Composite wood utility poles. Final report

An innovative approach was used to provide a substitute for solid wood poles, which have become increasingly expensive and at times are in short supply. The new poles (COMPOLES) were manufactured using a composite wood material (CWM) consisting of chemically treated wood flakes bonded together with a synthetic adhesive. The chemicals provide durability and dimensional stability. Composite wood material was produced which had strength properties comparable to those of the structural wood species. Particular attention was given to producing a high strength material with good durability. The effects of factors such as wood species, flake type, flake alignment, adhesives and preservatives were studied in this project. The COMPOLE design is not fixed by the shape of the tree. This provides flexibility in the design process, allowing the shape and cross-section dimensions to be varied. After analyzing square, hexagonal and octagonal sections, the latter was chosen for the prototype poles. The cross-section was built up from laminates of CWM with the number of laminates dependent on the stress at that point. Ten COMPOLES, 40-feet (12.2-m) long were produced. Two were tested to determine strength characteristics and the others will be field tested by several utilities. Economic analyses indicated that the compositemore » wood poles can compete effectively in the marketplace. Longer lengths were designed and analyzed, and found to be increasingly cost effective.« less