• Title, Summary, Keyword: seismic behavior

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Three-Dimensional Seismic Analysis for Spent Fuel Storage Rack

  • Lee, Gyu-Mahn;Kim, Kang-Soo;Park, Keun-Bae;Park, Jong-Kyun
    • Nuclear Engineering and Technology
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    • v.30 no.2
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    • pp.91-98
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    • 1998
  • Time history analysis is usually performed to characterize the nonlinear seismic behavior of a spent fuel storage rack(SFSR). In the past, the seismic analyses of the SFSR were performed with two-dimensional planar models, which could not account for torsional response and simultaneous multi-directional seismic input In this study, three-dimensional seismic analysis methodology is developed for the single SFSR using the ANSYS code. The 3D- Model can be used to determine the nonlinear behavior of the rack, i.e., sliding, uplifting, and impact evaluation between the fuel assembly and rack, and rack and the pool wall, This paper also reviews the 3-D modeling of the SFSR and the adequacy of the ANSYS for the seismic analysis. AS a result of the adquacy study, the method of ANSYS transient analysis with acceleration time history is suitable for the seismic analysis of highly nonlinear structure such as an SFSR but it isn't appropriate to use displacement time history of seismic input.

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Seismic Assessment and Performance of Nonstructural Components Affected by Structural Modeling

  • Hur, Jieun;Althoff, Eric;Sezen, Halil;Denning, Richard;Aldemir, Tunc
    • Nuclear Engineering and Technology
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    • v.49 no.2
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    • pp.387-394
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    • 2017
  • Seismic probabilistic risk assessment (SPRA) requires a large number of simulations to evaluate the seismic vulnerability of structural and nonstructural components in nuclear power plants. The effect of structural modeling and analysis assumptions on dynamic analysis of 3D and simplified 2D stick models of auxiliary buildings and the attached nonstructural components is investigated. Dynamic characteristics and seismic performance of building models are also evaluated, as well as the computational accuracy of the models. The presented results provide a better understanding of the dynamic behavior and seismic performance of auxiliary buildings. The results also help to quantify the impact of uncertainties associated with modeling and analysis of simplified numerical models of structural and nonstructural components subjected to seismic shaking on the predicted seismic failure probabilities of these systems.

Effect of Physical Shape on Seismic Performance of URM Structures (비보강 조적식 구조의 형상에 따른 내진성능 평가 해석)

  • Park, Joonam
    • Journal of the Earthquake Engineering Society of Korea
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    • v.20 no.5
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    • pp.277-283
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    • 2016
  • Unreinforced masonry (URM) buildings are known to be highly vulnerable to seismic loadings. Although significant physical variation may exist for URM buildings that fall into a same structural category, a single set of fragility curves is typically used as a representation of the seismic vulnerability of the URM structures. This study investigates the effect of physical variation of URM structures on their seismic performance level. Variables that describe the physical variation of the structure are defined based on the inventory analysis. Seismic behavior of the structures is then monitored by changing the variables to investigate the effect of each variable. The analysis results show that among the variables considered the seismic performance of URM building depends on the variation of the width, the aspect ratio, and the number of story. The need for further research on the modeling of the connections between the walls and diaphragms and the torsional effect is also addressed.

Experimental study on the deformation characteristics of RC beam-column subassemblages

  • Guo, Zixiong;Yang, Yong
    • Structural Engineering and Mechanics
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    • v.21 no.4
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    • pp.393-406
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    • 2005
  • Cyclic loading tests were carried out on six half-scale reinforced concrete beam-column subassemblages designed to the current Chinese Seismic Design Code for Buildings. The deformation behavior and restoring force characteristics of the subassemblages were studied. Emphasis was directed on their seismic behavior and deformation components. Based on test data and a simplified analysis model of the global and local deformation, the contribution of the deformation components due to beam flexure, column flexure, joint shear, and slippage of longitudinal reinforcement in the joint to the global deformation of subassemblages at different displacement amplitudes of cyclic loading was investigated.

Experimental study on seismic behavior of RC beam-column joints retrofitted using prestressed steel strips

  • Yang, Yong;Chen, Yang;Chen, Zhan;Wang, Niannian;Yu, Yunlong
    • Earthquakes and Structures
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    • v.15 no.5
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    • pp.499-511
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    • 2018
  • This paper aims to investigate the seismic performance of the prestressed steel strips retrofitted RC beam-column joints. Two series of joint specimens were conducted under compression load and reversed cyclic loading through quasi-static tests. Based on the test results, the seismic behavior of the strengthened joints specimens in terms of the failure modes, hysteresis response, bearing capacity, ductility, stiffness degradation, energy dissipation performance and damage level were focused. Moreover, the effects of the amount of the prestressed steel strips and the axial compression ratio on seismic performance of retrofitted specimens were analyzed. It was shown that the prestressed steel strips retrofitting method could significantly improve the seismic behavior of the RC joint because of the large confinement provided by prestressed steel strips in beam-column joints. The decrease of the spacing and the increase of the layer number of the prestressed steel strips could result in a better seismic performance of the retrofitted joint specimens. Moreover, increasing the axial compression ration could enhance the peak load, stiffness and the energy performance of the joint specimens. Furthermore, by comparison with the specimens reinforced with CFRP sheets, the specimens reinforced with prestressed steel strips was slightly better in seismic performance and cost-saving in material and labor. Therefore, this prestressed steel strips retrofitting method is quite helpful to enhance the seismic behavior of the RC beam-column joints with reducing the cost and engineering time.

Seismic Behavior of RC Beam-Column Exterior Joints with Unbonded Tendons and High Strength Concrete (비부착 강연선과 고강도 콘크리트를 적용한 철근콘크리트 외부 접합부의 내진 거동)

  • Kwon, Byung Un;Kang, Thomas H.-K.
    • Journal of the Earthquake Engineering Society of Korea
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    • v.19 no.6
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    • pp.283-292
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    • 2015
  • In the moment frame subjected to earthquake loads, beam-column joint is structurally important for ductile behavior of a system. ACI Committee 352 proposed guidelines for designing beam-column joint details. The guidelines, however, need to be updated because of the lack of data regarding several factors that may improve the performance of joints. The purpose of this study is to investigate the seismic performance of reinforced concrete exterior joints with high-strength materials and unbonded tendons. Three specimens with different joint shear demand-to-strength ratios were constructed and tested, where headed bars were used to anchor the beam bars into the joint. All specimens showed satisfactory seismic behavior including moment strength of 1.3 times the nominal moment, ductile performance (ductility factor = at least 2.4), and sufficiently large dissipated energy.

Seismic Shear Design of Composite Beam-Steel Column Joints (합성보-철골기둥 접합부의 내진전단설계)

  • 이승준
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.45-51
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    • 1992
  • Trilinear analytical models representing the behavior of composite beam-steel column joints and seismic shear design method for the joints are presented. Emphasis is placed on the effect of the concrete slab on the behavior of the joints. To validate the analytical models, Comparisons with the experimental results are made. Application of the proposed method to seismic shear design of joints improves the seismic resistance of the steel frame with composite slab.

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Seismic Performance of Circular Columns considering Transverse Steel Details (횡방향철근 상세에 따른 원형기둥의 내진성능)

  • 이재훈
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.259-266
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    • 2000
  • This study was conducted to investigate the seismic behavior assessment of circular reinforcement concrete bridge piers particularly with regard to assessing the displacement ductility curvature ductility response modification factor(R) and plastic hinge region etc, The experimental variables of bridge piers test consisted of transverse steel details amount and spacing different axial load levels etc. The test results indicated that reinforcement concrete bridge piers with confinement steel by the code specification exhibited suffcient ductile behavior and seismic performance. Also it is found that current seismic design code specification of confinement steel requirements may be revised.

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SEismic Performance of Circular RC Bridge Piers designed in Moderate on low Seismic Zone (중.약진 지역의 원형 내진 RC 교각의 내진성능평가)

  • 박종협;조창백;박희상;정영수
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.452-457
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    • 2000
  • This research aims at evaluating the seismic performance of the existing R/C bridge piers, which were seismically designed in accordance with the provision of moderate confinement design code (Eurocode 8). The work presented in this paper experimentally investigates the ductility and hysteretic behavior of circular reinforced concrete columns with moderate confinement. Pseudo-dynamic tests have been carried out on two scaled R/C column specimens to investigate their hysteretic behavior and other seismic performance.

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Peak seismic response of a symmetric base-isolated steel building: near vs. far fault excitations and varying incident angle

  • Pavlidou, Constantina;Komodromos, Petros
    • Earthquakes and Structures
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    • v.18 no.3
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    • pp.349-365
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    • 2020
  • Since the peak seismic response of a base-isolated building strongly depends on the characteristics of the imposed seismic ground motion, the behavior of a base-isolated building under different seismic ground motions is studied, in order to better assess their effects on its peak seismic response. Specifically, the behavior of a typical steel building is examined as base-isolated with elastomeric bearings, while the effect of near-fault ground motions is studied by imposing 7 pairs of near- and 7 pairs of far-fault seismic records, from the same 7 earthquake events, to the building, under 3 different loading combinations, through three-dimensional (3D) nonlinear dynamic analyses, conducted with SAP2000. The results indicate that near-fault seismic components are more likely to increase the building's peak seismic response than the corresponding far-fault components. Furthermore, the direction of the imposed earthquake excitations is also varied by rotating the imposed pairs of seismic records from 0◦ to 360◦, with respect to the major construction axes. It is observed that the peak seismic responses along the critical incident angles, which in general differ from the major horizontal construction axes of the building, are significantly higher. Moreover, the influence of 5% and 10% accidental mass eccentricities is also studied, revealing that when considering accidental mass eccentricities the peak relative displacements of the base isolated building at the isolation level are substantially increased, while the peak floor accelerations and interstory drifts of its superstructure are only slightly affected.