• 제목/요약/키워드: seismic effects

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노후도를 고려한 실크기 원형단면 교각의 내진성능 휨실험 (Seismic-performance Flexural Experiments for Real Scale Piers with Circular Cross-section Considering Aging Effects)

  • 이승건;이수형;이혜린;홍기증
    • 한국구조물진단유지관리공학회 논문집
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    • 제25권6호
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    • pp.131-142
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    • 2021
  • 노후 교각은 내진설계가 적용되지 않아 소성힌지구역에 겹침이음이 대다수 존재한다. 철근부식은 철근 단면적 감소 및 겹침이음부의 거동저하를 유발하여 교각의 내진성능을 저하시킨다. 본 연구에서는 이러한 노후교각의 특성에 따라 철근부식, 겹침이음, 내진설계 및 내진 보강 여부를 고려하여 실험체를 설계 및 제작하고 실험을 통해 그 영향을 조사하였다. 실험결과, 겹침이음 또는 철근부식은 변위연성도를 감소시킨다. 내진설계 상세 또는 강판 내진보강을 적용하면 충분한 변위연성도가 확보됨을 확인하였다. 모든 비내진실험체는 소성힌지구역 내의 횡철근 겹침이음부의 풀림으로 인해 주철근 좌굴과 심부콘크리트 압축파쇄가 발생하였다. 내진설계된 실험체는 철근부식에 의한 소성힌지구역 내 횡철근의 단면감소와 갈고리 풀림에 의해 주철근 좌굴 및 심부콘크리트 압축파쇄가 발생하였다.

역량스펙트럼법을 이용한 교량의 내진성능평가 (Evaluation of Seismic Performance for Bridge Structure Using Capacity Spectrum Method)

  • 이창수;김승익;김현겸
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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    • pp.75-80
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    • 2000
  • Evaluation method of seismic performance has mainly used elastic spectrum analysis. This method has simplicity of analysis but deficiency of accuracy. And evaluation method of seismic performance using inelastic dynamic analysis reflects accurately inelasticity of material but hardly reflects site effects. This study suggested evaluation scheme of seismic performance for bridge structure using capacity spectrum method applied inelastic static analysis and standard design response spectrum of Korea Standard Specification for Highway Bridge. Two results, capacity spectrum method and inelastic dynamic analysis method, are very similar. As a result, this study appropriately supply both simplicity of analysis and accuracy of result.

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화련 대형내진시험모델의 계측지진응답 평가 (Evaluation of Measured Seismic Responses of the Hualien LSST Model Structure)

  • 현창헌
    • 한국지진공학회:학술대회논문집
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    • 한국지진공학회 1997년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Fall 1997
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    • pp.249-256
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    • 1997
  • This paper deals with the prediction and the evaluation of the measured seismic responses of the Hualien large-scale seismic test soil-structure system. The predicted analysis was carried out for the model structure by the computer code SASSI utilizing soil properties derived from geotechnical investigations and correlation analysis of recorded earthquake responses of soil. Utilizing the soil properties, seismic responses were predicted and compared with measured ones. The nonlinear effects of soil on structural responses were also evaluated.

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중력식 옹벽에 작용하는 배면 동적 토력의 영향 인자 분석 (Analysis of influence factors on the seismic earth pressure acting on gravity walls)

  • 윤석재;김성렬;김명모
    • 한국지진공학회:학술대회논문집
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    • 한국지진공학회 2002년도 추계 학술발표회 논문집
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    • pp.75-82
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    • 2002
  • The Mononobe-Okabe method is generally used to evaluate the dynamic earth force for the seismic design of retaining walls. However, the Mononobe-Okabe method does not consider the effects of the dynamic interactions between the backfill soil and the wall. In fact, a phase difference exists between the inertia force and the seismic earth pressure. In this study, shaking table tests were peformed on gravity walls retaining dry backfill sand to analyze the influence of several parameters (the unit weight of the wall, the input acceleration and base friction) on the development of the seismic earth pressure. The experiments revealed that the magnitude of the inertia force mobilized during seismic loading affected the seismic earth pressure. The difference in the phase angles between the inertia force and the seismic earth pressure was retained at 180 degrees before the wall failed but its magnitude changed significantly as the wall began to fail.

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ISSUES IN PROBABILISTIC SEISMIC HAZARD ANALYSIS FOR NUCLEAR FACILITIES IN THE US

  • Mcguire, Robin K.
    • Nuclear Engineering and Technology
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    • 제41권10호
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    • pp.1235-1242
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    • 2009
  • Probabilistic seismic hazard analysis (PSHA) is routinely conducted in the US for nuclear plants, for the determination of appropriate seismic design levels. These analyses incorporate uncertainties in earthquake characteristics in stable continental regions (where direct observations of large earthquakes are rare), in estimates of rock motions, in site effects on strong shaking, and in the damage potential of seismic shaking for engineered facilities. Performance goals related to the inelastic deformation of individual components, and related to overall seismic core damage frequency, are used to determine design levels. PSHA has the ability to quantify and document the important uncertainties that affect seismic design levels, and future work can be guided toward reducing those uncertainties.

적층고무베어링을 사용한 면진구조물의 지진해석방법 (Seismic Analysis Method for the Seismically Isolated Structures Using LRBs)

  • Koo, Gyeong-Hoi;Lee, Jae-Han
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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    • pp.553-560
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    • 2001
  • To substantiate the application of LRB(Laminated Rubber Bearing) to the seismic isolation system, it is necessary to develop a seismic analysis method considering the non-linear behavior of LRBs, which may significantly affect the seismic responses. In this paper, seismic analyses and shaking table tests are carried out for a seismically isolated structure using four LRBs. The parameter equations of seismic isolation frequency are obtained from the shaking table tests and the quasi-static tests of LRB itself to investigate the effects of the LRB characteristics in the prediction of maximum peak acceleration responses by analysis. From the comparison of the maximum peak acceleration responses obtained from numerical analyses and experiments, it is verified that the horizontal stiffness variations of LRB should be carefully considered in seismic analysis to obtain more accurate results.

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Interaction of internal forces of interior beam-column joints of reinforced concrete frames under seismic action

  • Zhou, Hua;Zhang, Jiangli
    • Structural Engineering and Mechanics
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    • 제52권2호
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    • pp.427-443
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    • 2014
  • This paper presents detailed analysis of the internal forces of interior beam-column joints of reinforced concrete (RC) frames under seismic action, identifies critical joint sections, proposes consistent definitions of average joint shear stress and average joint shear strain, derives formulas for calculating average joint shear and joint torque, and reports simplified analysis of the effects of joint shear and torque on the flexural strengths of critical joint sections. Numerical results of internal joint forces and flexural strengths of critical joint sections are presented for a pair of concentric and eccentric interior connections extracted from a seismically designed RC frame. The results indicate that effects of joint shear and torque may reduce the column-to-beam flexural strength ratios to below unity and lead to "joint-yielding mechanism" for seismically designed interior connections. The information presented in this paper aims to provide some new insight into the seismic behavior of interior beam-column joints and form a preliminary basis for analyzing the complicated interaction of internal joint forces.

Why Worry about Earthquake in Regins of Moderate Seismicity : A Case-Study of Hong Kong

  • Kuang, Jun-Shang
    • 한국지진공학회논문집
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    • 제2권3호
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    • pp.111-119
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    • 1998
  • This paper reports a part of research work on earthquake resistance consideration in regions of moderate seismicity, which is being carried out in the Department of Civil Engineering, Hong Kong University of Science & Technology. The possible seismic hazard in Hong Kong, which is located in a region of moderate seismicity, is described. A case study is presented to compare the wind and earthquake effects on Hong Kong buildings and to assess whether seismic analysis and desing is necessary for building structure. Potential problems of reinforced concrete buildings under earthquake effects in regions of moderate seismicity are discussed.

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횡하중 분포와 등가단자유도 방법의 영향을 고려한 다경간 교량의 내진성능 평가 (Seismic Performance Evaluation of Multi-Span Bridges considering Effect of Lateral Load Distributions and Equivalent SDOF methods)

  • 송종걸;남왕현;정영화
    • 산업기술연구
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    • 제26권A호
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    • pp.163-171
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    • 2006
  • To evaluate inelastic seismic responses of multi-span-bridge, the equivalent single-degree-of-freedom (ESDOF) methods and the lateral load distributions are applied to the capacity spectrum method(CSM). From the pushover analysis results using the four ESDOF methods and the six types lateral load distributions, the ESDOF method more than lateral load distribution is found to have an important influence upon the pushover analysis. The effects of the higher mode on the bridge seismic behaviors are also increased as the number of pier increase. Therefore, it can be concluded that lateral load distributions and ESDOF methods for reflection of higher mode effects should be considered in the seismic analysis of the bridge structural.

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Seismic behavior of RC building by considering a model for shear wall-floor slab connections

  • Soleimani-Abiat, Mehdi;Banan, Mohammad-Reza
    • Computers and Concrete
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    • 제16권3호
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    • pp.381-397
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    • 2015
  • Connections are the most important regions in a structural system especially for buildings in seismic zones. In R.C. structures due to large dimensions of members and lack of cognition of the stress distribution in a connection, reaching a comprehensive understanding of the connection behaviors becomes more complicated. The shear wall-to-floor slab connections in lateral load resisting systems have a potential weakness in transferring loads from slabs to shear walls which might change the path of load transformation to shear walls. This paper tries to investigate the effects of seismic load combinations on the behavior of slabs at their connection zones with the shear walls. These connection zones naturally are the most critical regions of the slabs in RC buildings. The investigation carried on in a simulated environment by considering three different structures with different shear wall layout. The final results of our study reveal that layout of shear walls in a building significantly affects the magnification of forces developed at the shear wall-floor slab connections.