• 제목/요약/키워드: Schmidt hammer test

검색결과 73건 처리시간 0.027초

저변성퇴적암 사면에서 지질특성이 차별풍화에 미치는 영향 (Effect of geological characteristics on differential weathering of low-graded metasedimentary rock slopes)

  • 정해근;서용석;임명혁
    • 한국터널지하공간학회 논문집
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    • 제15권4호
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    • pp.375-385
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    • 2013
  • 본 논문에서는 천매암을 중심으로 저변성퇴적암류에 속하는 암석을 대상으로 암석학적 특징과 풍화도의 상관성에 대하여 분석하였다. 현장 지질조사를 통하여 암석의 풍화도를 결정하였고, 구성암석의 강도 값을 추정하기 위하여 슈미트해머 테스트를 실시하였다. 9개 시료의 현미경 박편 관찰을 통하여 주구성광물의 부피비와 엽리의 간격을 측정하였다. 암석시료의 현미경 분석 결과에 의하면 풍화도가 낮을수록 풍화에 강한 석영성분이 많고, 풍화도가 높을수록 풍화에 약한 운모성분이 많은 것으로 나타났다. 또한 엽리 간격이 좁을수록 강도는 낮고 풍화도는 높은 것으로 나타났다.

화재 피해를 입은 고강도 철근 콘크리트 압축부재의 비파괴 검사 (Non destructive test of Fire-damaged reinforced concrete columns with high strength concrete)

  • 서지민;이수진;최은규;신영수;이차돈;권영진
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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    • pp.13-16
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    • 2005
  • This study is aimed to investigate the strength variation of fire-damaged reinforced concrete column by non-destructive test. It is studied to infer the recovery degree of residual strength of fire-damaged concrete. For measuring the surface hardness of RC columns. Schmidt hammer test is used. Testing is performed three-times: before fire test, directly after fire test and after 20 days.

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비파괴방법에 의한 화해를 입은 고강도 콘크리트의 강도추정 (Strength Evaluation of Fire-Damaged High Strength Concrete by Non-Destructive Tests)

  • 김희선;박재영;최은규;신영수
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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    • pp.392-395
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    • 2004
  • When a concrete member is damaged by fire accident, it can lose its strength. And the degradation rate of losing its strength affected by many environmental conditions. But there is few research for equation for strength evaluation of fire-damaged concrete. Besides, it is impossible to destruct structural member from the building for the evaluation. So, I will suggest a new equation for strength evaluation of fire-damaged RC beam using non-destructive test. For this purpose, the researchers are exploring the performance of non-destructive testing methods using Ultrasonic test, Schmidt Hammer test and Coring test against fire damaged concrete specimen.

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지하구조물 공용년수를 고려한 반발경도법에 의한 강도추정식의 제안 (A Study on the Proposal of Strength Presumption Equation of Concrete Using Rebound Test and Aging Effects of Underground Structures)

  • 나성옥;윤태국;이종우
    • 한국재난관리표준학회지
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    • 제2권4호
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    • pp.59-65
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    • 2009
  • 현재 대부분 사용되고 있는 반발경도법을 이용한 강도 추정식을 서울의 대표적인 지하구조물에 적용할 경우 준공년도에 따른 재령계수의 적용이 부적합한 것으로 판단됨에 따라 본 연구에서는 최근 8년간 수행된 서울지하철 정밀안전진단결과를 이용하여 코어의 일축압축강도와 동일위치에서 실시된 반발경도 시험결과와의 상관관계에 준공년도를 고려하여 공용중인 박스 및 터널구조물에 대한 합리적인 강도평가 추정식을 제시하였다.

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암석의 종류와 방향에 따른 물리적 특성과 상호관계 (Characteristics of Physical Properties of Rocks and Their Mutual Relations)

  • 원연호;강추원;김종인;박현식
    • 터널과지하공간
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    • 제14권4호
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    • pp.261-268
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    • 2004
  • The main objectives of this study are to investigate the anisotropic characteristics of rocks and to evaluate the relationships between physical properties. A series of experiments were performed in three mutually perpendicular directions for three rock types, which are granite, granitic gneiss and limestone. The relationships of measured physical properties were evaluated. The results of ultrasonic wave velocity measurement show that granite of three rock types gives the largest directional difference, and that the wave velocity in a plane parallel to a transversely isotropic one is dominantly faster than that in a subvertical or vertical plane. It implies that ultrasonic wave velocity for rock could be used as a useful tool for estimating the degree of anisotropy. The ratio of uniaxial compressive strength to Brazilian tensile strength ranges approximately from 13 to 16 for granite. from 8 to 9 for granite gneiss, and from 9 to 18 for limestone. The directional differences for granite and granitic gneiss are very small, and on the other hand, is relatively large for limestone. It is suggested that strength of rock makes quite difference depending on the rock types and loading directions, especially for the anisotropic rocks such as transversely isotropic or orthotropic rocks. The ratio of uniaxial compressive strength to point load strength index ranges from 18 to 20 for granite, from 17 to 19 for granitic gneiss, and from 21 to 24 for limestone. These results show that point load strength index makes also a difference depending on rock types and directions. Therefore. it should be noted that the ratio of uniaxial compressive strength to point load strength index could be applied to all rock types. Uniaxial compressive strength shows relatively good relationship with point load strength index, Schmidt hammer rebound value, and tensile strength. In particulat, point load strength index is shown to be the best comparative relationship. It is indicated that point load test is the most useful tool to estimate an uniaxial compressive strength indirectly.

반발 경도법의 고강도 콘크리트 적용성 검토 (A Study on application of High Strength Concrete by Non-Destructive Test)

  • 김희두;임성주;박용규;김현우;윤기원;양성환
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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    • pp.69-70
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    • 2013
  • This is an foundational study to adequacy the non-destruction testing for the estimation of compressive strength of high strength concrete The results are as follows, In high strength concrete, H type is NR type rebound number rather than higher. The relation between rebound number and compressive strength of high strength concrete have lower coefficient. when compressive strength estimation of high strength concrete, it consider that rebound hardness test is not applied and should be consider to combined method or addition method.

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AE기법을 이용한 PSC보의 음파속도 및 음원위치 산정 (Evaluation of Velocity and Source Locations of Acoustic Signals in PSC Beam)

  • 윤석구;김은겸;최민석
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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    • pp.330-333
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    • 2006
  • In this paper experimental tests were performed to evaluate velocities of the acoustic waves through prestressed concrete beam and source locations using AE technique. Seven AE sensors are mounted on the surface of 5m length test beam with equal spacing and using Schmidt Hammer AE events are made 18 locations. The velocities of AE signals are evaluated using the time differences of arrival times and the distances between the AE source loactions and the AE sensor locations. In addition, using the Least Square Method, the AE source locations are re-evaluated reversely using both of the arrival times and the velocities of AE signals. Test results show the average velocity of the AE signals is about 4,000m/sec and the velocity decreased with the increase of the trevalling times due to the effect of attenuation. Based on the estimation of the source locations, it is observed that the accuracy of source location is increased when the velocity of each AE sensor used rather than the average velocity.

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석축구조물 및 배면지반의 안정성 검토사례연구 (A Case Study on the Stability Analysis for Masonry Retaining Walls and Backfill)

  • 천병식;여유현;김경민
    • 한국구조물진단유지관리공학회 논문집
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    • 제5권1호
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    • pp.149-160
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    • 2001
  • In this paper, the stability analyses were performed for masonry retaining wallls in Seoul subway System. This masonry retaining wallls were reinforced with earth anchor system for the construction, but it was removed after construction. Therefore, the stability of masonry retaining wallls should be checked after the earth anchors removed. For stability analysis of masonry retaining wallls. FDM analysis(FLAC Ver.3.3) and slope stability analysis (SLOPE/W) were performed applying the test results from laboratory and field tests(Schmidt hammer test, cack examination). As conclusion, the tension force of earth anchors should be kept, therefore, substitutional method was required in order to keep the tension force of earth anchor system.

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조합법에 의한 현장 콘크리트 강도의 비파괴 측정에 관한 연구 (A Study on the Determination of In-Situ Concrete Strength by Combined Nondestructive Testing Method)

  • 임선택;김창환;김영진;정한중
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1992년도 봄 학술발표회 논문집
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    • pp.114-119
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    • 1992
  • The main disadvantages of destructive testing methods are the delay in obtaining test results, the relatively high cost of testing, and the lack of reproducibility in the test results. As a result, nondestructive testing methods are generally used. There are three objectives in this paper. The first is to determine the equations of the compressive strength of concrete estimated by Schmidt hammer technique, ultrasonic pulse velocity method and combined method respectively in laboratory. The second is to determine the correction factors according to the concrete age which affects most in evaluating the compressive strength of in-situ concrete. The third is to examine the applicability of the equations to evaluation of the compressive strength of in-situ concrete structures.

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대구 지하철 터널의 적정지보패턴 선정에 관한 연구 (Optimum Support Pattern Design of the Tae-Gu Subway Tunnel)

  • 지왕률;최재진
    • 터널과지하공간
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    • 제4권2호
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    • pp.119-131
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    • 1994
  • This is a Double-Track Railway tunnel in typical Tae-Gu black and gray shale forming part of the No.1 Line of the Tae-Gu Subway. The main fault zone at tunnel is a moderately to highly weathered and closely jointed zone, 0.5 m wide with associated paralled jointing which is slickensided and fractured. After excavation by blasting, the soft rocks should need to be reinforced with optimal supporting pattern which might be better redesigned through the consideration of the results of in-situ rock measurements at the field. Performances fo the field tests included Point Load Test, Schmidt Hammer Test, and field joint measurement gave the detail data for the optimum support design and safe excavation of the No.1 Line of Tae-Gu Subway at the No.1-7 consturction site adn the safety of this redesigned supports system was analysed by the FDM program FLAC.

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