• 한국해안·해양공학회논문집
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• 제21권5호
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• pp.419-425
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• 2009

최근 우리나라에서는 지진으로 인한 피해가 미미하였지만, 역사기록에 의하면 피해유발 지진이 여러 차례 발생한 바 있으므로 지진으로 인한 피해 가능성을 항상 고려하여야 한다. 우리나라 대외 교역량의 99.6% 이상을 처리하는 항만시설의 중요성을 감안 할 때, 항만시설물의 지진 안전성 확보를 위한 설계 및 대응시스템 구축이 반드시 필요하다. 지진위험성 평가를 위하여 계기 지진 자료를 활용하는 것이 바람직하지만, 우리나라에서 본격적인 계기지진의 역사가 과거 30년에 국한된 관계로 계기지진 자료만으로는 우리나라의 지진 특성을 적절히 파악할 수 없다. 본 연구에서는 이러한 단점을 보완하기 위하여 규모 5.0 이상의 역사지진 자료를 계기지진 자료와 함께 활용하여 장기 광역 지진위험성 평가의 자료로 활용하였다. 역사지진자료 분석 결과에 의하면 포항항, 울산항, 인천항이, 계기지진자료 분석 결과에 의하면 옥계항, 묵호항, 동해항, 삼척항, 포항항, 울산항을 포함한 동해안의 항이 다른 지역에 비하여 지진위험성이 크게 나타난다.

• Earthquakes and Structures
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• 제10권3호
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• pp.645-667
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• 2016

The 750 m long "De Bosset" bridge in the Cephalonia Island of Western Greece, being the area with the highest seismicity in Europe, was constructed in 1830 by successive stone arches and stiff block-type piers. The bridge suffered extensive damages during past earthquakes, such as the strong M7.2 earthquake of 1953, followed by poorly-designed reconstruction schemes with reinforced concrete. In 2005, a multidisciplinary project for the seismic assessment and restoration of the "De Bosset" bridge was undertaken under the auspices of the Greek Ministry of Culture. The proposed retrofitting scheme combining soil improvement, structural strengthening and reconstruction of the deteriorated masonry sections was recently applied on site. Design of the rehabilitation measures and assessment of the pre- and post-interventions seismic response of the bridge were based on detailed in-situ and laboratory tests, providing foundation soil and structural material properties. In-situ inspection of the rehabilitated bridge following the strong M6.1 and M6.0 Cephalonia earthquakes of January 26th and February 3rd 2014, respectively, revealed no damages or visible defects. The efficiency of the bridge retrofitting is also proved by a preliminary performance analysis of the bridge under the recorded ground motion induced by the above earthquakes.

• Earthquakes and Structures
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• 제11권6호
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• pp.1043-1060
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• 2016

The engineering background of this article is an ancient wooden building with extremely high historic and cultural values in Tibet. A full understanding of the dynamic behaviour of this historic building under in-service environments is the basis to assess the condition of the structure, especially its responses to earthquake, environmental and operational loading. A dynamic monitoring system has been installed in the building for over one year and the large amounts of high quality data have been obtained. The paper aims at studying the dynamic behaviour of the wooden building in seismic and operational conditions using the field monitoring data. Specifically the effects of earthquake and crowd loading on the structure's dynamic response are investigated. The monitoring data are decomposed into principal components using the Singular Spectrum Analysis (SSA) technique. The relationship between the average acceleration amplitude and frequencies of the principle components and operational conditions has been discussed. One main contribution is to understand the health condition of complex ancient building based on large databases collected on the field.

• Earthquakes and Structures
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• 제18권6호
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• pp.731-742
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• 2020

Due to incessant earthquakes, many historic South Nias traditional timber houses have been damaged while some still stand today. As Nias is part of an extremely active tectonic region and the buildings are getting older by day, it is essential that these unique houses are well maintained and functioning well. A post-earthquake condition assessment was conducted on 2 selected buildings; 'Building A' survived the seismic shakings while 'Building B' got severely damaged. The overall condition assessment of "Building A' was found out to be poor and the main structural members were not performing as intended. In 'Building B', the columns were not well anchored to the ground, no tie beams to tie the columns together, and eventually, the timber columns moved in various directions during the earthquake. The frequent earthquakes along with deterioration due to lack of proper maintenance program are responsible for the non-survival of the buildings. Thus, a process guideline for managing the maintenance of these buildings was proposed. This is necessary because managing the maintenance works could help to extend the life of the buildings and seek to avoid the need for potentially expensive and disruptive intervention works, which may damage the cultural significance of the buildings.

• 암석학회지
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• 제25권3호
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• pp.253-260
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• 2016

2010년 2월 9일 수도권에서 모멘트 규모 3.1 지진이 발생했다. 수도권 지역에서는 계기지진 관측이 시작된 후 오랫동안 유감지진 보고가 없었기 때문에, 이 지진은 수도권의 지진 위험성과 위해성을 상기시키는 계기가 되었다. 수도권은 약 2천 5백만 명의 인구밀집지역으로서 인구수 측면에서 본다면 세계에서 가장 큰 대도시 중 하나이다. 이 지진이 발생한 위치에서 규모 6.5의 지진이 발생했음을 가정하여 지진동을 시뮬레이션 해보면, 많은 인구와 구조물의 취약성으로 인하여 서울을 포함한 수도권 지역은 매우 심각한 위해성을 가지고 있을 것으로 생각된다. 본 연구의 동기를 제공한 시흥 지진이 피해를 야기할 수 있는 주요 지진으로 간주될 수는 없지만, 이 지역의 역사적 지진기록과 최근 지진발생 현황에 비추어 볼 때 그 중요성을 간과해서는 안 된다. 또한 수도권처럼 지진발생이 많지 않은 곳에서는 기존의 지진관측망으로 감시하는 지진보다 작은 규모의 지진을 지진위험성 및 위해성 평가에 사용할 것을 제안한다.

• 한국지진공학회논문집
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• 제20권7_spc호
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• pp.443-451
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• 2016

A Gyeongju earthquake in the magnitude of 5.8 on the Richter scale (the moment magnitude of 5.4), which was recorded as the strongest earthquake in Korea, occurred in September 12, 2016. Compared with the 2011 Virginia earthquake, the moment magnitude was slightly smaller and its duration was 3 seconds, much shorter than 10 seconds of the Virginia earthquake, resulting in relatively minor damage. But the two earthquakes are quite similar in terms of the overall scale, unexpectedness, and social situation. The North Anna Nuclear Power Plant, which is a nuclear power plant located at 18 km away from the epicenter of the Virginia earthquake, had no damage to nuclear reactors because the reactors were automatically shut down as the design basis earthquake value was exceeded. Ground accelerations of the 2016 Gyeongju earthquake did not exceed the threshold value but the manual shutdown was carried out so that Wolsong Nuclear Power Site was not damaged. Damaged historic homestead house and masonry structures due to the Virginia earthquake have been repaired, reinforced, and rebuilt based on a long-term earthquake recovery project. Likewise, it will be necessary to carefully carry out an earthquake recovery planning program to improve overall seismic performance and to reconstruct the historic buildings and structures damaged as a result of the Gyeongju earthquake.

• 국제초고층학회논문집
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• 제4권3호
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• pp.191-198
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• 2015

It is important to accurately predict structural responses to external excitations such as typhoons and earthquakes when designing structures for serviceability. One of the key procedures to predict reliable vibration responses is to evaluate accurate structural dynamic properties using finite element (FE) models, which properly represent the realistic behavior of buildings. In the case of historic masonry buildings, structural damage could also be caused by ambient vibrations or impacts. Therefore, the preservation plans of historic buildings for low-level vibrations or impacts should be provided by analyzing structural damages within serviceability levels. For this purpose, it is required to provide FE model construction and response analysis methods verified with field measurement data. In this research, long-term field measurement was performed for a cathedral and its dynamic properties were evaluated using measured data. Then, the model was calibrated based on the measured dynamic properties and an overall construction method for the masonry cathedral was proposed. Using the measured accelerations, the vibrations of the belfry were analyzed using the calibrated FE model and finally, the FE model for the cathedral was verified by comparing the measured accelerations with the modeled results.

• Advances in concrete construction
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• 제5권6호
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• pp.639-658
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• 2017

Very limited studies have been accomplished concerning the historical structures around Harran area. Collected mortar samples from the historic structures in the area were tested to explore their mechanical, chemical and mineralogical properties. Mortar samples from three different points of each historical structure were taken and specified in accordance with the related standards taking into consideration their mechanical, chemical and mineralogical properties. By means of SEM-EDX the presence of organic fibres and calcite, quartz, plagioclase and muscovite minerals has been examined. Additionally, by means of XRF analysis, oxide ($SiO_2$, $Al_2O_3$, and $Fe_2O_3$) percentages of mortar ingredients have been specified, also. According to the test results obtained, it was confirmed that the mortars had densities ranging between $1.51-2.10g/cm^3$, porosity values ranging between 8.89-35.38% and compressive strengths ranging between 5.02-5.90 MPa. Specimen HU, which has the highest durability and lowest water absorption and porosity, was the mortar taken from the most intact building in the mosque complex. This result is most likely due to the very little fine aggregate content of HU. In contrast, HUC mortars with a small amount of fine particles and brick contents yielded slightly lower compressive strengths. The interesting point of this study is the mineralogical analysis results and especially the presence of ettringite in these historic mortars linked to the use of pozzolanic materials. Survival of these historic structures in Harran Area through centuries of use and, also, having been subjected to many earthquakes can probably be explained by these properties of the mortars.

• Earthquakes and Structures
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• 제12권2호
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• pp.223-236
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• 2017

Seismic assessment and rehabilitation of Monumental Buildings constitute an important issue in many regions around the world to preserve cultural heritage. On the contrary, many recent earthquakes have demonstrated the high vulnerability of this type of structures. The high nonlinear masonry behaviour requires ad hoc refined finite element numerical models, whose complexity and computational costs are generally unsuitable for practical applications. For these reasons, several authors proposed simplified numerical strategies to be used in engineering practice. However, most of these alternative methods are oversimplified being based on the assumption of in-plane behaviour of masonry walls. Moreover, they cannot be used for modelling the monumental structures for which the interaction between plane and out-plane behaviour governs the structural response. Recently, an innovative discrete-modelling approach for the simulation of both in-plane and out of-plane response of masonry structures was proposed and applied to study several typologies of historic structures. In this paper the latter model is applied with reference to a real case study, and numerically compared with an advanced finite element modelling. The method is applied to the St.Venerio church in Reggiolo (Italy), damaged during the 2012 Emilia-Romagna earthquake and numerically investigated in the literature.

• Computers and Concrete
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• 제18권1호
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• pp.99-112
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• 2016

Since the preservation of monuments is very important to human societies, different methods are required to preserve historic structures. In this paper, 3D model of arch stone bridge at Pont Saint Martin, Aosta, Italy, was simulated by 1660 integrated separate stones using ABAQUS$^{(R)}$ software to investigate the seismic susceptibility of the bridge. The main objective of this research was to study a method of preservation of the historical stone bridge against possible earthquakes using FRP techniques. The nonlinear behavior model of materials used theory of plasticity based on Drucker-Prager yield criterion. Then, contact behavior between the block and mortar was modeled. Also, Seismosignal software was used to collect data related to 1976 Friuli Earthquake Italy, which constitutes a real seismic loading. The results show that, retrofitting of the arch stone bridge using FRP techniques decreased displacement of stones of spandrel walls, which prevents the collapse of stones.