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.
Mulching is a common method of fuel treatment. However, it is not currently listed by the U.S. Forest Service as a fuel type in its recommendations for fire retardant coverage levels. FPInnovations researchers set up plots with different coverage levels of retardant on a mulch fuel bed and collected fire behaviour data when a fire interacted with these plots. The results are intended to help wildfire agencies understand the effectiveness of retardant on mulch fuels in developing better suppression plans.
This study investigated the effects of applying three mulch treatment intensities on fuel bed characteristics and the resultant fire behaviour. This is a companion report to a previously published report titled Mulching productivity in black spruce fuels: Productivity as a function of treatment intensity. The findings of these fire behaviour trials, in conjunction with productivity results, can assist fuel management practitioners in developing appropriate cost-effective mulching prescriptions.
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.
Modified oxygen consumption calorimetry was used to track the seasonal flammability of black spruce and tamarack. Age class related samples were collected for both species from May to September at research site in central Alberta. These samples were assessed for their differential heat release using test equipment at the Protective Clothing and Equipment Research Facility (PCERF) at the University of Alberta.
The test method was able to successfully quantify the differences in seasonal flammability between black spruce and tamarack. Data showed the age-related flammability differences were less pronounced, with the exception of new growth samples early in the season.
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.
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.