• 한국지반신소재학회논문집
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• 제5권4호
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• pp.35-42
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• 2006

최대 높이가 29.5m인 고성토 보강토옹벽에 대한 시공 및 계측이 수행되었다. 이와 같이 높은 보강토옹벽에 대한 설계 및 시공 경험이 그다지 많지 않기 때문에, 본 현장에서는 철저한 설계 및 시공관리가 이루어졌다. FHWA 설계기준에 근거하여 본 현장 보강토옹벽의 내적 및 외적안정을 검토하였고, Bishop의 간편법을 이용하여 전반활동에 대한 안정성 해석을 수행하였다. 또한 시공관리 및 안정성 검토를 위한 일련의 현장계측을 수행하였다. 본 논문에서는 높이가 20m 이상이고, 2단으로 시공된 대표단면 2개소에 대한 계측결과를 분석하였다. 계측결과, 벽체 및 보강재의 변형이 매우 작게 측정되었으며, 벽체작용 수평토압 또한 미소한 것으로 나타났다. 따라서 높이가 20m이상으로 매우 높은 옹벽구조물에 있어서, 보강토옹벽공법이 성공적으로 적용될 수 있음을 확인하였고, 또한 시공관리가 잘 이루어질 경우 이같이 높은 보강토옹벽에 대하여 FHWA 설계기준이 매우 보수적인 안전측 결과를 보임을 알 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.210-220
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• 2005

We have analyzed the stability for cut-slopes at main street 3-2 line section in Pa-ju local industrial complex. After studying an additional boring test, laboratory test and face mapping etc., we have determined the extent of reinforcement, slope inclinations and soil strength parameter from the analysis of test results. After changing the inclination of slopes for ground limit and carrying out the analysis of slope stability, we applied the Mass Nailing Method to the site because of need for reinforcement to soil and weathered rock slopes. In slope for soft and hard rock sections, we also reinforced the sections that are difficult to obtain the safety without reinforcement in alteration zone.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.547-552
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• 1999

The purpose of this study is to make a contribution to the construction of 40∼60 story R/C high rise building by developing the reinforcing details which can improve the seismic performance of high-strength (f'c=700㎏/㎠, fy=4000, 8000㎏/㎠) R/C beam-column joints. The reinforcing details which can make beam plastic hinging zones moved and spreaded from the column face is proposed to insure the ductile behavior of high-strength RC beam-column joints. The intermediate reinforcement which is vertically anchored by interlinking each intermediate reinforcements is proposed and tested to examine the mechanical performance of proposed details. Main variables are the shape of the intermediate reinforcements and yield strength of rebars. From the test results, the newly proposed intermediate reinforcement details can move and spread the beam plastic hinging zone about 1.0d from the column face.

• Computers and Concrete
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• 제24권6호
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• pp.499-511
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• 2019

In this paper, wave propagation of double-bonded Cooper-Naghdi micro sandwich cylindrical shells with porous core and carbon nanotube reinforced composite (CNTRC) face sheets are investigated subjected to multi-physical loadings with temperature dependent material properties. The governing equations of motion are derived by Hamilton's principle. Then, the influences of various parameters such as wave number, CNT volume fraction, temperature change, Skempton coefficient, material length scale parameter, porosity coefficient on the phase velocity of double-bonded micro sandwich shell are taken into account. It is seen that by increasing of Skempton coefficient, the phase velocity decreases for higher wave number and the results become approximately the constant. Also, by increasing of the material length scale parameter, the cut of frequency increases, because the stiffness of micro structure increases. The obtained results for this article can be used to detect, locate and quantify crack.

• Journal of Hospice and Palliative Care
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• 제24권4호
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• pp.245-253
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• 2021

Purpose: This study aimed to explore the experiences of hospice and palliative care (HPC) nurses at inpatient hospice centers in South Korea during the coronavirus disease 2019 pandemic. Methods: Data collection was conducted through individual interviews with 15 HPC nurses using face-to-face interviews, telephone calls, or Zoom videoconferencing. Data were analyzed using the thematic analysis method. Results: This study found that HPC nurses experienced practical and ethical dilemmas that reinforced the essential meaning and value of hospice and palliative care. The participants emphasized their practical roles related to compliance with infection prevention measures and their roles as rebuilders of hospice and palliative care. Conclusion: The findings of this study indicate that inpatient hospice centers must mitigate the practical and ethical dilemmas experienced by nurses, consider establishing explanation nursing units, and provide education to support nurses' highlighted roles during the pandemic. This study can be used to prepare inpatient hospice centers and the nurses that work there for future infectious disease outbreaks.

• 한국정밀공학회지
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• 제17권6호
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• pp.199-209
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• 2000

Particles reinforced MMCs have higher specific modulus, higher specific strength, better properties at elevated temperatures and better wear resistance than monolithic metals. But the coefficient of thermal expansion(CTE) of Al6061 is 5 times larger than that of SiCp. The discrepancy of CTE makes some residual stresses inside of MMCs. This work investigates Si$C_p$/Al6061 composites at high temperatures in the microscopic view by three-dimensional elasto-plastic finite element analyses and compares the analytical results with the experimental ones. The theoretical model is not able to consider the nonuniform shape of particle. So the shape of particle is assumed to be perfect global shape. And also particle distribution is not homogeneous in experimental specimen. It is assumed to be homogeneous in simulation model. The type of particle distribution is face-centered cubic array(FCC array). Furthermore, non-homogeneous distribution is modeled by combination of several volume fractions.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1989년도 가을 학술발표회 논문집
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• pp.77-82
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• 1989

In this paper an experimental approach of the relocation plastic hinging zones of nine reinforced concrete exterior beam-column subassemblages under cyclic loads was tried. The main parameters of the testing program were location of the plastic hinge, difference of the special reinforcement, inclined or intermediate layers of longitudinal reinforcement, applied maximum shear stress. The conclusions presented herein are based on the limited texts conducted. Inclined or intermediate layers of longitudinal reinforcement and extra top and bottom steel in the beam over a specific legnth can be used to move the beam plastic hinging zone away from the column face. But, for the use of intermediate layers of longitudinal reinforcement, sheat reinforcement detail need further investigation.

• Structural Monitoring and Maintenance
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• 제7권3호
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• pp.167-193
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• 2020

In this paper, the behavior of interior steel fiber reinforced concrete beam - column joints (BCJs) under cyclic loading is investigated. An experimental program including tests on twelve reinforced concrete (BCJs) specimens under cyclic loading was carried out. The test specimens are divided into two groups having different geometry: group (G1) (symmetrical BCJs specimens) and group (G2) (nonsymmetrical BCJs specimens). The parameters considered in this study are the steel fibers (SFs) content by volume of concrete (V_f), the spacing of shear reinforcement at the joint region, and the area of longitudinal flexural reinforcement. Test results show that the addition of 0.5% SFs with stirrups spacing S=S_max has effectively enhanced the overall performance of BCJs with respect to energy dissipation, ductility ratio, spreading and width of cracks. The failure of specimens is governed mainly by the formation of a plastic hinge at the face column and outside the beam-column junction. Secondary shear cracks were also observed in the beam-column junctions.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.125-128
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• 2005

Recently new materials, such as fiber reinforced polymer(FRP) and other composite materials are being applied in reinforcing plate or plate or prestressing cables of concrete structures. Although these new materials themselves show the excellent durability and high strength, the bond behaviour between concrete surface and FRP is not well recognized. Therefore, this paper propose a evaluation method for effective bond length between fiber reinforced polymer(FRP) and concrete. To develop the evaluation method, this paper presents a review of current evaluation methods for effective bond length. These methods are compared by single face test, expose merits and demerits. And based on them, new evaluation method was developed. Finally, the new method was compared with existing methods to verify a adequateness for evaluation of effective bond length.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1995년도 가을 학술발표회 논문집
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• pp.25.2-38
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• 1995

the Effect of steel pipe reinforced multi-step grouting(SPRG) technique to inrove the ground far ahead of the excavation face was investigated by means of numerical analysis. It was found taht the nonlinear 3-D FEM program performed well to evaluate the usefulness of the SPRG technique in soft ground tunnelling, and about 20% of settlement control in this particular case possible. Therefore in urban subway tunnel construction, the New Austirial Tunnelling Method can be satisfactorily applied even in poor ground conditon with aid of the SPRG technique.