• Geotechnical Engineering
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• v.12 no.2
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• pp.19-32
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• 1996

Based on Trifuilac's empirical model to transform earthquake acceleration time history in the time domain into Fourier amplitude spectrum in the frequency domail an earthquake scaling technique for simulating the earthquake record of certain magnitude as the required magnitude earthquake was suggested. Also, using the earthquake record of magni dude(M) 5.8, the simulated earthquake of magnitude(M) 8.0 was established and its application to dynamic testing system was proposed. The earthquake scaling technique could be considered by several terms : earthquake magnitude(M), earthquake intensity(MMI), epicentral distance, recording site conditions, component direction and confidence level required by the analysis. Albo, it had an application to the various earthquake records. The simulated earthquake in this study was established by two orthogonal horizontal components of earthquake acceleration-time history. The simulated earthquake shaking could be applied to the dynamic pile load test for the model tension pile and the model compressive open -ended piles driven into the pressure chamber. In the static pile load test, behavior of two piles was very different and after model tension pile experienced 2 or 3 successive slips of the pile relative to the soil, it was failed completely. During the simulated earthquake shaking, dynamic behavior and pile capacity degradation of two piles were very different.

• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.199-206
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• 2002

The bearing capacity of open-ended piles is affected by the degree of soil plugging, which is quantified by the incremental filling ratio, IFR. However, most design criteria for open-ended piles do not consider the variation of pile bearing capacity with IFR. In this study, new design equations for calculating the pile base and shaft load capacities, based on IFR value of the pile, were proposed using the results of model pile tests. A full-scale pile load test was also conducted on fully instrumented open-ended pile driven into gravelly sand. The IFR for the pile was continuously measured during pile driving. In order to check the accuracy of predictions made with the proposed equations, the equations were applied to two examples, including the pile load test preformed in this study. Based on the comparisons with the pile load tests results, the proposed equations appear to produce satisfactory predictions.

• Journal of the Korean GEO-environmental Society
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• v.6 no.3
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• pp.47-54
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• 2005

In many practical cases, design methods of pile have been used mainly semi empirical bearing capacity equations. It can be done that confirmation of pile bearing capacities through using of dynamic and static tests during constructing or after constructions. If a prediction of layered point pile bearing capacity could be done through simple tests during field investigation, it could be done that more reliable design of pile than a prediction of using semi empirical equations or static formulations. This paper suggests a method to estimated point bearing capacity during in-situ investigation by using the dynamic rod model pile and verifies the point bearing capacity compare with results of static pile load tests. From test results, the unit ultimate point bearing capacities are relatively similar through a dynamic rod model pile tests and static pile load tests. The unit ultimate point bearing capacity by using N value is shown about 50 % value of measured unit ultimate point bearing capacity from field test result and the prediction of the unit ultimate point bearing capacity by using N value is shown very conservative, illogical and uneconomical pile designs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4588-4594
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• 2014

In this study, small scaled (1/30) laboratory chamber tests of the pile foundation for a lightweight concrete pavement system were carried out to evaluate the safety of a pile foundation on sandy soil. The testing ground was simulated in the field and a standard pile-loading test was conducted. The test piles were divided into 3 types, Cases A, B and C, which is the location from the center of the slab by applying a vertical load. The interval between the piles was set to 8 cm. As a result of the pile foundation model test, the pavement settled when the vertical load was increased to 12kg from 1.5kg in sandy soil ground, particularly the maximum settlement of 0.04mm. Judging from the model chamber test, Case A showed compressive deformation, whereas Case B represented the compression and tensile forces with increasing vertical load. Case C showed an increase in tensile strain.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.128-138
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• 2022

In this study, in order to apply ultra-high-strength concrete beams of 100 MPa or more manufactured by centrifugal molding as the superstructure of the avalanche tunnel, the purpose is to verify the structural safety of the corner rigid joint in which the centrifugal molded beam is integrated with the substructure, which is the negative moment area. A full-size specimen was manufactured, and loading tests and analysis studies were performed. In order to expect the same effect that the maximum moment occurs in the corner joint part of the upper slab end when the standard model of the avalanche tunnel is designed with a load combination according to the specification, a modified cantilever type structural model specimen was manufactured and the corner rigid joint was fixedly connected. A study was performed to determine the performance of the method and the optimal connection construction method. The test results demonstrated that the proposed connection system outperforms others. Despite having differences in joint connection construction type, stable flexural behavior was shown in all the tested specimens. The proposed method also outperformed the behavior of centrifugally formed beams and upper slabs. The behavior of the corner rigid joint analysis model according to the F.E. analysis showed slightly greater stiffness compared to the results of the experiment, but the overall behavior was almost similar. Therefore, there is no structural problem in the construction of the corner rigid joint between the centrifugally formed beam and the wall developed in this study.

• Journal of the Korean Geosynthetics Society
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• v.19 no.3
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• pp.35-44
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• 2020

This study described the result of laboratory model tests, in order to compare the improvement effect of the DCM column installed on the soft ground according to DCM column type. In the laboratory model test, the non-reinforced type and the 3 types of DCM column were applied, and the behavior (settlement, lateral flow) of soft ground was evaluated under the surcharge load condition for each type. The settlement evaluation result showed that the settlement of soft ground without DCM column occurred rapidly under the low load condition, but the settlement of the soft ground with the DCM column had relatively small settlement. The evaluation result of lateral flow in the soft ground showed that the soft ground with DCM column had lower lateral displacement than the soft ground without DCM column. Especially, the lateral displacement under the same load condition decreased in the order of pile type, wall type, and grid type. Therefore, it confirmed that the improvement effect of soft ground was excellent when the DCM of grid type was applied for settlement and lateral flow.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1088-1093
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• 2010

The Smart bi-directional pile load test with variable end plate overcomes the shortcoming of the Osterberg cell test. It is possible that the ultimate bearing capacity of piles can be known by using two different end plates. The first step is to measure end bearing capacity with smaller end plate and the second step is similar to the conventional O-cell test. In this study, model test was performed to evaluate the smart bi-directional pile load test in sand. Vertical displacement of the model pile were messured at the axial loading condition.

• Journal of the Korean Geotechnical Society
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• v.19 no.2
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• pp.255-265
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• 2003

A series of laboratory tests were performed to evaluate engineering properties of geobag system which is used for urgent restoration of the collapsed roadbed. In this study, the suitable geobag size was proposed as 44cm wide and 66cm long, and the suitable filling ratio of geobag was also proposed as 80% through the static loading tests. Also a series of model tests were carried out to investigate the characteristics of the engineering behavior and the distribution of earth pressure of the geobag roadbed under static and dynamic loading.

• Journal of Korean Society of Steel Construction
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• v.22 no.6
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• pp.523-532
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• 2010

Concrete-filled square steel tube (CFT) columns have inherently high fire resistance and load-bearing capacity. Nevertheless, it is sometimes necessary to improve their fire resistance using external fire protection. This paper presents the experimental results of the temperature distribution of CFT columns with fire protection. A fire load test was carried out by exposing small-scale specimens to heat in an electric furnace that was especially built for testing loaded columns. The temperature distribution of CFT columns under constant axial loads was determined, as were its significant parameters, such as the types of fire protection and thickness, the thickness of the square CFT, and the fire duration times. The results of this study showed the temperature distribution of each specimen of the electric furnace and the temperature distribution properties of concrete and steel. In addition, the axial displacement and local buckling behavior of CFT columns based on temperature changes was observed.

• Journal of the Korean GEO-environmental Society
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• v.4 no.4
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• pp.85-96
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• 2003

The Geocell system is the advanced system of Geo-grids, and is one of geosynthetics used for earth reinforcement of weak soil. It is the way to increase earth strength and bearing capacity by using three dimension type of geo-composite. This paper analyzed the bearing capacity mechanism of Geocell system for earth reinforcement. Plate loading tests under the model laboratory condition were performed, and the increase of bearing capacity and the decrease of settlement with shallow foundation were evaluated.