• Title/Summary/Keyword: Strength of Concrete

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Reliability Analysis of Open Cell Caisson Breakwater Against Circular Slip Failure (무공케이슨 방파제의 원호활동에 대한 신뢰성 분석)

  • Kim, Sunghwan;Huh, Jungwon;Kim, Dongwook
    • Journal of the Korean Geosynthetics Society
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    • v.18 no.4
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    • pp.193-204
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    • 2019
  • Reliability analyses of sixteen domestic design cases of open cell caisson breakwaters against circular sliding failure were conducted in this study. For the reliability analyses, uncertainties of parameters of soils, mound, and concrete cap were assessed. Bishop simplified method was used to obtain load and resistance of open cell caisson breakwater for randomly generated open cell caisson breakwater. Sufficient number of Monte Carlo simulations were conducted for randomly generated open cell caisson breakwaters, and statistical analysis was conducted on loads and resistances collected from the large number of Monte Carlo simulations. Probability of failure produced from Monte Carlo simulation has a nonconvergence issue for very low probability of failure; therefore, First-Order Reliability Method (FORM) was conducted using the statistical characteristics of loads and resistances of open cell caisson breakwaters. In addition, effects of safety factor, uncertainties of load and resistance, and correlation between load and resistance on reliability of open cell caisson breakwaters against circular sliding failure were examined.

The Meridian Interpretation of Atopic Dermatitis Phases (아토피 피부염의 발생시긱별 변화에 대한 경락학적 해석)

  • Cho Yong-ju;Kim Jin-ju
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.17 no.1
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    • pp.1-15
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    • 2004
  • The different growth steps of human show the different energetic phenomenon such as the strength of triple energizer, the sale of extra meridian, and the stability of 12 meridians. So we have to understand the physiological and pathological phenomena on this point of view. Especially atopic dermatitis means the loss of adaptability under the lack of genuine energy. If you approach to this disease not with any perception of excess or deficiency of the human genuine energy but with simple symptom enumeration or partial diagnosis, it will be dangerous. So we must approach to this disease with more concrete and objective body-centered standard. Thus when we cure and diagnose infants with this disease, we should focus on stablizing the "Energy of Earth(土)" digestive ability, under the consideration of inducement to the enough "Byun-Jeung-Hu(變蒸候)" and the function of Triple Energizer. Through this process we can lead infants to the beginning equipment state(始全). Until 7 years old, we should stabilize the Link Vessel(維脈) by clarifying interior and exterior classification of Nutritive Element and Defensive Energy to control the child's energy of metal(金), water(水), wood(木) and fire(火) in the basis of the energy of earth(土). And also we should stabilize the Heel Vessel(?脈) through the Water and Fire complement each other to control the movements and to control sleep and awakening. Through this process, we can lead children to the basal equipment state(本全). After then, until adolescent phase, we should control 12 meridian and 8 extra meridian by leading vital function to be harmonized and prosperous on the basis of the meridian to reach the mature equipment state(旣全). Adult atopic dermatitis should be controlled through conciliation between meridian and internal organs by differentiating male from female.

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Psychology of Young Adulthood (청년기심리 (靑年期心理))

  • Cho, Doo-Young
    • Korean Journal of Psychosomatic Medicine
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    • v.5 no.2
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    • pp.223-236
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    • 1997
  • One faces four major developmental tasks to achieve in young adulthood, ages between 20 and 40 : intimacy, vocation, marriage and child-rearing. Intimacy is the capacity to commit oneself to concrete affiliations and partnerships and to develop the ethical strength to abide by such commitments, even though they call for significant sacrifices and compromises. Through vocation and marriage young adults become united to networks of persons, find tasks that demand involvement, and gain roles into which they fit and are fitted and which help define their identities. An occupation represents much more than a set of skills and functions : it means a way of life. The extent of vocational choice increases with educational level, and the unconscious factors are frequency the decisive element. The vocational choice stare with fantasy choices in childhood, passes through tentative choices in adolescence, realistic choices in college days, and crystallized choices in post-college days, and finally ends up to the choice of specification. Along with the hazards and the need for realignment of personality functioning, the marriage brings with it new opportunities for self-fulfillment and completion. Motives other than a romantic love gain more importance in the decision to marry and in the choice of a partner. The impulsions to marry are sexual gratification, the desire to propagate, narcissistic gratification, and a need of interdependence. Many factors such as oedipal wishes, sexuality and sexual attractions, socio-economic classes, and geography involve in selection of marriage partner. There are also various motivations to marry a romantic love, the desire for a home of one's own, sexual attractions, the wish for security and a shelter, and the wish for children. The hostile marriage, the marriage on the rebound, the marriage rooted in rescue fantasies, and sado-masochistic marriage are the examples of pathological marriages. A successful marriage will usually both Lead to and require a marked reorganization of the personality structure of each partner that will influence the lurker personality development of each. Many marital problems are largely dependent upon the personality characteristics of one partner which might well create difficulties no manor who was the spouse.

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Analysis of Application Cases and Evaluation of Effectiveness on Portable Dynamic Cone Penetration Test (DCPT) to Identify the Deterioration Cause of Damaged Reinforced Earth Walls (보강토옹벽의 피해원인 규명을 위한 휴대형 동적콘관입시험(DCPT) 적용사례 분석 및 효용성 평가)

  • Lee, Kwang-Wu;Cho, Sam-Deok
    • Journal of the Korean Geosynthetics Society
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    • v.19 no.4
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    • pp.95-109
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    • 2020
  • In this study, a total of six site cases were reviewed to assess the site applicability of portable dynamic cone penetration test (DCPT) by identifying the cause of damage to the damaged reinforced earth wall using portable dynamic cone penetration test. An improved dynamic concrete penetration tester was used at the site to enable ground surveys of more than 6 meters. The test results were compared with the results of the standard penetration test (SPT) and the correlation was analyzed. Through the analysis of various field application cases, it was found that portable dynamic cone penetration test was very convenient to apply at the site of the damaged reinforced earth wall, and DCPT could play a major role in identifying the cause of damage and verifying stability of the retaining wall by continuously identifying the ground strength. In addition, it was found that the results of the dynamic cone penetration test and the standard penetration test showed a correlation of N≒(1/3~2/3)·Nd in sandy soil.

Increasing the attractiveness of physical education training with the involvement of nanotechnology

  • Jinyan Ge;Yuxin Hong;Rongtian Zeng;Yunbin Li;Mostafa Habibi
    • Advances in concrete construction
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    • v.16 no.6
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    • pp.291-302
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    • 2023
  • As the first part of the body that strikes the ground during running, sports shoes are especially important for improving performance and reducing injuries. The use of new nanotechnology materials in the shoe's sole that can affect the movement angle of the foot and the ground reaction forces during running has not been reported yet. It is important to consider the material of the sole of the shoe since it determines the long-term performance of sports shoes, including their comfort while walking, running, and jumping. Running performance can be improved by polymer foam that provides good support with low energy dissipation (low energy dissipation). Running shoes have a midsole made of ethylene propylene copolymer (EPP) foam. The mechanical properties of EPP foam are, however, low. To improve the mechanical performance of EPP, conventional mineral fillers are commonly used, but these fillers sacrifice energy return. In this study, to improve the magnificence of physical education training with nanotechnology, carbon nanotubes (CNTs) derived from recycled plastics were prepared by catalytic chemical vapor deposition and used as nucleating and reinforcing agents. As a result of the results, the physical, mechanical, and dynamic response properties of EPP foam combined with CNT and zinc oxide nanoparticles were significantly improved. When CNT was added to the nanocomposites with a weight percentage of less than 0.5 wt%, the wear resistance, physical properties, dynamic stiffness, compressive strength, and rebound properties of EPP foams were significantly improved.

Evaluation of Shear Capacity of Wide Beam Reinforced with Shear Plates with Openings (유공형 판으로 전단보강된 넓은 보의 전단거동 평가)

  • Ko, Myung Joon;Lee, Young Hak;Kim, Min Sook;Park, Jong Yil;Kim, Heecheul
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.28 no.6
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    • pp.667-674
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    • 2015
  • In this paper, shear behavior of concrete wide beam reinforced with plates with openings was evaluated. For this evaluation, evelen specimens were manufactured. One specimen was non-shear reinforced, five specimens were reinforced with steel plates and the other five specimens were reinforced GFRP plates. Shear strengths measured through experiments were compared with ones calculated from the equation provided by ACI 318. Longitudinal spacing of shear reinforcement, transverse spacing of shear reinforcement and shear reinforcement material were considered as variables. Test results showed that the shear strength increased as the transverse and longitudinal spacing of shear reinforcement became narrow. Also, regardless of material type of shear reinforcement, the shear capacity was similar when the amount of shear reinforcement was the same.

Joint Stability and lateral behavior of composite piles (복합말뚝 연결부 안정성 평가 및 수평거동특성 분석)

  • Shin, Yun-Sup;Park, Jae-Hyun;Hwang, Ui-Seong;Cho, Sung-Han;Chung, Moon-Kyung;Boo, Kyo-Tag
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09a
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    • pp.553-558
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    • 2010
  • The behavior of composite piles composed of steel pipe pile in the upper part and concrete pile in the lower part by a mechanical splicing joint was examined by field lateral load tests and bending tests. A total of 7 piles including two instrumented piles for bending test were installed. The soil profile consists of soft clay with weak silt with shallow groundwater level. Laboratory tests were carried out to determine the basic soil characteristics and the strength parameters. This paper presents the composite pile behavior with various portions of the upper steel pile: 0, 20, 30, and 45% of the pile embedded pile length. Three-point bending tests were performed to investigate the stress-strain relation at the mechanical joint. Based on these test results, the behavior of composite piles with various upper steel pile length are evaluated and the stability of mechanical joints are examined. Through comparisons with results of field load tests, it was found that lateral load carrying capacity of the composite piles increased and deflections of the composite piles decreased with increasing the upper steel piles. The mechanical joint was proved to retain its structural stability against the tested load conditions. Economical benefits of composite pile of this kind can be gained by setting adequately the length of the upper steel pipe piles.

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A Study on the Determination of Stress Intensity Factors in Orthotropic Plane Elastic Bodies (직교이방성 평면탄성체의 응력확대계수 결정에 관한 연구)

  • Jin, Chi Sub;Lee, Hong Ju
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.13 no.5
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    • pp.19-27
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    • 1993
  • Recent work in the mechanics of fracture points out the desirability of a knowledge of the elastic energy release rate, the crack extension force, and the character of the stress field surrounding a crack tip in analyzing the strength of cracked bodies. The objective of this work is to provide a discussion of the energy rates, stress fields and the like of various cases for anisotropic elastic bodies which might be of interest. Reinforced concrete, wood, laminates, and some special types of elastic bodies with controlled grain orientation are often orthotropic. In this paper, determination of the stress intensity factors(SIFs) of orthotropic plane elastic body using crack tip singular element and fine mesh in near the crack tip is performed. A numerical method in this paper was used by displacement correlation method. A numerical example problem of an orthotropic cantilevered single edge cracked elastic body subjected to shear loading was analyzed, and the results of this paper are in good agreement with those of the others.

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Validation of the seismic response of an RC frame building with masonry infill walls - The case of the 2017 Mexico earthquake

  • Albornoz, Tania C.;Massone, Leonardo M.;Carrillo, Julian;Hernandez, Francisco;Alberto, Yolanda
    • Advances in Computational Design
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    • v.7 no.3
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    • pp.229-251
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    • 2022
  • In 2017, an intraplate earthquake of Mw 7.1 occurred 120 km from Mexico City (CDMX). Most collapsed structural buildings stroked by the earthquake were flat slab systems joined to reinforced concrete (RC) columns, unreinforced masonry, confined masonry, and dual systems. This article presents the simulated response of an actual six-story RC frame building with masonry infill walls that did not collapse during the 2017 earthquake. It has a structural system similar to that of many of the collapsed buildings and is located in a high seismic amplification zone. Five 3D numerical models were used in the study to model the seismic response of the building. The building dynamic properties were identified using an ambient vibration test (AVT), enabling validation of the building's finite element models. Several assumptions were made to calibrate the numerical model to the properties identified from the AVT, such as the presence of adjacent buildings, variations in masonry properties, soil-foundation-structure interaction, and the contribution of non-structural elements. The results showed that the infill masonry wall would act as a compression strut and crack along the transverse direction because the shear stresses in the original model (0.85 MPa) exceeded the shear strength (0.38 MPa). In compression, the strut presents lower stresses (3.42 MPa) well below its capacity (6.8 MPa). Although the non-structural elements were not considered to be part of the lateral resistant system, the results showed that these elements could contribute by resisting part of the base shear force, reaching a force of 82 kN.

Effect of Water-Containing Conditions on Concrete Substrates on Defects of Polyurethane-based Waterproofing Materials (콘크리트 바탕면의 함수조건이 폴리 우레탄계 방수재 하자에 미치는 영향)

  • Lee, Gun-Cheol;Kim, Jae-Yeob;Kim, Young-Min;Hong, Sung-Rok;Kim, Young-Sam;Shin, Hong-Chol
    • Journal of the Korea Institute of Building Construction
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    • v.23 no.1
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    • pp.1-9
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    • 2023
  • This study is to analyze the cause of the defects in polyurethane waterproofing, a material commonly used on the roof of buildings, and to determine if it has a relation with the curing conditions of humidity and temperature and the moisture content of the base structure. As a result, it was confirmed that the waterproofing coating did not adhere when the moisture content of the base plate was 10% or more. When the temperature and humidity conditions were 20℃ and 80%RH, none of the properties deteriorate but when the temperature was 40℃, 60%RH, air bubbles were formed on the surface, and at 40℃ and 80%RH, the basic properties of the dry coating film were less than the KS F 3211 performance standard.