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.
Building regulations require that key building assemblies exhibit sufficient fire-resistance to allow time for occupants to escape and to minimize property losses. The intent is to compartmentalize the structure to prevent the spread of fire and smoke, and to ensure structural adequacy to prevent or delay collapse. The fire-resistance rating of a building assembly has traditionally been assessed by subjecting a replicate of the assembly to the standard fire-resistance test, (ULC S101 in Canada, ASTM E119 in the USA and ISO 834 in most other countries).
Massive wood elements such as solid sawn timbers, glued laminated timber (glulam) and structural composite lumber (SCL) can provide excellent fire-resistance. This is due to the inherent nature of thick timber members to char slowly when exposed to fire allowing massive wood systems to maintain significant structural resistance for extended durations when exposed to fire. Calculating the fire-resistance of massive wood elements can be relatively simple because of the essentially constant and predictable rate of charring during the standard fire exposure. Charred wood is assumed to no longer provide any strength and stiffness; therefore the remaining (or reduced) cross-section must be capable of carrying the load.
This report presents two (2) mechanics-based design procedures as alternative design methods to conducting fire-resistance tests in compliance with ULC S101 or to using Appendix D-2.11 of the NBCC, which is limited to glulam members stressed in bending or axial compression. The procedures are applicable to solid sawn timber, glulam or SCL structural members and aim at developing a suitable calculation method that would provide accurate fire-resistance predictions when compared to test data. The long-term objective is to provide recommendations for incorporating either method into CSA O86 and/or NBCC.
The comparisons between the proposed methodologies and the experimental data for beams, columns and tension members show good agreement. While further refinement of these methods is possible, these comparisons suggest that the use of the CSA O86 equations and a load combination for rare events adequately address fire-resistance design of massive wood members.
The main objective of this study is to evaluate the fire-protection F- and T-ratings of selected fire stops and sealing joints in cross-laminated timber assemblies, in accordance with CAN/ULC S115 test method, “Standard Method of Fire-Tests of Firestop System”.
Recommendations are given in this report with respect to proper detailing to ensure that the tested closure devices, when used in mass timber plate construction, will perform as expected. It is noted that test data is to date limited, and further testing may result in revision of these recommendations.
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.
The key objective of this study is to conduct a preliminary evaluation of the structural fire-resistance of selected structural composite lumber (SCL), namely laminated veneer lumber (LVL) and laminated strand lumber (LSL), in accordance with CAN/ULC S101 “Standard Methods of Fire Endurance Tests of Building Construction and Materials”.
The key objective of this study was to evaluate the surface burning characteristics (flame spread rating) of glued-laminated timber (glulam) decking in accordance with CAN/ULC S102 test method . This is part of a test series aimed at evaluating the flame spread rating of mass timber components, such as cross-laminated timber (CLT) and structural composite lumber (SCL).
More specifically, this study is solely focused on mass timber assemblies that are thick enough to be treated theoretically as semi-infinite solids (thermally thick solids) as opposed to thermally-thin, which is typical of traditional combustible finish products. The tested specimen in this series meets the provisions related to “heavy timber construction”, per paragraph 126.96.36.199 of Division B of the National Building Code of Canada.
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.