The Effect Of Changeable Bathymetry Of Estuaries On Maritime Structure And The Countermeasure

While offshore constructions are in service, Bathymetries make much difference with original design due to the change of their natural environment and hydrodynamic conditions, especially in estuarine area. As a result, the dynamic response of constructions will change greatly and this change may obviously have something to do with the safety and stability of constructions. Based on sufficient investigations of the three most important Estuaries of china, both the cause of the change and its developing trend are discussed in details. With the field measurement of an oil platform, which located in the estuarine area of the Yellow River, a finite element model of the platform has been established using the ANSYS software. Model analysis and numerical evaluation show that the dynamic response of the platform has been doubled than the original design for the reason that water depth has been increased. As a result, the stability of the platform can be seriously menaced by the changeable bathymetry. In order to resolve the problem, Several vibration control systems, such as TLD, AMD, TMD and so on, have been introduced and compared. Since comparison shows that TMD stand out in economy and efficiency, TMD system is established and used to reduce the dynamic response of the platform. Numerical analysis shows that the TMD system can efficiently reduce the dynamic response. Moreover, semi-active control technology is also introduced, such as vibration-distribution structure. This may help the original design of maritime structure.