50 years in the Design of Towers and Masts. From IASS Recommendations to Current Procedures

Abstract

Up to the 1970s there were no recognized design procedures for the analysis and design of guyed masts. This was recognized in the industry in the early 1960s, when there was a rapid growth of these structures to accommodate the growth in radio and television broadcasting. Accordingly a Working Group of the IASS (WG4) was set up to examine the behaviour of these structures and to produce Recommendations for their design and analysis. These Recommendations were published in 1981 and they have formed the basis for the production of national and international codes for these structures since that date. The Recommendations contained innovative ideas at that time, including the treatment of relative structural reliability, the use of dynamic response procedures and the statistical treatment of wind actions. Such procedures have been adapted since in many design codes outside the field of towers and masts. This paper reviews the development of design procedures for both towers and masts, the background to the Recommendations and explains how these have been developed and applied in national codes (Australia, Canada, United Kingdom) and latterly in the published Eurocode for Lattice Towers and Masts.