An innovative multi-layer (3 and 5) composite laminated panel (CLP) with various layups were developed using sawn lumber and structural composite lumber (SCL) to address the rolling shear and gap issues of cross laminated timber (CLT). The bending properties including apparent and effective bending stiffness, shear stiffness, moment capacities and failure modes of CLPs were evaluated by a combination of modal tests and third-point bending tests of beam specimens cut from the panels. The static bending test results showed that the apparent bending stiffness values of 3-layer and 5-layer CLPs were up to 20% and 43% higher than the corresponding values of 3-layer and 5-layer generic CLT, respectively. The bending moment capacity values of 3-layer and 5-layer CLPs were up to 37% and 87% higher than the corresponding values of 3-layer and 5-layer generic CLT, respectively. The use of SCL in transverse layers eliminated the potential rolling shear failure in CLT and increased the stiffness properties. The apparent and effective bending stiffness predicted by shear analogy method had a good agreement with corresponding values measured by bending tests and/or modal tests. The prediction of bending moment capacity using shear analogy method cannot be validated due to the rolling shear failure and tension failure modes observed in certain groups.
Fifteen structural composite lumber (SCL) products including laminated-veneer lumber (LVL), laminated strand lumber (LSL), oriented strand lumber (OSL), and parallel strand lumber (PSL) provided by Boise Cascade, LP, West Fraser, and Weyerhaeuser were tested for moisture-related properties in this study, also covering four reference materials: 16-mm Oriented Strand Board (OSB), 19-mm Canadian Softwood Plywood (plywood), 38-mm Douglas-fir and lodgepole pine solid wood. Water absorption, vabour permeance, vapour sorption, and dimensional stability were measured with limited replication by following relevant standards for a purpose of assisting in improving building design and construction, such as hygrothermal modelling of building envelope assemblies, design for vertical differential movement, and on-site moisture management.
Overall moisture management during construction has become increasingly important due to the increase in building height and area, which potentially prolongs the exposure to inclement weather, and the overall increase in speed of construction, which may not allow adequate time for drying to occur. This report provides guidelines and relevant information about on-site moisture management practices that can be adapted to suit a range of wood construction projects. It aims to help designers and construction companies and builders assess the potential for moisture-related issues arising during the construction phase of a wood-building project and identify the appropriate actions to mitigate such risk.
In-plane shear and planar shear due to out-of-plane bending are important properties for the design of CLT-type floor systems. Properties of CLT-type panels are influenced by the orientation of the layer’s major stiffness directions and the properties of their layers. The layers are influenced by their characteristics, laminate aspect ratio, growth ring orientation and edge-gluing. In order to utilize the mechanical potential of CLT-type panels, it is necessary to understand the effects of layer and laminate properties on CLT performance. CLT and CLT-hybrid panels were tested in planar and in-plane shear tests. The shear properties were evaluated using static and modal test procedures, the accuracy of non-destructive test methods was evaluated. Relationships between specimen properties and the characteristics of laminates and layers, such as aspect ratio, growth ring orientation and edge-gluing, were established.
This guide provides the directives needed for designers of tall wood buildings to produce their designs, plans and specifications. It has been developed to give them the information and general concepts required, based on the selected system. The elements and details required to comply with the guidelines in this document must be incorporated from a project’s initial design phase.
Part 1 – Guidelines contains several sections, including one that deals with basic conditions and describes the minimum general conditions applicable to any project for the construction of a wood building exceeding 6 storeys. The following sections contain special provisions that specify and complete the basic conditions.
Acoustic emission (AE) characteristics of full-hole bolt-bearing testing on structural compositelumbers (SCL) including laminated veneer lumber (LVL) and oriented strand lumber (OSL) were investigated. The main conclusion is that AE cumulative counts vs time curves of the tested SCL in this study can be characterized with three distinct regions in terms of AE count rates: Region I with a lower constant count rate, Region II with varied and increased count rates, and Region III with a higher constant count rate. Differences in AE count rates of these three regions occurred between LVL and OSL. Also, within each tested SCL, differences in AE count rates were observed among the three regions. These differences in terms of AE count rates between two tested SCL indicate that different types of wood-based composites might have different AE characteristics in terms of the count rate changes when they are subjected to increased bolt compression load. In other words, these differences in AE characteristics between the two tested materials suggest AE “signatures” do exist for SCL bolt connections.
This note examined the effects of adding nanoclays to phenol-formaldehyde resin during the manufacture of oriented strand lumber (OSL) on its in-plane permeability. The panels were made from mountain pine beetle (MPB) attacked lodgepole pine (Pinus contorta) strands. Three different montmorillonite nanoclays were mixed with the PF resin: Na+, hydrophobic organics modified 10A, and hydrophilic organics modified 30B. None of the nanoclays changed the permeability of OSL significantly. The MPB-OSL had higher in-plane permeability than those conventionally made from aspen, which indicated that the pressing time could be shorter for MPB-OSL compared with OSL made from MPB-free strands.