• Title/Summary/Keyword: 상대감쇠법

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Dynamic Shear Properties of Nak-Dong River Sand Determined by Resonant Column/Torsional Shear Test (공진주/비듦전단시험을 이용한 낙동강모래의 동적전단변형특성)

  • Kim, Jin-Man;Park, Yo-Hwan;Lim, Suck-Dong
    • Journal of the Korean Geotechnical Society
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    • v.25 no.11
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    • pp.5-15
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    • 2009
  • Dynamic shear properties of Nak-Dong river sand were investigated to build a soil property database for Nak-Dong delta region. Samples were taken from the estuary and the midstream of the river. Laboratory specimens were prepared by air pluviation method, and were tested by using RC/TS apparatus at various confining stresses, relative densities and numbers of cycles. Shear modulus reduction and damping curves were developed using Ramberg-Osgood and Modified Hyperbolic Models. The developed curves, compared to those reported by other investigators, show only a slight difference. The outcome of this RC/TS experiments can be very important resources when accessing the dynamic response of sandy soils in Nak-Dong delta region in the future.

Effects of Stiffness Characteristics of Super-Structure on Soil-Structure Interaction (지반(地盤)에 대한 구조물(構造物)의 상대강도(相對剛度)가 지반(地盤)-구조물(構造物) 상호작용(相互作用)에 미치는 영향(影響))

  • Park, Hyung Ghee;Joe, Yang Hee;Lee, Yong Il
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.5 no.1
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    • pp.123-132
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    • 1985
  • The flexibility of base material gives considerable influences on seismic responses of a structure. The effects of relative stiffness between super-structure and base material on dynamic soil-structure interaction are evaluated by parametric studies. Two 5-story buildings are used for the study; one is shearwall structure with relatively higher fundamental frequency and the other is frame structure with relatively lower fundamental frequency. The structures are modeled as beam-sticks coupled with springs and dashpots representing the base material. Dynamic equilibrium equations of the soil-structure interaction system are sloved by mode superposition method using Rosset modal damping values. Soil-structure interaction effect is found to be major concern in seismic analysis of shearwall structure in most cases while it seldom becomes engineering problem in frame-type structure. It is also found that seismic responses at lower elevation of the super-structure are amplified though they decrease at higher elevation as soil-structure interaction effects of the system increase.

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