• Title/Summary/Keyword: 비탄성응답

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Evaluation of Heating and Buckling Effects on Inelastic Displacement Responses of Lead-Rubber Bearing Subject to Strong Ground Motions (강진 시 납-고무 면진장치의 비탄성 변위응답에 대한 온도상승 및 좌굴효과의 분석)

  • Yun, Su-Jeong;Hong, Ji-Yeong;Moon, Jiho;Song, Jong-Keol
    • Journal of the Earthquake Engineering Society of Korea
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    • v.23 no.6
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    • pp.289-299
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    • 2019
  • The tendency to use a probabilistic design method rather than a deterministic design method for the design of nuclear power plants (NPPs) will increase because their safety should be considered and strictly controlled in relation to various causes of damage. The distance between a seismically isolated NPP structure and a moat wall is called the clearance to stop. The clearance to stop is obtained from the 90th percentile displacement response of a seismically isolated NPP subject to a beyond design basis earthquake (BDBE) in the probabilistic design method. The purpose of this study is to analyze the effects of heating and buckling effects on the 90th percentile displacement response of a lead-rubber bearing (LRB) subject to a BDBE. The analysis results show that considering the heating and buckling effects to estimate the clearance to stop is conservative in the evaluation of the 90th percentile displacement response. If these two effects are not taken into account in the calculation of the clearance to stop, the underestimation of the clearance to stop causes unexpected damage because of an increase in the collision probability between the moat wall and the seismically isolated NPP.

Layered Section Analysis for PSC Girder with Variable Cross Section Using SI Technique (SI기법을 이용한 변단면 PSC 거더의 층상화 단면해석)

  • Kim, Byeong Hwa;Park, Taehyo;Jeon, Hye-Kwan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.6A
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    • pp.581-590
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    • 2010
  • This study introduces a layered sectional analysis for a PSC girder with a vaiable cross section and curved tendons. To consider the shear equilibrium at a concrete layer with curved tendons, the shear stress distribution has been computed at each section. In addition, to improve the convergence to the solution, a system identification technique is newly adopted in the solution process for strain computation. To examine the feasibility of the proposed approach, a static load test has been conducted for a full scale PSC girder with variable cross section. The prediction shows a good agreement with experiment. It is seen that a uniform cross section has the same moment capacity with a variable cross section while the variable cross section has more shear capacity than the uniform cross section. It is also noted that the maximum displacement of a variable cross section is a little smaller than a uniform cross section.

Modified Similitude Law for Pseudodynamic Test on Small-scale Steel Models (철골 축소모헝의 유사동적실험을 위한 수정된 상사법칙)

  • Kim, Nam-Sik;Kwak, Young-Hak;Chang, Sung-Pil
    • Journal of the Earthquake Engineering Society of Korea
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    • v.7 no.6
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    • pp.49-57
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    • 2003
  • Although there are several experimental techniques to evaluate the seismic behavior and performance of civil structures, small-scale models in mast of physical tests, instead of prototypes or large-scale models, would be used due to a limitation on capacities of testing equipments. However, the inelastic seismic response prediction of small-scale models has some discrepancies inherently because the similitude law is generally derived in the elastic range. Thus, a special attention is required to regard the seismic behavior of small-scale models as one of prototypes. In this paper, differences between prototypes and small-scale models pseudodynamically tested on steel column specimens are investigated and an alternative to minimize them is suggested. In general, small-scale models could have the distorted stiffness induced from some experimental errors on test setup, steel fabrication and so on. Therefore, a modified similitude law considering both a scale factor for length and a stiffness ratio of small-scale model to prototype is proposed. Using the modified similitude law to compensate experimental errors, the pseudodynamic test results from modified small-scale model are much improved as compared with the results of prototype. According to the pseudodynamic test results of small-scale steel models, it can be concluded that the modified similitude law proposed could be effective in simulating the seismic response of prototype structures.

An Equivalent Multi-Phase Similitude Law for Pseudodynamic Test on Small-scale RC Models (RC 축소모형의 유사동적실험을 위한 Equivalent Multi-Phase Similitude Law)

  • ;;;Guo, Xun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.7 no.6
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    • pp.101-108
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    • 2003
  • Small-scale models have been frequently used for experimental evaluation of seismic performance because of limited testing facilities and economic reasons. However, there are not enough studies on similitude law for analogizing prototype structures accurately with small-scale models, although conventional similitude law based on geometry is not well consistent in the inelastic seismic behavior. When fabricating prototype and small-scale model of reinforced concrete structures by using the same material. added mass is demanded from a volumetric change and scale factor could be limited due to size of aggregate. Therefore, it is desirable that different material is used for small-scale models. Thus, a modified similitude law could be derived depending on geometric scale factor and equivalent modulus ratio. In this study, compressive strength tests are conducted to analyze equivalent modulus ratio of micro-concrete to normal-concrete. Equivalent modulus ratios are divided into multi phases, which are based on ultimate strain level. Therefore, an algorithm adaptable to the pseudodynamic test. considering equivalent multi-phase similitude law based on seismic damage levels, is developed. In addition, prior to the experiment. it is verified numerically if the algorithm is applicable to the pseudodynamic test.