• Geomechanics and Engineering
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• v.11 no.1
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• pp.141-160
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• 2016

This study elucidates the uplift behaviors of the straight-sided and belled shafts. The field uplift load tests were carried out on 18 straight-sided and 15 belled shafts at the three collapsible loess sites under an arid environment on the Loess Plateau in Northwest China. Both the site conditions and the load tests were documented comprehensively. In general, the uplift load-displacement curves of the straight-sided and belled shafts approximately exhibited an initial linear, a curvilinear transition, and a final linear region, but did not provide a well defined peak or asymptotic value of the load, and therefore their uplift resistances should be interpreted from the load test results using an appropriate criterion. Nine representative uplift resistance interpretation criteria were used to define the "interpreted failure load" for each of the load tests, and all of these interpreted uplift resistances were normalized by the failure threshold, $T_{L2}$, obtained using the $L_1-L_2$ method. These load test data were compared statistically and graphically. For the straight-sided and belled shafts, the normalized uplift load-displacement curves were respectively established by the plots that related the mean interpreted uplift resistance ratio against the mean displacement at the corresponding interpreted criteria, and the comparisons of the normalized load-displacement curves were made. Specific recommendations for the designs of uplift belled and straight-sided shafts in the loess were given, in terms of both capacity and displacement.

• Journal of the Korean Geotechnical Society
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• v.22 no.12
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• pp.45-55
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• 2006

This paper presents the results of full-scale uplift load tests performed on 30 passive anchors grouted to various lengths at Taean site in Korea. Various rock types were tested, ranging from highly weathered to sound gneiss. Rock anchors were installed over a wide range of rock types and qualities with a fixed anchored depth of $1{\sim}4m$. The majority of installations used SD4O-D51 no high grade steel rebar to induce rock failure prior to rod failure. In many tests, rock failure was reached and the ultimate loads were recorded along with observations of the shape and extent of the failure surface. The test results, the failure mechanisms as well as uplift capacities of rock anchors depend mostly on rock type and quality, embedded fixed length, and the strength of rebar. Based on test results, the main parameters governing the uplift capacity of the rock anchor system were determined.

• Journal of the Korean Geotechnical Society
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• v.25 no.10
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• pp.5-15
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• 2009

This paper presents the results of full-scale uplift load tests performed on 24 passive anchors grouted to various lengths at Okchun and Changnyong site. Rock anchors were installed over a wide range of rock types and qualities with a fixed anchored depth of 1~6 m. The majority of installations used D51 mm high grade steel rebar to induce rock failure prior to rod failure. However, a few installations included the use of D32 mm rebar at relatively deeper anchored depth so as to induce rod failure. In many tests, rock failure was reached and the ultimate loads were recorded along with observations of the shape and extent of the failure surface. In addition to field tests, laboratory pullout tests were conducted to determine bond strength and bond stress-shear slip relation at the tendon/grout interface when a corrosion protection sheath is installed in the cement-based grout. The test results show that the ultimate tendon-grout bond strength is measured from 18~25% of unconfined compressive strength of grout. One of the important results from these tests is that the measured strains along the corrosion protection sheath were so small that practically the reduction of bond strength by the presence of sheath would be negligible.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.4
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• pp.257-262
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• 2019

Lattice steel towers for overhead transmission lines have been replaced by tubular steel poles due to the visual impact of large and complex shape of truss type. Demand for tubular steel poles consisting of a single frame member continues to grow because of its advantages such as visual minimization, architectural appeal and minimal site consumptions. However, there are some constraints on the transportation and construction. As the diameter of tower base has been enlarged, it may exceed minimum height limit required to pass the tunnel in case of land transportation. Also, in a narrow place where it is not easy to secure the installation areas such as mountainous places, there might be some areas wherein it must secure a wide working space so that large vehicles and working cranes will be allowed to enter. In this paper, we presented a vertical separated tubular steel pole, which is a new type of support that can be implemented for general purpose such as mountainous areas or narrow areas to improve the issues raised by breaking away from the conventional design and fabrication methods. Technical approaches for overcoming the limit of the cross-sectional size is to separate and modularize the cross-section of the tubular steel pole designed with a size that cannot be carried or assembled, and to lighten it with a weight capable of being transported and assembled in a narrow space or mountainous area. As a result of this research, it will be possible to enter small and medium sized vehicles in locations where it is restricted to transport by large-sized vehicles. In the case of mountainous areas, it will be possible to divide it into a weight capable of being carried by a helicopter and it will be easy to adjust and fabricate it with individual modules. Furthermore, in order to break away from the traditional construction method, we proposed the equipment that can be applied to the assembly of Tubular Steel Pole without using a large crane in locations where there is no accessible road or in locations wherein large cranes cannot enter. In particular, this paper shows the movable assembling equipment and some methods that are specialized for vertical separated tubular steel pole consisting of members with reduced weight. The proposed assembly equipment is a device for assembling the body of the Tubular Steel Poles. It will be installed inside the support and the modules can be lifted by using the support itself.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.3
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• pp.359-369
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• 2018

An essential measure to prevent healthcare-associated infections (HAI) is to develop a consistent system of surveillance, thereby promoting a reliable situation diagnosis to perform efficient control for the problem. Patient-to-patient transmission of pathogens within the hospital plays a substantial role in the epidemiology of HAIs. Contamination of healthcare environments commonly occurs, including facilities surfaces (e.g., bed rails, bedside tables), drinking water, cooling tower water, endoscopic instruments, food, airborne, endotoxin test, sterile test and medical equipment, with pathogenic organisms. In addition, epidemiological analysis is performed by multi locus sequence tying, pulsed-field gel electrophoresis for active surveillance. Therefore, an environmental surveillance culture test for prevention improves patient safety and blocks infection agents. Effective infection control and increased safety are possible by controlling the national infection control system. In conclusion, this study contributes to an effective infection control system through the standardization of active surveillance culture laboratory and secure expertise as infection control specialist. The primary objective of the standardization is to improve the safety of the nation's healthcare system by reducing the rates of HAIs.

• Journal of the Korean Geotechnical Society
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• v.23 no.2
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• pp.61-69
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• 2007

In this study, experimental analysis was performed about lateral load capacity and behavior of laterally loaded-bored piles for soil conditions and pile shape, i.e. cylindrical and taper piles. Also, Calibration chamber load tests were performed for cylindrical and taper piles considering the variations of relative densities and restraint stresses. According to the results of chamber tests, it was found that, while both vertical and horizontal stresses affect load-responses and ultimate lateral load capacity of laterally loaded piles, effect of the horizontal stress was larger than that of the vertical stress. Effect of lateral load capacity and behavior was relatively small compared to relative density and stress state of soils surrounding piles, but showed a little difference for soil conditions. From comparison between predicted and measured lateral load capacity, it was observed that predicted results differ significantly from measured results. This is mainly due to the fact that the effect of horizontal stress is not considered in the conventional prediction methods.