• Title/Summary/Keyword: Mass Disaster

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Retrofitting of vulnerable RC structures by base isolation technique

  • Islam, A.B.M. Saiful;Jumaat, Mohd Zamin;Ahmmad, Rasel;Darain, Kh. Mahfuz ud
    • Earthquakes and Structures
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    • v.9 no.3
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    • pp.603-623
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    • 2015
  • The scale and nature of the recent earthquakes in the world and the related earthquake disaster index coerce the concerned community to become anxious about it. Therefore, it is crucial that seismic lateral load effect will be appropriately considered in structural design. Application of seismic isolation system stands as a consistent alternative against this hazard. The objective of the study is to evaluate the structural and economic feasibility of reinforced concrete (RC) buildings with base isolation located in medium risk seismic region. Linear and nonlinear dynamic analyses as well as linear static analysis under site-specific bi-directional seismic excitation have been carried out for both fixed based (FB) and base isolated (BI) buildings in the present study. The superstructure and base of buildings are modeled in a 3D finite element model by consistent mass approach having six degrees of freedom at each node. The floor slabs are simulated as rigid diaphragms. Lead rubber bearing (LRB) and High damping rubber bearing (HDRB) are used as isolation device. Change of structural behaviors and savings in construction costing are evaluated. The study shows that for low to medium rise buildings, isolators can reduce muscular amount of base shears, base moments and floor accelerations for building at soft to medium stiff soil. Allowable higher horizontal displacement induces structural flexibility. Though incorporating isolator increases the outlay, overall structural cost may be reduced. The application of base isolation system confirms a potential to be used as a viable solution in economic building design.

A Study on Architectural Type and Design Characteristics of Floating Architecture (플로팅건축의 유형 및 디자인 특성에 관한 연구)

  • Pak, Sung-Sine
    • Journal of Navigation and Port Research
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    • v.35 no.5
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    • pp.407-414
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    • 2011
  • Floating architecture is the most effective way to accommodate itself to sea-level rise due to climate change. At the same time floating architecture is the best model to offer the new spatial experience through water-friendly environment. Domestic floating architecture is still on the early stage compared to Europe which has several companies specialized in designing and building floating architecture. Floating architecture is divided into 8 types according to its criteria such as program, form, scale, level, location, access, mobility and energy. The following are design characteristics of floating architecture : (1) composed of 2 stories, (2) having large deck, (3) designing rectangular plan and balanced mass, (4) maximizing view, (5) having water-friendly space, (6) multi-using space and minimizing surface, (7) planning section to control light reflecting from the water, (8) modular and unit system.

Measurement system developed for the analysis of Small mooring facilities, and Floating matters (계류된 부유체의 안전성 평가를 위한 계측시스템 개발)

  • Park, Kyung-Chul;Yang, Hye-Jung;Seong, Yu-Chang
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2013.06a
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    • pp.252-254
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    • 2013
  • When Coming alongside the shallow water or narrow pier, they apply sea area with small mooring facilities and Floating matter because of the diversity of ships and limitation and effective in cutting expenses. However, when ships, applying Small mooring facilities and Floating matter, come alongside, there can be some impulse by waves between the Floating things and ships which possibly leads to mass disaster. Therefore, there should be forecasts and analysis of the movement caused by waves. On this Study, it introduces the composition and principles of the developed system provides the base of the movement traits through measuring 3-D exercise data and acceleration of the Mooring and Floating matters.

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Agricultural support and solidarity devices development (농작물 버팀 지지용 대 및 결속 장치)

  • Han, Seung-Chul;Kim, Jin-Ho;Lee, Man-Gi;Lee, Seung-Cheol
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.10
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    • pp.5945-5949
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    • 2014
  • The rural population is aging and farmers need to aim for mass production. This study examined the work efficiency of clamping and protecting crops. Strong winds are a risk for damage, but there are no reports of studies of the geometric design problem for vegetation. The accuracy of the simulation to obtain a load applied to the actual support and index was examined. The model was selected according to its strength based on the reliability of the simulation. Also acts in force of 0.1N to 0.6N, which can withstand the force of 1.29N with the results of this thesis research. The fixed clamp fixing for agricultural crops designed as a support was examined. These results are expected to help shorten working hours, and improve the growth of crops and disaster prevention.

Free vibrations of a two-cable network inter-supported by cross-links extended to ground

  • Zhou, H.J.;Wu, Y.H.;Li, L.X.;Sun, L.M.;Xing, F.
    • Smart Structures and Systems
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    • v.23 no.6
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    • pp.653-667
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    • 2019
  • Using cross-ties to connect cables together when forming a cable network is regarded as an efficient method of mitigating cable vibrations. Cross-ties have been extended and fixed on bridge decks or towers in some engineering applications. However, the dynamics of this kind of system need to be further studied, and the effects of extending cross-links to bridge decks/towers on the modal response of the system should be assessed in detail. In this paper, a system of two cables connected by an inter-supported cross-link with another lower cross-link extended to the ground is proposed and analyzed. The characteristic equation of the system is derived, and some limiting solutions in closed form of the system are derived. Roots of cable system with special configurations are also discussed, attention being given to the case when the two cables are identical. A predictable mode behavior was found when the stiffness of inter-connection cross-link and the cross-link extended to the ground were the same. The vector of mode energy distribution and the degree of mode localization index are proposed so as to distinguish global and local modes. The change of mode behaviors is further discussed in the case when the two cables are not identical. Effects of cross-link stiffness, cross-link location, mass-tension ratio, cable length ratio and frequency ratio on $1^{st}$ mode frequency and mode shape are addressed.

"Adam and Eve" - Soviet Plot and Parody of M.A. Bulgakov (『아담과 이브』: 소비에트 슈제트와 M.불가코프의 패러디)

  • Kang, Su Kyung;Yang, min jong
    • Cross-Cultural Studies
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    • v.22
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    • pp.7-27
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    • 2011
  • This article is devoted to little-studied play of M.A. Bulgakov "Adam and Eve". By the end of 1920's - the beginning of 1930's soviet society is differentiated again, its construction is rebuilded. In the new condition drama is needed as much as possible. Drama on the stage is ideal model for instruction of "Mass". Thereupon soviet society asked "New Hero", "New play", which can rebuild soviet citizen in the new construction of government. Thereby the play of M.A. Bulgakov "Adam and Eve" is created by order of soviet society. In this play typical soviet people are represented: Adam Krasovsky(engineer), Daragan(pilot-terminator), Ponchik-Nepobeda(writer), Zahar Markizov(proletarian-baker). They are different from each other by their occupation and formation, but they have same consciousness and they think identically. Bulgakov makes stand such problems: impersonality and unfreedom of human being in the government of communism. Bulgakov, using Parody, doubt the possibility of realization of utopia of Soviet government. Bulgakov show to us that Adam Krasocsky is not real Adam-first human being. In the play we can see the real Adam is the scientist-intelligent Efrosimov. Bulgakov change the place of Ponchik with the place of Markizov. The idiot and the fool is recognized not Markisov-drinker, tyrant, but Ponchik-writer. After the disaster Markisov, reading a Bible, is changing and by the end of play he started writing his own novel. Indeed if Ponchik wrote hoked-up novel, Markisov writes a real own history. Request of Leningrad Theater for Bulgakov to write about the future war comes from the spirit of the time. But Bulgakov in this play "Adam and Eve" could insist that the "Life" is a supreme value.

The July 2, 2017, Lantian landslide in Leibo, China: mechanisms and mitigation measures

  • He, Kun;Ma, Guotao;Hu, Xiewen;Liu, Bo;Han, Mei
    • Geomechanics and Engineering
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    • v.28 no.3
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    • pp.283-298
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    • 2022
  • Landslides triggered by the combination of heavy precipitation and anthropological disturbance in hilly areas cause severe damage to human lives, properties, and infrastructure constructions. A comprehensive investigation of the influencing factors and failure mechanisms of landslides are significant for disaster mitigation and prevention. This paper utilized the combination of detailed geological investigation, physical experimental testing as well as numerical modelling to determine the failure mechanism, and proposed a countermeasures of the Lantian landslide occurred on 2, July 2017. The results reveal that the Lantian landslide is a catastrophic reactivated slide which occurred in an active tectonic region in Southwest China. Because of the unique geological settings, the fully to highly weathered basalts in the study area with well-developed fractures favored the rainwater infiltration, which is the beneficial to slide reactivation. Engineering excavation and heavy precipitation are the main triggering factors to activate the slide motion. Two failure stages have been identified in the landslide. The first phase involves a shallow mass collapse originated at the upper slopes, which extends from the road to platform at rear part, which is triggered by excavation in the landslide region. Subjected to the following prolonged rainfall from 19 June to 2 July, 2017, the pore water pressure of the slope continually increased, and the groundwater table successively rise, resulting in a significant decrease of soil strength which leads to successive large-scale deep slide. Thereinto, the shallow collapse played a significant role in the formation of the deep slide. Based on the formation mechanisms of the landslide, detailed engineering mitigation measures, involving slope cutting, anchor cable frame, shotcrete and anchorage, retaining wall and intercepting ditch were suggested to reduce the future failure risk of the landslide.

Effect of Corrosion Level and Crack Width on the Bond-Slip Behavior at the Interface between Concrete and Corroded Steel Rebar (부식 수준 및 균열폭에 따른 부식된 철근과 콘크리트 계면의 부착-미끄러짐 거동 )

  • Sang-Hyeon Jo;Seong-Hoon Kee;Jung-Jae Yee;Changkye Lee
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.27 no.1
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    • pp.54-63
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    • 2023
  • In this paper, the effect of corrosion level and crack width on the cohesive strength-slip behavior of corroded steel rebar and concrete interface is conducted. The existing studies mainly focus on the decrease in bond strength with respect to the level of corrosion; there are, however, few studies on the decrease in cohesive strength according to the crack width of the concrete surface due to corrosion. Therefore, in this study, a series of tests for the cohesive strength, slip behavior and mass loss of the reinforcing bar is evaluated at the surface of corroded rebar and concrete. It is found that the tendency to decrease the bond strength is closely related to the crack width rather than the corrosion level. Hence, to determine the degradation performance for the bond strength-slip behavior relation, the occurrence of cracks on the concrete surface can be a suitable index.

An Adaptive Tuned Heave Plate (ATHP) for suppressing heave motion of floating platforms

  • Ruisheng Ma;Kaiming Bi;Haoran Zuo
    • Smart Structures and Systems
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    • v.31 no.3
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    • pp.283-299
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    • 2023
  • Structural stability of floating platforms has long since been a crucial issue in the field of marine engineering. Excessive motions would not only deteriorate the operating conditions but also seriously impact the safety, service life, and production efficiency. In recent decades, several control devices have been proposed to reduce unwanted motions, and an attractive one is the tuned heave plate (THP). However, the THP system may reduce or even lose its effectiveness when it is mistuned due to the shift of dominant wave frequency. In the present study, a novel adaptive tuned heave plate (ATHP) is proposed based on inerter by adjusting its inertance, which allows to overcome the limitation of the conventional THP and realize adaptations to the dominant wave frequencies in real time. Specifically, the analytical model of a representative semisubmersible platform (SSP) equipped with an ATHP is created, and the equations of motion are formulated accordingly. Two optimization strategies (i.e., J1 and J2 optimizations) are developed to determine the optimum design parameters of ATHP. The control effectiveness of the optimized ATHP is then examined in the frequency domain by comparing to those without control and controlled by the conventional THP. Moreover, parametric analyses are systematically performed to evaluate the influences of the pre-specified frequency ratio, damping ratio, heave plate sizes, peak periods and wave heights on the performance of ATHP. Furthermore, a Simulink model is also developed to examine the control performance of ATHP in the time domain. It is demonstrated that the proposed ATHP could adaptively adjust the optimum inertance-to-mass ratio by tracking the dominant wave frequencies in real time, and the proposed system shows better control performance than the conventional THP.

Characteristics of Biological Agent and relavent case study (생물무기 특성과 사례연구)

  • Park, Minwoo;Kim, Hwami;Choi, Yeonhwa;Kim, Jusim
    • Journal of the Society of Disaster Information
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    • v.13 no.4
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    • pp.442-454
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    • 2017
  • Biological weapon is manipulated and produced from microorganisms such as bacteria, virus, rickettsia, fungi etc. It is classified as one of the Weapons of Mass Destruction (WMD) along with chemical weapon and radiological weapon. Biological weapon has a number of operational advantages over the other WMDs including ease of development and production, low cost and possibility of covert dissemination. In this study we analyze the history of biological weapon's development and the existing biological threats. Then, we predict the social impact of biological attack based on the physical properties of biological agent and infection mechanisms. By analyzing the recognition, dispersion pattern of agents, characteristics of the diseases in the biological weapon related historical events such as Sverdlovsk anthrax accident, 2001 anthrax attack, we found out some of the facts that biological attack would not likely to be recognized rapidly, produce large number of the exposed, increase number of paients who suffed from severe respiratory illness. It would lead the public health and medical service providers to be struggled with hugh burden. Base on the facts that we found from this case study, we suggested the main capabilities of public health required to respond to bioterrorism event efficiently. Syndromic surveillance and other reporting system need to be operated effeciently so that any suspicious event should be detected promptly. the pathogen which suspected to be used should be identified through laboratory diagnostic system. It is critical for the public health agency to define potentially exposed population under close cooperation with law enforcement agencies. Lastly, massive prophylaxis should be provided rapidly to the people at need by operating human and material resources effeciently. If those capacities of public health are consistantly fortified we would be able to deal with threat of bioterrorism successfully.