• Structural Monitoring and Maintenance
• /
• 제10권1호
• /
• pp.87-105
• /
• 2023

Seismic regulations have been updated from time to time to accommodate an increase in seismic hazards. Comparison of seismic fragility of the existing bridges in Indonesia from different historical periods since the era before 1990 will be the basis for seismic assessment of the bridge stock in Indonesia, most of which are located in earthquake-prone areas, especially those built many years ago with outdated regulations. In this study, seismic fragility curves were developed using incremental non-linear time history analysis and more holistically according to the actual strength of concrete and steel material in Indonesia to determine the uncertainty factor of structural capacity, βc. From the research that has been carried out, based on the current seismic load in SNI 2833:2016/Seismic Map 2017 (7% probability of exceedance in 75 years), the performance level of the bridge in the era before SNI 2833:2016 was Operational-Life Safety whereas the performance level of the bridge designed with SNI 2833:2016 was Elastic - Operational. The potential for more severe damage occurs in greater earthquake intensity. Collapse condition occurs at As = F_PGA x PGA value of bridge Era I = 0.93 g; Era II = 1.03 g; Era III = 1.22 g; Era IV = 1.54 g. Furthermore, the fragility analysis was also developed with geometric variations in the same bridge class to see the effect of these variations on the fragility, which is the basis for making bridge risk maps in Indonesia.

• 한국해양공학회지
• /
• 제24권5호
• /
• pp.48-54
• /
• 2010

The analysis of the seismic risk of an offshore structure with a control device is presented. First, a probability density function was developed to represent seismic hazard, and seismic fragility under artificial earthquake conditions was determined. Fragility curves for an offshore structure with both passive and active control devices were determined. Displacement criteria were set to evaluate the performance of the structure. Based on numerical analysis, the seismic risk to the structure was considerably reduced when the structure had a seismic control device. The seismic risk to the actively controlled structure was decreased by 80% compared to the uncontrolled case. Reasonable performance evaluations of offshore structure with control devices can be conducted through risk analysis.

• Earthquakes and Structures
• /
• 제9권6호
• /
• pp.1291-1311
• /
• 2015

This study investigates the seismic energy dissipation capacity of a hybrid passive damper composed of a friction and a hysteretic slit damper. The capacity of the hybrid device required to satisfy a given target performance of a reinforced concrete moment resisting frame designed with reduced design base shear is determined based on the ASCE/SEI 7-10 process, and the seismic performances of the structures designed without and with the hybrid dampers are verified by nonlinear dynamic analyses. Fragility analysis is carried out to investigate the probability of a specified limit state to be reached. The analysis results show that in the structure with hybrid dampers the residual displacements are generally reduced and the dissipated inelastic energy is mostly concentrated on the dampers. At the Moderate to Extensive damage states the fragility turned out to be smallest in the structure with the hybrid dampers.

• 한국전산구조공학회논문집
• /
• 제36권3호
• /
• pp.173-184
• /
• 2023

강진에 대한 다양한 비선형 거동을 하는 부재요소들로 이루어진 교량시스템의 현재까지의 일반적인 지진취약도 평가방법은 부재-수준에서 평가하는 것이다. 본 연구의 목적 부재-수준의 지진취약도 평가결과로부터 구조시스템을 대표하는 시스템-수준의 지진취약도 평가방법을 개발하는 것이다. 교량의 지진 거동을 일반적으로 교축방향과 교축직각방향으로 구분하기 때문에 본 연구에서도 시스템-수준 지진취약도를 두 방향에 대하여 구분해 평가하였다. 길이 방향에 대한 부재-수준의 지진취약도평가는 교각, 교량받침, 충돌, 교대, 낙교에 대하여 수행하였다. 교축직각 방향에 대해서는 충돌, 교대, 낙교의 손상이 영향을 주지 않으므로 부재-수준의 지진취약도평가는 교각과 교량받침에 대하여만 수행하였다. 다양한 구조부재의 비선형모델을 이용한 지진해석은 OpenSEES 프로그램을 사용하여 수행하였다. 시스템-수준의 지진취약도는 부재-수준 사이의 손상이 직렬연결이라고 가정하고 평가하였다. 교각의 손상이 다른 부재-수준의 손상보다 시스템-수준의 지진취약도에 지배적인 영향을 주는 것을 알 수 있었다. 다시 말하면 가장 취약한 부재-수준의 지진취약도가 시스템-수준의 지진취약도에 가장 지배적인 영향을 주는 것을 의미한다.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 2001년도 춘계학술대회 논문집
• /
• pp.329-336
• /
• 2001

This study examines the fragility curves of a bridge by Capacity Spectrum Method. A sample of 10 nominally identical but statistically different bridge and 80 ground-motion time histories are considered to account for the uncertainties related to the structural capacity and ground motion, respectively. The comparison of fragility curves by Capacity Spectrum Method with those by time-history analysis indicates that the agreement is excellent for the state of at least minor damage, but not as good for the state of major damage where nonlinear effects clearly play a crucial role. Overall, however, the agreement is adequate even in the state of major damage considering the large number of typical assumptions under which the analyses of fragility characteristics are performed.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
• /
• pp.235-238
• /
• 2005

The seismic fragility analyses of reinforced concrete propelled beam are performed to evaluate safety margin. The models were simulated by Latin Hyper-Cube (LHC) method considering various aging-related deterioration of RC beam. Fragility curves under various condition subjected to static load are compared. It is found that the 20$\%$ loss of top and bottom steel 15$\%$ lower than the undegraded beam in the ultimate strength. Seismic fragility analyses were performed to find out the effect of aging-related deterioration on the dynamic behaviour of RC beam.

• Computers and Concrete
• /
• 제20권4호
• /
• pp.419-427
• /
• 2017

A methodology, based on fragility functions, is proposed to evaluate the seismic performance of seismic isolated $45^{\circ}$ skewed concrete bridge: 1) twelve types of seismic isolation devices are considered based on two different design parameters 2) fragility functions of a three-span bridge with and without seismic isolation devices are analytically evaluated based on 3D nonlinear incremental dynamic analyses which seismic input consists of 20 selected ground motions. The optimum combinations of isolation device design parameters are identified comparing, for different limit states, the performance of 1) the Seismic Isolated Bridges (SIB) and 2) Not Seismic Isolated Bridge (NSIB) designed according to the AASHTO standards.

• 시큐리티연구
• /
• 제14호
• /
• pp.261-283
• /
• 2007

범죄두려움의 원인을 설명하기 위한 최근의 연구들에서는 성, 연령, 경제수준, 범죄 피해경험 등의 미시적인 개인수준과 거시적인 지역수준과의 연계를 시도하는 연구에 관심과 노력을 보이고 있다. 하지만 이 연구에서는 이러한 지역수준의 특성에 대한 개인의 관심과 해석은 개인의 특성으로서 과거의 범죄피해경험, 범죄피해의 취약성 정도, 범죄관련 정보에 대한 관심에 따라 다를 수 있다고 보며, 미시적인 수준과 거시적인 수준의 연계를 시도하기에 앞서 개인적인 수준에서 개인의 특성과 범죄두려움의 관계에 대해서 실증적인 분석을 실시하였다. 따라서 이 연구의 목적은 범죄두려움이 과연 개인의 특성에 따라서 어떻게 느끼게 되며 또한 얼마나 많은 영향을 받게 되는지를 실증적으로 검증하는 데에 그 목적이 있다. 이 연구의 조사결과 우선 범죄피해경험이 집단간의 차이가 통계적으로 유의미한 인구통계학적 특성은 연령, 결혼상태, 최종학력, 거주하는 장소였으며, 범죄피해의 취약성 정도는 성별과 결혼상태, 범죄관련 정보에 대한 관심은 성별, 연령, 최종학력, 가족 수입, 거주장소 위치에 따라서 집단 간의 통계적으로 유의미한 차이가 있는 것으로 나타났다. 둘째, 개인적 특성 요인과 범죄두려움의 상관관계 분석을 실시한 결과 독립변수 세요인 모두 범죄두려움과 통계적으로 유의미한 상관관계를 나타내고 있었으며, 특히 범죄피해에 대한 취약성 요인이 범죄두려움과 가장 상관관계가 높게 나타났다. 마지막으로 개인의 특성으로서 범죄피해의 취약성, 범죄정보에 대한 관심, 범죄피해경험은 범죄두려움에 영향을 미쳤으며, 특히 이러한 개인적 특성 요인 중 자신이 범죄피해에 대해 취약하다고 생각 하는 범죄피해의 취약성이 범죄두려움에 가장 많은 영향을 미치는 요인으로 나타났다.

• Earthquakes and Structures
• /
• 제10권2호
• /
• pp.367-388
• /
• 2016

Eccentrically braced frames (EBFs) represent an attractive lateral load resisting steel system to be used in areas of high seismicity. In order to assess the likely damage for a given intensity of ground shaking, fragility functions can be used to identify the probability of exceeding a certain damage limit-state, given a certain response of a structure. This paper focuses on developing a set of fragility functions for EBF structures, considering that damage can be directly linked to the interstorey drift demand at each storey. This is done by performing a Monte Carlo Simulation of an analytical expression for the drift capacity of an EBF, where each term of the expression relies on either experimental testing results or mechanics-based reasoning. The analysis provides a set of fragility functions that can be used for three damage limit-states: concrete slab repair, damage requiring heat straightening of the link and damage requiring link replacement. Depending on the level of detail known about the EBF structure, in terms of its link section size, link length and storey number within a structure, the resulting fragility function can be refined and its associated dispersion reduced. This is done by using an analytical expression to estimate the median value of interstorey drift, which can be used in conjunction with an informed assumption of dispersion, or alternatively by using a MATLAB based tool that calculates the median and dispersion for each damage limit-state for a given set of user specified inputs about the EBF. However, a set of general fragility functions is also provided to enable quick assessment of the seismic performance of EBF structures at a regional scale.

• 한국지진공학회논문집
• /
• 제19권1호
• /
• pp.29-36
• /
• 2015

Base isolation is considered as a seismic protective system in the design of next generation Nuclear Power Plants (NPPs). If seismic isolation devices are installed in nuclear power plants then the safety under a seismic load of the power plant may be improved. However, with respect to some equipment, seismic risk may increase because displacement may become greater than before the installation of a seismic isolation device. Therefore, it is estimated to be necessary to select equipment in which the seismic risk increases due to an increase in the displacement by the installation of a seismic isolation device, and to perform research on the seismic performance of each piece of equipment. In this study, modified NRC-BNL benchmark models were used for seismic analysis. The numerical models include representations of isolation devices. In order to validate the numerical piping system model and to define the failure mode, a quasi-static loading test was conducted on the piping components before the analysis procedures. The fragility analysis was performed by using the results of the inelastic seismic response analysis. Inelastic seismic response analysis was carried out by using the shell finite element model of a piping system considering internal pressure. The implicit method was used for the direct integration time history analysis. In addition, the collapse load point was used for the failure mode for the fragility analysis.