Fatigue Analysis of Steel Jacket Platform in Shallow Water Depth in the Gulf of Guinea

This work investigates the fatigue life of a steel jacket installed at a water depth of 22m in the Gulf of Guinea, both deterministic and spectral analysis was done using the Bentley SACS software. Wave data was collected every 3 hours for seven years resulting in 20440 sea states. The analysis was carried out using industry codes and standards for critical inspectable and non-inspectable members. The result of the analysis was obtained for 50 modal shapes, and the mass participation factors show the highest vibration at the mode shape of 2. The fatigue life of the joint was determined for a life of 50 years and applying the factor of safety of 5; the spectral analysis shows that none of the members investigated to meet the fatigue life of 250 years. However, the deterministic analysis shows some members that meet the fatigue life of 250 years. The analysis was also conducted for the piles both above and below the mud line, and the spectral and deterministic analysis show that the piles meet a fatigue life of 500 years using a factor of safety of 10. It was concluded and recommended that the joints on the jacket that do not meet the fatigue life should be rewelded and inspected for structural integrity. Also, the result shows that the spectral analysis is more detailed than the deterministic analysis. Keywords: jacket, fatigue analysis, Gulf of Guinea, SACS, spectral analysis, deterministic analysis, fatigue damage. DOI: 10.7176/ISDE/11-3-01 Publication date: April 30th 202

A media framing analysis of urban flooding in Nigeria: current narratives and implications for policy

© 2017, The Author(s). A critical element of current flood management is the importance of engaging key policy actors when policy decisions are to be made. However, there is still only limited understanding of how narratives of flood management actors may influence flood management policies, even though there is a suggestion that actors can strategically use their narratives to influence policy directions. In a developing country like Nigeria, there are still questions around lessons that can be learnt from understanding the narratives of policy actors, to unravel the complex nature of strategies and policy directions in managing urban floods. To help fill these gaps, this paper uses quantitative content analysis to explore the frame of five policy actor groups (government, local communities, business, multilateral organisations and non-governmental organisations (NGOs)) as expressed in local and national newspapers between 2012 and 2016 to understand their narratives of causes and strategies to solve the problem of urban flooding in Nigeria. The narratives of government, local communities and businesses align with the premise that flooding can and should be prevented whilst that of multilateral and business actors champion adaptation strategies on the basis that flooding is inevitable and hence more energy should be directed at ‘living with water’—emergency response, damage reduction and the aftermath. The study also identified areas of potential consensus and conflict between direct actors such as government and local communities on the one hand and funders on the other. Better discussion among actors aiding understanding of contemporary thinking and local realities will aid policy-making and policy implementation in the Nigerian context. An important step will be in the collaborative design of an urgently needed ‘Nigerian policy on flooding’ which currently does not exist