Timber frame structures often rely on pegged mortise and tenon connections to secure members together. Wood pegs, while large in diameter, are considerably more flexible than a steel dowel of the same size. Engineering design of these pegged tension connections is not addressed in the National Design Specification for Wood construction (NDS). In an effort to standardize the design procedure used for timber frame structures, the TFEC has developed the Standard for Design of Timber Frame Structures TFEC 1-09, which includes a straight-forward approach for analyzing the allowable capacity of pegged mortise and tenon tension connections. The design process included in TFEC 1-09, which is described in more detail in this article, is based on the NDS yield model equations and provides a similar level of performance to steel dowel connections. The TFEC approach is based on physical testing and numerical modeling of connections, coupled with corresponding reliability analyses. This bulletin provides a review and further explanation of the development of the design equations included in the TFEC approach, along with a numerical example of their application.
Click here for the Technical Bulletin (PDF)