• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.6
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• pp.293-303
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• 2020

Seismic fragility was assessed for non-seismic reinforced concrete shear walls in Korean high-rise apartment buildings in order to implement an earthquake damage prediction system. Seismic hazard was defined with an earthquake scenario, in which ground motion intensity was varied with respect to prescribed seismic center distances given an earthquake magnitude. Ground motion response spectra were computed using Korean ground motion attenuation equations to match accelerograms. Seismic fragility functions were developed using nonlinear static and dynamic analysis for comparison. Differences in seismic fragility between damage state criteria including inter-story drifts and the performance of individual structural members were investigated. The analyzed building had an exceptionally long period for the fundamental mode in the longitudinal direction and corresponding contribution of higher modes because of a prominently insufficient wall quantity in such direction. The results showed that nonlinear static analyses based on a single mode tend to underestimate structural damage. Moreover, detailed assessments of structural members are recommended for seismic fragility assessment of a relatively low performance level such as collapse prevention. On the other hand, inter-story drift is a more appropriate criterion for a relatively high performance level such as immediate occupancy.

• Journal of Ocean Engineering and Technology
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• v.33 no.6
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• pp.535-546
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• 2019

The paper presents a closed-form analytical solution for the ultimate strength of sandwich panels with metal faces and an elastic isotropic core during combined in-plane compression and lateral pressure under clamped boundary condition. By using the principle of minimum potential energy, the stress distribution in the faces during uni-axial edge compression and constant lateral pressure was obtained. Then, the ultimate edge compression was derived on the basis that collapse occurs when yield has spread from the mid-length of the sides of the face plates to the center of the convex face plates. The results were validated by nonlinear finite element analysis. Because the solution is analytical and closed-form, it is rapid and efficient and is well-suited for use in practical structural design methods, including repetitive use in structural optimization. The solution applies for any elastic isotropic core material, but the application that stimulated this study was an elastomer-cored steel sandwich panel that had excellent energy absorbing and protective properties against fire, collisions, ballistic projectiles, and explosions.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.2 s.152
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• pp.74-82
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• 2007

Recently, the erosion due to cavitation frequently occurs on a horn-type rudder of a high-speed large container carrier. It is necessary to understand the flow characteristics around a rudder in fully wetted and cavitating flow condition, and the process of generation and collapse of cavitation for a rudder design to minimize the cavity-induced erosion. The flow characteristics around a two-dimensional hydrofoil(NACA66) are investigated through the computational method utilizing a viscous flow theory applied to a cavitation model. The computational results from the viscous flow theory are verified by the comparison with the experimental results, and are compared with those from the potential flow theory. The effects of angle of attack, Reynolds number, cavitation number, and thickness ratio on the cavitating flow are also investigated.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.5
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• pp.60-67
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• 2003

For risk or reliability assessment of ship structures against particular hazardous situations such as total loss or sinking due to hull girder collapse, the short-term based response analysis rather than the long-term response analysis is required to determine wave-induced bending moments when the ship encounters a storm of specific duration and with a specified small encounter probability. In the present study, the effects of operational condition and sea states on wave-induced bending moments of large merchant vessels are investigated. A series of the short-term response analyses for a hypothetical VLCC and a Capesize bulk carrier (CSBC) are carried out with varying operational condition and sea states which include ship speed, significant wave height and wave persistence time, using the linear-strip theory based program ABS/SHIPMOTION and the MIT sea-keeping tables. The computed results are also compared with the IACS design formula predictions. The results and insights developed from the present study are summarized.

• Journal of Advanced Research in Ocean Engineering
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• v.3 no.1
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• pp.1-14
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• 2017

The safety analysis of an earthquake is carried out during the operation of a subsea pipeline and an onshore pipeline. Several cases are proposed for consideration. In the case of a buried pipeline, permanent ground deformation by the earthquake and an increase of internal pressure by the acceleration of the earthquake should be considered. In the case of a subsea pipeline, a bending moment is caused by liquefaction of the backfill material on a trenched seabed, etc., which results in a high bending moment of the buried pipeline. The bending moment causes the collapse of the subsea pipeline or a leak of crude oil or gas, which results in economic loss due to enormous environmental contamination and social economic loss owing to operation functional failure. Thus, in order to prevent economic loss and operation loss, structurally sensitive design with regard to seismic characteristics must be performed in the buried pipeline in advance, and the negative impact on the buried pipeline must be minimized by conducting a thorough analysis on the seabed and backfilling material selection. Moreover, it is proposed to consider the selection of material properties for the buried pipeline. A more economical review is also required for detailed study.

• Journal of Korean Association for Spatial Structures
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• v.14 no.4
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• pp.81-88
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• 2014

Construction of vinyl house structures is increasing because they do not have a large cross section as non-permanent structures. Vinyl house structures are apt to collapse by snow load because they have a small size member as a temporary building. Therefore, it is very important to ensure not only the stiffness of the individual member, but also the overall stability of three-dimensional arch-type vinyl house structures. The purpose of this study is to estimate the stability of arch-type vinyl house structures that have a various curvature under the vertical load such as snow load. As a result of the study, the buckling load of V27 model is the largest, and the values of buckling load have a tendency to increase with increasing H(height of arch) in the case of $H{\leq}2.75m$, but to decrease with increasing H in the case of $H{\geq}2.75m$.

• Journal of the Korean Society of Costume
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• v.50
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• pp.69-84
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• 2000

Th purpose of this study is three folds: to analyze postmodern fashion through the notion of pastiche to enhance an understanding of uncertain and confused situation in the late 1990s and to suggest a way of approach to creativity and originality in recent fashion design. The results can be summarized as follows: 1. Pastiche is an art work that borrows some parts of other artists authentic works and recombines them thus imitating their style technique or motifs selfconciously. 2. Pastiche is based onthe Deconstruction theory: the end of art as a result of deconstruction of the subject the collapse of the meaning the loss of history: the late Capitalism in which reality becomes chage into images or simulacre. 3. Pastiche represented by the death of author which means the exhaustion of creativity is shown in the fashion borrowing subculture styles and art works or religious images. Pastiche fashion which is equal to the play of signifiers floated as image is shown as graffiti and objects Time and space pastiche fashion can be explained by historical eclectism and ethnic looks, Finally pastiche means not the fixed aspect but the open concept of indeterminate condition which includes " anything goes" through the coesistence of various style in pastiche fashion.

• Earthquakes and Structures
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• v.15 no.5
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• pp.473-485
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• 2018

The buildings of architectural and cultural heritage are mostly built with stone or brick wall elements, which are connected using limestone or limestone cement mortar, without a full knowledge of the mechanical properties of masonry structures. The compatibility of heritage masonry buildings with valid technical specifications and the rules for earthquake resistance implies the need for construction work such as repairs, strengthening or reconstruction. By strengthening the masonry buildings, ductility and bearing capacity are increased to a level, which, in the case of the earthquake design, allows for some damage to happen, however the structure retains sufficient usability and bearing capacity without the possibility of collapse. Comparison between traditional and modern techniques for seismic strengthening of masonry buildings is given according to their effects, benefits and disadvantages. Recent Croatian provisions provided for heritage buildings enabling deviation of technical specifications are discussed.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.3
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• pp.116-126
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• 2010

The Korean rolling stock safety regulation stipulates that the collision deceleration of a car body should be maintained under average 5g and maximum 7.5g during train collisions. One-dimensional dynamic model of a full rake train, which is made up of nonlinear springs/bars-dampers-masses, is often used to estimate the collision decelerations of car bodies in a basic design stage. By the way, the previous studies have often used some average force-deformation curve for energy absorbing structures in rolling stock. Through this study, we intended to analyse how much the collision deceleration levels are influenced by the initial peak force modeling in the one-dimensional force-deformation curve. The numerical results of the one-dimensional dynamic model for the Korean High-Speed Train show that the initial peak force modeling gives significant effect on the collision deceleration levels. Therefore the peak force modeling of the force-deformation curve should be considered in one-dimensional dynamic model of a full rake train to evaluate the article 16 of the domestic rolling stock safety regulations.

• Steel and Composite Structures
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• v.22 no.2
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• pp.235-255
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• 2016

This paper experimentally investigated the behavior of steel frame structures of traditional-style buildings subjected to combined constant axial load and reversed lateral cyclic loading conditions. The low cyclic reversed loading test was carried out on a 1/2 model of a traditional-style steel frame. The failure process and failure mode of the structure were observed. The mechanical behaviors of the steel frame, including hysteretic behaviors, order of plastic hinges, load-displacement curve, characteristic loads and corresponding displacements, ductility, energy dissipation capacity, and stiffness degradation were analyzed. Test results showed that the Dou-Gong component (a special construct in traditional-style buildings) in steel frame structures acted as the first seismic line under the action of horizontal loads, the plastic hinges at the beam end developed sufficiently and satisfied the Chinese Seismic Design Principle of "strong columns-weak beams, strong joints-weak members". The pinching phenomenon of hysteretic loops occurred and it changed into Z-shape, indicating shear-slip property. The stiffness degradation of the structure was significant at the early stage of the loading. When failure, the ultimate elastic-plastic interlayer displacement angle was 1/20, which indicated high collapse resistance capacity of the steel frame. Furthermore, the finite element analysis was conducted to simulate the behavior of traditional-style frame structure. Test results agreed well with the results of the finite element analysis.