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Dynamic Response of Unreinforced Masonry Building (비보강 조적조의 동적 거동)

  • Kim, Nam-Hee;Kim, Jae-Kwan
    • Journal of the Earthquake Engineering Society of Korea
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    • v.8 no.5 s.39
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    • pp.1-14
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    • 2004
  • The seismic behavior of a 1/3-scale model of a two-story unreinforced masonry (URM) structure typically used in constructing low-rise residential buildings in Korea is studied through a shaking table test. The purposes of this study are to investigate seismic behavior and damage patterns of the URM structure that was not engineered against seismic loading and to provide its experimental test results. The test structure was symmetric about the transverse axis but asymmetric to some degrees about longitudinal axis and had a relatively strong diaphragm of concrete slab. The test structure was subjected to a series of differentlevels of earthquake shakings that were applied along the longitudinal direction. The measured dynamic response of the test structure was analyzed in terms of various global parameters (i.e., floor accelerations, base shear, floor displacements and storydrift, and torsional displacements) and correlated with the input table motion. Moreover, different levels of seismic performance were suggested for performance-based design approach. The results of the shaking table test revealed that the shear failure was dominant on a weak side of the 1stfloor while the upper part of the test model remained as a rigid body. Also, it was found that substantial strength and deformation capacity existed after cracking.

Bluefin tuna (Thunnus thynnus L.) Aquaculture in Yokjido, Tongyeong : Fluctuation of Phytoplankton and Reasonable Sinking Depth in Floating Cage (참다랑어 양식 : 욕지도 식물플랑크톤 군집구조 및 부침식 가두리 적정 침강수심)

  • Cho, Eun-Seob;Hwang, Hyung-Kyu
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.16 no.4
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    • pp.381-386
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    • 2010
  • We have cultured the bluefin tuna in Yokjido, Tongyeong with floating cage which was vulnerable to harmful dinoflagellate, Cochiodinium polykrikoides. This study inspected a vertical migration of phytoplankton and Chl-a for reasonable sinking depth in floating cage. Furthermore, we analyzed the fluctuation of the phytoplankton including harmful dinoflagellates occurring in Yokgido for 6 years. Total cell density showed a significant monthly variation and the flora was predominated with diatoms. Gymnodinium sp. occurred 19 times, the greatest number of occurrence in all kinds of dinoflagellates during summer. In particular, the total number of occurrence at C. polykrikoides was 8, and harmful dinoflagellates such as Karenia brevis/Fibrcapsa japonica occurred. The relationship between Chl-a concentration/total cell number and sunset/sunrise was significant and reasonable sinking depth in floating cage was found to be at least 3m from the water surface, which was associated with massive fish kills caused by C. polykrikoides.

An Experimental Study on Seismic Capacity Improvement of Masonry Buildings by Glass Fiber Reinforced Methods (유리섬유보강에 의한 조적조 건축물의 내진 성능향상에 관한 실험 연구)

  • Cho, Sang-Min;Choi, Sung-Mo;Kwon, Ki-Hyuk;Lee, Su-Cheul
    • Journal of the Korean Society of Hazard Mitigation
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    • v.4 no.2 s.13
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    • pp.47-52
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    • 2004
  • Whereas The masonry buildings are safe under gravity loads, most of the masonry buildings in Korea have many structural defects under a lateral load due to an earthquake acceleration. But there is no earthquake resistant design code for the Masonry in Korea. Therefore it may be necessary to be set up an seismic code and be suggested for reinforcing methods for existing masonry buildings. The purpose of this paper is to investigate seismic capacity of reinforced masonry buildings subjected to earthquake load. The typical two models of the masonry building in Korea are selected through a site investigation. On the basis of test results, the fiber reinforcing effect of the two models was considerable. The maximum base shear force and deformation capacity for RM were remarkably increased. It was found that the pier rocking failure was a dominant mode for the RM buildings during a seismic excitation.