• Smart Structures and Systems
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• 제4권2호
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• pp.209-220
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• 2008

A methodology for the seismic vulnerability assessment of historical monuments is presented in this paper. The ongoing work has been conducted in Tunisia within the framework of the FP6 European Union project (WIND-CHIME) on the use of appropriate modern seismic protective systems in the conservation of Mediterranean historical buildings in earthquake-prone areas. The case study is the five-century-old Zaouia of Sidi Kassem Djilizi, located downtown Tunis, the capital of Tunisia. Ambient vibration tests were conducted on the case study using a number of force-balance accelerometers placed at selected locations. The Enhanced Frequency Domain Decomposition (EFDD) technique was applied to extract the dynamic characteristics of the monument. A 3-D finite element model was developed and updated to obtain reasonable correlation between experimental and numerical modal properties. The set of parameters selected for the updating consists of the modulus of elasticity in each wall element of the finite element model. Seismic vulnerability assessment of the case study was carried out via three-dimensional time-history dynamic analyses of the structure. Dynamic stresses were computed and damage was evaluated according to a masonry specific plane failure criterion. Statistics on the occurrence, location and type of failure provide a general view for the probable damage level and mode. Results indicate a high vulnerability that confirms the need for intervention and retrofit.

• Structural Engineering and Mechanics
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• 제84권4호
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• pp.503-515
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• 2022

Based on the sliding isolation concrete LSS (liquid-storage structure), the specific seismic vulnerability is analyzed according to the general failure mode. In this study, 12 seismic inputs with different characteristics are used, and their acceleration peak values are modulated. By inputting these waves to the sliding isolation concrete storage structure, the finite-element models of different concrete rectangular LSSs are obtained and analyzed, and the failure probabilities are obtained according to the IDA (incremental dynamic analysis) curves of the structure. The results show that when the seismic acceleration peak value gradually increases from 0.1 g to 1.0 g, the failure probability of LSS gradually increases with the increase in friction coefficient. However, the failure probability of a sliding isolation LSS is less than 100% and far less than the failure probability of a non-isolated rectangular LSS, which shows that an isolated liquid storage structure continues working under a big earthquake. Thus, the sliding isolation for the concrete LSS has a significant damping effect.

• Earthquakes and Structures
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• 제19권1호
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• pp.45-57
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• 2020

This paper presents the experimental application of a new method for seismic vulnerability assessment of buildings recently introduced in literature, the SMAV (Seismic Model Ambient Vibration) methodology with reference to their operational limit state. The importance of this kind of evaluation arises from the civil protection necessity that some buildings, considered strategic for seismic emergency management, should retain their functionality also after a destructive earthquake. They do not suffer such damage as to compromise the operation within a framework of assessment of the overall capacity of the urban system. To this end, for the characterization of their operational vulnerability, a Structural Operational Index (IOPS) has been considered. In particular, the dynamic environmental vibrations of the two considered strategic buildings, the fire station and the town hall building of a small town in the South of Italy, have been monitored by positioning accelerometers in well-defined points. These measurements were processed through modern Operational Modal Analysis techniques (OMA) in order to identify natural frequencies and modal shapes. Once these parameters have been determined, the structural operational efficiency index of the buildings has been determined evaluating the seismic vulnerability of the strategic structures analyzed. his study aimed to develop a model to accurately predict the acceleration of structural systems during an earthquake.

• Earthquakes and Structures
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• 제22권6호
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• pp.609-623
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• 2022

To study the empirical seismic fragility of a reinforced concrete girder bridge, based on the theory of numerical analysis and probability modelling, a regression fragility method of a rapid fragility prediction model (Gaussian first-order regression probability model) considering empirical seismic damage is proposed. A total of 1,069 reinforced concrete girder bridges of 22 highways were used to verify the model, and the vulnerability function, plane, surface and curve model of reinforced concrete girder bridges (simple supported girder bridges and continuous girder bridges) considering the number of samples in multiple intensity regions were established. The new empirical seismic damage probability matrix and curve models of observation frequency and damage exceeding probability are developed in multiple intensity regions. A comparative vulnerability analysis between simple supported girder bridges and continuous girder bridges is provided. Depending on the theory of the regional mean seismic damage index matrix model, the empirical seismic damage prediction probability matrix is embedded in the multidimensional mean seismic damage index matrix model, and the regional rapid prediction matrix and curve of reinforced concrete girder bridges, simple supported girder bridges and continuous girder bridges in multiple intensity regions based on mean seismic damage index parameters are developed. The established multidimensional group bridge vulnerability model can be used to quantify and predict the fragility of bridges in multiple intensity regions and the fragility assessment of regional group reinforced concrete girder bridges in the future.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 봄 학술발표회 논문집
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• pp.427-439
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• 2003

A previous study evaluated the seismic response of typical multi-span simply supported (MSSS) and multi-span continuous (MSC) steel-girder bridges in the central and southeastern United States. The results showed that the bridges were vulnerable to damage resulting from impact between decks, and large ductility demands on nonductile columns. Furthermore, fixed and expansion bearings were likely to fail during strong ground motion. In this paper, several retrofit measures to improve the seismic performance of typical multi-span simply supported and multi-span continuous steel girder bridges are evaluated, including the use of elastomeric bearings, lead-rubber bearings, and restrainer cables. It is determined that lead-rubber bearings are the most effective retrofit measure for reducing the seismic vulnerability of typical bridges. While isolation provided by elastomeric bearings limits the forces into the columns, the added flexibility results in pounding between decks in the MSSS steel-girder bridge. Restrainer cables, which are becoming a common retrofit measure, are only moderately effective in reducing the seismic vulnerability of MSSS and MSC steel girder bridges.

• 한국지진공학회논문집
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• 제13권6호
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• pp.47-57
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• 2009

기존교량의 내진보강 우선순위 결정방법은 교량을 지진도 그룹으로 분류한 후 교량의 취약도 및 영향도를 고려하여 4개의 내진그룹으로 분류된다. 그러나, 현재 사용되고 있는 내진보강 우선순위 결정방법을 442개의 국도상 기존교량에 적용한 결과 비합리적인 부분이 조사되었다. 지진도를 정량화하여 좀 더 세분화할 필요가 있고, 연속경간장이 긴 PSC 박스거더교량의 취약도가 과소평가되는 모순점을 개선할 필요가 있었으며, 영향도 수준 또한 취약도 수준으로 증가시킬 필요가 있었다. 본 연구에서는 기존 교량의 조사 결과를 근거로 기존 평가기법을 수정 보완하여 개선된 내진보강 우선순위 결정방법을 제안하였다.

• Structural Engineering and Mechanics
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• 제42권5호
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• pp.609-629
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• 2012

This study deals with the assessment of low and mid rise multi-story buildings made of stone and /or brick, composite steel and masonry slabs from the sixties, known to be vulnerable to seismic hazard using the "vulnerability index" method based on buildings survey following Ain Temouchent (1999) and Boumerdes (2003) earthquakes, from where vulnerability curves are constructed using the translation method. The results obtained for the case study confirm what has been observed in situ.

• Earthquakes and Structures
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• 제14권6호
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• pp.615-626
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• 2018

The seismic vulnerability of Turkey is relatively high due to its active fault systems with potential to create destructive earthquakes. Thus, reducing the loss of life and property, the number of the earthquake-prone buildings and their retrofit requirements are considerably significant key issues under the scenario earthquakes. The street survey based rapid assessment (SSRA) method can be considered as a powerful tool to determine the seismic vulnerability of building stock of an earthquake-prone city/state. In this study, the seismic vulnerability of the building stock of the Kirikkale province in Turkey is aimed to be estimated adopting the street survey based rapid assessment method (SSRA). For this purpose, central 2074 existing reinforced concrete (R/C) buildings were structurally surveyed with rapid visual site screening and disadvantages such as, the existence of short-column, soft-story, heavy overhangs, pounding effect and local soil conditions were determined for obtaining the structural performance score of each. The results obtained from the study demonstrate that 11-25% of the surveyed buildings in the study region needs to be investigated through more advanced assessment methods. Besides, higher correlation between increasing story number and unsafe/safe building ratio is obtained for the buildings with soft-story parameter than that for those with heavy overhangs and short-column parameters. The conformity of the results of the current study with the previous documented cases of rapid assessment efforts in the recent earthquakes in Turkey shows that the SSRA method for the Kirikkale province performed well, and thus this methodology can be reliably used for similar settlement areas.

• 대한원격탐사학회지
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• 제36권6_1호
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• pp.1367-1377
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• 2020

본 연구는 2016년 발생한 9.12 경주지진을 중심으로 경주시 건축물의 지진 취약성을 평가하고 지도를 제작하는데 목적이 있다. 지진 취약성을 평가하기위해 지질공학, 물리, 구조적 요인과 관련된 11개의 영향인자를 선정하였으며, 이는 독립변수로 적용되었다. 종속변수로는 9.12 경주지진 당시 실제 피해 입은 건축물의 위치자료가 사용되었다. 평가 모델은 기계학습 방법의 RF와 SVM을 기반으로 구축하였으며, 훈련 및 검증 데이터셋은 70:30 비율로 무작위 선별되었다. 정확도 검증은 ROC 곡선을 사용하여 최적 모델을 선별하였으며, 각 모델의 정확도는 RF(1.000), SVM(0.998), 예측 정확도는 RF(0.947), SVM(0.926) 로 나타났다. RF 모델을 기반으로 경주시 전체 건축물의 예측 값을 도출하였으며, 이를 등급화 하여 지진 취약성 지도를 작성하였다. 행정동별 건물 등급 분포를 살펴본 결과, 황남동, 월성동, 선도동, 내남면이 취약성이 높은 지역으로, 양북면, 강동면, 양남면, 감포읍이 상대적으로 안전한 지역으로 나타났다.

• Earthquakes and Structures
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• 제18권3호
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• pp.321-335
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• 2020

The aim of the present contribution is to consider and underline the essential interactions among the historical knowledge, the seismic vulnerability assessment, the investigation experimental tools, the preservation of the architectural quality and the strengthening design in regard to architectural heritage conservation. These topics are argued in relation to Palazzo Murena in Perugia, designed in the eighteenth century by the famous Architect Luigi Vanvitelli, and currently headquarters of the city's University. Based on the surveys and the visual inspections, a preliminary a priori global analysis has been performed by means of the FME method. The obtained results permitted to plan an experimental tests campaign inclusive of structural health monitoring. The new achieved "knowledge" of the building allowed to refine the seismic safety assessment. In particular it was highlighted that the "mezzanine floor" can be a vulnerable element of the building with the collapse of its masonry walls. Preserving the architectural characteristics, a local reinforcement intervention is proposed for the above-mentioned level; this consists of the application of plaster with FRCM, assuring an adequate strength, without burden the masonry structure with additional weight, and therefore a decreasing of the seismic vulnerability. The necessity to consider, in this ongoing research, other local mechanisms is highlighted in the unfolding of the last part of work.