• Journal of the Korean GEO-environmental Society
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• v.13 no.5
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• pp.25-33
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• 2012

In this study, gathered measuring data at fields constructed by IPS(Innovative Prestressed Support) system controls the ground displacement and improves the constructability of earth work and structure work greatly, and compared with horizontal displacement calculated by Elasto-plastic analysis program(EXCAV/W). As the result, displacement of calculated by pre-loading data is reduced 13.2% average of general method, and measuring displacement is also reduced 26.7% average of general method. Therefore that IPS system is more safe than conventional strut method in contrast to displacement of underground wall. In addition, horizontal displacement is reduced through the pre-loading effect used by IPS system.

• Journal of the Korean Geotechnical Society
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• v.29 no.10
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• pp.5-18
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• 2013

The differential settlement between the foundations causes the critical damage on the transmission tower constructed in soft ground. Connected-pile foundation for transmission tower structures is an option to prevent the differential settlement. It consists of main foundations and connection beams that are placed between the individual foundations at each corner of tower. In this study, 24 model pile load tests were conducted at a construction site in jeonlabuk-do to investigate the effects of the connection beams on transmission tower foundation. In model tests, various load conditions and connection beam conditions were considered. As the test results, the displacements of connected-pile foundation differed in accordance with load directions. The settlements of connected-pile foundation decreased with the increased stiffness of connection beams, lateral load capacity decreased in accordance with load height, and the lateral load capacity on the failure criteria was similar regardless of load direction.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.8
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• pp.743-750
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• 2016

Track rollers are the key parts that support the weight applied to the caterpillar track of construction machinery. The operating conditions of construction machinery are harsh; hence, the track rollers exposed to these conditions can experience failures such as oil leakage and breakdown of the machine, because of impacts during driving. The failure of track-rollers has a major effect on the operation of the construction machinery. Therefore, each manufacturer tries to evaluate the performance of their products by conducting a self-test. However, only the vertical loads applied to the track rollers are considered in most of the self-tests. This method has the problem of ignoring the horizontal loads that are applied to the track rollers while rotary driving, and hence it does not create the practical operating condition of the construction machinery. In this study, we have determined the experimental conditions that effectively consider the magnitudes of the vertical and horizontal loads. The results of simulations and experiments conducted to assess the influence of horizontal loads on the failure of track rollers are presented in this paper.

• Proceedings of the KIEE Conference
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• 2008.04b
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• pp.16-18
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• 2008

연약지반에 시공된 콘크리트전주가 풍하중에 의해 받는 웅력-변형 특성을 파악하기 위해 전주 매설깊이, 버팀대의 위치 및 수량 등을 변수로 하중 파괴 시험을 실시한 결과, 전주가 깊이 묻혀질수록 재하하중에 따른 수평변위는 감소하였고 전주의 버팀대는 2개일 경우 가장 안정되는 것으로 조사되었다.

• Journal of the Korean GEO-environmental Society
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• v.10 no.6
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• pp.117-123
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• 2009

The mechanical behavior of a micropile due to horizontal load has not yet clearly identified in Korea. It has generally estimated from that of a traditional pile because there is no standard method even though it has shorter length. To tell the truth, its behavior is very different from a traditional pile's. Specifically, it is general fact that horizontal resistance of earth is one of the main factors to control the mechanical behavior of micropile. To this reason, a laboratory model has been made in this study to estimate the behavior of a micropile which loaded increasingly horizontally. The laboratory model has been designed to estimate both the behavior of load to displacement and skin friction to displacement. And the analysis of the latter was compared with the solution of strain wedge model. In the end, it was proved that the mechanical behavior of a micropile should be estimated from considering the horizontal resistance of earth.

• Journal of the wind engineering institute of Korea
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• v.22 no.4
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• pp.163-169
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• 2018

In this study, wind loads exerted on the offshore wind turbine rotor in parked condition were predicted with variations of wind speeds, yaw angles, azimuth angle, pitch angles, and power of the atmospheric boundary layer profile. The calculated wind loads using blade element theorem were compared with those of estimated aerodynamic loads for the simplified blade shape. Wind loads for an NREL's 5 MW scaled offshore wind turbine rotor were also compared with those of NREL's FAST results for more verification. All of the 6-component wind loads including forces and moments along the three axis were represented on a non-rotating coordinate system fixed at the apex of rotor hub. The calculated wind loads are applicable for the dynamic analysis of the wind turbine system, or obtaining the over-turning moment at the foundation of support structure for wind turbine system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.5
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• pp.391-398
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• 2016

This study focused on the aerodynamic loads of the horizontal axis wind turbine blade due to the normal turbulence inflow condition. Normal turbulence model (NTM) includes the variations of wind speed and direction, and it is characterized by turbulence intensity and standard deviation of flow fluctuation. IEC61400-1 recommends the fatigue analysis for the NTM and the normal wind profile (NWP) conditions. The aerodynamic loads are obtained at the blade hub and the low speed drive shaft for MW class horizontal axis wind turbine which is designed by using aerodynamically optimized procedure. The 6-components of aerodynamic loads are investigated between numerical results and load components analysis. From the calculated results the maximum amplitudes of oscillated thrust and torque for LSS with turbulent inflow condition are about 5~8 times larger than those with no turbulent inflow condition. It turns out that the aerodynamic load analysis with normal turbulence model is essential for structural design of the wind turbine blade.

• Journal of the Korea Institute of Building Construction
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• v.15 no.5
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• pp.473-481
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• 2015

The purpose of this research is to comprehend experimentally the characteristics of human strength for using as the basic data of impact resistance test method of lightweight wall. Human motions exerting static load are classified to 4 types. Pushes with two hands or shoulder are defined as the instantaneously forcing motions with hands or shoulder put on the force plate. Leanings back or one-hand against the wall are defined as motions of taking a rest in their respective comfortable posture. Human motions exerting dynamic load are classified to 3 types. Selecting 3 levels of motion strength (weak, middle, strong), 3 levels of force plate stiffness (A: 20kN/cm, B: 4.7kN/cm, C: 2.2kN/cm), and 30 male subjects, load was measured when they applied strength to the force plate. Results of this research are as follows: (1) The maximum load ratio (Pmax/W) of static load for each motion was 1.17-1.25 in two hands pushing, 0.95-0.99 in shoulder pushing, 0.16-0.18 in back leaning, and 0.12-0.15 in one hand leaning. (2) Human dynamic load and object collision were different in the load characteristics. (3) The maximum load ratio of dynamic load for each motion was 10.07 in heel kick, 4.46 in shoulder hitting, and 5.58 in fist blow.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.4
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• pp.331-341
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• 2007

Pre-loads could be imposed on the braced wall to prevent the horizontal displacements during the ground excavation adjacent to the existing tunnel. For this purpose, new pre-loading system through which large pre-loads could be applied to the braced wall was used in the model tests. Large scale model tests were performed in the real scale test pit which was 2.0 m in width and 6.0 m in hight and 4.0 m in length. Test ground was constructed by sand. Model tunnel in 1.2 m diameter was constructed before test ground excavation. Test ground was excavated adjacent to existing tunnel and was braced. To investigate the effect of pre-loading, tests without pre-load were also performed. During the ground excavation were the behavior of braced wall, test tunnel, and ground measured. Model tests were also numerically analysed and their results were compared to that of the real scale tests. As a result, it was found that the stability of the existing tunnel was greatly enhanced when the horizontal displacements of braced wall was reduced by applying pre-load larger than the design load.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.5
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• pp.10-19
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• 2022

Irregularity in structural shape is a ubiquitous phenomenon. Structural hazards evoked from irregularity need to be checked against extreme lateral loadings. Structures containing four distinct types of irregularities in terms of continuity and discontinuity in upper half-length and all story levels along with O-shape are investigated. The structures were analyzed numerically and different seismic responses such as displacements, bending moment, axial forces, torsions, story drift, etc. were scrutinized. The seismic and wind load analysis was conducted for ACI 318-11 conditions. Results show that buildings having discontinuous beams on the upper half exhibit better resilience. It is also concluded that O-shaped building structures provide better resistance to overturning, making this shape relatively safe.