Advanced industrialized construction methods enable complex building components and systems to be built with high precision and quality. This manufacturing technique has an advantage to provide cost-competitive and high energy efficient building components and systems for both retrofits and new construction. This document gives an overview of the use of prefabricated panels in building Net Zero Energy Ready wood-frame multi-unit residential buildings (MURBs) in Edmonton.
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.
In recent years, timber has been considered as an alternative source of building material because of its sustainability and design efficiency. However, the cost competitiveness of timber buildings is still under study due to the lack of available cost information. This paper presents a comprehensive cost comparative analysis of a mass timber building mainly developed with cross-laminated timber (CLT). The actual construction cost of the project is compared with the modeled cost of the same building designed as a concrete option. The result shows that the construction cost of timber building is 6.43% higher than the modeled concrete building. The study further investigated the change orders associated with the project and found that the total cost of change orders contributed 5.62% to the final construction cost of mass timber building. The study is helpful to provide insight into the construction cost of typical mass timber buildings. It also can be used as a guide for the project owners to make decisions regarding their initial investments on a mass timber project.
Innovative mass timber panels, known as composite laminated panels (CLP), have been developed using lumber and laminated strand lumber (LSL) laminates. In this study, strain distributions of various 5-layer CLP and cross-laminated timber (CLT) were investigated by experimental and two modelling methods. Seven (7) different panel types were tested in third-point bending and short-span shear tests. During the tests, the digital imaging correlation (DIC) technique was used to measure the normal and shear strain in areas of interest. Evaluated component properties were used to determine strain distributions based on the shear analogy method and finite element (FE) modelling. The calculated theoretical strain distributions were compared with the DIC test results to evaluate the validity of strain distributions predicted by the analytical model (shear analogy) and numerical model (FE analysis). In addition, the influence of the test setup on the shear strain distribution was investigated. Results showed that the DIC strain distributions agreed well with the ones calculated by the shear analogy method and FE analysis. Both theoretical methods agree well with the test results in terms of strain distribution shape and magnitude. While the shear analogy method shows limitations when it comes to local strain close to the supports or gaps, the FE analysis reflects these strain shifts well. The findings support that the shear analogy is generally applicable for the stress and strain determination of CLP and CLT for structural design, while an FE analysis can be beneficial when it comes to the evaluation of localized stresses and strains. Due to the influence of compression at a support, the shear strain distribution near the support location is not symmetric. This is confirmed by the FE method.
The research study focuses on different strengthening techniques for timber concrete composites (TCC) using different types of wire and wire mesh integrated with a layer of epoxy on a timber core embedded in concrete using experimental and analytical procedure. The impact of TCC on axial compression performance, modulus of elasticity, failure mode and post failure behavior and ductility were compared to reference concrete specimens. Different types of wire and wire mesh used in strengthening of the timber core, timber core size and reinforcement in the concrete cylinder were all parameters considered in this study. Timing of application of the epoxy on the wire strengthened timber core was very important. For structural applications, where the weight reduction and ductility as well as post failure endurance are essential, the development of this composite is recommended. The ratio of the ductility index to the weight is discussed. The light weight of the timber composite, and the increased ductility were noted in this study. An equation to estimate the axial compression capacity of the strengthened timber concrete composite was developed in this study. This study will pave the way for further applications for timber concrete composite aiming at reducing dead weight of concrete and the reducing the amount of concrete and steel in construction.
This study on Circular Economy & the Built Environment Sector in Canada was carried out by The Delphi Group in collaboration with Scius Advisory and completed in March 2021 on behalf of Forestry Innovation Investment Ltd. (FII) in British Columbia and Natural Resources Canada (NRCan) as the co-sponsors for the research. The work identifies a broad range of current efforts across Canada and undertakes a deeper dive on design for disassembly and adaptability (DfD/A) best practices, including an analysis of the ISO Standard 20887:2020 (i.e., design for disassembly and adaptability) in line with current Canadian industry practice and market readiness.
Forests can help mitigate climate change in different ways, such as by storing carbon in forest ecosystems, and by producing a renewable supply of material and energy products. We analyse the climate implications of different scenarios for forestry, bioenergy and wood construction. We consider three main forestry scenarios for Kronoberg County in Sweden, over a 201-year period. The Business-as-usual scenario mirrors today's forestry while in the Production scenario the forest productivity is increased by 40% through more intensive forestry. In the Set-aside scenario 50% of forest land is set-aside for conservation. The Production scenario results in less net carbon dioxide emissions and cumulative radiative forcing compared to the other scenarios, after an initial period of 30–35 years during which the Set-aside scenario has less emissions. In the end of the analysed period, the Production scenario yields strong emission reductions, about ten times greater than the initial reduction in the Set-aside scenario. Also, the Set-aside scenario has higher emissions than Business-as-usual after about 80 years. Increasing the harvest level of slash and stumps results in climate benefits, due to replacement of more fossil fuel. Greatest emission reduction is achieved when biomass replaces coal, and when modular timber buildings are used. In the long run, active forestry with high harvest and efficient utilisation of biomass for replacement of carbon-intensive non-wood products and fuels provides significant climate mitigation, in contrast to setting aside forest land to store more carbon in the forest and reduce the harvest of biomass.
Does it really cost more to build a high-performance building? Historically, this question has been addressed with theoretical studies based on varying the design of common building archetypes, but nothing beats the real thing. ZEBx, in partnership with BTY Group and seven builders from across BC, has completed a cost analysis of seven high-performance, wood-framed, mid-rise, multi-unit residential buildings that meet Step 4 of the Energy Step Code or the Passive House standard. The results of the study may surprise you!
In cross-laminated timber (CLT) buildings, in order to reduce the disturbing transmission of sound over the flanking parts, special insulation layers are used between the CLT walls and slabs, together with insulated angle-bracket connections. However, the influence of such CLT connections and insulation layers on the seismic resistance of CLT structures has not yet been studied. In this paper, experimental investigation on CLT panels installed on insulation bedding and fastened to the CLT floor using an innovative, insulated, steel angle bracket, are presented. The novelty of the investigated angle-bracket connection is, in addition to the sound insulation, its resistance to both shear as well as uplift forces as it is intended to be used instead of traditional angle brackets and hold-down connections to simplify the construction. Therefore, monotonic and cyclic tests on the CLT wall-to-floor connections were performed in shear and tensile/compressive load direction. Specimens with and without insulation under the angle bracket and between the CLT panels were studied and compared. Tests of insulated specimens have proved that the insulation has a marginal influence on the load-bearing capacity; however, it significantly influences the stiffness characteristics. In general, the experiments have shown that the connection could also be used for seismic resistant CLT structures, although some minor improvements should be made.
Timber has been used for building construction for centuries, until the industrial revolution, when it was often replaced by steel and concrete or confined to low-rise housings. In the last thirty years however, thanks to the development of mass timber products and new global interest in sustainability, timber has begun to make a resurgence in the building industry. As building codes and public perception continues to change, the demand for taller and higher-performance timber buildings will only grow. Thus, a need exists for new construction technology appropriate for taller mass timber construction, as well as for fabrication and deconstruction practices that respect wood’s inherent sustainable nature. With this in mind, this research program aims to develop a new hybrid shear connection for mass timber buildings that allows for easy construction, deconstruction, and reuse of the structural elements.
This report includes results of Phase 1, which focused on connections consisting of partially threaded 20M and 24M steel rods bonded into pockets formed in CLT and surrounded by thick crowns of high-strength three-component epoxy-based grout. A total of 168 specimens were designed and fabricated, and push-out shear tests carried out with a displacement-controlled monotonic loading protocol. Strength and stiffness values were assessed and effective failure modes in specimens identified. These latter, along with the recorded load-deformation curves, indicate that it is possible to develop mechanics-based design models and design formulas akin to those already used for typical dowel-type fastener timber connections. Additionally, the specimens were easily fabricated in the lab and quickly fastened to the test jig by means of nuts and washers, suggested such connections have a strong potential for prefabrication, disassembly, and reuse.