This project aims to support the construction of tall wood buildings by identifying encapsulation methods that provide adequate protection of mass timber elements; the intention is that these methods could potentially be applied to mass timber elements so that the overall assembly could achive a 2 h fire resistance rating.
The following topics in the field of seismic analysis and design of mid-rise (5- and 6-storey) wood-frame buildings are included in this paper: Determination of the building period, linear dynamic analysis of wood-frame structures, deflections of stacked multi-storey shearwalls, diaphragm classification, capacity-based design for woodframe...
FPInnovations initiated this project to demonstrate the ability of wood exit stairs in mid-rise buildings to perform adequately in a fire when NBCC requirements are followed, with the intent of changing perceptions of the fire safety of wood construction. The objective of this research is to investigate further the fire safety afforded by exit stair shafts of combustible construction, with the ultimate objective of better consistency between the provincial and national building codes with respect to fire requirements for exit stair shafts in mid-rise wood-frame construction.
During the past few years, a relatively new technology has emerged in North America and changed the way professionals design and build wood structures: Cross-laminated Timber (CLT). CLT panels are manufactured in width ranging from 600 mm to 3 m. As such, fastening them together along their major strength axis is required in order to form a singular structural assembly resisting to in-plane and out-of-plane loading. Typical panel-to-panel joint details of CLT assemblies may consist of internal spline(s), single or double surface splines or half-lapped joints. These tightly fitted joint profiles should provide sufficient fire-resistance, but have yet to be properly evaluated for fire-resistance in CLT assemblies.
The experimental portion of the study consisted at conducting ten (10) intermediate-scale fire-resistance tests of CLT floor assemblies with four (4) types of panel-to-panel joints and three (3) CLT thicknesses. The data generated from the intermediate-scale fire tests were used to validate a finite element heat transfer model, a coupled thermal-structural model and a simplified design model. The latter is an easy-to-use design procedure for evaluating the fire integrity resistance of the four commonly-used CLT floor assemblies and could potentially be implemented into building codes and design standards. Based on the test data and models developed in this study, joint coefficient values were derived for the four (4) types of CLT panel-to-panel joint details. Joint coefficients are required when assessing the fire integrity of joints using simple design models, such as the one presented herein and inspired from Eurocode 5: Part 1-2.
The contribution of this study is to increase the knowledge of CLT exposed to fire and to facilitate its use in Canada and US by complementing current fire-resistance design methodologies of CLT assemblies, namely with respect to the fire integrity criterion. Being used as floor and wall assemblies, designers should be capable to accurately verify both the load-bearing and separating functions of CLT assemblies in accordance with fire-related provisions of the building codes, which are now feasible based on the findings of this study.
This report begins with a discussion of the mechanisms of flame spread over combustible materials while describing the NBCC prescriptive solutions that establish the acceptable fire performance of interior finish materials. It is noted that while flame spread ratings do give an indication of the fire performance of products in building fires, the data generated are not useful as input to fire models that predict fire growth in buildings.
The cone calorimeter test is then described in some detail. Basic data generated in the cone calorimeter on the time to ignition and heat release rates are shown to be fundamental properties of wood products which can be useful as input to fire models for predicting fire growth in buildings.
The report concludes with the recommendation that it would be useful to run an extensive set of cone calorimeter tests on SCL, glue-laminated timber and CLT products. The fundamental data could be most useful for validating models for predicting flame spread ratings of massive timber products and useful as input to comprehensive computer fire models that predict the course of fire in buildings. It is also argued that the cone calorimeter would be a useful tool in assessing fire performance during product development and for quality control purposes.
The role of the building envelope research team in this project was to assess whether midrise wood-frame (LWF) and cross-laminated timber (CLT) building envelope solutions developed by the fire research team to meet the fire provisions of the National Building Code (NBC) 2010 Part 3 Fire Protection, would also meet the NBC Part 5 Environmental Separation requirements relating to the protection of the building envelope from excessive moisture and water accumulation. As well, these wood-based mid-rise envelope solutions were to be assessed for their ability to meet Part 3 Building Envelope of the National Energy Code for Buildings (NECB) 2011. Requirements relating to heat, air, moisture, and precipitation (HAMP) control by the building envelope are included in Part 5 Environmental Separation of the NBC 2010. Part 5 addresses all building types and occupancies referred to in Part 3, but unlike requirements for fire protection, this section of the code was written more recently and is generic, including requirements that are more objective-oriented rather than prescriptive requirements pegged to specific constructions systems. The investigated methodologies developed and adapted for this study took those code characteristics into account.
In order to expedite market acceptance and facilitate the commercial uptake of wood products and systems in Canada, it is necessary to showcase such applications through high-rise and non-residential building demonstration projects. This paper presents recent initiatives by the Government of Canada focused on increasing use of wood as a green building material in infrastructure projects by supporting such demonstration projects. The objective of Green Construction through Wood (GCWood) program (launched in 2017) is to support the design and construction of several high-rise and non-residential timber demonstration buildings and bridges in Canada through expression of interest (EOI) calls. The program is also supporting research and development activities to facilitate acceptance of provisions that would allow for the construction of tall wood buildings in Canadian building codes and advanced wood education at engineering and architectural colleges and universities to help develop the future design capacity in Canada.
The objective of the task is to select, from the 679 locations in Table C-2 of the 2010 National Building Code of Canada (NBC 2010), several representative locations for which long-term historical weather data exists. This information from these locations can subsequently be used to determine the exterior boundary conditions for input files for hygrothermal simulation programs and hygrothermal testing in the laboratory.
This report discusses the selection of locations for the hygrothermal simulation task of the project on Mid-rise Wood Buildings and the determination of spray-rates and pressure differentials for the water penetration testing portion of the project.
This paper examines CLT-steel hybrid systems at three, six, and nine storey heights to increase seismic force resistance compared to a plain wood system. CLT panels are used as infill in a steel moment frame combining the ductility of a steel moment frame system with a stiffness and light weight of CLT panels. This system allows for the combination of high strength and ductility of steel with high stiffness and light weight of timber. This thesis examines the seismic response of this type of hybrid seismic force resisting system (SFRS) in regions with moderate to high seismic hazard indices. A detailed non-linear model of a 2D infilled frame system and compared to the behavior of a similar plain steel frame at each height.
Parametric analysis was performed determining the effect of the panels and the connection configuration, steel frame design, and panel configuration in a multi-bay system. Static pushover loading was applied alongside semi-static cyclic loading to allow a basis of comparison to future experimental tests. Dynamic analysis using ten ground motions linearly scaled to the uniform hazard spectra for Vancouver, Canada with a return period of 2% in 50 years as, 10% in 50 years, and 50% in 50 years to examine the effect of infill panels on the interstorey drift of the three, six, and nine storey. The ultimate and yield strength and drift capacity are determined and used to determine the overstrength and ductility factors as described in the National Building Code of Canada 2010.
With the introduction of Cross Laminated Timber (CLT) into North America and gaining popularity it is of interest to the design and code development community to have codified provisions to facilitate the design of CLT structures. This paper addresses the design aspect of CLT panels subjected to combined bending and compressive axial loads. Fifteen specimens covering different combinations of grades and layups of commercially available Canadian CLT panels were tested at different eccentricities to validate the proposed interaction equation. Testing program was reported in this paper and the test data was compared with the model prediction. It was concluded that the current nonlinear interaction equation given in the Canadian timber design standard (CSA O86) for timber and glulam tends to overestimate the capacity of CLT wall panel. A linear interaction equation was found to be appropriate