Behaviour and retrofit of heavy timber structural systems against blast loading

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Wood is inherently light weight, flexible and brittle, which means that timber buildings are not expected to resist blast loading in a manner that adequately protects occupants against accidental and intentional explosions. In particular, protecting human lives requires prevention of progressive collapse and minimization of debris throw'. Studies by the applicant and collaborators using a unique Shock Tube Facility at the University of Ottawa has already influenced blast related design code requirements in Canada. However much more needs to be done.*******The overarching objective of proposed research is mitigation of hazards associated with blast loads on timber buildings. This will be achieved by establishing risk evaluation strategies and developing technically and economically viable innovative retrofit methods for new and existing buildings. The research program will generate completely new information and be the basis of HQP research training. The main focus of the experimental component of the research program will be on establishing the behaviour of heavy timber elements and devising retrofit options for existing buildings that may be vulnerable to blast events. This includes examining the effects of fibre reinforced polymers to provide confinement to the wood elements and the use of post-tensioning techniques using steel guy cable and carbon FRP bars. The analytical component will include development of nonlinear material compliance models. Once developed and verified, those models will be used for dynamic analysis and parametric studies of building structures and substructures.*******The proposed research program has a great potential to significantly impact the knowledge base in the field of blast design of wood structures. The output from the research will yield data that would introduce provisions to the blast design standard. Ductility ratios and support rotations for various levels of protection and values for the dynamic increase factor are important examples of potential contributions to the profession. The research program will help ensure that engineers in Canada have the best possible knowledge and information to support design decisions for wood structures. Furthering knowledge on the behaviour of timber structures under blast loads will improve safety while adding highly trained and dedicated professionals to the Canadian workforce. Importance and novelty of the proposed research is the creation of material models for wood elements, which will enable analysts to predict behaviour of timber buildings subjected to blast loading without reliance on empiricism. Intent is to enable a leap from need to rely on prescriptive method to engineering blast design practice, which is comparable to the transition which took fire design of timber buildings from an art to an applied science in the late 20th century.******