Abstract:
TTT Products Ltd developed the technology to quickly lathe 15 m long poles into “Unilogs” up to 480 mm in diameter. These lathed poles are widely used in retaining wall and structural applications. The development of 250 mm diameter connections that are capable of full axial strength for effective structural performance opens new opportunities for large scale round timber structures. As each pole is manufactured in a lathe, it is a simple operation to cut 4 annular grooves into the outside of both ends. A tubular steel connector, manufactured with raised annular bands on the inner surface to fi t the timber grooves, is clamped across the connection. The system modifies an existing tubular connection designed for manual erection of the towers in difficult terrain. Laboratory testing of the connection was undertaken for 1 and 3 annular bands and the results are compared with the full strength of 4 annular band connections used on site. The new connection performs well and failure occurred in timber bearing and/or compression at an average of 820 kN before the connection load decreased.
