FPInnovations carried out a survey with consultants and researchers on the use of analytical models and software packages related to the analysis and design of mass timber buildings. The responses confirmed that a lack of suitable models and related information for material properties of timber connections, in particular under combination of various types of loads and fire, was creating an impediment to the design and construction of this type of buildings. Furthermore, there is currently a lack of computer models for use in performance-based design for wood buildings, in particular, seismic and fire performance-based design.
In this study, a sophisticated constitutive model for wood-based composite material under stress and temperature was developed. This constitutive model was programmed into a user-subroutine and can be added to most general-purpose finite element software. The developed model was used to model the structural performance of a laminated veneer lumber (LVL) beam and a glulam bolted connection under force and/or fire. Compared with the test results, it shows that the developed model was capable of simulating the mechanical behaviour of LVL beam and glulam connection under load and/or fire with fairly good correlation.
With this model, it will allow structural designers to obtain the load-displacement curve of timber connections under force, fire or combination of the two. With this, key design parameters such as capacity, stiffness, displacement and ductility, which are required for seismic or fire design, can be obtained.
It is recommended that further verification and calibration of the model be conducted on various types of wood products, such as CLT, glulam, SCL and NLT, and fasteners, e.g. screw and rivet. Moreover, a database of the thermal and structural properties of the wood members and fasteners that are commonly used in timber constructions need to be developed to support and facilitate the application of the model.
Oriented residue piles and constructed burn piles have different characteristics, including fuel size, composition, and fuel arrangement. The comparative ignition trials conducted in this proof-of-concept study suggest that these characteristics influence the fuel environment, with a higher potential for ignition and sustained burning and greater resultant fire intensity in constructed burn piles. The intent of this proof-of-concept trial was to determine whether logging residue piles that have been oriented for biomass extraction (placed in parallel piles by the processor operator during primary harvesting activities) is a significant fuel hazard that requires further abatement.
The objective of the current project is to develop a performance-based design process for wood-based design systems that would meet the objectives and functional statements set forth in the National Building Code of Canada.
More specifically, this report discusses the fire and seismic performance of buildings, as identified as a priority in a previous FPInnovations report.
Data was collected within a burned out area on a steep mountain slope as part of FPInnovations’s Survival Zone project. The fire was a prescribed burn carried out by Parks Canada in Jasper National Park. The data collected shows that in this one instance, that temperatures and heat flux values fell within survivable range for firefighters wearing PPE. This report does not condone firefighters above a fire on a steep slope, but rather this PB was used as a data collecting opportunity.
FPInnovations conducted four separate underburns in August 2017 at the CBCFS research site north of Fort Providence, NWT. The burns were part of a fireguard for a future burn but allowed FPInnovations and the GNWT to study how and when underburning can be applied in a pine stand to reduce the potential spread of wildfire and lower the probability of embers landing and starting new fires. Underburns can also be used as lines from which to ignite backburns. To find the optimal fire weather and fuel conditions in which to burn, we burned four fires under different fire weather conditions and documented the resulting fire behaviour and the effects of the underburns.
In late June and early July of 2015, many large fires burned in Saskatchewan (Figure 1). Two of these fires threatened pre-existing community protection fuel treatments established to protect their villages. This report documents the treatments completed and the influence that the treatments had on fire behaviour as fire moved into them. The two communities that had their fuel treatments challenged were the hamlets of Weyakwin and Wadin Bay. Weyakwin had built a fuelbreak on the east side of town and thinned 4.6 ha of forest on the west side of the fuelbreak. Wadin Bay had also completed a thinning project to protect the hamlet from fire moving in from the west and south. Two trips were made to observe and document the fuel treatments and how fire behaved within them. Stand density data was collected within and beside the treatments to describe the fuel environment. Other data sources included fuel treatment plans, fire weather data, fire chronology information and personal communication with those who were involved in the projects and firefighting efforts.
Northwestern Alberta has been a focal point for agricultural expansion for many years. More recently, accelerated lands sales have led to the clearing of large tracks of land and significant burning projects aimed at preparing the land for agricultural use. Given the requirement for land owners to have burning permits during “Fire Season” (March 1st – October 31st) and the risks involved in large scale burning during fire season, sites are often differed to time frames outside the established fire season. Although windrow burning outside of fire season often poses less fire escape risk, other issues can arise and result in public safety concerns e.g. smoke, which can increase the potential for health issues and traffic accidents. Given these concerns local forestry and municipal authorities have engaged in discussions aimed at identifying potential burning options.
WoodST is capable of calculating heat transfer, charring rate, load-displacement curve as well as the time and mode of failure of timber structures exposed to fire, thus providing a cost-competitive solution for the fire safety analysis of timber structures. This InfoNote briefly introduces the development and verification of WoodST. Two applications of WoodST are also demonstrated.
WoodST est capable de calculer le transfert de chaleur, la vitesse de carbonisation, la courbe charge-déplacement ainsi que le moment et le mode de défaillance des structures en bois exposées au feu, offrant ainsi une solution à coût compétitif pour l'analyse de la sécurité incendie des ossatures en bois. La présente note d’information présente brièvement le développement et la vérification de WoodST. Deux applications de WoodST sont également présentées.