• Journal of Ocean Engineering and Technology
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• v.31 no.2
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• pp.111-120
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• 2017

It is generally acknowledged that the Steel Catenary Riser (SCR) is the most cost-effective riser type for deep-water offshore fields among various risers, including the SCR, flexible riser, and hybrid riser. However, in West Africa, the SCR type may not be suitable for FPSO systems because the large vertical motion of the floater brings about a considerable riser dynamic response. In this paper, an SCR system is designed for the FPSO in the West African field, where the use of a hybrid riser has been preferred. The proposed SCR configuration fulfills the design criteria of the API, such as the strength check and fatigue life. Moreover, a sensitivity analysis is also carried out to improve the certainty in the SCR design of a deep-water FPSO. The parameters affecting the strength and fatigue performance of the SCR are considered.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1992.04a
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• pp.85-88
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• 1992

In general, the strength and stiffness of laminated composite cylinderical shells are very sensitive to the variation of slenderness parameters, some coupling-stiffness parameters, lamination angles, stacking sequence and number of layers. In the paper, the effects of these factors on the strength and buckling reliabilities of GFRP laminated cyclinderical shells are investigated based on the proposed strength and buckling limit state models. It may be concluded that the applicable ranges of the slenderness limits of the strength and buckling failure criteria for laminated composite cylinderical shells should be indentified and incorporated into the design formula with appropriate safety factors which provide uniform consistent reliability for balanced design in practice.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.173-174
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• 2008

The four-point bending test is a widely used method to determine material parameters. The aim of the present study was to evaluate the flexural strength (or modulus of rupture) and the Weibull modulus of cordierite ceramic substrate by means of four-point bending tests. The strength data from experiments followed Weibull statistics. These data indicate that the fatigue effects are more severe when the substrate temperature in the peripheral region is near $200^{\circ}$. At temperatures well above $200^{\circ}C$ the available design strength can be as high as 65% as substrate's initial strength.

• Advances in concrete construction
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• v.3 no.2
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• pp.113-126
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• 2015

Holed-Incrementally Prestressed Concrete (H-IPC) girders are designed using the following new design concepts. At first, web openings reduce the self-weight of the girder, and also diffuse prestressing tendon anchorages. The reduced end anchoring forces decrease the web thickness of the end sections. Additionally, precast technology help to improve the quality of concrete and to reduce the construction period at the site. For experimentally verification, two 50 m full-scale H-IPC girders are manufactured with different concrete strength of 55 MPa and 80 MPa. The safety, stiffness, ductility, serviceability and crack development of H-IPC girder are measured and compared with each other for different strengths. Both girders show enough strength to carry live load and good stiffness to satisfy the design criteria. The experimental result shows the advantages of using high strength concrete and adopting precast girder. The test data can be used as a criterion for safety control and maintenance of the H-IPC girder.

• Journal of the Korean Geotechnical Society
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• v.24 no.11
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• pp.43-53
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• 2008

The rock mass classification systems used in Korea are not standardized. And also the criteria values differ between agencies. So different opinions for rock mass classification can occur among engineers who participate in each design process. In this research, a new rock mass classification system was suggested to correct these problems. For this purpose, the criteria used in the Korean agencies were compared with the criteria used in foreign agencies and standard criteria were selected. Thereafter rational and objective criteria values were suggested quantitatively for the new classification system.

• Special Issue of the Society of Naval Architects of Korea
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• 2017.10a
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• pp.38-45
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• 2017

FPSO is widely used to develop deep sea oil fields and HHI has constructed ten(10) FPSOs. During these constructions, relevant structural design criteria such as yielding, buckling, fatigue, collision and impact strength were applied to verify structural safety. To apply the buckling strength evaluation for structures, the critical buckling stresses and applied stresses of relevant panels should be calculated. The plate and stiffened panels are to be idealized, which are needed much time and efforts by designers. Therefore, program development is necessary in order to evaluate the buckling strength conveniently and accurately. In this study, the buckling strength assessment system by using offshore code, DNV-RP-C201 was developed under MSC/PATRAN, pre-post program of finite element method. Graphic user interface program is written in MSC/PATRAN PCL functions. Source program to evaluate the buckling strength is developed in FORTRAN programming languages. The developed program is verified by comparing with the results of the Nauticus Hull developed by DNV Classification Society, and applied to the marine construction project conducted by Hyundai Heavy Industries LTD.

• Computers and Concrete
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• v.11 no.6
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• pp.571-585
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• 2013

Asymmetrical reinforcement for circular sections in wall piles is an efficient construction component with reduced embodied energy. It has been proven that asymmetrical reinforced wall piles may save more than 50% of the reinforcement than the traditional symmetrically reinforced circular sections. The use of this new type of structural member increases the number of variables in the design problem, which makes its use by engineers more complicated. In order to facilitate the use of the asymmetrically reinforced piles, this paper presents a criterion for the design of this type of structural member. The chosen criterion has been analyzed with the help of flexural capacity-cost curves. The new criterion is similar to the design procedure traditionally used for RC beams.

• International Journal of High-Rise Buildings
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• v.3 no.1
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• pp.35-48
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• 2014

In designing a 300 meter high skyscraper expected to be the tallest building in Japan, an earthquake-ridden country, we launched on the full-scale performance based design to ensure redundancy and establish new specifications using below new techniques. The following new techniques are applied because the existing techniques/materials are not enough to meet the established design criteria for the large-scale, irregularly-shaped building, and earth-conscious material saving and construction streamlining for reconstructing a station building are also required: ${\bullet}$ High strength materials: Concrete filled steel tube ("CFT") columns made of high-strength concrete and steels; ${\bullet}$ New joint system: Combination of outer diaphragm and aluminium spray jointing; ${\bullet}$ Various dampers including corrugated steel-plate walls, rotational friction dampers, oil dampers, and inverted-pendulum adaptive tuned mass damper (ATMD): Installed as appropriate; and ${\bullet}$ Foundation system: Piled raft foundation, soil cement earth-retaining wall construction, and beer bottle shaped high-strength CFT piles.

• Journal of Welding and Joining
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• v.29 no.4
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• pp.67-72
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• 2011

The proportion of the welding in the production process of machinery, buildings and marine structures is increasing and the joining are mainly conducted by butt and fillet weld. In the case of fillet weld, the shape of structures is complicated depending on the constraint on the geometry of the structures, therefore, the full penetration is mostly difficult. Accordingly, it is necessary to establish safe and economical criteria of design of the structures through the strength based on the penetration state of the fillet weld. Patterns of fatigue failure in cruciform fillet weld jont appear in the form of the root, toe and mixed failure. In the case of toe and mixed failure, the fatigue strength is higher than root failure. Therefore, we have to make the enough depth of penetration or perform the welding work through improving the fatigue strength of cruciform joints in welded structures. So it is necessary to optimize the penetrated depth in the range of the possible mixed failure and find the way in the cost-effective design to lessen the amount of the welding work.

• Journal of the Korean Society for Advanced Composite Structures
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• v.3 no.2
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• pp.11-18
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• 2012

This study proposes flexural failure design criteria of continuous slabs enhanced by a hybrid system of fiber reinforced polymer (FRP) and ultra high performance concrete (UHPC). The proposed hybrid retrofit system is designed to be placed at the top surface of the slabs for flexural strengthening of the sections in both positive and negative moment zones. The enhancing mechanisms of the proposed system for both positive and negative moment regions are presented. The neutral axis of the enhanced sections in positive moment zone at flexural failure is enforced to be in UHPC overlay for preventing the compression in FRP. From this condition, a relationship between design parameters of FRP and UHPC is established. Although the capacity of the proposed retrofit system to enhance flexural strength and ductility is confirmed through experiments of one-way RC slabs having two continuous spans, the retrofitted slabs failed in shear. To prevent this shear failure, a design criteria of flexural failure is proposed.