Engineering, Procurement, and Construction (EPC) contractors with lump-sum turnkey contracts have recently been suffering massive profit losses due to re-works and schedule delays in offshore oil and gas EPC megaprojects. The main objective of this research is to develop and implement a detail engineering completion rating index system (DECRIS) to assist EPC contractors to optimize fabrication and construction works schedules while minimizing potential re-work/re-order. This is achieved through adequate detail design development and results in minimizing schedule delays and potential liquidated damages (i.e., delay penalties). The developed DECRIS was based on findings from an extensive review of existing literature, industry-led studies, expert surveys, and expert workshops. The DECRIS model is an evolution, and improvement of existing tools such as the project definition raking index (PDRI) and front-end loading (FEL) developed specifically for the early stage of engineering maturity assessment (i.e., planning, basic design, and front-end engineering design (FEED)), prior to EPC projects. The DECRIS was evaluated and validated with thirteen sample as-built offshore megaprojects completed recently. When the DECRIS was applied to the completed projects post-hoc, a correlation (R-squared 0.71) was found between DECRIS scores and schedule/cost performances. This is much superior to the PDRI-Industrial model's correlation (R-squared 0.04), which was primarily devised for owners' basic engineering or FEED completion assessment. Finally, as a means of further validation, project schedule and cost performance of an ongoing project was predicted based on the correlations found on the thirteen completed projects. The resultant predicted schedule and cost performance was well matched with the current project performance status. Based on the accuracy of the DECRIS model found in the validation, said model is an effective prospective tool for EPC contractors to manage their engineering and procurement/construction risks during the initial detail design stages. of the total global oil supply [1]. In 2011, shale oil and gas were introduced to the oil and gas market with the development of cost-effective hydrofracturing technologies. This has led to an over-supply of oil and gas and, consequently, an era of low oil prices decreasing major oil companies' profits [2].An offshore project requires a significant amount of early investment for drilling and production facility design and construction. To combat lower revenues and increase profits, major oil companies have placed a great deal of attention on cost-saving strategies in these early stages for offshore oil and gas projects [3]. However, these strategies are often poorly planned and implemented, leading to inadequate resource allocation, and improperly accelerated design and construction. This all results in poor quality of work, schedule overrun, and even safety-related accidents on site [2].Therefore, how can planning be improved? Merrow collected and analyzed project pe...

The main subject of this research is to develop a forecast and mitigation model of schedule and cost performance during a detailed engineering stage of offshore engineering, procurement and construction (EPC) projects. The weight factors of major elements in detailed engineering completion rating index system (DECRIS) were measured using a fuzzy inference system (FIS) and an analytic hierarchy process (AHP). At five key engineering milestones, from an EPC contract being awarded to the start of construction, detailed engineering maturities were assessed in fourteen historical offshore EPC projects using the DECRIS model. DECRIS cutoff scores for successful project execution were defined at the key engineering milestones. A schedule and cost performance was forecasted and validated through comparison of DECRIS and other models using statistical confidence of a fuzzy set qualitative comparative analysis (fsQCA) and a regression analysis. As a mitigation method for engineering risks to EPC contractors, engineering resource enhancement is recommended for trade-off optimization of cost overrun using a Monte Carlo simulation. The main contribution of this research is that EPC contractors could continuously forecast construction costs and schedule performance utilizing the DECRIS model, and could review the adequacy of engineering resources, assessing the trade-off between said resources and cost/schedule risk mitigation.

NOMENCLATURE E1,E2,E2 = Elastic Modulus G12,G23,G13 = Shear Modulus v12 ,v23, v13 = Poisson's ratio IntroductionUnderwater vehicles, that operate in deep water, are subjected to high external hydrostatic pressure. In general, the pressure hull of an underwater vehicle has a stiffened cylindrical shell structure, and the spherical or elliptic shells are attached to both ends. Shell is the structure often found in vessels, submarines, aircrafts, and buildings. Accordingly, there have been many studies on the analysis of shell structures, and the variety of shell theories has been suggested. In particular, when the shell undergoes a pressure load, the buckling can take place at a stress which is far lower than the material strength. Therefore, the compressive buckling strength of a shell should be taken into consideration. 1,2The performance of a structure can be improved if its weight is be reduced by using the low-density material such as a composite, compared to high strength steel, titanium alloy, and aluminum alloy. Experiments on composite buckling are limited by equipments and costs, and thus the finite element analysis (FEA) method is used to simulate the testing. 3 The FEA results for isotropic materials, such as metals, are in good agreement with experimental results. However, the FEA results for composite materials, that are anisotropic, can show a relatively large difference with experimental results. Accordingly, it is necessary to identify the problems with the FEA results and bridge the gaps by optimizing the finite element models.The majority of studies on conventional composites focus on composites made by prepreg method. 4,5 There are many studies on the bucking and postbucking of cylindrical shell, which are Underwater vehicles that operate in deep waters require a pressure hull to maintain the sufficient strength and stiffness against external hydrostatic pressure. We investigated the validity of the finite element method (FEM) that is applied to a buckling analysis of the filament-wound composite cylinder, subjected to an external hydrostatic pressure. Two methods were suggested for the buckling analysis of a filament-wound thick composite cylinder under hydrostatic pressure: using the equivalent properties of the composite, and using stacking sequence. The hydrostatic pressure test was conducted to verify the FEA. Test results were compared with the previous results obtained by FEM on the buckling of a filament-wound composite cylinder under hydrostatic pressure. FEM analysis results were in good agreement with the test results. The difference between FEM results and the test results was approximately 1~5%.