• Title/Summary/Keyword: foundation failure

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Effect of Base Roughness of Footing on Settlement Characteristics of Footing (기초저면의 조도가 기초의 침하 특성에 미치는 영향)

  • Yoo, Nam-Jae;Kim, Young-Gil;Park, Byung-Soo
    • Journal of Industrial Technology
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    • v.12
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    • pp.15-23
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    • 1992
  • This research is to investigate the effect of base roughness of footing on characteristics of load-settlement curve. Parametric experiments of small scaled model test were performed with changing the properties of base roughness of model footing; Gluing the vinyl, aluminum, sand paper, sand beneath the model footing surface. The width of model footing and relative density of soil foundation were also changed to investigate their effects on settlement characteristics of footing. The ultimate bearing capacity as well as the initial slope of load-settlement curve obtained from test results were compared with those from limit equilibrium methods proposed by Terzaghi, Hansen and Meyerhof. From test results, it was confirmed that the base roughness affected the failure mechanisms of showing different shapes of slip lines formed beneath the footing.

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Reliability and Risk Assessment of Reclaimed Soil (매립지반의 액상화 신뢰성 및 위험도 평가)

  • Yi Jin-Hak;Kwon O-Soon;Park Woo-Sun
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.473-480
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    • 2006
  • Liquefaction of soil foundation is one of the major seismic damage types of infrastructures. In this paper, deterministic and probabilistic approaches for the evaluation of liquefaction potential are briefly summarized and the risk assessment method is newly proposed using seismic fragility and seismic hazard curves. Currently the deterministic approach is widely used to evaluate the liquefaction potential in Korea. However, the there are a certain degree of uncertainties in the soil properties such as elastic modulus and resistant capacity, therefore the probabilistic approach is more promising. Two types of probabilistic approach are introduced including (1) failure probability for a given design earthquake and (2) the seismic risk of liquefaction of soil for a given service life. The results from different methods show a similar trend, and the liquefaction potential can be more quantitatively evaluated using risk analysis method.

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Experimental study on shear behaviors of Partial Precast Steel Reinforced Concrete beams

  • Yang, Yong;Li, Hui
    • Steel and Composite Structures
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    • v.37 no.5
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    • pp.605-620
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    • 2020
  • An innovative Partially Precast Steel Reinforced Concrete (PPSRC) beam is presented in this paper. To study the shear behavior of PPSRC beams, static loading experiments were conducted on 10 specimens, including 4 T-beam specimens and 4 PPSRC inverted T-beam specimens together with 2 PPSRC rectangular section beams. In the tests, the shear behaviors of the PPSRC beams were emphasized. On the basis of the experiments, the failure mode and ultimate bearing capacity were thoroughly examined. The calculation methods for shear capacity are also presented in this paper. The analysis of mechanical behavior and the calculation methods presented can be used as a reference to design these innovative composite PPSRC beams and provide a significant foundation for further research.

Failure of Intravenous Sedation due to Significant Hypertension -A Case Report- (혈압 상승으로 인한 의식하 진정 요법의 실패 -증례보고-)

  • Koh, Se-Wook
    • Journal of The Korean Dental Society of Anesthesiology
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    • v.7 no.2
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    • pp.126-130
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    • 2007
  • Sedation is often indicated for the relief of anxiety for outpatient oral surgery. In combination with local anesthesia, it is safe and effective method of treatment. However, it is not always effective in allowing the physician to complete the planned oral surgery procedure. On occasion, a procedure is left unfinished due to patient combativeness and discomfort and hypertension in spite of increase in sedative doses. Episodic increases in blood pressure were most commonly caused by light anesthesia or sedation and by the patient's experience of pain during treatment. Female patient was 42 years old. blood pressure is 150/90 mmHg. Extraction and implant surgery was done under IV sedation. During seadtion, her blood pressure was increased (200/100 mmHg). Surgery was stopped. She was done monitoring blood pressure. The blood pressure was decreased to 130/90 mmHg. Sedation was failed due to significant hypertension. Blood pressure is seldom increased during sedation but we should evaluate the patient's medical history and know guideline for hypertension crisis.

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Safety Assessment for Hydrogen Gas Filling Facilities(One-Bank) (One-Bank 방식의 수소충전장치에 대한 정성적 안전성 평가)

  • Rhie, Kwang-Won;Kim, Tae-Hun
    • Journal of the Korea Safety Management & Science
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    • v.14 no.1
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    • pp.95-100
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    • 2012
  • This study is about the qualitative safety assessment for hydrogen gas filling facilities in Korea operating with one-bank type. The purpose of this safety assessment is about the development of components for design, fabrication, assembly, operability of dispenser and systems of the safety. For the qualitative safety assessment method, the study used FMEA(failure mode & effect analysis) and HAZOP(hazard & operability). This study evaluated the safety through FMEA and HAZOP then by referring to P&ID and PFD of hydrogen dispenser, thereby examining the dangerousness of the equipments, defects of the structure and problems of the operation.

Double Peak Current Limiting Properties of Series Connection-Type SFCL with Two Magnetic Paths (두 개의 자속경로를 갖는 직렬연결형 초전도한류기의 이중 피크전류제한 특성)

  • Ko, Seok-Cheol;Han, Tae-Hee;Lim, Sung-Hun
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.28 no.7
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    • pp.62-68
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    • 2014
  • We proposed a series connection-type superconducting fault current limiter(SFCL) using E-I core that can prevent the internal magnetic flux generation of cores during normal operation, and prevent the saturation of cores due to a sudden magnetic flux generation at the initial stage of fault occurrence while limiting the peak current. Through a short-circuit simulation experiment, we analyzed the operating status of the two superconducting elements and limiting characteristics according to the size of the fault current peak before and after the failure. Further, the double peak current limiting characteristics according to the winding directions as well as the current and the voltage of each coil were compared and analyzed.

Dynamic response analysis of the caisson-type quay wall using the wavelet transform (웨이브렛 변환을 이용한 케이슨식 안벽의 동적응답해석)

  • Moon, Yong;Kim, Jae-Kwon;Shin, Hyun-Yang;Seok, Jeong-Woo
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2003.09a
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    • pp.74-81
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    • 2003
  • During the 1995 Hyogoken-Nambu earthquake, many caisson-type quay walls in Kobe Port moved several meters towards the seaside due to liquefaction and subsequent ground flow, To investigate the mechanism of quay wall damage, we carried out the numerical simulation using the 2-D effective stress analysis. Input earthquake motions used for the analyses are original Dip wave and the component wave in each compact support of wavelet transformation. The results suggested that the shear failure occurred in the foundation soil underneath the caisson type quay wall due to the deformation of the caisson type quay wall.

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The Spreading of Caodaism to Taiwan: Man's Will versus Divine Will

  • Nguyen, Tuan Em
    • Journal of Daesoon Thought and the Religions of East Asia
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    • v.1 no.2
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    • pp.115-132
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    • 2022
  • Caodaism officially came into existence in 1926 in Southern Vietnam and soon became a spiritual phenomenon, in the sense of spiritual and social influence. Despite being sandwiched between political forces and ruling governments, Caodaism steadily grew far beyond its national boundary. After 95 years, Caodaism eventually reached Taiwan when a new small Cao Đài Congregation, approved by top Cao Đài Dignitaries in Vietnam, was established in Zhongli District, Taoyuan City by a group identifying as 'Vietnamese New Immigrants' in Taiwan. This article traced this religious organization's doctrine, philosophy, prophecy and relevant socio-cultural factors and found that (1) Caodaists see the successful spreading of Caodaism to Taiwan as having been prophesied long ago; (2) Caodaists believe that any human efforts by Cao Đài missionaries to spread Caodaism overseas without approval from Divinities could end up in failure; and (3) the similarities in social, cultural, and religious practices between the peoples of Vietnam and Taiwan lay a strong foundation for Caodaism to further develop in Taiwan.

Nonlinear snap-buckling and resonance of FG-GPLRC curved beams with different boundary conditions

  • Lei-Lei Gan;Gui-Lin She
    • Geomechanics and Engineering
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    • v.32 no.5
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    • pp.541-551
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    • 2023
  • Snap-buckling is one of the main failure modes of structures, because it will lead to the reduction of structural bearing capacity, durability loss and even structural damage. Boundary condition plays an important role in the research of engineering mechanics. Further discussion on the boundary conditions problems will help to analyze the dynamic and static behavior of structures more accurately. Therefore, in order to understand the dynamic and static behavior of curved beams more comprehensively, this paper mainly studies the nonlinear snap-through buckling and forced vibration characteristics of functionally graded graphene reinforced composites (FG-GPLRCs) curved beams with two different boundary conditions (including clamped-hinged and hinged-hinged) using Euler-Bernoulli beam theory (E-BBT). In addition, the effects of the curved beam radius, the GLPs distributions, number of GLPs layers, the mass fraction of GLPs and elastic foundation parameters on the nonlinear snap-through buckling and forced vibration behavior are discussed respectively.

Evaluation of Bearing Capacity of Multi-layered Soil Deposits (개별요소법에 의한 다층지반의 지지력 산정)

  • Park Jun;Jee Sung-Hyun;Lee Seung-Rae;Park Hyun-Il
    • Journal of the Korean Geotechnical Society
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    • v.22 no.6
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    • pp.63-69
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    • 2006
  • In this paper, a method is presented for estimating the bearing capacity of shallow foundations based on the Discrete Element Method (DEM). By applying Winkler-springs for accounting for the compatibility between soil blocks, the proposed method can estimate the state of stress at failure surface and the ultimate bearing capacity. For the investigation of the application of the method, example problems about shallow foundations on the single layer and two layers soil are analyzed.