Design guidance for balloon-framed CLT structures

点击翻译按钮获取中文摘要

Wood structures are on the rise! Heightened public awareness regarding the environmental impact of building and maintaining structures has dramatically increased the demand for sustainable construction methods and has initiated a resurgence in the use of wood, in particular Cross-Laminated Timber (CLT). Tall residential and non-residential CLT construction is becoming common in North America, and design provisions for encapsulated mass timber structures up to 12 stories tall have been incorporated into the National Building Code of Canada. Most previous research and the resulting design guidance in the Canadian Standard for Engineering Design in Wood is limited to platform-type construction, where one storey's ceiling forms the platform for the next storey's walls. In contrast, balloon-framed structures, where the walls are continuous over multiple storeys, offer several advantages including eliminating perpendicular-to-the-wood-grain bearing between floors and cumulative shrinkage over the building height, and requiring fewer panels to create slender panel aspect ratios and fewer connections over the height of a building. The long-term goal of my research program is to develop, and make available, reliable engineering design guidance for balloon-type CLT buildings, specifically by addressing their seismic performance and the prevention of disproportionate collapse. Within the proposed NSERC DG research program, my team, in close collaboration with the design and construction industry, will advance three immediately relevant research areas: 1) Development of novel low-damage connection systems for balloon-type CLT shear walls, such as hyperelastic bearings combined with steel rods to connect individual wall segments; 2) Development of design provisions for balloon-type CLT lateral load resisting systems consisting of concrete cores with perimeter CLT shear walls and CLT cores with braced timber (or steel) perimeter frames; and 3) Providing the proof that balloon-type CLT systems are able to develop alternative load paths in the case of sudden supporting element loss, to prevent disproportionate collapse. My team will advance these research areas through conceptual, experimental, numerical, and analytical investigations. Addressing research questions related to balloon-type CLT buildings holistically will differentiate my research program from other efforts, which tend to focus on individual subsets of these problems. The proposed program will exploit and fuel the current momentum of initiatives focused on sustainability and innovative wood construction, leverage successful research initiatives in my group, and shape future research agendas in tall wood construction provincially, nationally and globally. Ultimately, by taking leadership in this area, successful implementation of the program will have a decisive impact on the structural use of wood and will increase its market share in tall residential and non-residential buildings.