• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.95-96
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• 2002

The operation of proceeding bearing in the conditions of misaligned axis of proceeding and bush leads to the load concentration on the bearing edges causing further mixed lubrication conditions, unstable operation and intensive wear of mating parts. For the design process of proceeding bearing the knowledge of static characteristics determined from the oil film pressure and temperature distribution is very important. For the 3-lobe proceeding bearing, the pressure, temperature and viscosity fields, load capacity, minimum oil film thickness, power loss, oil flow and maximum oil film temperature have been determined by iterative solution of the Reynolds', energy and viscosity equations. The paper introduces the results of theoretical investigations of static characteristics of 3-lobe proceeding bearing operating at misaligned axis of proceeding and bush. An effect of misalignment ratio, length to diameter ratio of the proceeding bearing, the lobe clearance ratio on the static characteristics was investigated. Laminar, adiabatic model of oil film for the solution of Reynolds, energy and viscosity equations was applied.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.115-118
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• 2005

In this study, small scale model test was performed to verify the ultimate load capacity of spillway pier structure under static load. The 1/20 scale test specimen was made of specially designed micro-concrete and wire mesh. From the test result, the cracking load of specimen was 10 tonf and the ultimate was 19tonf. From the similarity rule, cracking and ultimate load of prototype pier structure were predicted 4000 tonf, 7600 ton, respectively.

• Land and Housing Review
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• v.11 no.2
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• pp.75-86
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• 2020

As the urban regeneration project and the old housing maintenance project are actively progressing in Korea, small-scale building construction is being carried out in downtown areas. Small buildings in the downtown area are constructed on about 4 to 10 floors, and since they are carried out in small units in residential areas, it is difficult to enter large equipment to construct existing piles, and it is more vulnerable to complaints about noise and vibration. in this study, helical piles suitable for urban areas or small sites where it is difficult to enter large equipment, such as noise and vibration. Reliability analysis was performed on the results of the static load tests and dynamic load tests conducted at the LH site and the bearing capacity calculated by the hydrostatic method and the empirical formula (N value). As a result of comparing and analyzing the design formula and the results of static load test and dynamic load tests, the correlation between the design formula of the bored pile (Road bridge design standard) formula using N value and the design formula by the modified Davisson method frequently used by method commonly European helical file practitioners.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.307-314
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• 2001

The bearing capacity of drilled shafts that take excavation by Percussion Rrotary Drilling(PRD) into consideration was evaluated using static and dynamic pile load tests. The emphasis was on quantifying the allowable bearing capacity and point load-transfer at the pile tip on seven instrumented steel piles. Of the seven instrumented piles, five piles are placed to the bottom of the excavation by rotary and pushing into the final depth of the excavation, as opposed to the two driven piles. Based on the results obtained, it is shown that the skin friction mobilized by PRD is much greater than point resistance, whereas in driven piles, the point resistance is greater than skin friction. It is also found that much greater pile capacity was proved in the case of drilled shafts, compared to the driven piles and thus, the excavation by rotary drilling gives reliable pile capacity required to design axially loaded piles.

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.263-272
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• 2019

This paper describes the results of bearing capacity using field loading test of pile, in order to extend the applicability of drilled shaft with mid-size, and the results were compared with the prediction results of design bearing capacity by empirical formular. The static load test result showed that the allowable bearing capacity of high pile strength was about 2.4 times higher than that of low pile strength. The dynamic load test result showed that the allowable bearing capacity of high pile strength was about 1.4 times~1.5 times higher than that of low pile strength. The comparison result of allowable bearing capacity between static and dynamic load test showed that the difference of allowable load ranged from 3% to 6% under the same settlement conditions. As a result of comparing the ultimate bearing capacity by load test and design bearing capacity, it was found that the FHWA proposed equation could be more reasonable than the other proposed equation in load sharing ratios of end bearing and skin friction.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.3
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• pp.60-68
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• 2017

Since the bridge is the main facility of the road that is the core of the civil infrastructure, the bridge is constructed to ensure stability and serviceability during the traffic use. In order to secure the safety of bridges, evaluating the integrity of bridges at present is an important task in the maintenance work of bridges. In general, to evaluate the load carrying capacity of bridges, it is possible to confirm the superimposed behavior and symmetric behavior of bridges by estimating the lateral load distribution factor of the bridges through vehicle loading tests. However, in order to measure the lateral load distribution factor of a commonly used bridge, a static loading test is performed. There is a difficulty in traffic control. Therefore, in this study, the static displacement component of the bridge measured in the dynamic loading test and the ambient vibration test was extracted by using empirical mode decomposition technique. The lateral load distribution was estimated using the extracted static displacement component and compared with the lateral load distribution factor measured in the static loading test.

• Smart Structures and Systems
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• v.4 no.1
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• pp.1-17
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• 2008

This study proposes a conceptual framework of in-situ vibration tests and analyses for quality appraisal of non-slender, cast-in-place piles with irregular cross-section configuration. It evaluates a frequency index from vibration recordings to a series of impulse loadings that is related to total soil-resistance forces around a pile, so as to assess if the pile achieves the design requirement in terms of bearing capacity. In particular, in-situ pile-vibration tests in sequential are carried out, in which dropping a weight from different heights generates series impulse loadings with low-to-high amplitudes. The high-amplitude impulse is designed in way that the load will generate equivalent static load that is equal to or larger than the designed bearing capacity of the pile. This study then uses empirical mode decomposition and Hilbert spectral analysis for processing the nonstationary, short-period recordings, so as to single out with accuracy the frequency index. Comparison of the frequency indices identified from the recordings to the series loadings with the design-based one would tell if the total soil resistance force remains linear or nonlinear and subsequently for the quality appraisal of the pile. As an example, this study investigates six data sets collected from the in-situ tests of two piles in Taipu water pump project, Jiangshu Province of China. It concludes that the two piles have the actual axial load capacity higher than the designed bearing capacity. The true bearing capacity of the piles under investigation can be estimated with accuracy if the amplitude of impact loadings is further increased and the analyses are calibrated with the static testing results.

• Journal of the Korean Geotechnical Society
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• v.24 no.1
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• pp.111-118
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• 2008

In the study a 2 dimensional model test was executed to grasp the effect of the taking load of equipments on the ground when improving a soft ground like dredging reclaimed ground. The static load and the dynamic load in the consolidated model ground was $0.02kg/cm^2,\;0.03kg/cm^2\;and\;0.04kg/cm^2$ respectively. After consolidating far two months by consolidation load of $0.02kg/cm^2,\;0.03kg/cm^2\;and\;0.04kg/cm^2$ respectively, the ultimate bearing capacity was $0.16kg/cm^2,\;0.19kg/cm^2,\;0.24kg/cm^2$ respectively. And the energy price of dynamic load test at the same point as the settlement of static load test indicated $E=336{\sim}945kg{\cdot}cm,\;E=252{\sim}780kg{\cdot}cm\;and\;E=323{\sim}727kg{\cdot}cm$ for each consolidation load. When the static load and the dynamic load operated at the same ground condition, the heaving quantity was bigger in the case of the dynamic load than in the case of the static load, and the horizontal displacement quantity the in the case of dynamic load was exhibited very deficiently compared to the quantity in the case of static load test.

• Journal of the Korean Geotechnical Society
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• v.15 no.2
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• pp.165-180
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• 1999

Static load tests were performed for open-ended piles, closed-ended piles, piles with grouted toe, and base-grouted piles by using calibration chamber. Then vertical bearing capacities determined from load tests were compared with each other. The stability of base-grouted pile during a simulated seaquake was investigated by changing the penetration depth. Also, static load tests and seaquake tests for 2-piles and 4-piles group were performed. The bearing capacity of the pile grouted inside the toe was 11.2~30.8% less than that of open-ended pile because of reduction of base resistance due to disturbance of base soil under pile toe. The bearing capacity of a base-grouted pile was 23.8~33.9% more than that of an open-ended pile and was similar to that of a closed-ended pile. The bearing capacity of base-grouted group pile was increased ; the bearing capacity of base-grouted 2-piles group increased 14.6~31.8% compared to that of open-ended 2-piles group, and that of base-grouted 4-piles group increased 15.3~22.4% compared to that of open-ended 4-piles group. During the simulated seaquake in deep sea, stability of base-grouted pile was found to be dependent on the pile penetration depth. During seaquake motion, single long base-grouted pile longer than 20m was stable and short base-grouted pile shorter than 12m failed. But relatively long base-grouted pile longer than 12m kept mobility state. Bearing capacity of base-grouted group pile with penetration depth less than 7m was degraded a little bit ; so, base-grouted group pile could maintain mobility condition.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.5
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• pp.35-40
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• 2010

The present study proposes the strengthening method to use Conclinic Advanced FiberWrep(CAF) so as to improve Load Carrying Capacity of the RC slab bridge. In order to evaluate the strengthening performance, we strengthen 50cm per unit-width of CAF to the slab's bottom of the test bridge that designed with DB 18, then perform Static and Dynamic Field Load Test. As a result of this, 14.7% of the maximum displacement, 5.0% of the strain and 33.7% of the impact factor are reduced after strengthening. At the middle of the test spans, nominal resisting ratio is increased by 27% and Service Load Carrying Capacity is increased by 44.6%, 48.9% of each span 1 and 2. In conclusion, this study indicates that the strengthening method using CAF is very effective to improve the deteriorated RC slab bridge designed with DB 18, to the DB 24 of the first class bridge design load.