ABSTRACT
When natural-draft cooling towers started to exceed tower heights of about 100 m in the early 1960s, they turned out to be the most unsafe existing engineering structures: within less than 20 years, worldwide at least 10 towers were lost out of approximately 100. Nearly none of the deadly problems was known in detail at that time: internal stress distributions, influences of meridional shape, role of sufficient shell thickness and of double layer reinforcements at both faces, adequately stiff edge members, shape imperfections, effects of wind dynamics. It was a severe struggle to introduce into design and detailing of cooling towers more advanced structural mechanics and computational concepts. But only by such tools tower safety could be increased; they further contributed to the challenge of durability and to designed service lives. This presentation addresses some mentioned aspects and focusses on the use of modern computational concepts for increased safety and reliability, mainly related to the design of the largest tower in the world, the 200 m high tower at the RWE Power Station at Niederaussem, situated some 30 km west of Cologne in Germany.