• Title/Summary/Keyword: structural safety assessment

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Development of Analytical Model to Predict The Inelastic Behavior of Reinforced Concrete And Masonry Structures (RC 및 조적조구조물의 비탄성 거동예측을 위한 해석적 모델개발)

  • 홍원기;이호범;변근주
    • Proceedings of the Korea Concrete Institute Conference
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    • 1993.04a
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    • pp.160-167
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    • 1993
  • In earthquake structural engineering towards a better understanding of both the earthquake ground motion and structural response, the design of concrete structures to resist strong ground input motions is not a simple matter, and analytical models for such structures must be developed from a design perspective that accounts for the complexities of the structural responses. The primary objective earthquake structural engineering research is to ensure the safety of structures by understanding and improving a design menthodology. Ideally, this would require the development of an analytical model related to a design methodology that ensures a dectile performance. For the accurate assessment of the adequacy of analytically developed model, experiments conducted to study the inplane inelastic cyclic behavior of structures should verify the analytical approach. The paper is to demonstrate experimentally verified analytical method that provide the adequate degree of safety and confidience in the behavior of R.C. structural components and further attempts to extend the developed modeling technique for use by practicing structural engineers.

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Probabilistic Safety Assessment of Gas Plant Using Fault Tree-based Bayesian Network (고장수목 기반 베이지안 네트워크를 이용한 가스 플랜트 시스템의 확률론적 안전성 평가)

  • Se-Hyeok Lee;Changuk Mun;Sangki Park;Jeong-Rae Cho;Junho Song
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.36 no.4
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    • pp.273-282
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    • 2023
  • Probabilistic safety assessment (PSA) has been widely used to evaluate the seismic risk of nuclear power plants (NPPs). However, studies on seismic PSA for process plants, such as gas plants, oil refineries, and chemical plants, have been scarce. This is because the major disasters to which these process plants are vulnerable include explosions, fires, and release (or dispersion) of toxic chemicals. However, seismic PSA is essential for the plants located in regions with significant earthquake risks. Seismic PSA entails probabilistic seismic hazard analysis (PSHA), event tree analysis (ETA), fault tree analysis (FTA), and fragility analysis for the structures and essential equipment items. Among those analyses, ETA can depict the accident sequence for core damage, which is the worst disaster and top event concerning NPPs. However, there is no general top event with regard to process plants. Therefore, PSA cannot be directly applied to process plants. Moreover, there is a paucity of studies on developing fragility curves for various equipment. This paper introduces PSA for gas plants based on FTA, which is then transformed into Bayesian network, that is, a probabilistic graph model that can aid risk-informed decision-making. Finally, the proposed method is applied to a gas plant, and several decision-making cases are demonstrated.

Advanced Structural Monitoring System Using Fiber Optic Sensors (광섬유 센서를 이용한 첨단 구조계측)

  • 김기수;김종우
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.10a
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    • pp.717-723
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    • 2002
  • Recently, the interest in safety assessment of civil infrastructures is increasing in Korea. Especially, as bridge structures become large-scale, it is necessary to monitor and maintain the safety state of bridges, which requires the monitoring system that can make a long-term measurement during the service time of bridge. In this paper, advanced fiber optic sensors for long-term measurement, setup techniques of bridge monitoring system and the assessment of measured data are introduced. Attached or embedded optical fiber sensors to structural members of small and big structures including Sung San Bridge are surveyed. For the Sung San Bridge, the responses of the fiber optic sensors by 30 ton weigh truck loads with various speeds ate measured. Monitoring system is also applied to the mock-up of bridges. The monitoring capability of the advanced fiber optic sensor system was confirmed.

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System Reliability-Based Safety Assessment of Steel Cable-Stayed Bridges (체계신뢰성방법에 기초한 강사장교의 안전도평가)

  • 조효남;임종권;박경훈
    • Computational Structural Engineering
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    • v.11 no.4
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    • pp.351-360
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    • 1998
  • 본 논문에서는 실용적 체계신뢰성에 기초한 강사장교의 안전도평가를 위한 체계적인 모형을 제안하였다. 공용중인 강사장교의 시스템 안전도평가를 위하여 요소신뢰성해석을 위한 케이블, 주형 그리고 주탑의 한계 상태모형과 각 요소들간의 조합파괴를 포함하는 주파괴경로를 정의할 수 있는 체계신뢰성해석 모형을 제안하였다. 요소신뢰성해석을 위한 수치해석기법으로는 AFOSM(Advanced First Order Second Moment) 방법을 사용하였고, 체계신뢰성해석을 위해서는 부분 ETA(partial Event Tree Analysis) 모형을 사용하였다. 제안된 방법의 타당성을 고찰하기 위하여 진도대교의 안전도 평가에 적용하였다. 부분 ETA 모혀을 사용한 체계신뢰성 평가 방법은 기존의 요소신뢰성 방법에 비해 구조물의 여용성을 충분히 반영하는 상당히 합리적이며 실제적인 결과를 보여주는 실용적인 방법으로 판단된다.

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A RELIABILITY-BASED CAPACITY RATING OF EXISTING BRIDGES BY INCORPORATING SYSTEM IDENTIFICATION (동특성 추정 기법과 신뢰성 해법에 의한 기설교량의 내하력 판정 방법)

  • Cho, Hyo-Nam;Yun, Chung-Bang
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1990.04a
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    • pp.37-43
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    • 1990
  • This paper develops practical models and methods for the assessment of safety and rating of damaged and/or deteriorated bridges by incorporating a system identification technique for the explicit inclusion of the degree of deterioration or damage and of the actual bridge response. And, based on the proposed model, reliability-based rating methods are proposed as LRFR(Load and Resistance Factor Rating) and system reliability-index rating criteria. The proposed limit state model explicitly accounts for the degree of deterioration or damage in terms of the damage and response factors. The damage factor in the paper is proposed as the ratio of the current stiffness to the intact stiffness. Based on the observation and the results of applications to existing bridges, it may be concluded that the proposed rating models, which explicitly account for the uncertainties and the effects of degree of deterioration or damage based on the system identification technique, provide more realistic and consistent safety-assessment and capacity-rating.

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Application of Risk-Informed Inservice Inspection for Piping in Nuclear Power Plants (리스크 정보를 활용한 배관 가동중검사 적용)

  • Jin, Young Bok;Jin, Seuk Hong;Moon, Yong Sig
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.7 no.4
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    • pp.31-37
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    • 2011
  • Pressurized Water Reactor Owners Group(PWROG) proposed and applied a risk-informed inservice inspection(RI-ISI) program to alternate existing ASME Section XI periodic inspections. The RI-ISI programs enhance overall safety by focusing inspections of piping at high safety significant(HSS) and locations where failure mechanisms are likely to be present, and by improving the effectiveness on inspection of components because the examination methods are based on the postulated failure mode and the configuration of the piping structural element. The RI-ISI programs can reduce NDE, man-rem exposure, costs of engineering analysis, outage duration and chance of complicating plant operations etc. RI-ISI methods of piping inservice inspection were applied on 3 units(KSNP : Korea Standard Nuclear Power Plant) and are scheduled to apply on the other units. In this paper, we compared and showed the results of the 2 units and we concluded that the RI-ISI application could enhance and maintain plant safety and give unquantifiable benefits.

Development of an Expert System for Fatigue Strength Assessment based on FEA (유한 요소 해석 기반 피로평가 전문가시스템 개발)

  • 최홍민;서정관;이제명;백점기;안규백
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2004.10a
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    • pp.118-125
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    • 2004
  • The assessment of fatigue property is one of the most indispensable factors to design mechanical structures or parts. For accurately assessing fatigue property, it is necessary to precisely identify the loading condition and material property of the objective structure. However, there are many kind of problems in conducting predictive activity for a design concerned with variable factor such as fatigue phenomenons and environments. Therefore, most of the fatigue problems have been assessed from exiting experiment data and prediction method. In this study, expert system is developed for simply conducting performance assessment of weldments based on Finite element Analysis carrying out performance improvement and safety assessment of welded structures.

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Derivation of Building Fire Safety Assessment Factors for Generating 3D Safety Status Map (3D 안전상태지도 제작을 위한 건물 화재안전 평가항목 도출)

  • Youn, Junhee;Kim, Taehoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.10
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    • pp.40-47
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    • 2020
  • Various technologies, systems, and legal systems are applied to prevent and quickly respond to fire disaster; nevertheless, the damages to life and property caused by fires are not reduced every year. For managing fire disaster, generating spatial information-based safety status map and procuring suitability of attribute information for each position information are essential. The safety status map is generated by deriving the fire safety status assessment factors, indexing, and locating the surveying results through various methods. In this paper, we deal with derivation of building fire safety assessment factors for 3D safety status map. At first, we survey the foreign and domestic fire assessment model cases and its factors, and analyze the applicability of Korean 3D fire safety status map. Next, assessment factors for fire safety assessment model are derived. Assessment factors are derived and categorized by their information collecting activity; factors that can be accessed through basic building information and factors that can be accessed through field survey. As a derivation result, 14 assessment factors were derived over five categories(Industry Risk, Structural Risk, Fire Fighting Facility, Fire Dangerousness, Fire Response Status).

Safety factor calibration for bridge concrete girders

  • Silva, Rita C.;Cremona, Christian
    • Structural Engineering and Mechanics
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    • v.49 no.2
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    • pp.163-182
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    • 2014
  • Safety factors proposed in codes CEB, B.A.E.L 91 and EUROCODE 1 cover a great number of uncertainties; making them inadequate for the assessment of existing structures. Suitable safety factors are established using a probabilistic assessment, once real dimensions, materials strength and existing structures deterioration mechanisms are taken into account. This paper presents a calibration method for safety factors using a typical set of RC bridges in France. It considers the principal stages of corrosion provoked by $CO_2$ and $Cl^-$ penetration and threshold indexes (${\beta}_0$) for existing structures. Reliability indexes are determined by the FORM method in the calibration method.

Reliability Assessment of Long-Period Cable-Stayed Bridges on Near Fault Earthquake(NFE) (근거리지진에서 장주기사장교의 신뢰성평가)

  • Bang, Myung-Seok
    • Journal of the Korean Society of Safety
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    • v.27 no.1
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    • pp.44-48
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    • 2012
  • The seismic safety of long-period cable-stayed bridges is assessed by probabilistic finite element analysis and reliability analysis under NFE. The structural response of critical members of cable-stayed bridges is evaluated using the developed probabilistic analysis algorithm. In this study, the real earthquake recording(Chi-Chi Earthquake; 1997) was selected as the input NFE earthquake for investigating response characteristics. The probabilistic response and reliability index shows the different aspect comparing the result from FFE earthquake. Therefore, the probabilistic seismic safety assessment on NFE earthquakes should be performed for the exact evaluation of long-period cable-stayed bridges and the earthquake resistant design criteria should be complemented.