• Title/Summary/Keyword: test road

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A study on the design of tunnel lining insulation based on measurement of temperature in tunnel (터널 온도계측을 통한 라이닝 단열 설계에 관한 연구)

  • Kim, Dea-Young;Lee, Hong-Sung;Sim, Bo-Kyoung
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.13 no.4
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    • pp.319-345
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    • 2011
  • In case of tunnels in cold regions, a freeze of groundwater around tunnel may act as a barrier of tunnel drainage in winter, or may cause the inner extrusion of lining. In spite of that, a design of insulation for preventing the frost damage of tunnel lining has not been introduced in Korea, while foreign countries such as Norway and so on have a standard on insulation. In this study, a few freezing cases of road tunnels have been reviewed, and the results show that the freezing protection is necessary. In order to characterize the thermal distribution in the tunnel, following measurements have been performed at Hwa-ak tunnel; the temperature distribution by longitudinal lengths, the internal temperature of lining and the temperature distribution of the ground under pavement. From these measurements, the characteristics of the tunnel's internal temperature distribution due to temperature change in the air has been analyzed. Based on the measurement results on the temperature distribution at Hwa-ak tunnel, thermal flow tests on the rock specimen with and without insulation have been performed in the artificial climate chamber to investigate the performance of the insulation. Also, a number of 3D numerical analyses have been performed to propose appropriate insulation and insulation thicknesses for different conditions, which could prevent the frost damage of tunnel lining. As a result of the numerical analysis, air freezing index of 291$^{\circ}C{\cdot}$ Hr has been suggested as the threshold value for freezing criteria of groundwater behind the tunnel lining.

International Research Status on Spent Nuclear Fuel Structural Integrity Tests Considering Vibration and Shock Loads Under Normal Conditions of Transport (정상운반조건의 진동 및 충격하중을 고려한 사용후핵연료의 구조적 건전성 시험평가 해외연구현황)

  • Lim, JaeHoon;Cho, Sang Soon;Choi, Woo-seok
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.17 no.2
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    • pp.167-181
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    • 2019
  • Currently, the development of evaluation technology for vibration and shock load characteristics and spent nuclear fuel structural integrity under normal conditions of transport is being conducted in the Republic of Korea. This is the first such research conducted in the Republic of Korea and, thus, previous international studies need to be investigated and will be referred to in the ongoing project. Before 2000, several studies related to measurement of vibration and shock loads on spent nuclear fuel were conducted in the US. US national research institutes conducted uniaxial fuel assembly shaker tests, concrete block tests, and multi-axis fuel assembly tests between 2009 and 2016. In 2017, multi-modal transportation tests including road, sea, and rail transport were also performed by research institutes from the US, Spain and the Republic of Korea. Therefore, test preparation procedures, acceleration and strain measurement results, and finite-element and multi-body dynamics analysis were investigated. Based on the measured strain data, the preliminary conclusion was obtained that the measured strain was too small to cause damage to spent nuclear fuel rods. However, this conclusion is a preliminary conclusion that only reviews part of the results; a detailed review is being conducted in the US. The investigation of international studies on spent nuclear fuel structural integrity tests considering vibration and shock loads under normal conditions of transport in the US will be useful data for the project being conducted in the Republic of Korea.

Material Characteristics, Provenance Interpretation and Deterioration Diagnosis of Shilla Stone Monuments in Jungseongri and Naengsuri, Pohang (포항 중성리신라비와 영일 냉수리신라비의 재질특성과 산지해석 및 훼손도 진단)

  • Lee, Myeong Seong;Han, Min Su;Kim, Jae Hwan;Kim, Sa Dug
    • Korean Journal of Heritage: History & Science
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    • v.43 no.3
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    • pp.122-143
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    • 2010
  • The Shilla Stone Monument in Jungseongri was found during the road-construction in Pohang. It has approximately two hundreds of letters inscribed on the surface of one side, and it is estimated to be older than Shilla Stone Monument in Naengsuri which had been known for the oldest stele in Shilla Period. This monument is made of fine to medium-grained biotite granite, while the Shilla Stone Monument in Naengsuri is made of fine-grained granodioritic porphyry bearing feldspar and amphibole phenocrysts. Both rock types of the monuments are interpreted to be cognate with biotite granite in Shinkwangmyeon, and with granodioritic porphyry in Gigyemyeon. They are characterized by xenolith and miarolitic cavity. Damage aspects in both monuments are discoloring, cracking and breaking. These damages do not cause structural instability of the monuments, but attenuate aesthetic value. Black and brown discoloring contaminants on the surface of the Jungseongri Monument contain a high amount of manganese and iron. As a result of ultrasonic test, both monuments were evaluated to be medium-weathered (MW), although the velocity of the Shilla Monument in Jungseongri was slightly lower than the Shilla Monument in Naengsuri. This is because the Monument in Juengseongri had been exposed to outdoor environment for long time until the discovery. It is necessary for Shilla Monuments to be protected by appropriately environmental control and management.

Security Credential Management & Pilot Policy of U.S. Government in Intelligent Transport Environment (지능형 교통 환경에서 미국정부의 보안인증관리 & Pilot 정책)

  • Hong, Jin-Keun
    • Journal of Convergence for Information Technology
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    • v.9 no.9
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    • pp.13-19
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    • 2019
  • This paper analyzed the SCMS and pilot policy, which is pursued by the U.S. government in connected vehicles. SCMS ensures authentication, integrity, privacy and interoperability. The SCMS Support Committee of U.S. government has established the National Unit SCMS and is responsible for system-wide control. Of course, it introduces security policy, procedures and training programs making. In this paper, the need for SCMS to be applied to C-ITS was discussed. The structure of the SCMS was analyzed and the U.S. government's filot policy for connected vehicles was discussed. The discussion of the need for SCMS highlighted the importance of the role and responsibilities of SCMS between vehicles and vehicles. The security certificate management system looked at the structure and analyzed the type of certificate used in the vehicle or road side unit (RSU). The functions and characteristics of the certificates were reviewed. In addition, the functions of basic safety messages were analyzed with consideration of the detection and warning functions of abnormal behavior in SCMS. Finally, the status of the pilot project for connected vehicles currently being pursued by the U.S. government was analyzed. In addition to the environment used for the test, the relevant messages were also discussed. We also looked at some of the issues that arise in the course of the pilot project.

A Study for Improved Design Criteria of Composite Pile Joint Location based on Case Analysis (사례 분석을 통한 복합말뚝 이음위치의 설계 기준식 개선 연구)

  • Hwang, Uiseong
    • Journal of the Korean GEO-environmental Society
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    • v.20 no.3
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    • pp.21-30
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    • 2019
  • Composite pile, which is composed of the steel pipe pile in which the large horizontal force acts and the PHC pile in which the small horizontal force acts by a special connecting devices, is being commercialized as a base material for civil engineering structures. The core of such a composite pile can be said to be a design criterion for estimating the joint position and stability of the connection device between steel pipe pile and PHC pile. In Korea, there is no precise specification for the location of composite pile joints. In the LH Design Department (Korea Land & Housing Corporation, 2009), "Application of composite pile design and review of design book marking" was made with reference to Road Design Practice Volume 3 (Korea Expressway Corporation, 2001). this is used as a basis of the design of the composite pile. It can not be regarded as a section change of the composite pile, so it has a limitation in application. Therefore, In this study, we propose a design criterion for the location of the section of the composite pile (joint of steel pipe pile and PHC pile) and evaluate the stability and economical efficiency of it by using experimental method and analytical method. Analysis of composite pile design data installed in 79 domestic bridges abutment showed that the stresses, bending moments, and displacements acting on the pile body and connection of the pile were analyzed. Through the redesign process, it was confirmed that the stresses generated in the connecting device occur within the allowable stress values of the connecting device and the PHC pile. In conclusion, the design proposal of composite pile joint location through empirical case study in this study is an improved design method considering both stability and economical efficiency in designing composite pile.

Numerical Simulation on Control of Tsunami by Resonator (I) (for Imwon and Mukho ports) (공진장치에 의한 지진해일파의 제어에 관한 수치시뮬레이션(I) (임원항과 묵호항에 대해))

  • Lee, Kwang-Ho;Jeon, Jong-Hyeok;Kim, Do-Sam;Lee, Yun-Du
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.32 no.6
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    • pp.481-495
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    • 2020
  • After the resonator on the basis of the wave-filter theory was designed to control the waves with a specific frequency range surging into the harbor, the several case with the use of resonator have been reported in some part of sea, including the port of Long Beach, USA, and yacht harbor at Rome, Italy in order to control the long-period wave motion from the vessels. Recently, the utility and applicability of the resonator has been sufficiently verified in respect of the control of tsunami approximated as the solitary wave and/or the super long-period waves. However, the case with the application of tsunami in the real sea have not been reported yet. In this research, the respective case with the use of existing resonator at the port of Mukho and Imwon located in the eastern coast of South Korea were studied by using the numerical analysis through the COMCOT model adapting the reduction rate of 1983 Central East Sea tsunami and 1993 Hokkaido Southwest off tsunami. Consequently, the effectiveness of resonator against tsunami in the real sea was confirmed through the reduction rate of maximum 40~50% at the port of Mukho, and maximum 21% at the port of Imwom, respectively. In addition, it was concluded that it is necessary to study about the various case with application of different shape, arrangement, and size of resonator in order to design the optimal resonator considering the site condition.

Numerical Simulation on Control of Tsunami by Resonator (II) (for Samcheok port) (공진장치에 의한 지진해일파의 제어에 관한 수치시뮬레이션(II) (삼척항에 대해))

  • Lee, Kwang-Ho;Jeon, Jong-Hyeok;Kim, Do-Sam;Lee, Yun-Du
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.32 no.6
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    • pp.496-505
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    • 2020
  • In the previous research, the effectiveness of resonator was confirmed through the numerical analysis on two cases with the use of existing resonator at the Mukho and Imwon ports located in the eastern coast of South Korea by discussing the reduction rates of 1983 Central East Sea tsunami, and 1993 Hokkaido Southwest off tsunami, respectively. In this study, the reduction rates of tsunami height with three different resonators, Type I, II-1, and II-2, at the Samcheok port were examined respectively through the numerical analysis using COMCOT model under the same condition as the previous study. It was discussed the spatial distribution of maximum height of tsunami, change of water level, and effectiveness of resonator with the presence of new types of resonator, and change of their sizes. As a result, the effectiveness of resonator was verified through the application of new types of resonator reducing about maximum 40% of tsunami height. In order to design the optimal resonator for the variety of site condition, it is necessary to research about the various cases applying different shape, arrangement, and size of resonator as further study.

The Mechanical Properties of SMA Concrete Mixture Using Steel Slag Aggregate (제철 슬래그 골재를 이용한 SMA 혼합물의 역학적 특성)

  • Kim, Hyeok-Jung;Na, Il-Ho
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.9 no.1
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    • pp.109-116
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    • 2021
  • In order to replace mineral aggregate used as road pavement materials with steel slag aggregate, this present study evaluated mechanical properties of SMA Concrete mixtures using steel slag aggregate as oxidized slag from electric furnace in iron works. The variables of this experiment are the aggregate type of mineral and steel slag and the sieve sized of 10mm and 13mm. The physical properties inclu ding the specific gravity and absorption rate etc. of the slag aggregate mixtu res satisfied the KS standard as asphalt mixtu re. As a resu lt of evalu ating the mechanical properties of the asphalt mixtures, the optimum asphalt content of the slag aggregate mixtures were lower than that of the mineral aggregate mixtures, but other quality standards were all satisfied. In the deformation strength evaluation, the slag aggregate mixtures were measu red slightly higher than that of the mineral aggregate mixtu res, and the dynamic stability test satisfied the 2,000pass/mm standard value in all specimens. And, the moduli of resilient of the slag aggregate mixtures showed an improved value compared with the mineral aggregate mixtures. Therefore, as the resilient rate of the slag aggregate mixtures improved, it is speculated that there will be an effect of improving public performance according to the repeated traffic load of the vehicle.

Two Types of Post-human in Recent Korean SF Films : Focusing on (2021), (2021) (최근 한국영화 속 포스트-휴먼의 두 가지 양상: <승리호>(2021), <서복>(2021)을 중심으로)

  • Yoo, Jae-eung;Lee, Hyun-Kyung
    • The Journal of the Convergence on Culture Technology
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    • v.8 no.1
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    • pp.379-384
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    • 2022
  • The year 2021 is a monumental year for the history of Korean cinema that inferiority of the sci-fi genre, by the appearance of two sci-fi blockbuster films- produced by Netflix and produced by TVing-at the same time. Coincidentally, both of movies are sci-fi films which appear post-human such as robot and clone. As can be seen in 『Frankenstein』 story, the progenitor of science fictions, the mankind have imagined beings similar to humen or post-human who are another human being for a long time. deals with the unusual subject matter of a space scavenger and a space janitor, and the main character is a robot that very familiar with human. is the story of a man who lives for a limited life protects and accompanies a clone named Seobok who was created as a test subject. This film deals with the philosophical themes like death and eternal life through the existential concerns of two characters. use Korean Shinpa -Korean specific senimental code-sentiment on narrative, and has the character of a road movie set in Korea's geographical space.

Basic Performance Evaluation of a Tack Coat Material for Use with a Spray Paver (동시포설 공법을 위한 택코트 재료의 기초 성능 평가 연구)

  • Jo, Shinheang;Kim, Kyungnam;Cui, Wenhui;Kim, Nakseok
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.41 no.6
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    • pp.737-744
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    • 2021
  • Spray paving minimizes material lost during the construction or repair of a road surface, and it can be done in conjunction with tack coating. This approach involves applying the asphalt mixture at the same time as spraying the tack coat by attaching a spraying device to the asphalt paver. When applying an asphalt overlay to an aged concrete surface, it is important to ensure the adhesion performance between different material properties. Accordingly, there is a need for a tack coat that can be applied by spray paving and that exhibits good adhesive performance on different materials. In this study, bonding strength tests under various conditions were performed to evaluate the basic performance of a tack coat developed for use with a spray paver. The bonding performance of the tack coat was observed to be affected by curing conditions and material lost during construction. The test results also showed that the tensile and shear bonding strengths of the developed tack coat were 1.21 and 1.99 times higher than those of a conventional one, respectively. As a result, the developed tack coat is considered suitable for application to spray paving.