On combination formulae for the extremes of wave-frequency and low-frequency responses
Journal article, 1999

One special feature in moored floating platforms is the co-existence of the first-order wave-frequency (WF) response and the second-order low-frequency (LF) resonant response. Non-linear properties inherent in moored floating platforms cause the platform motions and mooring cable tensions to be non-Gaussian (not normal) distributed, both for the WF and for the LF components. As the LF and the WF components are not independent, it is important and necessary to find a simple, reliable and yet physically sound technique to estimate their combination. In this paper, on the basis of some model test results, different combination formulae are compared and a formula considering WF and LF correlation effects is suggested. A simple approach is also proposed to estimate the correlation factor.


low frequency

wave frequency

non-Gaussian process


Yungang Liu

Department of Hydraulics

Lars Bergdahl

Department of Hydraulics

Applied Ocean Research

0141-1187 (ISSN)

Vol. 21 1 41-46

Subject Categories

Civil Engineering



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