• Title/Summary/Keyword: Reinforced earth

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Behavior Analysis of Approach Slabs of IPM Bridges according to Unsupported Length and Settlement (토압분리형 교량 접속슬래브의 비지지길이와 지반 침하에 따른 거동 해석)

  • Park, Min-Cheol
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.5
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    • pp.650-660
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    • 2018
  • The approach slab plays an important role in the driving comfort of the connection section on a bridge. On the other hand, the approach slab only calculates the section force of a simple beam, and does not analyze the behavior. In this study, the unsupported length and settlement of approach slabs of IPM Bridges were examined using structural analysis. First, the section force was calculated by designing a simple beam, according to the length of the approach slab. The structural analysis was conducted to examine the behavior of the unsupported length and settlement. As the result, the bending moment decreased when the unsupported length was increased, and the bending moment increased when the settlement was increased. In addition, the design section force was estimated to be larger than the force of structural analysis, and the design of the approach slab according to the design guideline showed no problem in stability. Nevertheless, the vertical displacement exceeded the maintenance criterion of a 1/200 curve when the settlement exceeded 10 mm regardless of the unsupported length. Therefore, excessive settlement occurs in the reinforced earth retaining wall supporting the approach slab, and the design bending moment may be exceeded. Therefore, strict management is required.

A Study on Applicability and External / Internal Stability of true MSEW abutment with slab (순수형 보강토교대의 슬래브교에 대한 적용성 및 외적/내적 안정성 검토)

  • Park, Min-Cheol
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.5
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    • pp.263-274
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    • 2018
  • In this study, the applicability and external/internal stability of a MSEW abutment with a slab were investigated. Structural analysis of slab bridges between 10 ~ 20.0 m and thicknesses of 0.7 ~ 0.9 m was carried out to calculate the reaction forces due to dead and live loads acting on the bridge supports. The slab bridge with a length of 20.0 m satisfied the allowable contact pressure of 200 kPa for the true MSEW abutment. Because the external stability of the true MSEW abutment was dominated by the geometry of the MSE wall, the change in the factor of safety due to the load of the super-structure is small. Because the stiffness of the foundations is fixed and the load of the super-structure is increased, the factor of safety of the bearing capacity was reduced. As the load of the super-structure was increased, the horizontal earth pressure of the true MSEW abutment increased greatly. As a result, the pullout and fracture of the uppermost reinforcement, which are the factors of safety, did not meet the design criteria. Therefore, it is necessary to increase the pullout resistance and the long-term allowable tensile force of the reinforcement placed on the top of the reinforced soils to ensure efficient design and performance of a true MSEW abutment.

A Study on the Development of an Evaluation System of CO2 Emission in the Production of Concrete (콘크리트 생산에 의한 CO2 배출량 평가 시스템 개발에 관한 연구)

  • Kim, Tae-Hyoung;Tae, Sung-Ho
    • Journal of the Korea Concrete Institute
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    • v.22 no.6
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    • pp.787-796
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    • 2010
  • The main reason of the earth global warming is $CO_2$ and the regulation about it in the whole world has been reinforced to reduce $CO_2$ emission. It is needed that we should reduce it in the process at the production of concrete generated much of $CO_2$ emission as the primary material of construction industry recognized unfriendly environment industry. Based on a concrete, this study was constructed the system to evaluate $CO_2$ emission generated in the stage of material production, transportation, manufacture and developed the program to reduce and evaluate it efficiently. As a result, most of $CO_2$ emission is generated in the stage of material and it is quantitatively evaluated $CO_2$ emission generated in the stage of materials, transportation and manufacture. Moreover, the evaluation system of the volume of $CO_2$ emission which has the friendly environment technology about reduction of $CO_2$ emission at each stage is suggested for quantitatively evaluation $CO_2$ emission generated in the process at the production of concrete and remicon production company could use it to evaluation $CO_2$ emission.

Performance Evaluation of Underground Pipe with In-Situ Recycled Controlled Low Strength Materials (현장발생토사 재활용 유동성채움재를 이용한 지하매설관의 거동평가)

  • Lee Kwan-Ho;Song Chang-Seob
    • International Journal of Highway Engineering
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    • v.8 no.2 s.28
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    • pp.1-12
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    • 2006
  • An existing Steel pipe, Cast iron pipe and Concrete pipe is can not escaped from aging, specially Metal tube is causing many problems that the quality of water worse is concerned about many rust and mike efficient use of preservation of water. The use of Glassfiber Reinforced Plastic Pipe(GRP PIPE) should be one of the possible scheme to get over these problems. The GRP PIPE has an excellent resistance power and the life is lasting from 50 to 100 years roughly. It's to be useful as a result of high durability and a good construction work also it is a light weight therefore can be expected to short the time of construction and man power. In this research, to executed the small-scaled model test, in-situ model test using CLSM of in-situ soil and to evaluated the stress - strain of the pipe also try to estimated how useful is. From the model test in laboratory, the vertical and horizontal deformation of the GRP PIPE measured in six instance using 200mm and 300mm in diameters. The value of experimentation, theory, analysis got the same results of the test, but the vertical and horizontal deformation gauged in small and the earth pressure was almost zero using CLSM of in-situ soil..

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Study on the Conservation of Scale Armor Using Duplication Technique - Focused on the Case of the Conservation Treatment of the Excavated Artifact from Jinyoung 2-Area, Gimhae - (복제 기법을 이용한 찰갑의 보존처리 - 김해 진영 2지구 출토품의 보존처리 사례를 중심으로 -)

  • Kim, Dong Min;Park, Jung Hyeok;Cho, Hyun Kyung;Cho, Nam Chul
    • Journal of Conservation Science
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    • v.31 no.1
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    • pp.75-86
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    • 2015
  • A scale Armor is usually excavated in a scattered form weakened by corrosion after its burial. Therefore, they should be brought into the indoor in a safe environment for the on-site conservation treatment as it was excavated. They should be placed on a stable support with a reinforced base in the indoor treatment. In this process, the bottom surface which can not be observed after the conservation treatment is placed for a record by actual survey and photography. But this method had a limit on figuring out the whole aspects of the artifact. For compensating the defect, duplication of the artifact was considered as an alternative method for the previous two methods in the case of conservation of the scale Armor from Jinyoung 2-Area, Gimhae. Neck guard was excavated in a distorted form by the earth pressure, and was hard to recognize the original shape. However, whole real material of its original form was secured through the combination of each duplicated lamellae. Throughout the application of the duplication technique in the process of conservation of scale Armor and neck guard, it could secure the real material of the bottom surface and elevate the understanding of the artifact. Moreover, a constitution of the armor could be identified more effectively.

Target Reliability Index of Single Gravel Compaction Piles for Limit State Design (한계상태설계를 위한 단일 쇄석다짐말뚝의 목표신뢰도지수)

  • You, Youngkwon;Lim, Heuidae;Park, Joonmo
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.2
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    • pp.5-15
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    • 2014
  • Target reliability index in the limit state design indicated the safety margin and it is important to determine the partial factor. To determine the target reliability index which is needed in the limit state design, the six design and construction case histories of gravel compaction piles (GCP) were investigated. The limit state functions were defined by bulging failure for the major failure mode of GCP. The reliability analysis were performed using the first order reliability method (FORM) and the reliability index was calculated for each ultimate bearing capacity formulation. The reliability index of GCP tended to be penportional to the safety factor of allowable stress design and average value was ${\beta}$=2.30. Reliability level that was assessed by reliability analysis and target reliability index for existing structure foundations were compared and analyzed. As a result, The GCP was required a relatively low level of safety compared with deep and shallow foundations and the currd t reliability level were similar to the target reliability in the reinforced earth retaining-wall and soil-nailing. Therefore the target reliability index of GCP suggested as ${\beta}_T$=2.33 by various literatures together with the computed reliability level in this study.

Searching for a Curriculum to Reconceptualize Sexuality for Youth Sex Education : Nth Room Era, New Talk of 'Body' and 'Sex' from a Feminist Theological Point of View (청소년 성교육을 위한 성성(性性)의 재개념화 커리큘럼 모색 : N번방 시대, 여성신학적 관점에서 '몸'과 '성'을 새롭게 이야기하다)

  • Lee, Jooah
    • Journal of Christian Education in Korea
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    • v.67
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    • pp.301-337
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    • 2021
  • The researcher looked at the differences in views and various controversies surrounding Korean youth sexuality education in the wake of the Nth Room incident, which had a great impact on modern Korean society. Sex education for adolescents in Korea can be divided into public sex education through school sex education and the Youth Sexuality Center, and conservative/traditional Protestant sex education. Public sex education is partly influenced by feminist sexual ethics and comprehensive sex education abroad. Based on gender sensitivity and the right to sexual self-determination, four major projects are prevention of sexual harassment, prostitution, sexual violence, and domestic violence. However, the school sex education standard was criticized for stereotypes of gender roles and gender-discriminatory content, reinforced distorted myths about sexual violence, and exclusion of sexual diversity and various family types. Conservative/traditional Protestantism is based on the normal family ideology such as bisexual marriage, premarital chastity, and sexual ethics recognized only within marital relationships. It is a form of confrontation with public sex education while strongly opposing it. The researcher first analyzed the characteristics of public sex education, conservative/traditional Protestant sexual ethics and sex education, feminist sex ethics and sex education, and overseas youth sex education, respectively, while composing the curriculum for Korean youth sexuality education. And as a more fundamental solution to youth sexuality education, I pointed out that there are limits to asceticism, premarital chastity, gender sensitivity and sexual self-determination education, and found an alternative to the concept of body and sex in feminist theology. The researcher pointed out that it is necessary to reconceptualize the body and sex under the recognition that the most fundamental cause of distorted sexual culture is dualistic sex and understanding the body, centering on the research of various feminist theologians. And this was conceptualized into three concepts: holistic sexuality, mutual solidarity understood in relationships with others, and sexuality as a spirituality that extends to the global community. And with each curriculum, 1) Holistic Sexuality: Breathing, Narrative, Making the Shape of One's Body and Mind 2) mutual solidarity : Feeling the Breath of Others, Media Literacy through Conscientization, Sending a Good Wind 3) Sexuality as a spirituality that extends to global concern: It was proposed to pay attention to nature and to co-cultivate it, to listen to the earth's moans and create a new way of life, and to write a prayer with the earth and fellow living beings.

Reliability Based Stability Analysis and Design Criteria for Reinforced Concrete Retaining Wall (신뢰성(信賴性) 이론(理論)에 의한 R.C.옹벽(擁壁)의 안정해석(安定解析) 및 설계규준(設計規準))

  • Cho, Tae Song;Cho, Hyo Nam;Chun, Chai Myung
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.3 no.3
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    • pp.71-86
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    • 1983
  • Current R.C. retaining wall design is bared on WSD, but the reliability based design method is more rational than the WSD. For this reason, this study proposes a reliability based design criteria for the cantilever retaining wall, which is most common type of retaining wall, and also proposes the theoretical bases of nominal safety factors of stability analysis by introducing the reliability theory. The limit state equations of stability analysis and design of each part of cantilever retaining wall are derived and the uncertainty measuring algorithms of each equation are also derived by MFOSM using Coulomb's coefficient of the active earth pressure and Hansen's bearing capacity formula. The levels of uncertainties corresponding to these algorithms are proposed appropriate values considering our actuality. The target reliability indices (overturning: ${\beta}_0$=4.0, sliding: ${\beta}_0$=3.5, bearing capacity: [${\beta}_0$=3.0, design for flexure: [${\beta}_0$=3.0, design for shear: ${\beta}_0$=3.2) are selected as optimal values considering our practice based on the calibration with the current R.C. retaining wall design safety provisions. Load and resistance factors are measured by using the proposed uncertainties and the selected target reliability indices. Furthermore, a set of nominal safety factors, allowable stresses, and allowable shear stresses are proposed for the current WSD design provisions. It may be asserted that the proposed LRFD reliability based design criteria for the R.C. retaining wall may have to be incorporated into the current R.C. design codes as a design provision corresponding to the USD provisions of the current R.C. design code.

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A Study on Religious Thought Regarding Hospitality for the Phenomenon of Transnational Migration: Focusing on the Concept of 'Conscience' in Daesoon Thought (초국적 이주 현상에 대한 환대의 종교사상 고찰 -대순사상의 '양심'을 중심으로-)

  • Seog Chang-hoon
    • Journal of the Daesoon Academy of Sciences
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    • v.43
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    • pp.1-29
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    • 2022
  • In this era of transnational migration, it is necessary to recognize the signs of the times regarding religion. During the globalization of Korean society, migration cannot be avoided, and as such, Korea should look towards hospitality with practical themes of religion and religious people aiming for peace. Therefore, this study examines the concept of 'conscience' in Daesoon Thought because this understanding of the conscience connects people to their heavenly endowed nature and their original selves. First, in order to explore the religious ideas of hospitality for transnational migration, this study viewed the issue through three analytical frames: exclusive perception, tolerant perception, and pluralistic perception, and then criticized these from the perspective of hospitality. Furthermore, hospitality was viewed as an attitude of attempting to expand one's sense of self in dealing with others. Religiously, it was derived that the expansion of one's sense of self should aim for relationships of Sangsaeng (相生 mutual beneficence) as these go beyond mere symbiosis. In addition, as a way to overcome otherness, the religious idea of unconditional hospitality towards migrants was explored focusing on the concept of conscience in Daesoon Thought. In Daesoon Thought, the mind is the source of Heaven and Earth and also the essence of human existence. There are two aspects of mind that arise in humans: conscience and private interest. In Daesoon Thought, the conscience enables human potential and aims for a return to the source. In other words, it is to abandon private-interest and regain one's nature and the essence of one's personality. This can be done through Mujagi (無自欺 Guarding against Self-deception); embodying and maintaining a mind that does not deceive itself. In Daesoon Thought, the practice of Sangsaeng ethics based on Mujagi is expressed as Haewon Sangsaeng (解冤相生 the Resolution of Grievances for Mutual Beneficence) and working for the betterment of others. Therefore, when the relational and communal perspectives of Daesoon Truth and Sangsaeng are reinforced, the argument for developing the practical ethics of Haewon Sangsaeng based on Mujagi into the transformation of the human spirit expressed as unconditional hospitality was found to be sound.