Christian Dagenais

• Doctor of Engineering
• Researcher at FPInnovations

To maximize the amount of carbon-sequestering mass timber and demonstrate the potential for mass timber across a range of building types and scales, DIALOG and EllisDon have developed a hybrid timber floor system (HTFS) that is composed of post-tensioned (PT) concrete beams, cross laminated timber (CLT) panels, and concrete topping connected to eac...

Whether noncombustible or combustible construction is used, the presence of combustible materials is likely to be used for various reasons, such as interior finishes, flooring, and insulation. Consequently, how regulations consider the degree of combustibility in their fire classifications will influence the level of fire safety provided in these b...

Combustible and noncombustible notions have evolved with time, along with the associated fire tests by which legislation classifies building materials. New Zealand, Japan, and Europe are just some of the many legislations that have followed this evolution, except for North American regulations, which remain attached to methods dating back to 1944....

Exposed timber in buildings has proven to have a positive effect on the building’s sustainability, occupant wellness, and increases the aesthetic appeal of the building but is currently limited by most building codes mainly due to fire safety concerns. While compartment fire testing can be carried out to prove a design performance, this approach is...

Major occupants' complaints received in light-frame wood-joisted floors of Impact Insulation Class (IIC) above 55, are low-frequency footstep thumping noise. Lack of understanding of fundamentals and solutions motived this study. A series of experiments were conducted to answer the following questions: 1) what are the frequency range of the low-fre...

Lack of understanding of wood building noise control fundamentals motivated this study. The well-known mass law and the theory of sound transmission through isotropic and uniform plate are too simple too be effectively applied for wood construction, especially for lightweight wood-frame construction due to its complexity. Wood is not a uniform and...

Wood is an anisotropic material. Because of its inherent characteristics, the mechanical behaviour of wood depends on the direction of the grain and the load type. The mechanical properties of wood change as temperature, moisture, and loading time. Moreover, growth characteristics such as slope of grain and knots significantly affect the mechanical...

Analyses of timber components under various loads are essential for structural design and product optimisation. In this chapter, analysis methods and key modelling considerations for wood-based components are introduced. Classic analytical methods are appropriate for specific wood-based products with limited configurations of loading and boundary c...

Major occupants' complaints received in light-frame wood-joisted floors of Impact Insulation Class (IIC) above 55, are low-frequency footstep thumping noise. Lack of understanding of fundamentals and solutions motived this study. A series of experiments were conducted to answer the following questions: 1) what are the frequency range of the low-fre...

This chapter discusses fire service considerations relevant to timber buildings. Firefighting practices may be different in timber buildings compared with non-combustible construction. Internationally, fire services have raised concerns regarding the increased use of wood within buildings and specifically the use of timber structural elements of ta...

The susceptibility of plants to burn raises concerns about fire hazard that green roofs may pose to buildings. Main concerns relate to cases when such roofs are poorly maintained or stressed by drought conditions which leads to drying out of plants and the accumulation of dead organic material, greatly increasing the availability of fuel load. Exis...

In this work, intumescent coatings were prepared for protection of wood from fire. The fire-retardant chemical ammonium polyphosphate (APP) is known to have poor resistance to water and high humidity as it is hygroscopic in nature. To improve the water resistance, durability and fire resistance of the intumescent coating, APP was modified using a h...

The National Building Code of Canada 2015 stipulates the minimum requirements of the airborne sound insulation transmission through common interior walls and ceiling/floor assemblies. The required minimum Apparent Sound Transmission Class (ASTC) is 47 in Canada, whereas the Impact Insulation Class (IIC) for floors is recommended to be higher than 5...

Building elements are required to provide sufficient fire resistance based on requirements set forth in the National Building Code of Canada (NBCC). Annex B of the Canadian standard for wood engineering design (CSA O86-19) provides a design methodology to calculate the structural fire-resistance of large cross-section timber elements. However, it l...

Because of their availability, mechanical properties and distinctive appearance, there is a growing interest for the use of hardwood species in structural products such as glued-laminated timber. Previous work on bonding and structural grading of northern hardwoods has shown that white ash (Fraxinus americana L.), yellow birch (Betula alleghaniensi...

The objective of this study was to develop a new drywall wood-based particleboard as an alternative to gypsum board. Various development iterations have led to the use of wood particles, steatite powder and Portland cement. The resulting outcome shows that screw withdrawal resistance was improved by 37% and bending properties by 69% compared to gyp...

Strength grading of hardwoods is required for their use in structural engineered wood products. However, hardwood strength grading is considerably less developed than it is for softwood species. Previous study has shown that white ash and yellow birch are promising species for the manufacture of glued-laminated timber. However, no dedicated strengt...

The growing demand for engineered wood products in the construction sector has resulted in the diversification of the product offer. Used marginally in structural products in North America, northern hardwoods are now attracting a growing interest from industry and policy makers because of their outstanding strength as well as their high availabilit...

Assessing the fire risk of vegetated roofs includes the determination of their possible contribution to fire. Green roof components such as plants and growing media are organic materials and present a fuel that can catch and support the spread of fire. The flammability characteristics of these components were analyzed and compared to a typical roof...

Fire safety regulations impose very strict requirements on building design, especially for buildings built with combustible materials. It is believed that it is possible to improve the management of these regulations with a better integration of fire protection aspects in the building information modeling (BIM) approach. A new BIM-based domain is e...

The construction sector continues to adapt to the challenges posed by climate change. Architects and engineers aim to build sustainable, energy, resource, and cost‐efficient structures by increasingly using bio‐based building materials. However, fire safety has always been a significant concern for timber building construction internationally. The...

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The thermomechanical behavior of members and connections plays a crucial role in the fire safety of timber construction. In this study, a unique constitutive model, Wood ST , combining a number of mechanics-based submodels was developed for numerical simulation of wood-based materials and connections under forces and fire. The extended Yamada-Sun s...

Currently, green roof fire risks are not clearly defined. This is because the problem is still not well understood, which raises concerns. The possibility of plants catching fire, especially during drought periods, is one of the reasons for necessary protection measures. The potential fire hazard for roof decks covered with vegetation has not yet b...

The fire performance of green roofs has never been assessed numerically. In order to simulate its fire behavior, the thermal conductivity of a growing media must be determined as an important input parameter. This study characterized the thermal conductivity of a dry substrate and its prediction as a function of temperature, considering temperature...

The growing demand for engineered wood products in the construction sector has resulted in the diversification of the product offer. Used marginally in structural products in North America, northern hardwoods are now attracting a growing interest from industry and policy makers because of their outstanding strength as well as their high availabilit...

The thermo-mechanical behaviour of members and connections plays a crucial role in the fire safety of timber construction. In this study, a unique constitutive model, WoodST, combining a number of mechanics-based sub-models was developed for numerical simulation of wood-based materials and connections under forces and fire. The extended Yamada-Sun...

L’utilisation du bois pour la construction de bâtiments est en forte hausse au Québec. En remplaçant des matériaux comme l’acier ou le béton, les produits de bois d’ingénierie, dont le bois lamellé-collé, permettent de diminuer l’empreinte écologique des bâtiments (Thormark 2006). À ce jour au Québec, ces produits sont exclusivement composés de boi...

The nature and the complexity of building codes, including the fire regulations, result in mainly manual verification and, therefore, in subjective potential interpretations or errors. In the case of timber construction, the fire safety regulations are moreover a challenge due to the combustibility of the material. Further integration of fire safet...

Laminated timber structural elements are gaining popularity as mass timber options since they can provide an economical and readily available alternative to cross-laminated timber (CLT), namely for use in upper mid-rise buildings (7 to 11 storeys). These types of assemblies include nail-laminated timber (NLT), dowel-laminated timber (DLT), screw-la...

Le International Residential Code (IRC) a adopté en 2012 des exigences prescriptives liées à la protection incendie des planchers résidentiels. L’IRC ne fournit cependant pas de lignes directrices ou de critères de performance lorsque l’on tente de démontrer l’équivalence à une solive de 2x10 conformément à l’exception 4 de l'article R302.13. Si un...

Structural fire resistance and charring behaviour of cross-laminated timber (CLT) have been well documented in the past decade. It was found from these standard fire-resistance tests that once the 1st lamination charred, the general trend is that the charring rate of the subsequent laminations increased, regardless of whether it was a floor or wall...

Nail-laminated timber (NLT) is a mass timber element that has traditionally been used for floors in old industrial facilities and is now gaining popularity again for use in new mass timber constructions. Although not commonly used for walls, it can be used in the construction of vertical shafts, such as for elevators. NLT has many potential applica...

Intumescent fire retardant (IFR) coatings are nowadays considered as the most effective flame retardant (FR) treatment. Nevertheless, the principal compound in an IFR system, ammonium polyphosphate (APP), is highly sensitive to moisture and IFR coating effectiveness decreases quickly. The main objective of this study is to encapsulate APP in a hybr...

Engineered wood products e.g. cross-laminated timber (CLT) and glued-laminated timber (glulam) are increasingly used as the material of choice for mid-rise to tall construction timber projects. However, the requirements to manufacture these timber elements are considerably different among countries and, consequently, do have an influence on their f...

Three timber-concrete composite floor assemblies were evaluated for fire performance to understand how shear connectors might impact heat transfer into the assemblies. The floor assemblies tested included a CLT-concrete floor with self-tapping screws, a screw-laminated 2x8-concrete using truss plates, and a LVL-concrete using lag bolts as shear con...

Twenty-three (23) cross-laminated timber (CLT) panels were exposed to a standard fire at an intermediate scale. This paper discusses several encapsulation methods used to increase the fire resistance of those panels, with emphasis on encapsulation times and the impact of encapsulation on the charring rate of CLTs. The encapsulation methods used inc...

This technical guide describes the technical requirements, evaluation procedures, and performance criteria for the assessment of physical and mechanical properties of cross-laminated timber (CLT). The technical guide also provides design provisions for use of CLT products and connections in structural applications.

In Canada, wood construction has historically been confined to low-rise buildings (up to 4-storeys) and to relatively small areas. With the adoption of the National Building Code of Canada (NBCC) in 2005, an objective-based code, wood-use in mid-rise buildings is now possible. Compliance with NBCC can now be achieved by using the acceptable solutio...

In Canada, wood constructions have historically been confined to low-rise buildings (up to 4-storeys) and to relatively small areas. With the adoption of the National Building Code of Canada (NBCC) in 2005, an objective-based code, wood-use in mid-rise buildings is now possible. Compliance with NBCC can now be achieved by using the acceptable solut...

Presently, finger-jointed softwood lumber is used in manufacturing of structural engineered wood products such as glued laminated (glulam) beams and prefabricated wood I-joists. However, the use of high-density hardwoods appears to be an attractive alternative material to achieve a higher performance of these products. Certain machining parameters...