There is growing interest from the Canadian wood products industry to produce and use cross-laminated timber (CLT) panels in construction. Because this is a new product in North America, there is a need to demonstrate that the product meets various performance attributes such as structural resistance, sound transmission and fire resistance.
This research aims to address two primary objectives which will support the North American adoption of CLT. First, a generic calculation method for determining the fire-resistance of CLT assemblies is needed to enable producers to manufacture a number of different configurations of panels without the need to run a large number of full-scale fire tests. Second, the CLT assemblies chosen for testing have been identified as the most likely configurations to be used thereby providing test data to support the claims of fire-resistance to help satisfy the authority having jurisdiction.
This report provides results of a state-of-the-art literature review of studies and surveys on seismic performance of wood structures. The review was performed to develop an understanding of the seismic response and design of mid-rise/multi-storey wood buildings and to explore gaps and challenges in the seismic design of these structures. This report includes summaries from results of the previous experimental, numerical and analytical studies as well as post-earthquake surveys on seismic response/resistance of wood buildings. The main structural systems considered in this study were wood light frames, commonly used in North America. The results of this review showed the dynamic response characteristics of multi-storey wood buildings, e.g. effects of higher modes, would play a major role in the seismic design of such structures. However, a proper design of timber structures would mitigate their damage and failure in the event of earthquakes.
Hygrothermal Modelling Benchmark: Comparison of hygIRC Simulation Results with Full Scale Experiment Results (Report to Research Consortium for Wood and Wood-Hybrid Mid-Rise Buildings)
hygIRC 1D and 2D are hygrothermal simulation models developed at NRC Construction. hygIRC 1D is a one-dimensional version of hygIRC 2D. The objective of the task described in this report was to compare the results derived from the use the hygrothermal simulation models hygIRC 1D and hygIRC 2D to the results of a laboratory experiment (conducted as part of Task 5) to measure the drying rate of a specific wall assembly when subjected to nominally steady state conditions in an environmental chamber. The intended outcome was to duplicate the laboratory results as closely as possible as a means of benchmarking the simulation models both of which were subsequently used as part of the parametric simulation task (Task 6).
Solutions for Mid-Rise Wood Construction: Cone Calorimeter Results for Acoustic Membrane Materials Used in Floor Assemblies (Report to Research Consortium for Wood and Wood-Hybrid Mid-Rise Buildings)
The objective of the Hygrothermal Modelling and Analysis Task was to estimate the risk of moisture damage to the structural elements of a mid-rise wood building. Specifically, the objective was to characterize the risk of moisture damage to the load-bearing wall components of two wall constructions specified in “MID-RISE WOOD CONSTRUCTIONS – Specifications of Mid-rise Envelopes for Hygrothermal Assessment” Client Report A1-100035-03.1 [ ] due to trapped construction moisture.
In general for both wall constructions simulation results tended to point to the exterior of the stud in the Lightweight Wood Frame (LWF) and Cross Laminated Timber (CLT) construction cases to be the area most at risk, specifically toward the exterior surface of the stud. Generally the total Moisture Content (MC) of the stud decreased to an acceptable level within the simulation period however the exterior surface appeared to remain at relatively high of moisture content level for significant periods of time. The presence of wood strapping covering the exterior face of the stud seemed to exacerbate the situation. If a support system for the cladding can be designed that does not rely on wood strapping or covers a minimum area of the stud the performance of this critical area could be improved. If the initial moisture content of the wood materials could be reduced before close up the performance would also be improved for all locations that did not show an increase in moisture content and the RHT index in the second year, at least with respect to computer modelling. This work however was not in scope of the work.
Solutions for Mid-Rise Wood Construction: Full-Scale Standard Fire Test for Exterior Wall Assembly using a Simulated Cross-Laminated Timber Wall Assembly with Gypsum Sheathing
One of the tasks in the project, Wood and Wood-Hybrid Midrise Buildings, was to develop further information and data for use in developing generic exterior wall systems for use in mid-rise buildings using either lightweight wood frame or cross-laminated timber as the structural elements. This report describes a standard full-scale exterior wall fire test conducted on May 22, 2012 on a simulated cross-laminated timber (CLT) wall assembly with an attached insulated lightweight wood frame assembly protected using gypsum sheathing. The test was conducted in accordance with CAN/ULC-S134.
A research project, Wood and Wood-Hybrid Midrise Buildings, was undertaken to develop information to be used as the basis for alternative/acceptable solutions for mid-rise construction using wood structural elements. One of the Tasks in the project was to investigate the effectiveness of three materials for use as encapsulation materials for combustible structural elements: Type X gypsum board, cement board and gypsum-concrete. Cone calorimeter and intermediate-scale furnace tests were conducted for these materials. The results of the tests on these materials using the cone calorimeter and the intermediate-scale furnace are provided in References 3 and 4, respectively. In addition to the tests for the three encapsulation materials, data from previous NRC fireresistance projects were reviewed for data on the encapsulation time for structural elements afforded by gypsum board in the context of standard fire-resistance testing. In this report, the results of the data-mining from several of NRC’s fire-resistance testing projects are provided.
This client report on the acoustics research component regarding sound insulation of elements and systems for mid-rise wood buildings is structured into a main part and four appendices. The main part outlines the background, main research considerations and summarizes conducted research and major outcomes briefly. It is structured like the Acoustics tasks in the Statement of Work of the Mid-rise Wood research project to identify accomplishments. For details on the research, testing and results, the main part references to four appendices that contain more details including test plans, test methods, specimen descriptions and all test data that is vetted so far.
Working in collaboration with the Canadian Wood Council and FPInnovations and in partnership with Natural Resources Canada and the governments of Ontario, Quebec and British Columbia, the National Research Council conducted a comprehensive research project, Research Consortium for Wood and Wood-Hybrid Mid-rise Buildings. This consortium project aimed to develop technical information that could be used to support acceptable solutions that meet the NBC’s objectives for fire safety, acoustics, and building envelope performance, in order to facilitate the use of wood-based structural materials in mid-rise buildings. The objectives of the Wood and Wood-Hybrid Midrise Buildings research project were to develop performance data and technical solutions in the areas of fire safety, acoustics and building envelope pertinent to the use of wood-based structural materials in mid-rise buildings, i.e. to develop an alternative solution to meet the 2010 NBC requirements for non-combustible construction for 5-6 storey (and taller) buildings. This project was intended to address the immediate needs for technical solutions for mid-rise wood buildings that do not compromise the minimum levels of safety and performance required by the 2010 NBC in the areas of fire safety and fire protection, acoustics, and building envelope performance.
To evaluate the building envelope performance of the generic exterior wall assemblies developed for use in mid-rise wood buildings, hygrothermal properties of materials used in the assemblies are needed as input data for hygrothermal modelling. Hygrothermal properties were developed for fire retardant treated plywood, regular gypsum sheathing, spray polyurethane foam and cross-laminated timber. This report documents results of the hygrothermal property determinations.
The objective of this part of the research project was to generate a set of reliable and representative data on hygrothermal properties of a number of selected building materials as mentioned below.
1. D-Blaze Treated Plywood
2. Dricon Treated Plywood
3. Gypsum Sheathing
4. Closed Cell Spray Polyurethane Foam Insulation (Purple in Colour)
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