Damage Detection in Offshore Platforms Using Vibration Information

Abstract

Damage detection based on changes in dynamic characteristics is considered for eight-legged k-braced steel offshore oil and gas production towers. Both experimental and analytical results are presented to improve damage detection capabilities. A 1/50th scale plastic model representing the structural system of a typical full-scale tower in 218 ft (66m) of water is used for the studies. Effects of severance of diagonal bracing members on selected vibration frequencies and mode shape parameters measurable at the deck are investigated. The effects of changes in deck mass, increase in jacket mass, and deck mass eccentricity on the selected parameters are also investigated and are shown to be different from the effects of damage.