North American practices for connections in wood construction

摘要

This paper presents results of a formal survey of current North American practices for connections in wood construction and synthesizes the data with related knowledge and experience. The primary aim of the survey was to assess current practices for selecting, designing, and specifying connections that join lumber and other structural wood-based products to each other, or components made of other material. The survey instruments were broad based electronic questionnaires and follow-up discussions with selected respondents, experts and producers of engineered wood products. Different questionnaires were distributed to structural engineers in Canada and the US, and architects in Canada. Follow-up discussions were focussed on specific issues and removal of ambiguities in responses to questionnaires. It was found that traditional fasteners like bolts, nails, spikes and screws are most widely utilized. Connection selection, design and specification practices have not changed significantly owing to the introduction of modern engineered wood products into the market place. Major perceived deficiencies in engineering design information are: complexity of code rules, lack or scarcity of appropriate information related to screwed connections, non-factory gluing, practical difficulty of using split ring and shear plate connectors, and appropriateness of using power-driven nails when design codes only address use of hammer-driven nails. The findings of the surveys are helping with prioritization of research activities within Canada and proposed revision of the Canadian wood design code.