Figure 1 shows a floor plan and elevation along with the preliminary shear wall locations for a sixstorey wood-frame building. It is assumed some preliminary calculations have been provided to determine the approximate length of wall required to resist the lateral seismic loads.
If the preliminary design could not meet the drift limit requirement using the base shear obtained based on the actual period, the shear walls should be re-designed until the drift limit requirement is satisfied.
Fire separations and fire-resistance ratings are often required together but they are not interchangeable terms, nor are they necessarily mutually inclusive. The National Building Code of Canada (NBC)1 provides the following definitions: A fire separation is defined as “a construction assembly that acts as a barrier against the spread of fire.” A fire-resistance rating is defined as “the time in minutes or hours that a material or assembly of materials will withstand the passage of flame and the transmission of heat when exposed to fire under specified conditions of test and performance criteria, or as determined by extension or interpretation of information derived therefrom as prescribed in [the NBC].” In many buildings, the structural members such as beams and columns, and structural or non-structural assemblies such as walls and floors, are required to exhibit some degree of resistance to fire in order to prevent the spread of fire and smoke, and/or to minimize the risk of collapse of the building in the event of a fire. However, fire separations are assemblies that may or may not be required to have a specific fire-resistance rating, while structural members such as beams and columns that require a fireresistance rating to maintain the structural stability of a building in the event of a fire are not fire separations because they do not “act as a barrier against the spread of fire.”
The 2009 edition of CSA Standard O86, Engineering Design in Wood (CSA 2009), provides an equation for determining the deflection of shear walls. It is important to note that this equation only works for a single-storey shear wall with load applied at the top of the wall. While the equation captures the shear and flexural deformations of the shear wall, it does not account for moment at the top of the wall and the cumulative effect due to rotation at the bottom of the wall, which would be expected in a multi-storey structure.
In this fact sheet, a mechanics-based method for calculating deflection of a multi-storey wood-based shear wall is presented.
The vulnerability of any building, regardless of the material used, in a fire situation is higher during the construction phase when compared to the susceptibility of the building after it has been completed and occupied. This is because the risks and hazards found on a construction site differ both in nature and potential impact from those in a completed building; and these risks are occurring at a time when the fire prevention elements that are designed to be part of the completed building are not yet in place. For these reasons, construction site fire safety includes some unique challenges. Developing an understanding of these hazards and their potential risks is the first step towards fire prevention and mitigation during the course of construction (CoC).
Report of Testing Cross-Laminated Timber Panels for Compliance With CAN/ULC-S101 Standard Methods of Fire Endurance Test of Building Construction and Materials: Loadbearing 3-Ply CLT Wall with 1 Layer Of 5/8'' Fire-Rated Gypsum Board (60% Load)
Intertek Testing Services NA, Inc. (Intertek) has conducted testing for the Canadian Wood Council, on Cross-Laminated Timber Panels, to evaluate their fire resistance. Testing was conducted in accordance with the applicable requirements, and following the standard methods, of ASTM E119-12a Standard Test Methods for Fire Tests of Building Construction and Materials, January 2012 Edition, and CAN/ULC-S101-07 Standard Methods of Fire Endurance Tests of Building Construction and Materials. This evaluation took place on December 19, 2013.
Report of Testing Cross Laminated Timber Panels for Compliance with Can/ULC-S101 Standard Methods of Fire Endurance Tests of Building Construction and Materials: Loadbearing 3-Ply CLT Wall with 1 Layer of 5/8'' Type X Gypsum Board
Intertek Testing Services NA, Inc. (Intertek) has conducted testing for the Canadian Wood Council, on Cross-Laminated Timber Panels, to evaluate their fire resistance. Testing was conducted in accordance with the applicable requirements, and following the standard methods, of ASTM E119-14 Standard Test Methods for Fire Tests of Building Construction and Materials, OCtober 2014 Edition, and CAN/ULC-S101-07 Standard Methods of Fire Endurance Tests of Building Construction and Materials. This evaluation took place on November 12, 2014.
Report of Testing Cross Laminated Timber Panels for Compliance with CAN/ULC-S101 Standard Methods of Fire Endurance Tests of Building Construction and Materials: Loadbearing 3-Ply CLT Wall with Attached Wood Frame Partition
Intertek Testing Services NA, Inc. (Intertek) has conducted testing for the Canadian Wood Council, on Cross-Laminated Timber Panels, to evaluate their fire resistance. Testing was conducted in accordance with the applicable requirements, and following the standard methods, of CAN/ULC-S101 Standard Methods of Fire Endurance Tests of Building Construction and Materials, fourth edition, July 2007. This evaluation took place on December 30, 2011.
The rate at which flame spreads on the exposed interior surfaces or a room or space can have an impact on the rate of fire growth within an area, especially if the materials of the exposed surfaces are highly flammable. Therefore, the National Building Code of Canada (NBC) regulates the surface flammability of any material that forms part of the interior surface of walls, ceilings and, in some cases, floors, in buildings. Based on a standard fire-test method, the NBC uses a rating system to quantify surface flammability that allows comparison of one material to another, and the ratings within that system are called flame-spread ratings (FSR).
Most buildings are designed to accommodate a certain range of movement. In design, it is important for designers to identify locations where potential differential movement could affect structural integrity and serviceability, predict the amount of differential movement and develop proper detailing to accommodate it. To allow non-structural materials to be appropriately constructed, estimate of anticipated differential movement should be provided in the design drawings.
Simply specifying wood materials with lower MC at time of delivery does not guarantee that the wood will not get wet on construction sites and will deliver lower shrinkage amounts as anticipated. It is therefore important to ensure that wood does not experience unexpected wetting during storage, transportation and construction. Good construction sequencing also plays an important role in reducing wetting, the consequent wood shrinkage and other moisture-related issues.
Existing documents such as the APEGBC Technical and Practice Bulletin on 5- and 6-Storey Wood Frame Residential Building Projects, the Best Practice Guide published by the Canadian Mortgage and Housing Corporation (CMHC), the Building Enclosure Design Guide – Wood Frame Multi-Unit Residential Buildings published by the BC Housing- Homeowner Protection Office (HPO) provide general design guidance on how to reduce and accommodate differential movement in platform frame construction.
It is not possible or practical to precisely predict the vertical movement of wood structures due to the many factors involved in construction. It is, however, possible to obtain a good estimate of the vertical movement to avoid structural, serviceability, and building envelope problems over the life of the structure.
Typically “S-Dry” and “S-Grn” lumber will continue to lose moisture during storage, transportation and construction as the wood is kept away from liquid water sources and adapts to different atmospheric conditions. For the purpose of shrinkage prediction, it is usually customary to assume an initial moisture content (MC) of 28% for “S-Green” lumber and 19% for “S-Dry” lumber. “KD” lumber is assumed to have an initial MC of 15% in this series of fact sheets.
Different from solid sawn wood products, Engineered Wood Products (EWP) are usually manufactured with MC levels close to or even lower than the equilibrium moisture content (EMC) in service. Plywood, Oriented Strand Board (OSB), Laminated Veneer Lumber (LVL), Laminated Strand Lumber (LSL), and Parallel Strand Lumber (PSL) are usually manufactured at MC levels ranging from 6% to 12%. Engineered wood I-joists are made using kiln dried lumber (usually with moisture content below 15%) or structural composite lumber (such as LVL) flanges and plywood or OSB webs, therefore they are usually drier and have lower shrinkage than typical “S-Dry” lumber floor joists. Glued-laminated timbers (Glulam) are manufactured at MC levels from 11% to 15%, so are the recently-developed Cross-laminated Timbers (CLT). For all these products, low shrinkage can be achieved and sometimes small amounts of swelling can be expected in service if their MC at manufacturing is lower than the service EMC. In order to fully benefit from using these dried products including “S-Dry” lumber and EWP products, care must be taken to prevent them from wetting such as by rain during shipment, storage and construction. EWPs may also have lower shrinkage coefficients than solid wood due to the adhesives used during manufacturing and the more mixed grain orientations in the products, including the use of cross-lamination of veneers (plywood) or lumber (CLT). The APEGBC Technical and Practice Bulletin emphasizes the use of EWP and dimension lumber with 12% moisture content for the critical horizontal members to reduce differential movement in 5 and 6-storey wood frame buildings.