Detectability Of Structural Failures In Offshore Platforms By Ambient Vibration Monitoring

摘要: Historically, undewater visual examination by divers has been employed to monitor the structural integrity of fixed offshore platforms. Alternative approaches for inspection are being sought lessen cost and hazard diver operations, especially in deep hostile waters. An approach applied North Sea makes use ambient vibration monitoring with above-water accelerometers identify lower global modes platform vibration. Changes natural frequencies mode shapes indicators possible below-water breakage. The United States Geological Survey (USGS) sponsored studies at Aerospace Corporation examine feasibility this approach. As part study, producing Shell Platform SP-62C Gulf Mexico was instrumented 17 locations between decks boat landing level detection its vibrations during normal operation platform. Some vertical angular accelerations were measured, addition lateral accelerations. is an eight-leg diagonally braced jacket construction consisting eight ungrouted main piles grouted skirt piles, stands a 327-ft (100-m) water depth. interpretation random data via spectral analysis already reported, includes favorable comparison modal parameters derived subsequent results from forced shaking overall conclusion field experiment that acquisition aspects method practical, readily available hardware software.