• Earthquakes and Structures
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• 제22권2호
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• pp.121-135
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• 2022

Many public buildings such as schools, hospitals, etc., where partial infill walls are present in reinforced concrete (RC) structures, have undergone undesirable damage/failure attributed to captive column effect during a moderate to severe earthquake shaking. Often, the situation gets worsened when these RC frames are non-ductile in nature, thus reducing the deformable capability of the frame. Also, in many parts of the Indian subcontinent, it is mandatory to use fly-ash bricks for construction so as to reduce the burden on the disposal of fly-ash produced at thermal power plants. In some scenario, when the non-ductile RC frame, partially infilled by fly-ash bricks, suffers major structural damage, the challenge remains on how to retrofit and restore it. Thus, in this study, two full-scale one-bay, one-story non-ductile RC frame models, namely, bare frame and RC partially infilled frame with fly-ash bricks in 50% of its opening area are considered. In the previous experiments, these models were subjected to slow-cyclic displacement-controlled loading to replicate damage due to a moderate earthquake. Now, in this study these damaged frames were retrofitted and an experimental investigation was performed on the retrofitted specimens to examine the effectiveness of the proposed retrofitting scheme. A hybrid retrofitting technique combining epoxy injection grouting with an innovative and easy-to-implement steel jacketing technique was proposed. This proposed retrofitting method has ensured proper confinement of damaged concrete. The retrofitted models were subjected to the same slow cyclic displacement-controlled loading which was used to damage the frames. The experimental study concluded that the hybrid retrofitting technique was quite effective in enhancing and regaining various seismic performance parameters such as, lateral strength and lateral stiffness of partially fly-ash brick infilled RC frame. Thus, the steel jacketing retrofitting scheme along with the epoxy injection grouting can be relied on for possible repair of the structural members which are damaged due to the captive column effect during the seismic shaking.

• Earthquakes and Structures
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• 제21권5호
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• pp.505-514
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• 2021

A formulation based on structural reliability and cost effectiveness is proposed to provide recommendations to select the best retrofit strategy for schools with reinforced concrete frames and masonry walls, among three proposed alternatives. The cost calculation includes the retrofit cost and the expected costs of failure consequences. Also, the uncertainty of the seismic hazard is considered for each school site. The formulation identifies the potential failure modes, among shear and bending forces for beams, and flexure-compression forces for columns, for each school, and the seismic damages suffered by the schools after the earthquake of September 17, 2017 are taken into account to calibrate the damaged conditions per school. The school safety level is measured through its global failure probability, instead of only the local failure probability. The proposed retrofit alternatives are appraised in terms of the cost/benefit balance under future earthquakes, for the respective site seismic hazard, as opposed to the current practice of just restoring the structure original resistance. The best retrofit is the one that corresponds to the minimum value of the expected life cycle cost. The study, with further developments, may be used to develop general recommendations to retrofit schools located at seismic zones.

• Earthquakes and Structures
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• 제25권1호
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• pp.43-56
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• 2023

Banda Aceh is one of the areas that sustains the most damage during a natural disaster because it contains so many houses, office buildings, public facilities, and schools. Public structures in coastal areas are highly susceptible to earthquakes, resulting in high casualties and property damage. Several public structures were reconstructed during the reconstruction and rehabilitation period. Because this building is located in an area with a high risk of earthquakes, its capacity must be analyzed initially. Additionally, history indicates that Aceh Province has been struck by numerous earthquakes, including the largest ever recorded in 1983 and the most recent earthquake with a magnitude of 9.3 SR on December 26, 2004. The city of Banda Aceh was devastated by this earthquake, which was followed by a tsunami. The possibility of a large earthquake in Banda Aceh City necessitates that the structures constructed there be resistant to seismic risk. This study's objective was to evaluate the seismic performance of the existing building by applying the method of strengthening the structure in the form of jacketing columns and the addition of steel bracing in order to estimate the performance of the structure using multiple ground motions. Therefore, several public buildings must be analyzed to determine the optimal seismic retrofitting technique.

• 한국재난관리표준학회지
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• 제3권1호
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• pp.67-73
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• 2010

학교는 지진재해시 학생 및 교직원의 안전을 확보하고 지역주민의 대피소로서 기능을 수행할 수 있도록 방재교육과 대피소에 필요한 방재기능 및 내진성능을 확보해야 한다. 학생 및 교직원의 지진방재능력 향상을 위해서는 도덕, 과학, 체육 등 교과과목에 지진방재에 관한 내용을 수록하여 지도하고, 지역주민과 교직원이 학교 방재시설 및 대피소를 효과적으로 활용할 수 있도록 방재계획과 매뉴얼 개발이 필요하다. 학교시설 내진화 및 내진보강은 내진설계가 적용되지 않은 건축물을 우선적으로 선정하여 철골브레이스와 내진벽체 공법 중심으로 추진하되, 사회적 합의를 위해 노후시설의 개축 등 교육환경 개선사업과 병행해야 한다. 또한, 학교시설을 대피소로 활용하기 위해서는 필요한 방재시설을 갖추고 방재기능 개선이 필요함을 제시하였다.