• 한국지반신소재학회논문집
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• 제23권1호
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• pp.49-60
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• 2024

최근 기후변화 등 달라진 해양 환경으로 인해 태풍 파랑의 빈도 및 강도가 증가하고 있다. 뿐만 아니라 일본, 칠레, 아이티, 중국, 인도네시아 등 세계적으로 잦은 지진으로 인해 많은 피해가 발생하고 있다. 우리나라 역시 2000년대에 들어서 태풍에 의한 피해가 증가하고 있으며, 지진의 발생 빈도와 강도도 증가하고 있다. 우리나라는 삼면이 바다로 되어있어 태풍에 의해 해안구조물에 많은 피해가 발생할 수 있으며 지진 역시 해안구조물에 많은 피해를 야기시킨다. 이처럼 국내·외적으로 태풍 파랑과 지진의 빈도 및 강도가 증가하는 추세이나 태풍과 지진을 연계한 연구는 전무하다. 따라서, 본 연구에서는 케이슨식 방파제에 태풍 파랑과 지진을 연계하여 총 4가지 Case에 대해 수치해석을 수행하였다. Case 1은 파랑하중, Case 2는 지진파를 각각 적용하였고, Case 3은 파랑하중 이후 지진 발생, Case 4는 지진파 이후 파랑하중까지 적용하여 수치해석을 수행하였다. 수치해석 결과 태풍과 지진을 연계한 Case 3과 Case 4의 경우 기존에 지반의 강도가 저하된 상태에서 하중을 적용하여 각 하중에 의한 피해가 Case 1과 Case 2에 비해 증가한 것을 확인하였다. 또한, 파랑하중 이후 지진파를 적용한 Case 3에서 피해가 가장 큰 것을 확인하였다.

• Earthquakes and Structures
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• 제11권5호
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• pp.861-871
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• 2016

The Groningen gas field shows exponential growth in earthquake event counts around a magnitude M1 with a doubling time of 6-9 years since 2001. This behavior is identified with dimensionless curvature in land subsidence, which has been evolving at a constant rate over the last few decades essentially uncorrelated to gas production. We demonstrate our mechanism by a tabletop crack formation experiment. The observed skewed distribution of event magnitudes is matched by that of maxima of event clusters with a normal distribution. It predicts about one event < M5 per day in 2025, pointing to increasing stress to human living conditions.

• 농업과학연구
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• 제47권4호
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• pp.963-978
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• 2020

Earthquakes can induce a large number of landslides and cause very serious property damage and human casualties. There are two issues in study on earthquake-induced landslides: (1) slope stability analysis under seismic loading and (2) debris flow run-out analysis. This study aims to review technical studies related to the development and application of earthquake-induced landslide models (seismic slope stability analysis). Moreover, a pilot application of a physics-based slope stability model to Mt. Umyeon, in Seoul, with several earthquake scenarios was conducted to test regional scale seismic landslide mapping. The earthquake-induced landslide simulation model can be categorized into 1) Pseudo-static model, 2) Newmark's dynamic displacement model and 3) stress-strain model. The Pseudo-static model is preferred for producing seismic landslide hazard maps because it is impossible to verify the dynamic model-based simulation results due to lack of earthquake-induced landslide inventory in Korea. Earthquake scenario-based simulation results show that given dry conditions, unstable slopes begin to occur in parts of upper areas due to the 50-year earthquake magnitude; most of the study area becomes unstable when the earthquake frequency is 200 years. On the other hand, when the soil is in a wet state due to heavy rainfall, many areas are unstable even if no earthquake occurs, and when rainfall and 50-year earthquakes occur simultaneously, most areas appear unstable, as in simulation results based on 100-year earthquakes in dry condition.

• 한국지진공학회논문집
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• 제21권6호
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• pp.295-301
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• 2017

This paper relates to the study of load characteristics applicable to wind turbine generators induced by earthquakes. An artificial design earthquake wave generated through the target spectrum and the envelope function of Richter Magnitude Scale (ML) 7.0 as in ASCE4-98 was created. A simulation of earthquake loads were performed according to the design load cases (DLC) 9.5~9.7 of GL guidelines. Additionally, simulation of seismic loads experienced by Wind Turbines installed in the Gyeongju region were carried out utilizing artificial earthquakes of ML 5.8 simulating the real earthquakes during the Gyeongju Earthquakes of Sept. 2016.

• Earthquakes and Structures
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• 제10권6호
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• pp.1391-1404
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• 2016

Peninsular Malaysia lying on the stable Sunda Plate has traditionally been considered safe with low to moderate seismicity. However, far field Sumatran mega-earthquakes have been shown to be capable of triggering ground motions felt in high rise structures in the major Malaysian cities while seismic impact from local earthquakes of moment magnitude 3.8 have reportedly induced nominal structural damages to nearby buildings. This paper presents an overview of the recent seismic activities in and around Peninsular Malaysia with reference to prominent earthquakes generated by far field interplate and local intraplate sources. Records of ground motion data and seismic hazard assessment (SHA) results available in the literature have been analyzed and discussed. The peak ground acceleration (PGA) values from historical records for few local intraplate events were observed to be higher than those for the events from Sumatran Subduction Zone. This clearly points to the need for a detailed and comprehensive SHA incorporating both far field and local sources. Such an analysis would contribute the knowledge required for secure and reliable infrastructure design and safeguard the Malaysian people and economy.

• 한국산학기술학회논문지
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• 제16권4호
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• pp.2818-2827
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• 2015

본 연구는 최근 뉴질랜드 Canterbury 지역에서 연속적으로 일어난 지진의 지진계 기록과 지리정보체계(GIS)의 정규크리깅을 이용하여 최대지반속도(PGV)와 기하평균최대지반속도(GMPGV) 컨투어를 생성하였고 이들의 공간적 패턴과 특징을 조사하였다. 지진발생 후 얻어진 데이터를 이용하여 지하의 상수도관 시스템의 성능에 주안점을 두고 연구를 수행하였다. 기하평균최대지반속도의 공간분포와 일시적인 지반거동으로 인하여 발생된 상수도관 시스템의 GIS 중첩과 비액상화지역의 기하최대지반속도와의 관계를 통하여 서로 다른 재질의 상수도관에 따른 1 km 당 매설된 상수도관 손상 개수로 산정되는 손상율을 산정하였다. 또한, 본 연구는 매설된 상수도관의 지진성능을 요약하여 설명하였다.

• Earthquakes and Structures
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• 제1권4호
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• pp.371-390
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• 2010

Historical buildings in seismically active regions are severely damaged by earthquakes, since they certainly were not designed by the original builders to withstand seismic effects. In particular the reports after major ground motions indicate that earthquake-induced pounding between buildings may lead to substantial damage or even collapse of colliding structures. The research on structural pounding during earthquakes has been recently much advanced, although most of the studies are conducted on simplified single degree of freedom systems. In this paper a detailed pounding-involved response analysis of three adjacent structures is performed, concerning the main bodies of the "Quinto Orazio Flacco" school. The construction includes a main masonry building, with an M-shaped plan, and a reinforced concrete building, separated from the masonry one and realized along its free perimeter. By the analysis of the capacity curves obtained by suitable pushover procedures performed separately for each building, it emerges that masonry and reinforced concrete buildings are vulnerable to earthquake-induced structural pounding in the longitudinal direction. In particular, due to the geometric configuration of the school, a special case of impact between the reinforced concrete structure and two parts of the masonry building occurs. In order to evaluate the pounding-involved response of three adjacent structures, in this paper a numerical procedure is proposed, programmed using MATLAB software. Both a non-linear viscoelastic model to simulate impact and an elastic-perfectly plastic approximation of the storey shear force-drift relation are assumed, differently from many commercial softwares which admit just one non-linearity.

• 한국구조물진단유지관리공학회 논문집
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• 제6권2호
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• pp.121-126
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• 2002

Due to few earthquakes in our country, one generally has thought to be safe from earthquakes. However, severe earthquakes occurred in Dangsan and Hyogohyeon which one had regarded as the zone that had not been risky for earthquakes, so that so many people died and a lot of buildings and bridges were destroyed. This event surprised our country and we undertook preparation for earthquakes on the full scale. The concept of seismic design was induced in the country which was poor in it for the scarcity of recognition and insufficiency of funds. Recently, many specialists are enforcing the provisions of seismic design. Therefore, this study introduces the method which combines PC-LEADeR( design program for L.R.B.) with LUSAS(linear elastic analysis) and performs the seismic isolation design more elaborately and simply. It verifies the propriety of that method, and it also examine the factors that affect the response of the bridges. Seismic isolation design for bridge using L.R.B. provides both economical efficiency and superior seismic performance. Second, the results between by the method proposed and by time history analysis have 20% error at the maximum. That is, the method proposed very appropriate.

• 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.

• 한국공간구조학회논문집
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• 제23권2호
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• pp.79-90
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• 2023

Existing reinforced concrete (RC) frame buildings have seismic vulnerabilities because of seismically deficient details. In particular, since cumulative damage caused by successive earthquakes causes serious damage, repair/retrofit rehabilitation studies for successive earthquakes are needed. This study investigates the repair effect of fiber-reinforced polymer jacketing system for the seismically-vulnerable building structures under successive earthquakes. The repair modeling method developed and validated from the previous study was implemented to the building models. Additionally, the main parameters of the FRP jacketing system were selected as the number of FRP layers associated with the confinement effects and the installation location. To define the repair effects of the FRP jacketing system with the main parameters, this study conducted nonlinear time-history analyses for the building structural models with the various repairing scenarios. Based on this investigation, the repair effects of the damaged building structures were significantly affected by the damage levels induced from the mainshocks regardless of the retrofit scenarios.