OPTIMAL SENSORS POSITION FOR STRUCTURAL HEALTH MONITORING OF STEEL JACKET OFFSHORE PLATFORMS

The VEGA-A platform is an 8-legs fixed steel offshore structure that has been operating since 1988 in the Sicily channel (Italy). From its installation onwards, VEGA-A has been equipped with an environmental and structural (via above water accelerometers) monitoring system, and it is now time to consider an improvement of this system. Today the technological development makes it possible to consider additional underwater accelerometer measurements and this paper investigates on a possible optimal sensor position for new underwater accelerometers to improve - if any - detection of early damage in main structural elements. The final optimal sensor grid must be assessed to ensure a low-cost and sustainable dynamic monitoring system but, at the same time, to maximize the information contents for the identification of the mode shapes.