Timber Frame Tension Joinery - Timber Frame Engineering Council

1. Introduction
1.1 General Overview
The goal of this project was to quantify the strength of the timber mortise and tenon
connection when loaded in tension. This connection is made entirely of wood and has been
used for centuries; however, its behavior has never been described mathematically. A typical
application of the mortise and tenon connection is to join a beam to a post (Figure 1-1) in a
heavy timber structure. A mortise is notched out of the post and a tenon on the end of the
beam is then fit into the mortise. The entire system is held together with hardwood pegs.
An example of a situation in which this connection is loaded in tension in a timber frame is
at the end of a tie beam (Figure 1-2) (Hewett, 1980).
This method of connecting wood members became obsolete in the early 1800’s as
inexpensive nails began to replace the all-timber connections (Elliot and Wallas, 1977). This
traditional style of timber framing has only recently regained popularity in housing and other
heavy timber construction. The modern timber frame is energy efficient (through use of
stress-skin panel insulation), comfortable to live or work in, elegant in style, and efficient in
its use of timbers.
Mortise
Tenon
Wood
Pegs
Post
Beam
Figure 1-1 Typical Mortise and Tenon Connection
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