and moisture buffering to reduce energy consumption and improve thermal resilience of wood buildings in Canadian climates.

PI: Phalguni Mukhopadhyaya, University of Victoria                               HQP: Dipendra Paneru

While small-scale lab testing and field monitoring studies have been conducted on mid-rise and tall wood buildings in terms of hygrothermal, indoor thermal conditions, and energy performance (McClung et al. 2014; Wang 2019; Schmidt et al. 2019), to improve building designs and help develop models and best practice guides, more field data is needed. In this sub-project, a comprehensive field performance monitoring of MT buildings in different climatic regions will be carried out to monitor hygrothermal performance of building envelope, indoor environment, and energy consumption. The expected outcomes are (1) field performance data in representative Canadian regions; and (2) design recommendations to achieve durable, energy efficient, healthy and resilient mass timber buildings. The field monitoring data will be used for model validation in other sub-projects, e.g., sub-project T3-1-A.

PI: Phalguni Mukhopadhyaya, University of Victoria                                       HQP: Shrish Sharma

This project addresses the challenges of drying mass timber structures after severe construction wetting, a common issue in areas with high moisture exposure. As mass timber buildings become more prevalent, efficient moisture management during construction becomes critical. The research will evaluate various drying methods, including electrical/propane heaters and dehumidifiers, to identify the most effective, energy-efficient, and sustainable techniques for use on construction sites. The outcomes aim to speed up construction, reduce costs, lower the carbon footprint, and enhance the durability of mass timber buildings. The project involves an MASc student and will span two years.

PI: Yuyang Chen, University of Alberta                                                          HQP: Aynkaran Aymmugan

In order for mid-rise and taller wood buildings to achieve net-zero energy under projected future climate conditions, their building envelopes must (1) provide optimal thermal resistance in order to reduce heat loss in the Winter and heat gain in the Summer; (2) enhance passive solar heating while providing proper solar control in the Summer; (3) support renewable energy. In this sub-project different archetype buildings located in different Canadian climate zones will be evaluated. The expected outcomes are optimal design solutions that meet both net-zero energy and durability requirements for future climates, while not compromising structural performance. Given the need for design optimization, this sub-project will involve collaborators from Theme 1 (Chui) and Theme 4 (Al-Hussein), both from UAlberta.

PI: Hua Ge, Concordia University and  Leon Wang, Concordia University                 HQP: Zahra Salehí, TBD

This sub-project will evaluate the overheating risks in wood-frame buildings built to the current energy codes and the proposed NZER standard under current and projected future climates. With the increased frequency of “heatwaves” and projected rising temperatures, energy-efficient buildings designed to reduce energy consumption for space heating in Canada may be subject to a risk of overheating in warm seasons (Baba and Ge 2019; Laouadi et al. 2020). The expected outcomes of this sub-project are design and operational strategies, such as natural ventilation, night-time cooling, solar control through passive solar design and dynamic shading, thermal mass, and pre-cooling to reduce overheating risks in wood- frame multi-unit residential buildings, located in different Canadian climate zones.

PI: Phalguni Mukhopadhyaya, University of Victoria                                          HQP: Bisrat Tariku

While most performance issues for mid-rise wood-frame construction related to structural, fire, and energy performances have been addressed, potential water damage due to accidental indoor water leakage has not been investigated in depth and remains a concern for owners and insurance companies (Ni and Popovski 2015; Hodgin 2018). This sub-project will focus on identifying potential sources of indoor water leaks, their impacts, and measures that can be taken to improve the resilience of wood- frame construction against such risks. The expected outcomes are effective moisture management guidelines for dealing with indoor leaks to prevent damage to wood components.

PI: Leon Wang,  Concordia University                                                                      HQP: Fuad Baba

Air-tight energy efficient buildings rely on mechanical ventilation to ensure indoor air quality (IAQ), while higher ventilation rates may be required to deal with emergencies such as COVID-19 (Lewis 2021). Maintaining a safe, healthy, and comfortable indoor environment while limiting energy consumption has become particularly important for all residential buildings (Memmott et al. 2021). This sub-project aims to develop ventilation strategies to achieve optimal IAQ in energy-efficient wood buildings. The expected outcomes are design tools and energy-efficient ventilation design and operational strategies and guidelines for achieving healthy wood buildings.

PI: Cynthia Cruickshank, Carleton University                                                     HQP: John Dikeos, Teema Arnouk

Deep energy retrofitting of existing buildings has become critically important as a means of reducing energy consumption and carbon emissions from the built environment. It also makes older buildings more comfortable, durable, and climate-resilient. One of the most effective approaches to deep energy retrofitting is exterior retrofitting carried out by adding prefabricated panels to the exterior walls and roof to improve thermal performance. This sub-project will examine the use of light-wood or MT assemblies for exterior energy retrofits. Conventional light-wood-frame panels and innovative wood fibre insulation-based panels will be used for low- and mid-rise wood buildings, while CLT-based assemblies may be applied to non-wood buildings up to 12 storeys. The expected outcomes are a comprehensive strategy and innovative assembly designs with wood-based, low-carbon products for the exterior envelope energy retrofit of existing buildings that has the potential to be scaled up for existing buildings, including non-wood structures. The work will also facilitate and expand the use of innovative bio- products, including wood fibre insulation, in North America. Collaborators from Theme 1 (Erochko) and Theme 2 (Hajiloo) will be part of the project team (all from CarletonU).