• Title, Summary, Keyword: earthquake loading

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An Experimental Study on the Bond Stress Distribution along the Reinforcing Bar Subjected to Repeated Loading $\mid$ (반복하중을 받는 철근의 부착 응력도에 관한 실험적 연구)

  • Chung, L.;Cho, D.C.;Park, H.S.
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.66-71
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    • 1990
  • The prediction and estimation of R/C structure behavior subjected to earthquake type loading is partly based on the experimental results of the monotonically increased cyclic loading, rather than that of the irregularly increased cyclic loading. However, actual earthquake is typical random vibration. In this respect, comparing and analysing experimental test results of R/C specimens subjected to monotonically increased cyclic loading and irregularly increased cyclic loading, this study proposes the research direction of irregularly increased cyclic loading during earthquake.

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An Experimental Study on the Liquefaction Behavior under Various Loading Conditions (다양한 입력하중에서의 액상화 발생 특성 비교 연구)

  • Kim, Soo-Il;Hwang, Seon-Ju;Park, Keun-Bo;Choi, Jae-Soon
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.320-327
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    • 2005
  • Liquefaction characteristics of saturated sand under various dynamic loadings such as sinusoidal, wedge, increasing wedge and real earthquake loading are investigated focusing on the excess pore water pressure build up instead of liquefaction resistance strength in this paper. There are large differences between two types of earthquake loading - impact and vibration in liquefaction characteristics. The angle of phase change line of sinusoidal loading is very close to the vibration type, whereas the cumulative deviator stress and cumulative plastic strain are larger than two types of real earthquake loadings. On the other hand, the liquefaction characteristics of increasing wedge loadings are located in the range between vibration and impact earthquake loadings. It is concluded that the sinusoidal loading overestimates the resistance of soil under real earthquake loading. Based on results obtained, the increasing wedge loading can reflect the liquefaction behavior under real earthquake loadings more efficiently than sinusoidal loading based on equivalent uniform stress concept.

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Sensitivity Analysis of Rockfill Parameters Influencing Crest Displacements of CFRD Subjected to Earthquake Loading (지진하중을 받는 필댐 정부변위에 영향을 미치는 입력물성에 대한 민감도 분석)

  • Ha, Ik-Soo;Shin, Dong-Hoon
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.351-357
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    • 2006
  • In this study, quantitative sensitivity analysis on rockfill material influencing the dam crest displacement of Concrete-Faced Rockfill Dam(CFRD) subjected to earthquake loading was carried out. The purpose of this study is to indicate the most important input parameter and to show the quantitative variation of displacement at the crest of CFR type dam during earthquake loading with this input parameter. From the sensitivity analysis, it was found that the crest displacement of CFR type dam subjected to dynamic loading was absolutely affected by the shear modulus of rockfill material and the effect of friction angle of it was negligible. This relative difference of sensitivity was more outstanding in case of crest settlement than in case of crest horizontal displacement. Also, it was found that the extent of effect of shear modulus on the displacement at the crest of CFRD due to dynamic loading decreased as maximum amplitude of input acceleration increased.

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Earthquake Response Analysis of K-TGV against El Centro Earthquake (경부 고속철도차량의 El Centro 지진에 대한 지진응답해서)

  • 김준희
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.435-442
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    • 2000
  • In this thesis the dynamic behavior of the vehicles is analyzed while the track is subjected to lateral vibration due to earthquakes. A computer program is developed which can simulate dynamic responses of vehicles subjected to earthquake loading. The analysis considers two types of two types of vehicles : I. e. a 2-axle vehicle with 13 DOF's an da power car of K-TGV with 38 DOF's It can also consider the interaction with substructures such as tracks and bridges. El Centro record is considered as earthquake loading. The creep force module developed in this study is verified and the results of this study are compared with those of others. Furthermore he running safety of high-speed railway vehicles(K-TGV) subjected to earthquake loading is studied. Based on the results of this study the running safety of the K-TGV can be confirmed against el centro earthquake.

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Experimental Study on Seismic Resistance of A Unreinforced Cement Brick Building (비보강 시멘트벽돌 건물의 내진성능 실험연구)

  • 김장훈
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.298-307
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    • 2000
  • The behavior of a unreinforced cement brick building structure subjected to earthquake loading was experimentally investigated. for this four full size wall specimens were tested under quasi-static in-plane cyclic loading. Experimental observations indicate that the failure modes of unreinforced masonry walls are principally governed by sliding or/and rocking depending on the aspect ration and magnitude of axial loading. Also found was the flexure or shear mode resulting from the degraded strength of brick and/or mortar due to the cyclic loading effect.

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Bi-Axial Alternate Cyclic Loading Test of Rectangular Reinforced Concrete Columns (이축방향 교번반복하중을 받는 구형 철근콘크리트교각의 거동특성 시험)

  • 김재관;김익현;이재호;김남식
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.323-328
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    • 2001
  • The behavior of bridge column under multi-directional loading as well as uni-directional loading need to be studied because bridge columns will be subjected to the multi-directional cyclic loading during a strong earthquake. To evaluate the capacity of columns, uni-axial cyclic loading tests and bi-axial alternate cyclic loading tests were carried out. The number of cycles of alternate bi-axial loading were determined considering the ratio of natural frequencies in two orthogonal directions. From the test results, strength degradation and ductility reduction were observed in biaxial loading conditions. Their rates were found to be more rapid in the loading pattern that was determined considering the different natural frequencies.

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Evaluation of Liquefaction Resistance Strength based on the Cyclic Triaxial Tests using Real Earthquake Loading (실지진하중의 진동삼축시험에 기초한 액상화 저항강도 산정)

  • 심재욱;김수일;최재순;박근보
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.67-74
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    • 2002
  • An experimental assessment on the dynamic behavior of saturated sand which can consider the irregular characteristics of earthquakes was proposed. The equivalent uniform stress concept presented by Seed and Idriss has been applied to evaluate the liquefaction resistance strength to simplify earthquake loading. However, it was known that the liquefaction resistance strength of soil based on the equivalent uniform stress concept can't exactly mirror the dynamic characteristics of the irregular earthquake motion. In this study, estimation of the criterion of the liquefaction resistance strength was determined by applying real earthquake loading to the cyclic triaxial test. From the test results, relationships between excess pore water pressure and the earthquake characteristics such as magnitude or duration were determined. Magnitude scaling factors to determine the soil liquefaction resistance strength in seismic design were also proposed.

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A Study on the Liquefaction Resistance of Anisotropic Sample under Real Earthquake Loading (이방 구속 조건에서 실지진 하중을 이용한 액상화 저항강도 특성 분석)

  • Lee, Chae-Jin;Jeong, Sang-Seom;Kim, Soo-Il
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.1188-1191
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    • 2009
  • In this study, cyclic triaxial tests were performed with the samples which were anisotropically consolidated using irregular earthquake loading to consider in-situ condition and seismic wave. The consolidation pressure ratio(K) was changed from 0.5 to 1.0. The Ofunato and Hachinohe wave are applied as irregular earthquake loading and liquefaction resistance strength was estimated from excess pore water pressure(EPWP) ratio. As results of the cyclic triaxial tests, buildup of EPWP ratio increased as K value increased. It shows, that the isotropically consolidated sands is more susceptible to liquefaction than anisotropically consolidated sands under equal conditions such as confining pressure and dynamic loading.

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The effects of vertical earthquake motion on an R/C structure

  • Bas, Selcuk;Kalkan, Ilker
    • Structural Engineering and Mechanics
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    • v.59 no.4
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    • pp.719-737
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    • 2016
  • The present study investigated the earthquake behavior of R/C structures considering the vertical earthquake motion with the help of a comparative study. For this aim, the linear time-history analyses of a high-rise R/C structure designed according to TSC-2007 requirements were conducted including and excluding the vertical earthquake motion. Earthquake records used in the analyses were selected based on the ratio of vertical peak acceleration to horizontal peak acceleration (V/H). The frequency-domain analyses of the earthquake records were also performed to compare the dominant frequency of the records with that of the structure. Based on the results obtained from the time-history analyses under the earthquake loading with (H+V) and without the vertical earthquake motion (H), the value of the overturning moment and the top-story vertical displacement were found to relatively increase when considering the vertical earthquake motion. The base shear force was also affected by this motion; however, its increase was lower compared to the overturning moment and the top-story vertical displacement. The other two parameters, the top-story lateral displacement and the top-story rotation angle, barely changed under H and H+V loading cases. Modal damping ratios and their variations in horizontal and vertical directions were also estimated using response acceleration records. No significant change in the horizontal damping ratio was observed whereas the vertical modal damping ratio noticeably increased under H+V loading. The results obtained from this study indicate that the desired structural earthquake performance cannot be provided under H+V loading due to the excessive increase in the overturning moment, and that the vertical damping ratio should be estimated considering the vertical earthquake motion.

An Experimental Study on the Liquefaction Resistance Strength Using Real Earthquake Loadings Considering Seismic Magnitude in Moderate Earthquake Region (실지진하중을 이용한 중진지역에서의 액상화 저항강도에 관한 실험적 연구)

  • 김수일;최재순;박성용;박근보;심재욱
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.569-576
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    • 2003
  • Based on the equivalent uniform stress concept Presented by Seed and Idriss, sinusoidal cyclic loads which simplified earthquake loads have been applied in evaluating the liquefaction resistance strength experimentally. However, the liquefaction resistance strength of soil based on the equivalent uniform stress concept can not exactly reflect the dynamic characteristics of the irregular earthquake motion. The liquefaction assessment method which was invented by using the equivalent uniform stress concept is suitable for the severe earthquake region such as Japan or USA, so the proper method to Korea is needed. In this study, estimation of the resistance to liquefaction was conducted by applying real earthquake loading to the cyclic triaxial test. From the test results, the characteristics of the fine sand under moderate earthquake were analyzed and compared with the results under strong earthquakes. Typically real earthquake loads used in this study are divided into two types - impact type and vibration type. Furthermore, results of the liquefaction resistance strength based on the equivalent uniform stress concept and tile concept using real earthquake loading were compared.

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