Fixed Steel Offshore Structure Design - Past, Present & Future

1998 ◽  
Author(s):  
D.J. Wisch
Keyword(s):  
Structure Design ◽  
Offshore Structure ◽  
Offshore Structure Design

Evaluation of pack ice pressure approaches and engineering implications for offshore structure design

2018 ◽  
Vol 149 ◽  
pp. 71-82
Author(s):  
Lawrence Charlebois ◽  
Robert Frederking ◽  
G.W. Timco ◽  
David Watson ◽  
Martin Richard
Keyword(s):  
Structure Design ◽  
Offshore Structure ◽  
Pack Ice ◽  
Offshore Structure Design ◽  
Ice Pressure

Improved Model for Ice Force on Conical Structure

2005 ◽  
Author(s):  
W. Feng ◽  
Z. M. Shi ◽  
L. M. Liu
Keyword(s):  
Ice Sheet ◽  
Bending Moment ◽  
Offshore Structures ◽  
Structure Design ◽  
Offshore Structure ◽  
Conical Structure ◽  
Offshore Structure Design ◽  
Improved Model ◽  
Ice Force ◽  
Bending Failure

Ice force is an important factor to be taken into account for offshore structures in cold region, and the calculation method of the ice force is meaningful for the offshore structure design. Cone is now used as optimal ice-resistant structure because it can cause bending failure of the ice sheet. The interaction between ice sheet and conical structure is studied in this paper and Croasdale’s model is modified based on the field observations. The newly built model separates the ice sheet into emersed part and floating part, and the equilibrium analyses are carried out respectively. The bending moment distribution of the ice sheet is analyzed to determine the position of bending failure, which serves as a supplementary restriction. Analytic solution of ice force on conical structure is got and it is verified by the experimental data of previous researches.

scholarly journals Ship and Offshore Structure Design in Climate Change Perspective

2013 ◽  
Author(s):  
Elzbieta Maria Bitner-Gregersen ◽  
Lars Ingolf Eide ◽  
Torfinn Hørte ◽  
Rolf Skjong
Keyword(s):  
Climate Change ◽  
Structure Design ◽  
Offshore Structure ◽  
Offshore Structure Design

Offshore structures – why all offshore facilities should have a demanning requirement

2019 ◽  
Vol 59 (2) ◽  
pp. 789 ◽  
Author(s):  
Matt Keys
Keyword(s):  
Offshore Structures ◽  
Structure Design ◽  
Risk Level ◽  
Design Codes ◽  
Offshore Structure ◽  
Sea State ◽  
The North ◽  
Offshore Structure Design ◽  
Cost Implications ◽  
Level Of Risk

Most offshore structure design codes focus on setting appropriate safety factors to achieve an acceptable annual level of risk. Recent work by Atkins SNC-Lavalin, together with a large number of operators in Australian waters and the North Sea, has discovered that a large number of aging assets are implementing a demanning requirement to limit the risk of platform collapse to personnel, due to changes in loading or degradation of the structure. This work has shown there are two risk scenarios that should drive this requirement. The first scenario which is intended by the codes in limiting the overall annual risk. The second is to limit the collapse risk associated with a known forecast storm, as the level of risk from helicopter demanning is much lower. For all the older offshore fixed and permanently mooring floating structures assessed for a risk level considered acceptable for a forecast storm, this risk level would govern the sea-state demanning criteria. For recently installed facilities that are compliant with current standards, the findings were the same: that all facilities should have a demanning requirement. The level of this demanning sea-state limit has been shown to be lower than expected and is likely to occur only once in the asset’s life; therefore, the cost implications of implementing demanning procedures are minor. This paper presents the basis and range of findings for calculating the risks associated with an annual occurrence and an ‘in a forecast storm’ risk. Further, this paper proposes acceptable demanning limits for facilities designed to current and historical design codes.

Harmony Search for Multiple Dam Scheduling

2011 ◽  
pp. 803-807 ◽  
Author(s):  
Zong Woo Geem
Keyword(s):  
Music Composition ◽  
Harmony Search ◽  
Mathematical Optimization ◽  
Structure Design ◽  
Optimization Techniques ◽  
Offshore Structure ◽  
Artificial Intelligent ◽  
Dam Operation ◽  
Benchmark System ◽  
Offshore Structure Design

The dam is the wall that holds the water in, and the operation of multiple dams is complicated decisionmaking process as an optimization problem (Oliveira & Loucks, 1997). Traditionally researchers have used mathematical optimization techniques with linear programming (LP) or dynamic programming (DP) formulation to find the schedule. However, most of the mathematical models are valid only for simplified dam systems. Accordingly, during the past decade, some meta-heuristic techniques, such as genetic algorithm (GA) and simulated annealing (SA), have gathered great attention among dam researchers (Chen, 2003) (Esat & Hall, 1994) (Wardlaw & Sharif, 1999) (Kim, Heo & Jeong, 2006) (Teegavarapu & Simonovic, 2002). Lately, another metaheuristic algorithm, harmony search (HS), has been developed (Geem, Kim & Loganathan, 2001) (Geem, 2006a) and applied to various artificial intelligent problems, such as music composition (Geem & Choi, 2007) and Sudoku puzzle (Geem, 2007). The HS algorithm has been also applied to various engineering problems such as structural design (Lee & Geem, 2004), water network design (Geem, 2006b), soil stability analysis (Li, Chi & Chu, 2006), satellite heat pipe design (Geem & Hwangbo, 2006), offshore structure design (Ryu, Duggal, Heyl & Geem, 2007), grillage system design (Erdal & Saka, 2006), and hydrologic parameter estimation (Kim, Geem & Kim, 2001). The HS algorithm could be a competent alternative to existing metaheuristics such as GA because the former overcame the drawback (such as building block theory) of the latter (Geem, 2006a). To test the ability of the HS algorithm in multiple dam operation problem, this article introduces a HS model, and applies it to a benchmark system, then compares the results with those of the GA model previously developed.

Offshore structure design and development

1982 ◽  
Vol 307 (1499) ◽  
pp. 263-277
Keyword(s):  
Deep Water ◽  
Oil And Gas ◽  
Offshore Structures ◽  
Structure Design ◽  
Offshore Structure ◽  
Oil And Gas Exploration ◽  
Exploration And Production ◽  
Offshore Oil And Gas ◽  
Offshore Structure Design ◽  
Offshore Oil

The kinds of technology currently being applied to the design, construction, installation and operation of offshore structures for oil and gas exploration and production are quite sophisticated and include many examples of innovative configurations and approaches. The decade of the 1990s should see further evolution, reinterpretation and improvements of concepts that are already in service or being readied for service. The importance of offshore oil and gas may be judged by the projection that over half of overall exploration investments will go to offshore prospects in future years. This paper surveys some expected evolutions, with particular emphasis on the challenging area of deep-water applications. Some features of a tension leg platform design are discussed as an example of a deep-water oil production system. An attempt is made to recognize the problems of applying advanced engineering and analytical capabilities, when many specialists must interact, to producing a thoroughly engineered design, which is also balanced and economical, for such innovative systems.

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