• Title/Summary/Keyword: earthquake risk assessment

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Case Study on the Analysis of Disaster Vulnerabilities (Focused on the Fire & Explosion in the N-Industrial Complex) (재난 취약성 분석에 관한 사례연구(N공단의 화재·폭발을 중심으로))

  • Ha, Kag Cheon
    • Journal of the Korean Society of Safety
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    • v.36 no.2
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    • pp.94-100
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    • 2021
  • In general, the industrial complex is a place where factories of various industries are concentrated. It is only as efficient as it is designed. However, the risks vary as there are various industries. These features are also associated with various types of disasters. The dangers of natural disasters such as a typhoon, flood, and earthquake, as well as fire and explosions, are also latent. Many of these risks can make stable production and business activities difficult, resulting in massive direct and indirect damage. In particular, decades after its establishment, the vulnerabilities increase even more as aging and small businesses are considered. In this sense, it is significant to assess the vulnerability of the industrial complex. Thus analysing fire and explosion hazards as stage 1 of the vulnerability evaluation for the major potential disasters for the industrial complex. First, fire vulnerabilities were analyzed quantitatively. It is displayed in blocks for each company. The assessment block status and the fire vulnerability rating status were conducted by applying the five-step criteria. Level A is the highest potential risk step and E is the lowest step. Level A was 11.8% in 20 blocks, level B was 22.5% in 38 blocks, level C was 25.4% in 43 blocks, level D was 26.0% in 44 blocks, and level E was 14.2% in 24 blocks. Levels A and B with high fire vulnerabilities were analyzed at 34.3%. Secondly, the vulnerability for an explosion was quantitatively analyzed. Explosive vulnerabilities were analyzed at 4.7% for level A with 8 blocks, 3.0% for level B with 5, 1.8% for level C with 3, 4.7% for level D with 8, and 85.8% for level E with 145. Levels A and B, which are highly vulnerable to explosions, were 7.7 %. Thirdly, the overall vulnerability can be assessed by adding disaster vulnerabilities to make future assessments. Moreover, it can also assist in efficient safety and disaster management by visually mapping quantified data. This will also be used for the integrated control center of the N-Industrial Complex, which is currently being installed.

Nonlinear incremental dynamic analysis and fragility curves of tall steel buildings with buckling restrained braces and tuned mass dampers

  • Verki, Amir Masoumi;Preciado, Adolfo
    • Earthquakes and Structures
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    • v.22 no.2
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    • pp.169-184
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    • 2022
  • The importance of seismicity in developing countries and the strengthening of buildings is a topic of major importance. Therefore, the study of several solutions with the development of new technologies is of great importance to investigate the damage on retrofitted structures by using probabilistic methods. The Federal Emergency Management Agency considers three types of performance levels by considering different scenarios, intensity and duration. The selection and scaling of ground motions mainly depends on the aim of the study. Intensity-based assessments are the most common and compute the response of buildings for a specified seismic intensity. Assessments based on scenarios estimate the response of buildings to different earthquake scenarios. A risk-based assessment is considered as one of the most effective. This research represents a practical method for developing countries where exists many active faults, tall buildings and lack of good implementable approaches. Therefore, to achieve the main goal, two high-rise steel buildings have been modeled and assessed. The contribution of buckling-restrained braces in the elastic design of both buildings is firstly verified. In the nonlinear static range, both buildings presented repairable damage at the central top part and some life safety hinges at the bottom. The nonlinear incremental dynamic analysis was applied by 15 representative/scaled accelerograms to obtain levels of performance and fragility curves. The results shown that by using probabilistic methods, it is possible to estimate the probability of collapse of retrofitted buildings by buckling-restrained braces and tuned mass dampers, which are practical retrofitting options to protect existing structures against earthquakes.

Assessment of seismic stability of finite slope in c-ϕ soils - a plasticity approach

  • Shibsankar, Nandi;G., Santhoshkumar ;Priyanka, Ghosh
    • Geomechanics and Engineering
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    • v.31 no.5
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    • pp.439-452
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    • 2022
  • A forecast of slope behavior during catastrophic events, such as earthquakes is crucial to recognize the risk of slope failure. This paper endeavors to eliminate the significant supposition of predefined slip surfaces in the slope stability analysis, which questions the relevance of simple conventional methods under seismic conditions. To overcome such limitations, a methodology dependent on the slip line hypothesis, which permits an automatic generation of slip surfaces, is embraced to trace the extreme slope face under static and seismic conditions. The effect of earthquakes is considered using the pseudo-static approach. The current outcomes developed from a parametric study endorse a non-linear slope surface as the extreme profile, which is in accordance with the geomorphological aspect of slopes. The proposed methodology is compared with the finite element limit analysis to ensure credibility. Through the design charts obtained from the current investigation, the stability of slopes can be assessed under seismic conditions. It can be observed that the extreme slope profile demands a flat configuration to endure the condition of the limiting equilibrium at a higher level of seismicity. However, a concurrent enhancement in the shear strength of the slope medium suppresses this tendency by offering greater resistance to the seismic inertial forces induced in the medium. Unlike the traditional linear slopes, the extreme slope profiles mostly exhibit a steeper layout over a significant part of the slope height, thus ensuring a more optimized solution to the slope stability problem. Further, the susceptibility of the Longnan slope failure in the Huining-Wudu seismic belt is predicted using the current plasticity approach, which is found to be in close agreement with a case study reported in the literature. Finally, the concept of equivalent single or multi-tiered planar slopes is explored through an example problem, which exhibits the appropriateness of the proposed non-linear slope geometry under actual field conditions.

Decision Making of Seismic Performance Management for the Aged Road Facilities Based on Road-Network and Fragility Curve (취약도곡선을 이용한 도로망기반 노후도로시설물 내진성능관리 의사결정)

  • Kim, Dong-Joo;Choi, Ji-Hae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.25 no.5
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    • pp.94-101
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    • 2021
  • According to the Facility Management System (FMS) operated by the Korea Authority of Land & Infrastructure Safety, it is expected that the number of aging facilities that have been in use for more than 30 years will increase rapidly to 13.9% in 2019 and 34.5% in 2929, and end up with a social problem. In addition, with the revision of "Common Application of Seismic Design Criteria" by the Ministry of Public Administration and Security in 2017, it is mandatory to re-evaluate all existing road facilities and if necessary seismic reinforcement should be done to minimize the magnitude of earthquake damage and perform normal road functions. The seismic performance management-decision support technology currently used in seismic performance management practice in Korea only determines the earthquake-resistance reinforcement priority based on the qualitative index value for the seismic performance of individual facilities. However with this practice, normal traffic functions cannot be guaranteed. A new seismic performance management decision support technology that can provide various judgment data required for decision making is needed to overcome these shortcomings and better perform seismic performance management from a road network perspective.

Establishment of Complex Disaster Scenario on the Utility Tunnel Study for Digital Twin System Application (디지털트윈 시스템 적용을 위한 공동구 복합재난 시나리오 구축)

  • Yon Ha Chung; So Dam Kim;Hyun Jeong Seo;Hojun Lee;Tae Jung Song
    • Journal of the Society of Disaster Information
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    • v.18 no.4
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    • pp.861-872
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    • 2022
  • The purpose of this study was to establish a complex disaster scenario that can comprehensively consider various disaster situations that may occur in the utility tunnel. Method: In order to comprehensively consider the correlation between disasters, a composite disaster scenario was derived from a combination of damage factors, respectively. A risk assessment was performed in order to derive the priorities of the scenarios. And based on the results, the priorities of complex disaster scenarios were set. Result: Based on the disaster cases in the utility tunnel, a plan was prepared for complex disaster scenarios centered on damage. A complex disaster scenario was specified using a semi-quantitative evaluation method for single and multiple disaster factors such as fire, flooding, and earthquake. Conclusion: The composite disaster scenario derived from this study can be used for the prevention and preparation of damage when the precursor symptoms of a disaster are detected. In addition, the results of this study are expected to be used as basic data for preparing strategic plans and preparing complex disaster response technologies to induce rapid response and recovery in case of emergency disasters.