Timber Pole Space Frames

Abstract

Timber poles are not often used for structural purposes in building, although they are a cheap material with good mechanical qualities. This is due to the fact that the poles often suffer from shrinkage cracks, which makes it difficult to transfer the load from one element to another in a way that is structurally sound. To overcome this particular problem, in the Civil Engineering Department of the Delft University of Technology a manually operated tool has been developed with which strong and tight lacings of galvanized steel wire can be strung around the poles in order to keep them together. This principle has been applied in spatial-type structures, where larger numbers of identical, relatively thin, poles of 10 cm diameter are interconnected to form double-layer grids. According to this principle a few prototype structures have been built and test-loaded, including the load-bearing frames of two agricultural buildings, one at Lelystad in The Netherlands and one at Winchester in England. A few others are under construction. The tool was originally designed for use in developing countries. For other countries a more industrialized way of producing the laced connections is considered.