The strength of wire-connected round timber joints

In many developing countries, poles are used for the construction of a wide range of structures on farmsteads. They provide an inexpensive source of structural timbers and are readily available within farmsteads or in local forests. The use of round timber has considerable potential in comparison to the use of sawn timber because of its higher structural strength and its low material cost. There are, however, problems associated with working with non-uniform sections and also with jointing. The craft methods for constructing joints using sisal rope or strips of bark do not permit the full strength of the poles to be utilized. Improved low-cost methods of connecting poles could lead to stronger structures and more economical use of materials. This paper describes techniques of constructing round timber joints using cheap fencing wire. The paper also compares the strength properties of round timber joints which include the load-displacement characteristics, failure loads and failure modes, permissible joint loads and joint stiffnesses, with the strength properties of equivalent sawn timber joints designed according to the recommendations of the British Standards for timber structures. (C) 2002 Silsoe Research Institute. Published by Elsevier Science Ltd. All rights reserved.