Project contact is Frank Lam at the University of British Columbia
The objective of this project is to develop a large span timber-based composite floor system for the construction of highrise office buildings. This prefabricated floor system could span over 10 m under regular office occupation load, and its use will expedite the construction significantly, converting to multi-million financial savings in a typical 40+ story project, besides the impact on reducing carbon footprint and enhancing living experience.
Opening new markets for the use of CLT that can capitalize on the strength and speed of construction allowed by the technology creates the best opportunity for wood product market growth. One such market is the Department of Defense (DoD), representing an estimated 148 million board feet of additional lumber production. Wood products have been significantly under-represented in the DoD construction market because of their perceived performance in blast conditions. The objectives of this project are to develop a design methodology and to demonstrate performance for exterior bearing CLT walls used in buildings subject to force protection requirements. This methodology should be published by U.S. Army Corp of Engineers – Protective Design Center to be used by engineers for designing CLT elements to withstand blast loads as determined by code requirements and specific project conditions.
As part of Fast + Epp’s ongoing work to push the boundaries of Tall Wood construction in seismic zones, this testing program aims to develop a new dissipative system for use in timber braced frames or other timber lateral systems where the connections provide energy dissipation. The connections are designed to dissipate energy through ductile steel plates to provide robust and well understood dissipative systems. In collaboration with the Advanced Research in Timber Systems’ team at the University of Alberta, Fast + Epp is working on a four-phase testing program for cyclic and monotonic testing of various configurations of perforated plate connections. Small scale tests have been completed on perforated plates, and entire connections will be examined in advance of a full-scale timber brace frame test to evaluate the overall behaviour. One phase of physical testing was completed in January 2020, with the next 3 phases intended to be completed in 2021. Initial data analysis of the first phase testing has resulted in tuning of the system in advance of later phase testing. Results on the first two or three phases of testing are anticipated to be completed in 2020 with initial publication of the results in early 2021.
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.
Project contacts are Julian Fagnan at Entuitive and William Johnston at WSP
The project develops a tool that allows clients and all those involved in the early stage of a project the ability to better compare the implications of a timber-framed system against conventionally accepted materials such as concrete and steel. A parametric automated workflow will be used to populate a database from which the proposed end-user application can draw the optimal solution for each structural material based on the user-selected inputs, objectives and constraints.
Auburn University’s (AU) School of Forestry and Wildlife Sciences (SFWS) in Alabama actively works to increase awareness of the benefits of CLT along with hybrid systems for more widespread adoption in multiple building segments. AU’s two-year project proposal outlines a plan that will establish a preliminary design for the usage of a timber-steel composite system, utilizing CLT or laminated veneer lumber (LVL), as an option that will replace reinforced concrete slabs to improve the structural performance for buildings six stories or more.
Project contact is Luca Sorelli at Université Laval
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.
The objective of this research is to characterize concrete-insulation-MTP connection properties, develop structural design procedures for strength and deflection of MTP-concrete composite floors (may account for two-way action) and test MTP-concrete strip beam and full-size floor.
Project contact is Erica Fischer, Oregon State University
Previous large-scale fire testing of mass timber buildings has occurred on a single floor of a building. The data collected from these experiments were used to demonstrate the fire performance of cross-laminated timber (CLT) buildings and to change the International Building Code (IBC) prescriptive fire protection design provisions for mass timber buildings. The scope of the tests was limited to compartment fires with varying levels of encapsulation. However, multi-story mass timber buildings are being constructed in the United States and fire science experts understand that fire threats can move beyond compartment fires and into travelling (moving fires) and vertical fire spread. In addition, many buildings are being proposed outside of the scope of the IBC prescriptive fire protection design approach (i.e. open floor plans), thereby requiring the employment of performance-based structural fire engineering. Performance-based structural fire engineering requires quantifying fire demands within the structure and calculating the resistance of the structure throughout the fire to provide safety to the occupants during egress, safety to fire fighters during and after the fire, and to ensure the building will not collapse introducing a threat of fire spread and damage to the surrounding buildings. To date, engineers are employing performance-based structural fire engineering on mass timber buildings; however, engineers are typically forced to make simplifications, be very conservative, and/or frequently use unproven assumptions. These simplifications and assumptions need to be tested experimentally to ensure that engineers are providing adequate levels of safety. Some of these assumptions include exterior wall and façade details that can prevent vertical fire spread, and detailing by engineers that considers the effects of charring during the decay phase of the fire.
The PIs have an opportunity to perform large-scale fire tests on a multi-story mass timber building in Corvallis, OR. Future large-scale fire tests will utilize a portion of the 10-story building being tested as a part of the Natural Hazards Engineering Research Infrastructure (NHERI) Tall Wood project (http://nheritallwood.mines.edu/). After the seismic testing of the 10-story building, the top four stories will be demolished and not utilized. Therefore, the research team will transport these floors to Corvallis to be re-assembled at the Corvallis Fire Training Center. In this preliminary stage, a multi-disciplinary team will perform computer simulation modeling of the fire tests, fully develop the scope of the tests and create a detailed experimental plan for the large-scale fire tests. The tests will be designed with considerations for the ability to address the following questions. These questions are consistent with future research needs that were identified by the Forest Products Laboratory  and the recent National Fire Protection Association (NFPA) Fire Safety in Tall Timber Buildings Workshop.
(1) How does the façade detailing of a mass timber building influence the vertical fire spread behavior?
(2) How can engineers better design mass timber buildings to enhance the safety for firefighters?
(3) How do glulam beam-to-column connections perform in real fires?
(4) What engineering solutions can be implemented within mass timber buildings to account for the behavior of the mass timber during the decay phase of the fire in the case that suppression is not available?
(5) How can engineers better design mass timber buildings to enhance the safety for fire fighters during the firefight and during overhaul/investigation?
Project contact is Luca Sorelli at Université Laval
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.