• Title/Summary/Keyword: Hazard investigation

Search Result 266, Processing Time 0.025 seconds

Field Investigation of Scour-Protection Methods for Bridges in Small Size Streams of Central Region of Korea (중부 지역 중.소하천 교량의 세굴보호공에 관한 조사연구)

  • Kim, Byoung-Il;Yoon, Ki-Yong;Lee, Seung-Hyun
    • Journal of the Korean Society of Hazard Mitigation
    • /
    • v.5 no.1 s.16
    • /
    • pp.45-53
    • /
    • 2005
  • Scour plays a principal role in maintaining stability and durability of bridges. Especially, in case of severe flood events, flow rate getting increase in a short time, scour can impede the functioning of bridges to the extent that they must be taken out of operation, and even can imperil their stability and structural integrity. In Korea, about 100 bridges were collapsed or damaged every you. Sufficient field investigation, however, was not made and, therefore, no adequate countermeasure for scouring is available. In this study, literature on scour-protection methods are reviewed and data on countermeasures of scouring which were collected through field investigation in central region of Korea are analyzed.

Advancement and Application of Integrated Damage Investigation System using Stereo Images and IT (Stereo Images와 IT 기술을 이용한 피해조사 통합운영시스템 개발 및 현장 운용)

  • Choi, Woo-Jung;Cho, Jae-Woong;Shim, Jae-Hyun
    • Journal of the Korean Society of Hazard Mitigation
    • /
    • v.11 no.3
    • /
    • pp.57-61
    • /
    • 2011
  • Large scale natural disasters such as floods and typhoons due to climate change have recently occurred with severe damage in all over the world. Especially, current disaster investigation in affected area takes too much time because it can be done by handcrafted. Also, it is lack of somewhat accuracy and objectiveness because it is influenced by investigator's judgment. Further, the current disaster investigation is difficult when damage area is very wide or investigator can't reach the affected area. Hence, we developed the integrated damage investigation system using stereo images and information technology for quick, accurate and objective investigation. Also, we applied the system to Bonghwa-gun in Gyeongsangbuk-do in 2008, Jecheon-si in Chungcheongbuk-do in 2009, and Namwon-si in Jeollabuk-do and Hapcheon-gun in Gyeongsangnam-do in 2010. This paper presents advancement and application of integrated damage investigation system using stereo images and information technology considering mobility, stability and user convenience in field.

Evaluation on Risk Assessment for Landslide Hazard of Soil Slope Using the Checklists as a Preliminary Investigation Method (점검표를 이용한 토질사면 산사태 예비조사 방법 평가)

  • Kim, Jae Min;Choi, Jung Chan
    • Economic and Environmental Geology
    • /
    • v.48 no.2
    • /
    • pp.177-185
    • /
    • 2015
  • The objective of this study is to evaluate landslide hazard susceptibility and produce the landslide hazard maps for soil slope using checklists as a preliminary investigation method. Tables, proposed by NDMI (National Disaster Management Institute), are applied for slope stability assessment, and are comprised of checklists on soil slopes. Database including engineering properties of soil is constructed through the field survey and results from previous studies for The Mt. Hwangryoeng area at center of Busan. All data related to creating the thematic maps was carried out using ArcGIS 10.0. Results from using this method indicated that soil slope are evaluated from very stable to stable. Moderate stability has been partially presented along the edge of mountain. Results from landslide hazard maps can be used to prevent damage from landslides and facilitate appropriate land use planning.

The Health Hazard Evaluation Program by NIOSH (NIOSH의 건강유해도 평가 프로그램)

  • Jeong, Jee Yeon
    • Journal of Korean Society of Occupational and Environmental Hygiene
    • /
    • v.10 no.1
    • /
    • pp.147-159
    • /
    • 2000
  • The NIOSH health hazard evaluation program (HHE program) was created in response to the mandate to determine the toxic effect and potential health hazard of workplace exposure, which is found in Occupational Safety and Health Act of 1970 and the Federal Mine Safety and Health Act of 1977, A primary benefit of HHE program is its ability to provide current health hazard data to employers and employees, which assists them in identifying solutions to occupational health and safety problems in their workplaces, The HHE program also stimulates research in the development and review of sampling methods and diagnostic tests and may prompt additional exposure assesment efforts and toxicological and epidemiological studies. HHE projects also provide human exposure-toxicity data that are used to asses the validity of existing occupational health standards and to support criteria for new standards of recommendation, The HHE request is classified into four categories: 1) category 1: As a administratively invalid, 2) category 2: These are valid requests for which a site visit is not essential to an appropriate response, 3) Category 3 : These are valid requests for which a site visit is necessary for an adequate evaluation, 4) These are valid request which present a complex problem or an opportunity for research, To carry out HHE program one or methods of investigation might be used: 1) direct observation and evaluation of production processes and employee work practices 2) employees exposure level and air contamination level 3) medical test or physical examinations of employees 4) private, confidential interviews with employees 5) review of employer's record of injuries and illness, employee exposure data, medical tests and job histories. After investigation and analysing the data, NIOSH issues a final report, giving finding and recommendation.

  • PDF

Study on qunatified management for tunnel collapses on construction based on the KICT Tunnel Collapse Hazard index(KTH-Index) (터널 붕괴 위험도 지수(KTH-Index)에 기반한 터널 시공 중 붕괴 위험도 정량적 관리 사례 연구)

  • Kim, Young-Yun;Choi, Yu-Mi;Baek, Yong;Shin, Hyu-Soung;Kim, Bum-Joo
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2010.09a
    • /
    • pp.1294-1301
    • /
    • 2010
  • In this study, a case study, where a hazard management for tunnel collapses has been quantitatively undertaken based on the KICT Tunnel Hazard(KTH) index, is presented. From this, it was able to timely inform the field engineers when the more detailed investigation is required for checking if any risky factor is shown on the tunnel face. At the same time, variable additional information such as sensitivities of major influence factors are also provided to field engineers from the methodology given in this study. The additional information would be helpful for better understanding of tunnel hazard level at the current tunnelling stage and following the required actions for more detailed checks of risky factors.

  • PDF

A Study on the Thermal Characteristics and Fire Hazard of Iron Powder Accumulated on Circuit Break (차단기 누적 철분진의 열적특성과 발화위험성 연구)

  • Kim, Doo-Hyun;Kang, Yang-Hyun
    • Journal of the Korean Society of Safety
    • /
    • v.27 no.4
    • /
    • pp.20-25
    • /
    • 2012
  • The purpose of this study is to analyze the thermal characteristics and to study fire hazard of electric leakage by iron power accumulated on circuit breaker in an iron processing factory. The thermal characteristics were analyzed while current was applied to the powder for ten minutes. Results showed that temperature of iron powder at 100 mA is $160^{\circ}C$ and at 175mA is $240^{\circ}C$. The sparks have occurred as iron powder drops between two(hot line and neutral line) wires and then iron powder explosion occurred while dropping continuously the iron powder on two lines. Those who work in the iron processing industry need to periodically remove and maintain the iron powder. The thermal characteristics in this paper can be used for electrical fire investigation and for basic data of thermal characteristic of leakage current through iron powder at iron processing factories.

A Case Study on the Seismic Hazard Classification of Domestic Drinking Water Earthfill Dams Using Zero Seismic Failure Probability Curve (지진파괴확률 영곡선 활용 국내 식수전용 흙댐의 지진 위험도 분류 사례 연구)

  • Ha, Ik-soo
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.26 no.4
    • /
    • pp.173-180
    • /
    • 2022
  • Most of the drinking water dams managed by the local governments in Korea are earthfill dams, and these dams have almost no geotechnical property information necessary for seismic performance evaluation. Nevertheless, in the rough planning stage for improving seismic safety for these dams, it is necessary to classify their relative seismic hazard against earthquakes and conduct an additional ground investigation. The zero seismic failure probability curve is a curve suggested in this study in which the probability of failure due to an earthquake becomes '0' regardless of the geotechnical properties of the earthfill dam. By examining the method and procedure for calculating failure probability due to an earthquake suggested in previous researches, the zero seismic failure probability curves for an earthquake in 1,000-year and 2,400-year return periods in Korea were presented in the form of a hyperbola on the plane of the dam height versus freeboard ratio (ratio of freeboard to dam height), respectively. The distribution characteristics of the dam height and the freeboard ratio of 81 Korean earthfill dams were presented. The two proposed zero seismic failure probability curves are shown on the plane of the dam height versus freeboard ratio, and the relative seismic hazard of 81 dams can be classified into three groups using these curves as boundaries. This study presented the method of classifying the relative seismic hazard and the classification result.

Evaluation of Caisson Quay Wall Behavior during the 1995 Kobe Earthquake by Nonlinear Effective Stress Analysis (비선형 유효응력해석을 이용한 1995 Kobe 지진시 케이슨 안벽의 거동 평가)

  • Lee, Jin-sun;Noh, Gyeong-do
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.20 no.6
    • /
    • pp.401-412
    • /
    • 2016
  • On Tuesday, January 17, 1995, an earthquake of magnitude 7.2 struck the Port of Kobe. In effect, the port was practically destroyed. After a hazard investigation, researchers reached a consensus to adopt a performance-based design in port and harbor structures in Japan. A residual displacement of geotechnical structures after an earthquake is one of the most important engineering demands in performance-based earthquake-resistant design. Thus, it is essential to provide reliable responses of geotechnical structures after an earthquake through various techniques. Today, a nonlinear explicit response history analysis(NERHA) of geotechnical structures is the most efficient way to achieve this goal. However, verification of the effective stress analysis, including post liquefaction behavior, is difficult to perform at a laboratory scale. This study aims to rigorously verify the NERHA by using well-defined field measurements, existing numerical tools, and constitutive models. The man-made, Port Island, in Kobe provides intensive hazard investigation data, strong motion records of 1995 Kobe earthquake, and sufficient engineering parameters of the soil. Two dimensional numerical analysis was conducted on the caisson quay wall section at Port Island subjected to the 1995 Kobe earthquake. The analysis result matches very well with the hazard investigation data. The NERHA procedure presented in this paper can be used in further studies to explain and examine the effects of other factors on the seismic behavior of gravity quay walls in liquefiable soil areas.