Enhancing the structural performance of wood I-joists and system behaviour of structures containing wood I-joists

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Wood I-joists are a dominant product in residential floor construction and are used in about 60% of new floor construction in North America. Further research is required to expand the application of the product to non-residential construction and in tall buildings. The proposed research program will build on earlier research achievements at the University of New Brunswick on wood I-joists. The overall goal of the proposed research program, which consists of 4 thesis projects, is to develop technical tools and building systems that will allow wood I-joists to be used in non-residential and tall building applications. For this overall goal to be fulfilled there is a need to address the features of the product that limit its load-carrying capacity. To this end two of the four projects will investigate the strengths of the product in bearing at support points and when a web opening is present, whereas the remaining two will investigate the performance of structural sub-systems comprising wood I-joists. Project 1 will develop an analytical approach to predict the load-carrying capacity of wood I-joist with a web opening. The innovation of this approach is its ability to account for the influence of bending moment and can be simplified to be used for design purpose. Project 2 is aimed at developing a method to improve the bearing strength of wood I-joists. It will investigate the use of mechanical fasteners to improve bearing strength, which may be the critical design factor in non-residential applications. Project 3 will study the application of deep wood I-joists in long span floor applications in multi-storey buildings. Of specific interest is the diaphragm action of floor systems built with these deep wood I-joists, and how it affects the performance of mid-rise wood frame buildings when subjected to lateral loads arising from seismic and wind events. Project 4 will investigate the performance of an innovative composite floor system consisting of wood I-joists and cross laminated timber (CLT) plate. The proposed research will complement the research activities of a 5-year NSERC Strategic Network on Innovative Wood Products and Building Systems which is led by the applicant.