• Geotechnical Engineering
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• 제14권5호
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• pp.67-76
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• 1998

The commonly used method to secure the stability of reinforced retaining structure is the reinfocement of backfill with connection attached or unattached to the geogrid type wall. Laboratory model tests for both cartes were conducted to investigate the effectiveness of geogridreinforcement, length of reinforcement inclusion, failure envelop, and the relationships between the face wall displacement and vertical settlement. The bearing capacity of each case was also determined. According to the model test results, geogrid-reinforced rigid wall is very effective for increasing the bearing capacity and reducing the displacement of retaining wall. The observed sliding line of model test is similar to the theoretical one.

• Journal of the Korea Institute of Building Construction
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• 제6권2호
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• pp.81-89
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• 2006

A down construction method is frequently used in these days to reduce popular discontent and to assure sufficient working space at early stage in downtown area. There are two main problems in the existing down construction method. One is a confliction between frame works and excavation works, and the other is a cold joint in retaining wall which is unavoidable due to a sequence of concrete placement and induces a water leakage. Therefore, a new method is needed to overcome these problems. The CWS (buried wale Continuous Wall System) method was developed by authors. By replacing RC perimeter beam with embedded steel wale, the steel frame works of substructure can be simplified and the water leakage can be prevented using continuous retaining wall. Consequently, the improved qualify and reduction of construction period can be obtained from CWS method.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제17권11호
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• pp.604-609
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• 2016

This study evaluated the long-term performance of RSR (Reinforced Subgrade for Railways) technology which increases the railway line capacity without the need for additional land. Its characteristics include the use of a short reinforcement with rigid wall, which make it possible to apply it in confined spaces. The 7m high and 40m long testbed employed to evaluate the long-term performance was designed and constructed near Jupo station on the Chang-hang line. This line, located close to a local bus route, had collapsed at the subgrade following heavy rainfall. The performance of the new type of subgrade was verified with long term measurements over a 2 year period including the surface and ground settlement, horizontal displacement of the wall, tensile strain of the reinforcement, and settlement of the rail top on the side track. Based on the results of the measurements made until now, we concluded that it had sufficient safety and serviceability for use as a railway subgrade. It is expected that RSR technology could be frequently used at sites which lack the necessary construction materials for an embankment and are located close to functional railway lines and boundaries, in order to settle civil complaints.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 한국전산구조공학회 1991년도 가을 학술발표회 논문집
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• pp.49-56
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• 1991

Seismic analysis of liquid storage structures is carried out by utilizing 2-dimensional fluid elements of a general purpose structural analysis computer program(ADINA), The present analysis focuses on the effects of the wall flexibility and the sloshing of the free water surface. Due considerations are given to the facts that the fluid has no shear resistance and the free surface motion is subjected to the gravity effect. To validate the present method using 2-dimensional fluid elements, the results of several example cases are compared with those by the Housner's approach for rigid wall case, and with those by the Eulerian formulation for flexible wall case.

• Journal of the Korean Society of Industry Convergence
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• 제5권3호
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• pp.247-254
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• 2002

This study has researched the following conclusion to compare to the existing theory and to examine lateral earth pressure, which have measured to add incremental load on sandy soil, and were different in types of compaction by modeling earth pressure test. Lateral earth pressure by incremental load shows that it is increasing at depth forty four centimeters as 2/3H point for wall high, and under 2/3 H point the variation of earth pressure on incremental load is not conspicuous. Therefor, the more a position of surcharge load is close with fixed wall, the more a variation of lateral earth pressure marks considerably. According to relative compaction density of soil, lateral earth pressure turns up larger effective value for layer compaction test to a thickness of thirty three centimeters than layer compaction test to a thickness of twenty centimeters by the roller.

• Earthquakes and Structures
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• 제10권4호
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• pp.965-988
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• 2016

This paper investigates the seismic behavior of reinforced concrete shear wall buildings with multiple underground stories. A base-case where the buildings are modeled with a fixed condition at ground level is adopted, and then the number of basements is incrementally increased to evaluate changes in performance. Two subsurface site conditions, corresponding to very dense sands and medium dense sands, are used for the analysis. In addition, three ground shaking levels are used in the study. Results of the study indicated that while the common design practice of cropping the structure at the ground surface leads to conservative estimation of the base shear for taller and less rigid structures; it results in unpredicted and nonconservative trends for shorter and stiffer structures.

• Coupled systems mechanics
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• 제7권4호
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• pp.421-440
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• 2018

In this study, a computational method for wall shear stress combined with an implicit direct-forcing immersed boundary method is presented. Near the immersed boundaries, the sub-grid stress is determined by a wall model in which the wall shear stress is directly calculated from the Lagrangian force on the immersed boundary. A coupling mathematical model of the transition process for a model Francis turbine comprising turbulent flow and rotating rigid guide vanes is established. The spatiotemporal distributions of pressure, velocity, vorticity and turbulent quantity are gained with the transient process; the drag and lift coefficients as well as other forces (moments) are also obtained as functions of the attack angle. At the same time, analysis is conducted of the characteristics of pressure pulsation, velocity stripes and vortex structure at some key parts of flowing passage. The coupling relations among the turbulent flow, the dynamical force (moment) response of blade and the rotating of guide vane are also obtained.

• Transactions of the Korean Society of Mechanical Engineers B
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• 제27권3호
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• pp.294-301
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• 2003

We examine a problem in which porous/viscoelastic compliant thin plates are subject to pressure fluctuations under transitional or turbulent boundary layer. Measurements are presented of the frequency spectra of the near-field pressure and radiated sound by compliant surface. A porous plate consisting of 5mm thick. open-cell foam with fabric covering and a viscoelastic-painted plate of 1mm thick over an acoustic board of 4mm thick were placed over a rigid surface in an anechoic wind tunnel. Streamwise velocity and wall pressure measurements were shown to highly attenuate the convective wall pressure energy when the convective wavenumber (k$_{c}$h) was 3.0 or more. The sound source localization on the compliant walls is applied to the measurement of radiated sound by using an acoustic mirror system.

• Proceedings of the KSME Conference
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• 대한기계학회 2003년도 추계학술대회
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• pp.628-633
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• 2003

An analysis on the steady-state has been made of flow of a compressible fluid rapidly-rotating in a pipe. The flow is induced by an small arbitrary azimuthally-varying thermal forcing added on the basic state of rigid body isothermal rotation. The system Ekman number is assumed to be very small value. Analytic solutions have been obtained for axisymmetric and non-axisymmetric types, in which the axisymmetric solution comes from the azimuthally-averaged wall boundary condition and the non-axisymmetric solution from fluctuating wall boundary condition.

• Structural Engineering and Mechanics
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• 제53권1호
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• pp.147-158
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• 2015

Elements used in steel structures may be considered as an assembly of number of thin flat walls. Local buckling of these members can limit the buckling capacity of axial load resistance or flexural strength. We can avoid a premature failure, caused by effects of local buckling, by limiting the value of the wall slenderness which depend on its critical buckling stress. According to Eurocode 3, the buckling stress is calculated for an internal wall assuming that the latter is a simply supported plate on its contour. This assumption considers, without further requirement, that the two orthogonal walls to this wall are sufficiently rigid to constitute fixed supports to it. In this paper, we focus on webs of steel profiles that are internal walls delimited by flanges profiles. The objective is to determine, for a given web, flanges dimensions from which the latter can be considered as simple support for this web.