Commercial construction has witnessed a new enthusiasm in the use of timber as primary structural material. Engineered wood products such as glued-laminated timber and cross-laminated timber (CLT) play an important part in this development. These products allow wood construction to reach new heights. However, certain gaps in knowledge need to be filled to attain the full potential of wood construction, especially with regards to connections. First, current equations for dowel embedment strength and withdrawal resistance of fasteners in sawn timber and glued-laminated timber are deficient. Secondly, no design methods are provided for dowel embedment strength or withdrawal resistance of fasteners in cross-laminated timber in the 2009 edition of Canadian standard for engineering design in wood CSA O86-09 (2009). For these reasons, the goals of the research project are established in three main objectives: -Develop a design equation for withdrawal resistance for threaded fasteners in sawn timber and glued-laminated timber; -Evaluate the performance of dowel embedment equations for sawn timber and glued-laminated timber from different international standards, and determine the influence of variables on their accuracy; -Develop equations for dowel embedment strength and withdrawal resistance of fasteners in cross-laminated timber. After the compilation of results and analysis of withdrawal and embedment tests with threaded fasteners on sawn timber, glued-laminated and cross-laminated timber, the most accurate design models for each product were proposed. Each proposal includes an impact study showing the influence of the proposed design models, in case of adoption in the next edition of the CSA O86 standard.
Project contact is Christian Dagenais at Université Laval
Summary
The National Building Code of Canada (NBCC, NRC 2015) proposes equations to limit acceleration at the top of a tall building. These equations were developed and validated on several buildings designed between 1975 and 2000. The buildings built during these years are made of concrete or steel. It is therefore not certain that the NBCC equations can be applied for tall wooden buildings; wood being a lighter material than concrete and steel. In this project, the PhD candidate will study the impact of lateral load resistance systems and fastening systems used in timber framing on natural frequency and damping as well as its response due to wind loads. The influence of non-structural elements will also be studied. Two high-rise wooden buildings (Origine, 13 floors in Quebec City and Arbora, 8 floors in Montreal) are currently being instrumented to obtain information on the dynamic behavior of the structure. The measurements taken on these two buildings will be used, among other things, to validate theoretical models developed in the context of the doctorate.
Project contact is André Potvin at Université Laval
Summary
The biomimetic approach in architecture explores the genius of organic natural forms resulting from a long process of environmental adaptation. These forms often have a high compactness and an optimal material / volume ratio in line with the importance of reducing the material in the building to limit its environmental impact in terms of energy and resources. What are the natural forms and processes of growth of the form most appropriate to the physical properties of wood? What design process promotes the integration of a biomimetic approach from the earliest stages of design? Based on a review of the main achievements claiming this approach, this project will develop a taxonomy of the different biomimetic typologies and identify the most promising in the context of a wood realization. A digital manufacturing process will be developed to reflect the complexity of natural shapes and flows in an organic architecture that optimizes environmental performance and aesthetics.
Project contact is Pierre Blanchet at Université Laval
Summary
The use of Building Information Modeling (BIM) models is not yet standardized. This situation limits the scope of the tool and this is particularly the case for systems not defined in the libraries of major BIM software. This results in a loss of productivity because each stakeholder will redefine materials and/or systems to a level of information corresponding to his own needs. This project aims, with the help of a research professional, to develop a BIM library that can contain the main information related to materials and systems to fully cover the needs of all users of the BIM model. This library will be made available to the public and will facilitate the use of wood systems by stakeholders.
Project contact is Luca Sorelli at Université Laval
Summary
Hybrid wood-concrete structures are emerging in the multi-storey wood building market, as they provide effective solutions in terms of lightness, rigidity, vibration and fire resistance (Yeoh et al., 2010, Dagenais et al., 2016). This project aims to reduce the cost of these hybrid floors by reducing the time of construction by prefabrication technology with emphasis on use. In addition, the goal is to explore the use of Ultra High Performance Fiber Composite Concrete (UHPC) to reduce the thickness of the wood slab, and also the use of ductile connections to increase the reliability of the floor (Habel and Gauvreau). 2008, Zhang and Gauvreau 2014, Auclair-Cuerrier et al 2016a). Finally, the concrete slab improves the diaphragm behavior of the floor to seismic actions.
Project contact is Louis Gosselin at Université Laval
Summary
The volume occupied by all components between the ceiling of a floor and the floor of the upper floor (slab, ventilation duct, plumbing, etc.) is of great importance and it is best to minimize its thickness. This project aims to develop a multi-objective optimization strategy to design this sandwich type assembly according to various structural, acoustic, thermal and mass transfer criteria (Alev and Kalamees, 2017), while minimizing its volume, its size and its cost. and this, according to a given context. A case study will be conducted to assess the degree of optimality of the solutions chosen. Multidisciplinary tools facilitating the optimal design of this system will be proposed.
Project contact is Luca Sorelli at Université Laval
Summary
To minimize the built-in energy of the floor, we need to replace the current system with lighter solutions that retain the key features for robustness and maintenance, and are cost-effective and easy to build (Spadea et al., 2015). This project aims to explore innovative flooring solutions that make up a light wood load-bearing structure reinforced underneath by naturally occurring polymeric fibers (FRP) (Bencardino and Condello 2016), which work well in tension, and above an Ultra-Thin Ultra High Performance Concrete Slab (UHPC) that works exceptionally well in compression. Considering the application of very large floors in multi-storey buildings, the following key questions will be addressed: 1) what form should such a system have, 2) how will this be analyzed, and what mode of failure will be desirable? (3) what practical limitations would be imposed by constructability, (4) what would be the gain on economic cost and environmental impact from a life cycle analysis point of view, and (5) is possible to use biosourced epoxy for connections. The methodology consists of: (i) systems analysis and shape optimization using finite element numerical techniques, (ii) connection shear tests, and (iii) proof of concept on a beam prototype.
Project contact is Luca Sorelli at Université Laval
Summary
This project aims to develop a new precast wood / concrete floor system that can push the span limits in multi-storey wood buildings. The multidisciplinary methodology includes a finite element analysis technique using the “DDuctileTCS” software developed at CIRCERB, shear tests on connections, bending tests of the composite beam and an extension of technical standards for the design of composite structures. This project will develop solutions to optimize the composite action and vibration of long-span precast and mixed floors. The methodology consists of: (i) analysis of systems and optimization of shapes by numerical finite element techniques; (ii) connection shear tests; (iii) proof of concept on a prototype beam in the laboratory.
Project contact is Luca Sorelli at Université Laval
Summary
This project aims to develop a new prefabricated wood / concrete floor system that is innovative and competitive in multi-storey wood buildings. The design of the floor will be carried out through a multidisciplinary approach that considers the composite action of the precast floor, the integration of sound insulation, vibrations, the weight of the structure, construction time and environmental impact. Among other things, the construction method and the use of ultra high performance green composite concretes with CLT slabs or GLULAM beams will be considered. The methodology includes digital analysis tools and a new method for the design of mixed structures as well as the life cycle tool. The laboratory proof of concept will assess the performance of the optimized floor system and compare it to existing floors.
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