FPInnovations a effectué un essai en laboratoire afin d’étudier la teneur en humidité (TH) du bois lamellé-croisé (CLT) découlant du coulage de chapes de béton, et l’efficacité avec laquelle un enduit imperméabilisant et une membrane permettent de de prévenir cette humidification.
FPInnovations conducted a laboratory test to investigate the potential wetting of cross-laminated timber (CLT) from the pouring of concrete topping, and the effectiveness of a water repellent coating and membrane in preventing such wetting.
The objective of this work is to generate fire resistance data for NLT assemblies to address significant gaps in technical knowledge. This research will support designers and builders in the use of mass timber assemblies in larger and taller buildings, as well as provide scientific justification for Authorities Having Jurisdiction (AHJ) to review and accept this construction method. The intent is to demonstrate that NLT construction can meet or exceed NBCC fire safety requirements for use in buildings of mass timber construction.
The data could be used towards the inclusion of an NLT fire resistance calculation methodology into Annex B of CSA O86 – Engineering Design for Wood [4], which currently addresses only glue-laminated timber (GLT), structural composite lumber (SCL) and cross-laminated timber (CLT).
The objective of this work is to generate fire performance data for NLT assemblies to address gaps in technical knowledge. This project aims to study how the size of gaps between NLT boards might affect charring of an assembly and its overall fire performance. This research will support designers and builders in the use of mass timber assemblies in larger and taller buildings, by ensuring fire safe designs.
The objective of this project is to establish fundamental fire performance data for the design and specification of NLT assemblies; this project specially addresses determining FSRs for NLT. The goal of this project is to confirm that NLT, when used as a mass timber element, has a lower FSR than standard thickness SPF boards when tested individually and flatwise. The project also considers how the surface profiles, design details, and the direction of an assembly might influence flame spread. This includes the evaluation of typical architectural features, such as a ‘fluted’ profile.
Having this technical information will support project approvals for the use of NLT elements in larger and taller wood buildings, as well as provide scientific justification for Authorities Having Jurisdiction (AHJ) to review and accept this construction method. This research will provide the evidence for designers to demonstrate their design have met or exceeded fire safety requirements. Ultimately the intent is to expand the adoption of manufactured solid timber construction for larger and taller buildings, as well as for non-traditional wood markets (such as institutional or commercial buildings).
Other aspects of this project (in separate reports) include evaluating fire resistance of NLT, and assessing how NLT charring rates might be affected by gaps between boards.
In the first year of this project, literature reviews were conducted to identify the code requirements on MT components and to survey the available LLRSs used in the MT structures. Conceptual MT midply wall systems meeting structural, fire, and acoustical performance requirements were proposed. An advisory group meeting was held to evaluate the practicability of the proposed MT midply systems. In the next fiscal year, the proposed MT Midply will be optimised further according to the comments and suggestions from the advisory group. Analytical evaluation of the proposed MT Midply wall systems along with necessary tests will be conducted. Based on the evaluation, a go / no-go decision will be made as to whether the study should be continued for the proposed MT Midply.
Building on the success of midply shear walls for wood-frame construction, a multi-year research project was initiated at FPInnovaitons to develop MT version of midply shear wall systems that have greater structural capacities, fire, and acoustical performance.
Computer modelling is an essential part in the analysis and design of mid- and high-rise residential and commercial buildings as well as long-span structures. It is also a valuable tool in the optimisation of wood-based products, connections, and systems. An FPInnovations’ survey shows that practicing engineers are unfamiliar with timber structure modelling, and researchers generally lack resources for advanced modelling of timber systems. Furthermore, wood analysis and design modules currently implemented in a few structural analysis software are usually not suitable for complex or hybrid timber structures. This does not bode well given that performance-based design which is the future direction of building codes and material standards will rely even more on demonstrating the structural performance through computer modelling. In this project, a modelling guide for timber structures is being developed by FPInnovations with a global collaborative effort involving experts in various areas, with the aim of (a) assisting practicing engineers apply computer modelling to timber structures; (b) enriching researchers’ resources for advanced computer modelling of timber systems; and (c) assisting software companies to identify the gaps and upgrade their programs accordingly to accommodate advanced computer modelling of timber structures.
Braced timber frames (BTFs) are one of the most efficient structural systems to resist lateral loads induced by earthquakes or high winds. Although BTFs are implemented as a system in the National Building Code of Canada (NBCC), no design guidelines currently exist in CSA O86. That not only leaves these efficient systems out of reach of designers, but also puts them in danger of being eliminated from NBCC. The main objective of this project is to generate the technical information needed for development of design guidelines for BTFs as a lateral load resisting system in CSA O86. The seismic performance of 30 BTFs with riveted connections was studied last year by conducting nonlinear dynamic analysis; and also 15 glulam brace specimens using bolted connections were tested under cyclic loading.
In the second year of the project, a relationship between the connection and system ductility of BTFs was derived based on engineering principles. The proposed relationship was verified against the nonlinear pushover analysis results of single- and multi-storey BTFs with various building heights. The influence of the connection ductility, the stiffness ratio, and the number of tiers and storeys on the system ductility of BTFs was investigated using the verified relationship. The minimum connection ductility for different categories (moderately ductile and limited ductility) of BTFs was estimated.
Midply shear wall (hereafter Midply), which was originally developed by researchers at Forintek Canada Corp. (predecessor of FPInnovations) and the University of British Columbia, is a high-capacity shear wall system that is suitable for high wind and seismic loadings. Its superior seismic performance was demonstrated in a full-scale earthquake simulation test of a 6-storey wood-frame building in Japan. In collaboration with APA–The Engineered Wood Association and the American Wood Council (AWC), a new framing arrangement was designed in this study to increase the vertical load resistance of Midply and make it easier to accommodate electrical and plumbing services. In this study, a total of 14 Midply specimens in six wall configurations with different sheathing thicknesses and nail spacing were tested under reversed cyclic loading. Test results showed that Midply has approximately twice the lateral load capacity of a comparable standard shear wall. The drift capacity and energy dissipation capability are also greater than comparable standard shear walls. For Midply to use the same seismic force modification factors as standard shear walls, seismic equivalency to standard shear walls in accordance with ASTM D7989 was also conducted. Although Midply has superior lateral load and drift capacities, it does not seem to be as ductile as the standard shear walls at the same over-strength level. Additional testing and dynamic analysis are recommended to address this issue.
