Revisiting the Design, Construction and Damage Assessment of Large Hyperbolic Cooling Towers

Abstract

Hyperbolic cooling towers of ever greater height have been constructed since 1914. As the height of the shells increased, engineers became increasingly concerned about the effects of wind loads on these structures and likely adapted methodologies from tall building and chimney practice for the designs. The failure of three of a group of eight completed cooling towers with height 114 meters at Ferrybridge, UK in 1965 exposed the inadequacy of the then prevailing procedures for wind design and served to initiate and accelerate research programs on a wide variety of subjects. Topics included wind pressure magnitude and distribution, stability, ring stiffeners, column supports, reinforcement quantities and placement, seismic resistance, imperfections, temperature and shrinkage, soil-structure interaction, concentrated surface loads, openings and construction loading. In this paper, several of these research topics are discussed briefly, with emphasis on those that have influenced the design, construction and damage assessment of cooling towers in the US. The evolution of tower design procedures is traced and a discussion of unanticipated damage and failures during construction is offered. The application of modern analytical methods and experimental research studies to understand the cause of the damages and failures and to propose corrective procedures is emphasized. This paper is based on an invited lecture presented at ISCM-2012 in Cologne Germany, June 2012. Permission for the use of the materials contained in the proceedings was obtained from the conference chairman Prof. Dr-Ing. Reinhard Harte. Due to page limitations, the paper has been slightly abridged here. The longer version is available from the Proceedings, ISCT 2012 6 th International Symposium on Cooling Towers, R. Harte and R. Meiswinkel, eds, Faculty