• Journal of Advanced Marine Engineering and Technology
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• v.37 no.6
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• pp.623-630
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• 2013

This study was to evaluate hydrodynamic performance evaluation between an abroad product, a developed inflatable kayak and new developed kayaks. In order to test, inclining and turning trial test were carried out in the Ocean engineering Basin. Also, resistance test was carried out using a reduced scale model in the circulating water channel. In conclusion, stability of KONA was evaluated was the most greatest, the coefficient of resistance and center of gravity from RD-FK-12 were considerable, and turning performance of RD-FK-11 was greater than this of KONA and RD-FK-12.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.407-414
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• 2001

The severe shortage of the available sites in the highly developed downtown area in Korea necessitates the construction of high-rise buildings which meet the need of residence and commercial activity simultaneously. The objective of this study is to investigate the seismic performance of this type of building structures. For this purpose, two 1 :12 scale 17-story reinforced concrete model structures were constructed according to the similitude law, in which the upper 15 stories have a bearing-wall system while the lower 2-story frames have two different layouts of the plan The one is a moment-resisting frame system and the other is a moment-resisting frame system with a infilled shear wall. Then, this model was subjected to a series of earthquake excitations. The test results show that the existence of shear wall reduced the shear deformation at the piloti frame, but has almost the negligible effect on the reduction of the overturning-moment angle.

• Korean Journal of Remote Sensing
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• v.19 no.5
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• pp.341-349
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• 2003

The so-called B-method, a simplified surface energy budget, permits calculation of daily actual evapotranspiration (ET) using remotely sensed data, such as NOAA-AVHRR. Even if the use of satellite data allows estimation of the albedo and surface temperature, this model requires meteorological data measured at ground-level to obtain the other inputs. In addition, a difficulty may be occurred by the difference of temporal scales between the net radiation in daily scale and instantaneous measurement at midday of the surface and air temperatures because the data covered whole day are necessary to obtain accumulated daily net radiation. In order to solve these problems, this study attempted a modification of B-method through an extension of hourly ET value calculated using a complete instantaneous inputs. The estimation of the daily apparent ET from newly proposed system showed a root mean square error of 0.26 mm/day as compared the output obtained from the classical model. It is evident that this may offer more rapid estimation and reduced data volume.

• Journal of the Korean Geosynthetics Society
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• v.11 no.4
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• pp.1-8
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• 2012

In this study, the earth pressure, displacement and strain were compared with reinforcement types at segmental retaining wall through full scale model test. The test results found that the measurement of earth pressure and displacement at wall for the fully reinforced retaining wall are different from those for the partly reinforced retaining wall. The analyses of these results would suggest that the used of geoogrid allowed the vertical earth pressure and displacement at wall to be reduced. The horizontal earth pressure in upper and lower part of wall can change with reinforcement type and earth deformation and were larger than the active and the rest pressure. Also, the lateral earth pressure and displacement of wall have a very high a correlation. It was found that the strain contour distribution of reinforcements was occurred a large strain at cental part of wall in segmental retaining wall system.

• Fire Science and Engineering
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• v.14 no.2
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• pp.21-32
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• 2000

In this study, reduced-scale experiments as the alternative to a real-scale fire test were conducted to understand fire properties in tunnel, and their results were compared with those of numerical simulation. The 1/20 scale experiments were conducted under the Froude scaling since smoke movement in tunnel is governed by buoyancy farce. A numerical simulations were on performed 3D unstructured meshes with PISO algorithm and buoyant plume models. Results showed that data was in reasonable agreement with the numerical data of smoke velocity, temperature distribution, and clear height.

• Journal of the Korean Geotechnical Society
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• v.34 no.12
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• pp.7-17
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• 2018

Test bed additional wall combined with PHC-W pile retaining wall has been constructed. To determine the dimensions of test bed additional wall, bending and shear tests of full scale core members of additional wall were tested. Basement additional walls utilizing PHC-W pile retaining wall, which were developed by modifying the cross-section of PHC piles, were classified into the composite additional wall and the non-composite additional wall. Their tests were conducted to obtain bending strength and shear strength of basement additional walls ultilizing PHC-W pile retaining wall. Since bending strengths and shear strengths of the composite additional wall and the non-composite additional wall were similar, it could be confirmed that the non-composite additional wall could be applied instead of the composite additional wall. Full-scale model additional wall was 200 mm thick, thus the thickness of additional wall combined with PHC-W pile retaining wall could be reduced by 100~200 mm.

• International Journal of Highway Engineering
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• v.17 no.6
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• pp.105-115
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• 2015

PURPOSES : This study aimed to evaluate the appropriateness of safety with the standard for threshold zone luminance as specified in the Recommendation for Lighting of Traffic Tunnel, which has been widely adopted worldwide. METHODS : A driving test of the subject in a full-scale road tunnel was conducted. The adaptation luminance and threshold zone luminance, which should be known for the driver to perceive an object within stopping sight distance, were obtained. These values were compared with the adaptation luminance and threshold zone luminance obtained by the existing reduced model test and tunnel lighting standard that has served as a guideline for the current threshold zone luminance standard. RESULTS : According to this study, threshold zone luminance should be increased to at least 1.8 times the value proposed in the existing studies and to twice the domestic tunnel lighting standard (KS C 3703: 2014). CONCLUSIONS : The threshold zone luminance proposed in this study differs largely from that obtained from indoor tests and from the current tunnel lighting standard used worldwide; this difference may be attributed to the fact that the indoor tests did not incorporate driving workload, non-uniformity of luminance distribution in terms of sight, and factors that reduce the visibility of the driver, such as the light reflected into the driver's eyes. Hence, it is necessary to further review the factors that reduce the visibility of drivers approaching tunnels in order to determine the rational tunnel threshold zone luminance.

• Structural Engineering and Mechanics
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• v.76 no.2
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• pp.251-267
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• 2020

Transmission tower-line systems have come to represent one of the most important infrastructures in today's society. Recent strong earthquakes revealed that transmission tower-line systems are vulnerable to earthquake excitations, and that ground motions may arrive at such structures from any direction during an earthquake event. Considering these premises, this paper presents experimental and numerical studies on the dynamic responses of a 1000 kV ultrahigh-voltage (UHV) transmission tower-line system under different seismic incidence angles. Specifically, a 1:25 reduced-scale experimental prototype model is designed and manufactured, and a series of shaking table tests are carried out. The influence of the seismic incidence angle on the dynamic structural response is discussed based on the experimental data. Additionally, the incidence angles corresponding to the maximum peak displacement of the top of the tower relative to the ground (referred to herein as the critical seismic incidence angles) are summarized. The experimental results demonstrate that seismic incidence angle has a significant influence on the dynamic responses of transmission tower-line systems. Subsequently, an approximation method is employed to orient the critical seismic incidence angle, and a corresponding finite element (FE) analysis is carried out. The angles obtained from the approximation method are compared with those acquired from the numerical simulation and shaking table tests, and good agreement is observed. The results demonstrate that the approximation method can properly predict the critical seismic incidence angles of transmission tower-line systems. This research enriches the available experimental data and provides a simple and convenient method to assess the seismic performance of UHV transmission systems.

• Journal of the Korean Geotechnical Society
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• v.23 no.6
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• pp.5-21
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• 2007

Despite a number of advantages of reinforced earth walls over conventional concrete retaining walls, there exit concerns over long-term residual deformation when they are subjected to repeated and/or cyclic loads, especially when used as part of permanent structures. In view of these concerns, in this paper time-dependant deformation characteristics of geosynthetic reinforced modular block walls under sustained anuor repeated loads were investigated using reduced-scale model tests. The results indicated that a sustained or repeated load can yield appreciable magnitude of residual deformation, and that the residual deformations are influenced not only by the loading characteristics but by the mechanical properties of geogrid. It is also found that the preloading technique can be effectively used in controlling residual deformations of reinforced soils subjected to sustained and/or repeated loads.

• Tunnel and Underground Space
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• v.20 no.5
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• pp.369-377
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• 2010

Applied to the braced wall in order to stabilize the adjacent tunnel. A pre-load of bracing was imposed to prevent the horizontal displacement of the braced wall during the ground excavation. For this purpose, real scale model tests were conducted, without and with pre-load on braced wall. Real scale model tests were conducted, without and with building load (0 m, 1D, 2D) on ground surface. As a result, it was found that the stability of the existing tunnel adjacent to the braced wall could be greatly enhanced when the horizontal displacement of the braced wall was reduced by applying a pre-load, which was larger than the designated axial force of bracing. In this paper, the behaviors of braced wall and adjacent tunnel was studied. Model tests in 1:10 scale were performed in real construction sequences. Adjacent tunnel was 12 m in diameter and the size of test pit was 2.0 m (width) ${\times}$ 6.0 m (height) ${\times}$ 4.0 m (length) in dimension.