• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.1
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• pp.189-197
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• 2011

In the field of structural test, it is a very important factor to apply with an appropriate test jig to enhance test accuracy and efficiency. Especially in the large scale structure test, proper test apparatus scheme will reduce overall cost and time of the test project. Actuators, oil jack and UTM is generally used to evaluate the flexural capacity of the test beam. But in the case of multiple loading point or asymmetric loading of large scale test specimen, existing test method such as UTM have a difficulty in giving an accurate load. In this study new test method which is composed of existing test apparatus will be developed to improve test accuracy and economic efficiency.

• Journal of the Korean Geotechnical Society
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• v.34 no.12
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• pp.133-143
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• 2018

Concrete filled steel tube (PCFT) piles, which compose PHC piles inside thin steel pipes, were developed to increase the flexural strength of the pile with respect to the horizontal load. In order to compare the flexural strength of PCFT pile with that of steel pipe pile, several flexural tests were performed on the PCFT and steel pipe piles with the same diameter and the P-M curves for both piles were constructed by the limit state design method. Four test piles were also installed and lateral pile load tests were performed to compare the lateral load capacities and lateral behaviors of the hybrid composite piles using PCFT piles and the existing piles such as HCP and steel pipe piles. The flexural test results showed that the flexural strength of PCFT piles was 18.7% higher than that of steel pipe piles with thickness of 12mm and the same diameter, and the mid-span deflection of piles was 50% lower than that of steel pipe piles at the same bending moment. From the P-M curves, it can be seen that the flexural strength of PCFT piles subjected to the vertical load is greater than that of steel pipe piles, but the flexural strength of PCFT piles subjected to the pullout load is lower than that of steel pipe piles. In addition, field pile load tests showed that the PCFT hybrid composite pile has 60.5% greater lateral load capacity than the HCP and 35.8% greater lateral load capacity than the steel pipe pile when the length of the upper pile in hybrid composite piles was the same.

• Journal of the Korean GEO-environmental Society
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• v.5 no.3
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• pp.17-30
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• 2004

In this study, a new formula of settlement at the head of IGM was suggested and the applicability of suggested formula was verified with field test results. This suggested formula was the function of the settlement at the shaft head and the elastic compression of shaft. The applicability of suggested formula was verified with the result of in-situ load test. Also, the bearing capacity of drilled shaft with the IGM's theory was compared with those of classical theories. The results showed that classical method showed smaller values of bearing capacity than those of field load test data. The results of analysis also showed that the suggested formula and IGM's theory were applicable for the estimation of bearing capacity with the increase of shaft settlement. Especially, settlement correction factor($k_m$), which reflects ground condition and load transfer characteristics, increases as the applying load and shaft deformation increase. This suggested formula was applicable for medium density or higher density of soil condition and $k_m=1$ means yielding load for firm soil condition.

• Journal of the Korean Geotechnical Society
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• v.34 no.11
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• pp.107-119
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• 2018

PHC piles, extension-plate attached PHC piles, and steel pipe attached PHC piles were installed in field test site. Axial compressive static load tests including load distribution test and Pile Driving Analyzer (after driving) were done on the tip-transformed PHC piles and the grouted tip-transformed PHC piles. Load-displacement curves of three different type of PHC piles, which are PHC pile (TP-1), extension plate attached PHC pile (TP-2) and steel pipe attached PHC pile (TP-3), showed almost the same behavior. Thus bearing capacity increase effect of the tip-transformed PHC piles was negligible. Share ratio of side resistance and end bearing resistance for PHC pile, extension plate attached PHC pile, and steel pipe attached PHC pile were 95.8% vs. 4.2%, 95.6% vs. 4.4%, and 97.8% vs. 2.2% respectively.

• Journal of Industrial Technology
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• v.21 no.B
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• pp.195-203
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• 2001

The purpose of this study is to estimate ultimate uplift capacity of permanent anchor which was cast into weathered rock. The ultimate uplift capacity was estimated from the load-displacement curve of four different anchors which have different bond length. The creep test was performed for 15minutes under the maximum load of each step in order to understand the load-transfer property of permanent anchor and to decide which anchor to choose. The destruction range of soil due to the changes in load was estimated by installing dial gauge on the ground which was cast into the weathered rock. Ultimately, the study on the behavior of the anchor case into the weathered rock was performed by comparing and analyzing the estimated result of the UUC obtained by the full scale pull out test in the field with the exsting theoretical and practical results of soil and rock anchor.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1995.10a
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• pp.132-141
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• 1995

This study is intended to propose practical but systematic and rational approaches for proof load test and integrity assessment of segmental PC box-girder bridges. The proposed models cover the whole range of field tests and assessment of such as inspections, nondestructive tests, static and dynamic load tests, structural analysis, and integrity assessment for the evaluation of load carrying capacity, serviceability, and durability of PC box-girder bridges. They are applied to a newly constructed precast segmental PC box-girder bridge which is a part of the Seoul interior circuit elevated expressway.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1065-1072
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• 2010

Case studies published in Korea versus the low ground fault is applied on the bridge based on theory or experience in the design of pile bearing capacity by the value of the expression is designed to conduct field tests Disclosure Load bearing capacity value, the result of applying a reasonable construction cost savings of approximately 10 eokyeowon Has, in the design of site investigation was insufficient to require additional efforts. Apply the appropriate value from the extra support in the design of accurate ground survey and air speed to cut the budget and social technology can ensure the reliability was unknown.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.743-749
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• 2009

In this study, the field test for suction drain method which does not require a surcharge load and a sealing sheet was performed at west seashore's site constructed by the dredged and reclaimed clay. The improvements of soft ground by suction drain method was analyzed by the results of real-time field measurement, SPT(Standard Penetration Test) and laboratory tests. The results indicated that the soft ground improvement is effective the vertical drain method used with vacuum pressure rather than surcharge load with considering settlements, dissipation of pore water pressure and shear strength.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.4
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• pp.59-65
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• 2011

The purpose of this study was to analyze the water quality change when wastewater applied to study paddy fields. CREAMS-PADDY (Chemical, Runoff and Erosion from Agricultural Management System) model was used to estimate the field-scale water quality. Simulated results were compared with observed data monitored from Byeongjeom study paddy fields which is located near the Suwon sewage treatment plant in Gyeonggi-do. Significance analysis was performed for the three different irrigation water quality level and five fertilizer reduction scenarios using LSD (Least Significant Difference) and DMRT (Duncan's Multiple Range Test). Total nitrogen was found to be significant for both irrigation water quality level and fertilizer reduction while total phosphorus was not. Annual drainage load for total nitrogen was reduced by 66~92 % compared to irrigation load when treated wastewater irrigated to study paddy fields from 2002 to 2007. Total phosphorus was reduced by 70~86 %.

• Smart Structures and Systems
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• v.30 no.2
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• pp.209-219
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• 2022

The determination for bearing capacity of precast nodular piles is conventionally time-consuming and high-cost by using numerous experiments and empirical methods. This study proposes an intelligent method to evaluate the bearing capacity and shaft resistance of the nodular piles with high efficiency based on long short-term memory (LSTM) approach. A series of field tests are first designed to measure the axial force, shaft resistance and displacement of the combined nodular piles under different loadings, in comparison with the single pre-stressed high-strength concrete piles. The test results confirm that the combined nodular piles could provide larger ultimate bearing capacity (more than 100%) than the single pre-stressed high-strength concrete piles. Both the LSTM-based method and empirical methods are used to calculate the shift resistance of the combined nodular piles. The results show that the LSTM-based method has a high-precision estimation on shaft resistance, not only for the ultimate load but also for the working load.