• Title/Summary/Keyword: failure block

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Block Shear Failure : State of the Arts (블록전단파괴 : State of the Arts)

  • Jang, Sun-Jae;Lee, Woo-Chul;Lim, Nam-Hyoung;Lee, Chin-Ok
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.75-78
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    • 2008
  • Limit states of a tension member are the yielding of gross section, fracture of net section, and block shear failure. Block shear failure is very complicated than other limit state because of interaction of tension and shear failure. Block shear failure is studied continuously since the 1970s. However, failure model to estimate the strength of block shear failure provided in current design specifications is not reflective of the failure mode observed in the various experimental studies. Comparisons between the experimental results and design rules in various specifications about the block shear failure were conducted in this study. Also, the need for further studies of block shear failure were proposed.

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Gross dynamic failure of toppling block structures

  • Wilson, James F.
    • Structural Engineering and Mechanics
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    • v.8 no.5
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    • pp.491-504
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    • 1999
  • The initiation of toppling is explored for a uniform stack of blocks that rotates slowly about its mid-base. As the stack passes through its vertical position ($\theta$=0), it is in free-fall rotation, and a critical inclination angle ${\theta}_c$ is reached at which the toppling stack "fails" or begins to crack or separate. For tall stacks (high aspect ratios), two modes of failure are hypothesized, for which the dynamic failure analyses are shown to correlate with experimental results. These block failure modes are similar to those observed for tall, toppling masonry structures with weak binding material between their brick or stone blocks.

Acute Respiratory Failure during Splanchnic Nerve Block in COPD Patient (만성폐색성 폐질환 환자에서의 내장신경차단중 발생한 급성호흡부전)

  • Chang, Won-Young;Choe, Kun-Chun
    • The Korean Journal of Pain
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    • v.4 no.2
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    • pp.200-204
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    • 1991
  • Neurolytic splanchnic nerve block is a relatively safe and effective method for the relief of intractable pain caused by upper abdominal cancer. We have experienced a case of severe acute respiratory failure during splanchnic nerve block under control of X-ray fluoroscopy. We think that the most likely cause of the acute respiratory failure was an asthmatic attack due to anxiety and dyspnea from the injury or stimulation of the diaphragm and pleura in this case.

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A Case Study of Tunnel Keyblock Stability by the Block Failure Likelihood (블록파괴가능성을 이용한 터널키블록의 안정해석 사례연구)

  • 이인모;박준경;이석원
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.03a
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    • pp.315-322
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    • 1999
  • The probabilistic keyblock concept which was based upon block theory was applied to the example site by using the observed block moulds data. The more was the block failure likelihood (P(B)) which was defined by the product of the joint combination probability, the shape parameter and the instability parameter, the more were the frequencies of failures observed. If we can acquire these data during a tunnel construction stage, they will be used as a very useful data to construct another tunnel in the neighborhood. Furthermore, a sedimentary rock may have larger P(B) values than a crystalline rock, and for the given P(B) value, the percent block moulds are larger in the former than latter.

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A Case of Erection Failure due to Unilateral Lumbar Sympathetic Block (편측 요부 교감신경절 차단에 의해 발생한 성기능 -증례 보고-)

  • Shin, Dong-Yeop;Moon, Soon-Hong;Hong, Ki-Hynk
    • The Korean Journal of Pain
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    • v.6 no.2
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    • pp.258-260
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    • 1993
  • We experienced a rare case of erection failure which developed after unilateral lumbar sympathetic block. A 43 year old male patient suffering from reflex sympathetic dystrophy, which had developed after multiple communitted fracture of the right ankle, underwent right lumbar sympathetic block with 99.9% alcohol. The effectiveness of the lumbar sympathetic block was evaluated by monitoring the clinical symptoms, signs and temperature changes by digital infrared thermographic imaging. Postoperatively, the temperature of the affected side limb rose about $2^{\circ}C$, but the patient's conditions gradually returned to normal. Ten days after the operation the patient complainted of difficulty in achieving an erection. The patient was examined by a urologst without much results. The patient gradually recovered his ability to achieve an erection approximately 5 weeks after the lumbar sympathetic block.

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Recovery of complete left bundle branch block in dilated cardiomyopathy after optimal heart failure treatment: a case report

  • Geum Ko;Jae-Geun Lee
    • Journal of Medicine and Life Science
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    • v.21 no.3
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    • pp.112-116
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    • 2024
  • Complete left bundle branch block (CLBBB) is a significant cardiac conduction abnormality often associated with dilated cardiomyopathy (DCM). This case report highlights the improvement in CLBBB and symptom relief through reverse cardiac remodeling in a patient diagnosed with DCM following an optimized heart failure treatment regimen consisting of an angiotensin-converting enzyme inhibitor, beta-blocker, and mineralocorticoid receptor antagonist. This case highlights the potential of electrical remodeling and conduction system improvement in patients with DCM receiving optimized medical therapy.

Estimation of Internal Friction Angle by the Back Analysis on Collapsed Rock Slope (붕괴된 암반사면에서 역해석에 의한 내부마찰각의 추정)

  • 이달원;김갑중
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.45 no.6
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    • pp.172-182
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    • 2003
  • In this study, the back analysis was performed by means of stereo-net, plane failure and block failure method to collapsed fields among the rock slopes designed by standardized criterion, and the internal frictions from the back analysis were compared with those used to reinforcement design. It was concluded that in the result of the analysis by means of stereo net, plain failure and block failure methods, the internal frictions used to re-design of collapsed slope underestimated 10$^{\circ}$, 5$^{\circ}$ and 10$^{\circ}$ in average. At present, the internal friction on the design is used the experience value according to the state of weathering, but internal friction angle by the back analysis on collapsed slope with various methods were more reliable values than those from the present method. And it was concluded that re-design was made extravagantly because the internal friction used to re-design for reinforcement of the collapsed slope was less than back analysis.

Case Study of Environmental Segmental Retaining Wall(SRW) Using Greenstone Block (환경친화적 블록식 보강토옹벽의 설계 및 시공사례연구)

  • Han, Jung-Geun
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.7 no.6
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    • pp.19-28
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    • 2004
  • Segmental Retaining Wall(SRW) has been variously applying in Civil and Architecture construction. Recently, the application of environmental element in all type's structures came to essential requirement, and the construction cases of retaining wall using reinforced soil and block are more increased than the past. But, this trend more widely was spread environmental element as landscape work for the backside of reinforced retaining wall as well as block itself. New environmental block, Greenstone Block, developed to apply of this tendency. The retaining wall system using Greenstone can be environmental constructing at both block itself and backside of retaining wall. The material tests, the axial compressive strength test of block and bending test of fiber-pipe, exercised to design and construction of vertical SRW, which were satisfied NCMA standard. Through this procedure, Rewall (ver 1.0) was developed, which can be automation design of SRW including internal stability, external stability and local stability. And these can be considered setback of retaining wall, as well the examples of vertical retaining wall using block presented to satisfying the follows; strength of reinforced geotextile, height of retaining wall, surcharge, types of backfill and groundwater level etc. Many problems investigated on after or before of construction were due to local failure, insufficiency of bearing capacity and groundwater level. Especially, the local failure was many occurred to during compaction or after construction, and the cases of SRW construction is similar to the results of model test on vertical SRW.

A Case Study on Joint System Simulation Results Application to Rock Slope Design (절리계 모사결과의 암반사면설계 적용 사례)

  • Kim, Dong-Hee;Jung, Hyuk-Il;Kim, Seouk-Ki
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.10a
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    • pp.669-680
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    • 2005
  • It is very difficult to determine the failure block scale in great rock slopes. Especially, postulating entire slope domain as a failure block without attention to discontinuity trace lenth makes very confuse and difficult to design rock slopes. In this paper, we estimate realistic failure block scale using joint system simulation method and introduce the application procedures on rock slope analysis. Besides, presenting how joint characteristics measurement and statistical analysis results are applicated to slope stability analysis design flow.

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Simultaneous operation of two group of Auxiliary Block for Korean High Speed Train (고속전철용 보조전력변환장치 1,2군 동시 기동)

  • Cho, Hyun-Wook;Kim, Yuen-Chung;Kim, Tae-Hwan;Jang, Kyung-Hyun;Choi, Jong-Mook
    • Proceedings of the KSR Conference
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    • 2007.11a
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    • pp.1626-1632
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    • 2007
  • Power Car PC1 and PC2 of Korean high speed train have a auxiliary block which consists of two PWM converter respectively. If a auxiliary block happens a critical failure, the other supplies power to full load of train. In this case, a stability of auxiliary block reduces by a increasing load. For increasing a stability of auxiliary block and train system, a auxiliary block consists of two group four PWM converter which operates simultaneously. If a group of a auxiliary block happens a critical failure, the other supplies power to load of a auxiliary block. This paper describes a method for simultaneous movement of auxiliary block which consists of two group four PWM converter.

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