Nocdap results: On the relationship of extreme waves and currents for design of offshore structures

Gordon, Richard; Dahl, Finn-Erik; Peters, David J.

doi:10.1016/0029-8018(85)90069-1

Cited by 5 publications

(3 citation statements)

References 7 publications

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“…Gordon et al [7], Heideman et al [8], Forristall et al [6] and Prior-Jones and Beiboer [9] have summarised much of the literature on the joint probability of environmental variables, particularly wind, wave and current. Studies for waters off Europe, USA and Australia suggest that accounting for joint probability in the specification of environmental conditions reduces design loads on drag dominated structures by 10 to 40%.…”

Section: Joint Met-ocean or Response Based Design Conditionsmentioning

confidence: 99%

Response Based Design Conditions in the North Sea: Application of a New Method

Tromans

Vanderschuren

1995

All Days

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The estimation of rare, extreme environments from a relatively short oceanographic database is crucial to the calculation of loads and responses of offshore structures. A novel and consistent approach has been developed that makes use of a number of asymptotic properties of extremes. A storm can be adequately characterised by its most probable extreme wave or the resultant structural response. This allows us to treat storms, rather than sea states, as the essential random, independent events; to account correctly for uncertainty in the largest wave and structural response within a storm; and to deal with the uncertainty in the seventy of randomly arriving storms, including the rare storms that are more severe than those in the database. The method provides the long term load statistics essential to reliability analysis and to the calibration of environmental Ioad factors in design codes.We demonstrate the application of the method to the prediction of extreme waves, loads and "response based" environmental design conditions for a drag dominated structure in the North Sea.

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Section: Joint Met-ocean or Response Based Design Conditionsmentioning

confidence: 99%

Response Based Design Conditions in the North Sea: Application of a New Method

Tromans

Vanderschuren

1995

All Days

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“…There are few available studies of the joint probability of waves and currents in the surface of the water column, probably due to the lack of simultaneous measured wave and current data and the complicated, far from fully understood, wave-current interaction mechanisms. However, based on simultaneous wave and current measurements at Tromsøflaket, both Gordon, Dahl [29] and Heideman, Hagen [30] investigated the relationship of extreme waves and currents and established very simplified joint distributions to be used in design and load calculations for offshore structures. Wen and Banon [31] developed a probabilistic methodology that lead to joint probability distributions of hurricane induced winds, waves and currents at a generic site in the Gulf of Mexico.…”

Section: Introductionmentioning

confidence: 99%

Waves and associated currents–experiences from 5 years metocean measurements in the northern North Sea

Bruserud

Haver

2019

Marine Structures

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“…There are few available studies of the joint probability of waves and currents, probably due to the lack of simultaneous wave and current data and the complicated wave-current interaction mechanisms. However, both Gordon, Dahl [17] and Heideman,…”

Section: Introductionmentioning

confidence: 99%

Joint description of waves and currents applied in a simplified load case

2018

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In order to perform a more accurate analysis of marine structures, joint probability distributions of different metocean parameters have received an increasing interest during the last decade, facilitated by improved availability of reliable joint metocean data. The main objective of this article is twofold; first to establish a joint distribution of significant wave height and current speed and then to assess the possible conservatism in the Norwegian design standard by applying this joint distribution in a simplified load case. As there still seems to be no general consensus with regard to the approach of estimating the joint probability distributions of metocean parameters, a general overview of recent studies exploring different joint models for metocean parameters is first presented. Based on simulated current data and NORA10 wave data, a joint model for significant wave height and current speed at one location in the northern North Sea is presented. Since episodes of wind-generated inertial oscillations is the governing current conditions at this location, a conditional joint model with current speed conditional on significant wave height is suggested. A peak-overthreshold approach is selected and the significant wave height is found to be very well modelled by a 2-parameter Weibull distribution for significant wave height exceeding 8 m, while a log-normal distribution describes the current speed well. This model is used to Monte-Carlo simulate joint significant wave heights and current speeds for periods corresponding to the ultimate and accidental limit states (ULS and ALS), i.e. 100 and 10 000 years. The possible conservatism in the Norwegian design standard is assessed by a simplified case study. The results give a clear indication that the Norwegian design standard in not necessarily conservative, neither at ULS nor ALS level.

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Nocdap results: On the relationship of extreme waves and currents for design of offshore structures

Cited by 5 publications

References 7 publications

Response Based Design Conditions in the North Sea: Application of a New Method

Response Based Design Conditions in the North Sea: Application of a New Method

Waves and associated currents–experiences from 5 years metocean measurements in the northern North Sea

Joint description of waves and currents applied in a simplified load case

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