The objective of this research is to address a knowledge gap related to fire performance of midply shear walls. Testing has already been done to establish the structural performance of these assemblies. To ensure their safe implementation and their broad acceptance, this project will establish fire resistance ratings for midply shear walls. Fire tests will provide information for the development of design considerations for midply shear walls and confirm that they can achieve at least 1-hour fire-resistance ratings that are required for use in mid-rise buildings.
This research will support greater adoption of mid-rise residential and non-residential wood-frame construction and improve competition with similar buildings of noncombustible construction. This work will also support the development of the APA system report for midply walls, which will be a design guideline for using midply walls in North America.
FPInnovations is involved in a large research project regarding CLT construction. One objective of this research is the creation of a design methodology for calculating the fire-resistance of CLT assemblies/construction. This methodology will foster the design of fire-safe buildings of wood or hybrid construction. In order to establish such calculation methods, a series of experimental tests has been undertaken. A total of eight full-scale CLT fire resistance tests have been conducted at the NRC fire laboratory where the panels were subject to the standard ULC S101  fire exposure. The series consisted of three wall and five floor tests. Each test was unique using panels with a different number of plies and varying thicknesses. Some of the assemblies were protected using CGC Sheetrock® FireCode® Core Type X gypsum board while others were left unprotected.
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. As one approach, encapsulation materials could be used to protect the combustible (wood) structural materials for a period of time in order to delay the effects of the fire on the combustible structural elements, including delay of ignition. In delaying ignition, any effects of the combustion of the combustible structural elements on the fire severity can be delayed. In some cases, and depending upon the amount of encapsulating material used (e.g. number of layers), ignition of the elements might be avoided completely. This scenario would primarily depend upon the fire event and the actual fire performance of the encapsulating materials used. The effectiveness of the encapsulation approach in limiting the involvement of wood structural materials in fires was demonstrated in the research project through bench-, intermediate- and full-scale fire experiments.
This project will document the flammability of Douglas-fir and spruce-pine-fir CLT panel assemblies produced in the United States. Tests are being conducted on wall and floor panel assemblies with standard overlapping connections and produced with two different types of commonly-used adhesives. Sensors placed throughout panels will provide data about how fire affects the interior and exterior of a panel. A thermal imaging camera will provide information on how the structural integrity of panels is affected by fire and fire suppression activities.
Project contact is Thomas Tannert at the University of Northern British Columbia
The project will validate an innovative hold-down system for tall mass-timber structures that will satisfy the seismic performance demands of the revised CSA-O86 design provisions for such components. Subsequent to a numerical optimization of the hold-downs, full-scale CLT shear walls equipped with the hold-downs will be coupled with different energy-dissipative shear connectors (U-shaped dissipaters and self-tapping screws) and tested under monotonic push-over and reversed-cyclic loads. The project will facilitate the development of reliable design guidance for CLT systems that constitute a promising solution for many applications including tall structures where reduced weight is advantageous for seismic design.
A series of 3 cross-laminated timber (CLT) fire-resistance tests were conducted in accordance with ULC S101 standard as required in the National Building Code of Canada.
The first two tests were 3-ply wall assemblies which were 105 mm thick, one unprotected and the other protected with an intumescent coating, FLAMEBLOC® GS 200, on the exposed surface. The walls were loaded to 295 kN/m (20 250 lb./ft.). The unprotected assembly failed structurally after 32 minutes, and the protected assembly failed after 25 minutes.
The third test consisted of a 175 mm thick 5-ply CLT floor assembly which used wood I-joists, resilient channels, insulation and 15.9 mm ( in.) Type X gypsum board protection. A uniform load of 5.07 kPa (106 lb./ft²) was applied. The floor assembly failed after 138 min due to integrity.
To support the associated elementary school projects in pushing the boundaries forward for wood construction in seismic zones, this testing project aims to establish the seismic behaviour of two-storey continuous cross-laminated (CLT) timber shear walls in comparison to typical single-storey CLT shear walls and ensure they are able to provide necessary ductility in a seismic event. Working with the University of Northern British Columbia (UNBC), Fast + Epp aimed to complete a series of monotonic and reversed cyclic tests on CLT shear walls. The test setup was developed to determine the behaviour of these types of shear walls for the project specific application, as well as provide a basis to further develop this type of system for the engineering community. The multi-storey continuous CLT panel shear walls will allow for more efficient and cost-effective construction – reducing construction time, material handling, and the number of connectors required. The lab testing of these shear walls is complete, with data analysis underway. Results are intended to be published in 2021.
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. The effectiveness of the encapsulation approach in limiting the involvement of wood structural materials in fires was demonstrated in this research project through bench-, intermediate- and full-scale fire experiments. These results for encapsulated lightweight wood-frame (LWF) systems and encapsulated cross-laminated timber (CLT) systems are documented in a series of reports [3, 4, 5, 6].
In addition to developing the encapsulation approach for protecting the wood structural materials to meet the above code intent, research was undertaken to examine standard fire resistance of encapsulated wood structural assemblies for use in mid-rise wood/timber buildings. One of the major differences between structural LWF assemblies used in mid-rise wood buildings (5-6 storeys) and low-rise wood buildings (= 4 stories) is the wall assemblies for the lower storeys. For mid-rise wood buildings, loadbearing wall assemblies on the lower storeys have to be designed to resist higher axial loads due to the self-weight of the upper storeys, which often result in the need for larger-size stud members and/or a greater number of studs, and higher lateral loads in case of seismic events or wind loads, which often requires the use of wood shear panels within the wall assembly. These wall assemblies very often will need to meet standard fire resistance requirements, and therefore, information regarding their standard fire-resistance ratings should be developed. This report documents the results of fullscale furnace tests conducted to develop standard fire-resistance ratings of encapsulated LWF assemblies for use in mid-rise applications.
The key objective of this study is to analyze full-scale fire-resistance tests conducted on structural composite lumber (SCL), namely laminated veneer lumber (LVL), parallel strand lumber (PSL) and laminated strand lumber (LSL). A sub-objective is to evaluate the encapsulation performance of Type X gypsum board directly applied to SCL beams and its contribution to fire-resistance of wood elements.
The test data is being used to further support the applicability of the newly developed Canadian calculation method for mass timber elements, recently implemented as Annex B of CSA O86-14.