• Journal of the Earthquake Engineering Society of Korea
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• v.15 no.2
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• pp.11-22
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• 2011

The design comparison and nonlinear analysis of totally prefabricated bridge substructure systems are performed. The prefabricated bridge substructures are designed by the methods of present design and load and resistance factor design (LRFD). For the design, the current Korea Highway Bridge Code (KHBD), with DB-24 and DL-24 live loads, is used. This study evaluates the present design method of KHBD (2005) and AASHTO-LRFD (2007) for totally prefabricated bridge substructure systems. A computer program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures, was used.

• Journal of the Korean Institute of Gas
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• v.11 no.3
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• pp.49-55
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• 2007

Polyethylene pipes have been widely used as they are easy to construct and suitable for economical efficient when they are compared with metal pipelines. This paper studies the effect of various external loadings on stress and deflection of the buried PE pipes using Finite Element Method(FEM). For this purpose, stresses of buried PE pipes are calculated according to the loading condition such as pipe types (pipe diameter $50{\sim}400mm$), burial depths ($0.6{\sim}1.2m$) and internal pressures ($0.4{\sim}4bar$). As a result, it is founded the effect and relation with each of loading conditions under the buried condition.

• Smart Structures and Systems
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• v.16 no.1
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• pp.101-139
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• 2015

In this paper, it is aimed to investigate the restoration effect on the structural behavior of masonry arch bridges. Dandalaz masonry arch bridge located on the 4km east of Karacasu town of Aydin, Turkey is selected as a numerical example. The construction year of the bridge is not fully known, but the bridge is dated back to 15th century. Considering the current situation, it can be easily seen that the structural elements such as arch, side walls and timber blocks are heavily damaged and the bridge is unserviceable. Firstly finite element model of the bridge is constituted to reflect the current situation (before restoration) using building survey drawings. After, restoration project is explained and finite element model is reconstituted (after restoration). The structural responses of the bridge are obtained before and after restoration under dead load, live load and dynamic earthquake loads. For both conditions, maximum displacements, maximum-minimum principal stresses and maximum-minimum elastic strains are given with detail using contours diagrams and compared with each other to determine the restoration effect. From the study, it can be seen that the maximum internal forces are consisted under dynamic loads before and after restoration. Also, the restoration projects and studies have important and positive effects on the structural response of the bridge to transfer these structures to future.

• Transactions on Electrical and Electronic Materials
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• v.14 no.4
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• pp.211-215
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• 2013

Partial discharge diagnosis techniques using ultra high frequencies do not affect load movement, because there is no interruption of power. Consequently, these techniques are popular among the prevention diagnosis methods. For the first time, this measurement technique has been applied to the GIS, and has been tested by applying an extra high voltage switchboard. This particular technique makes it easy to measure in the live state, and is not affected by the noise generated by analyzing the causes of faults ? thereby making risk analysis possible. It is reported that the analysis data and the evaluation of the risk level are improved, especially for poor location, and that the measurement of Ultra high frequency (UHF) partial discharge of the real live wire in industrial switchgear is spectacular. Partial discharge diagnosis techniques by using the Ultra High Frequency sensor have been recently highlighted, and it is verified by applying them to the GIS. This has become one of the new and various power equipment techniques. Diagnosis using a UHF sensor is easy to measure, and waveform analysis is already standardized, due to numerous past case experiments. This technique is currently active in research and development, and commercialization is becoming a reality. Another aspect of this technique is that it can determine the occurrences and types of partial discharge, by the application diagnosis for live wire of ultra high voltage switchgear. Measured data by using the UHF partial discharge techniques for ultra high voltage switchgear was obtained from 200 places in Gumi, Yeosu, Taiwan and China's semiconductor plants, and also the partial discharge signals at 15 other places were found. It was confirmed that the partial discharge signal was destroyed by improving the work of junction bolt tightening check, and the cable head reinforcement insulation at 8 places with a possibility for preventing the interruption of service. Also, it was confirmed that the UHF partial discharge measurement techniques are also a prevention diagnosis method in actual industrial sites. The measured field data and the usage of the research for risk assessment techniques of the live wire status of power equipment make a valuable database for future improvements.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.3
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• pp.91-100
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• 2006

In this study, the characterization of unit load generation and discharge from various type stall of piggery was conducted by investigation and analysis of contaminants loading from piggery urine, manure and wastewater. The results are summarized as follows: The unit load generation of filth increases as piggery grow older, but there was not large enough difference among those values of unit load evaluated for various stall types if mean values of each type of stall are considered. The generation amounts of manure and urine were total 4.57kg/head/d of 1.49kg manure/head/d and 3.08kg urine/head/d with consideration of 3 seasons and live weight. The finalized mean unit load generation of filth were estimated at BOD 199.5g/head/d, $COD_{cr}\;413.5g/head/d$, T-N 27.8g/head/d, T-P 5.3g/head/d with consideration of seasons and the type of stalls. The wastewater unit loads discharged from cement type stall were estimated at BOD 31.3g/head/d, $COD_{cr}\;95.6g/head/d$, T-N 8.9g/head/d, T-P가 3.1g/head/d. The sum of manure unit load generation considered with manure collection ratio(80%, 90%) and wastewater unit load was almost similar when compared to the unit load discharged from slurry type stall even though more or less difference were appeared according to each contaminants and parameters.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6A
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• pp.597-605
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• 2009

The safety of expressway bridges was estimated by checking the external condition rank based on the nondestructive inspection and material test and by measuring load carrying capacity based on the result of load test. Although the load carrying capacity of the bridges was clearly low compared to the design standard, it was examined that many of the bridges have good external condition rank relatively. Also, it can be assured that load carrying capacity shows a considerable difference according to various condition even though the bridges have similar construction year and a structural type. Therefore, this study showed various problems of the current safety measurement of expressway bridges by considering the status of the expressway bridges, external condition rank, and method of safety diagnosis and repair, rehabilitation for maintenance. Based on the existing data of over 400 expressway bridges, the load carrying capacity was analyzed quantitatively considering bridge type, serviced life, design live load, external condition rank and traffic count as variables. The result of this study will be expected to provide the basic information for a reasonable safety assessment of expressway bridge.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.730-736
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• 2016

In a previous study, the impact factor response spectrum and corresponding method for evaluating the load carrying capacity of bridges was suggested to improve the existing evaluation method. To verify the applicability of the suggested method, which is based on the frequency of bridges, the dynamic characteristic test for an actual single span simply-supported bridge was conducted. Through a field test under ambient traffic conditions, the dynamic response of the bridge was obtained using wireless accelometers and its fundamental frequency was identified. The peak impact factor was determined from the identified frequency and the impact factor response spectrum. The load carrying performance variation of the bridge was estimated considering the performance reduction factor, which was calculated using the current and previous natural frequency and impact factor. From the result, the load carrying capacity of the bridge was decreased, but the capacity was still enough because its value is greater than the design live load. Through the overall procedures and technical details presented in this paper, the suggested evaluation method can be applied to actual bridges with the acceleration data measured under ambient traffic conditions and the impact factor response spectrum.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.4
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• pp.82-90
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• 2008

The generation amounts of manure and urine were total 4.57kg/head/d of 1.49kg manure/head/d and 3.08kg urine/head/d with consideration of 3 seasons and live weight. The finalized mean unit load generation of filth were estimated at BOD 199.5g/head/d, CODCr 413.5g/head/d, T-N 27.8g/head/d, T-P 5.3g/head/d with consideration of seasons and the type of stalls. The unit load generation of manure and urine from korean cow were analyzed as 10.9kg/head/day and 3.3kg/head/day, respectively. The unit load generation of manure from milch cow was analyzed to be 24.6L/head/day which was similar to the report of MOE(2006). The urine generation, 10.5L/head/day, was higher than the results from MOA(2000) and NIAR(2000), but was lower than the results from MOE(2006), NIER(1986) and KIST(1990). The unit load generation from egg layers estimated by discharged amount and concentration analysis increases in due to the difference of planting head numbers, feed stuffs and manure disposal. In case of deer unit load generation by herbivora were calculated to be higher than data from existing references because of the gap between weight per livestock and the generation amounts of manure and urine.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.2
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• pp.171-183
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• 2020

The purpose of this study is to analyze in advance the problems and improvements that may occur during the construction of intermediate slabs and the loading of intermediate slabs through the preliminary structural safety evaluation of intermediate slabs for Test bed structures in deep depth tunnels. The Test bed construction can verify and confirm the results of the design and construction technology development of large depth double deck tunnel through the process, and can also be used as a learning site for engineers and the general public to speed up the time of underground space development. There will be an opportunity to do this. In particular, the design load of middle slab built inside the circular deep-depth double-sided tunnel cross-section varies depending on the construction method and the construction equipment load used. Class 3 truck load of KL-510 assumed to be common load to upper and middle slab during loading and installation is loaded on upper and lower slab with different working position for each load combination Analyzed.

• Journal of the Korea Concrete Institute
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• v.16 no.6 s.84
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• pp.733-740
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• 2004

This study presents the behaviors of the typical architectural precast prestressed concrete beams, inverted tee and rectangular beams, subjected to combined flexural and torsional loads. For this purpose, two inverted-tee beams were designed with a parking live load, $5 kN/m^2$, and a market load $12 kN/m^2$ according to the currently used typical shape in the domestic building site. Also, two rectangular beams were also designed as the same bottom dimension and area, and reinforced for similar strength as in the cases of inverted tee beams. Total of four beams were tested, under combined bending and torsion, analysed and compared. Test results showed that the cracking and ultimate flexural strength of the beams decreased under torsional loading. However, two different shaped-beams had roughly the same load resisting capacity in service and ultimate states.