Collision Risk Analysis Fixed Platform and Semisubmersible
This paper summarizes the North Sea experience pertaining to mooring line failures of conventional 8 and 12 anchor line systems. Mooring system calculations, experience and test results...
Tension Leg Platform Response to Drag Forces by Equivalent Stochastic Quadratization
An equivalent stochastic 'quadratization' method is described for performing nonlinear stochastic response analyses of offshore platforms subject to wave and...
Probabilistic Risk Analysis of TLP Tether Fracture
A stochastic model for fatigue crack growth and final fracture of TLP tethers is formulated. Model updating through in-service inspection is included. The integrity of the cracked tether...
A Methodology for Assessing the Reliability of TLP Tethers Under Maximum and Minimum Lifetime Loads
The Tension Leg Platform (TLP) is a large, floating offshore platform for producing oil and gas in deep water. The TLP is moored to the ocean floor by vertical tethers. Loads in the tethers...
Towards Improved Loading Model for Design of Offshore Structures
The study presented in this paper uses geometries of different offshore platforms to quantify the effects of uncertainties in design calculations. The effect of wave directionality and...
Loading Uncertainties in Extreme Waves
Uncertainties associated with extreme base shear forces and extreme overturning moments are estimated for an idealized eight-legged jacket platform. The structure is assumed to respond...
Reliability Analysis for Offshore Structures
This study presents the reliability analysis of an offshore structure. The mechanical model includes various elasto-plastic diagrams with and without the combination of the normal force...
Stochastic Evaluation of Landing Pier Construction
This paper discusses the process of determining the magnitude of external force such as wind and wave pressure exerted on marine structures under construction, and the learning curve of...
Correlated Non-Gaussian Models in Offshore Structural Reliability
Correlated non-Gaussian models of offshore loads and responses are developed. These require only correlation coefficients and either marginal distributions or moments. Simple estimates...
Reliability Analysis of Offshore Structures Using the Virtual Distortion Method
This paper describes a new and efficient methodology for structural reliability analysis applicable to offshore jacket structures. The proposed methodology uses the Virtual Distortion...
Autocorrelation Functions for Offshore Geotechnical Data
Autocorrelation functions are described. Data from several North Sea sites are analyzed with respect to the vertical and horizontal autocorrelation of a number of soil properties. Based...
Multi-Hazard Risk Assessment of an Offshore Structure
This paper develops and illustrates a methodology for multi-hazard modal risk assessment. The case study involves assessing risk to an offshore structure in a load environment consisting...
Reliability Analysis of Weldings Considering Defects
The welds generally represent the most critical part of large structural systems, i.e. offshore structures. Hence they affect significantly the structural reliability. A realistic model...
Adaptive Reliability-Based Inspection Strategies for Structures Subject to Fatigue
Metallic structures subject to substantial load-induced fatigue must be inspected from time to time and, possibly, repaired or even put out of service if the damage has reached critical...
The N-Year Maximum Mean Values and the Coefficients of Variation of Loads Subjected to Port and Offshore Structures
It is necessary to know mean values and coefficients of variation of loads in order to verify the safety of structures. In this paper, the N-year maximum mean values and the coefficients...
Extreme Value Distribution for Stochastic Processes Subject to a Full Load Climate
Reliability analysis of structures subject to environmental loads generally involves load effects which are properly treated as stochastic processes, and requires determination of the...
The Extremes of Combinations of Environmental Loads
The objectives and the general approach of an offshore environmental data and extremal analysis are described. The intention is to develop long-term design values of wave, wind and current...
Optimal Inspection Planning for Fatigue Damage of Offshore Structures
A formulation of optimal design, inspection and maintenance against damage caused by fatigue crack growth is formulated. A stochastic model for fatigue crack growth based on linear elastic...
Uprating an In-Service Offshore Pipeline
The Ekofisk to Emden 36-inch pipeline, transmits gas 275 miles from the Ekofisk field to Emden, West Germany, and has been in operation since 1977. The operator Phillips Petroleum Company...
Geometrical Nonlinearity in Offshore Pipelines
Pipelines are very flexible structural systems which are subjected to various boundary conditions. For instance, during the laying process, the pipes roll on the guidance tracks on the...
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