• 제목/요약/키워드: In-situ vibration

검색결과 107건 처리시간 0.029초

In-situ measurement of railway-traffic induced vibrations nearby the liquid-storage tank

  • Goktepe, Fatih;Kuyuk, Huseyin S.;Celebi, Erkan
    • Earthquakes and Structures
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    • 제12권5호
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    • pp.583-589
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    • 2017
  • In this study, result of a field investigation of railway traffic-induced vibrations is provided to examine acceptability levels of ground vibration and to evaluate the serviceability of a liquid-storage tank. Free field attenuation of the amplitudes as a function of distance is derived by six accelerometers and compared with a well-known half-space Bornitz's analytical solution which considers the loss of the amplitude of waves due to geometrical damping and material damping of Rayleigh. Bornitz's solution tends to overlap vertical free field vibration compared with in-situ measured records. The vibrations of the liquid-storage tank were compared with the USA, Federal Transportation Railroad Administration (FTA) criteria for acceptable ground-borne vibrations and with the criteria in DIN 4150-3 German standard. Comparing the thresholds stated in DIN 4150-3, absolute peak particle velocities are within the safe limits, however according to FTA velocity level at the top of the water tank exceeds the allowable limits. Furthermore, it is intended to indicate experimentally the effect of the kinematic interaction caused by the foundation of the structure on the free-field vibrations.

펄스파워를 이용한 현장타설말뚝의 지지력 특성 (Bearing Capacity of In-situ Pile Installed using Pulse Power)

  • 김태훈;채수근;정규점
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2005년도 지반공학 공동 학술발표회
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    • pp.521-527
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    • 2005
  • In the past decades, complain about ground vibration and noise induced by pile driving has been quickly increased. Because of that, auger drilled piling methods have frequently used specially in urban area. However, the present auger drilled piling methods induce inevitable ground disturbance as well as a certain degree of vibration and noise due to the final hammering. For these reasons, a new auger drilled piling method is required to be developed. This paper introduces PDT(Pulse Discharge Technology) piling method and presents the characteristics of bearing capacity. The PDT piling method is to install in-situ piles using electric power so called Pulse. The pile installed by PDT appears to be able to develop shaft and end bearing capacity efficiently.

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Modelling and integrity assessment of shear connectors in precast cast-in-situ concrete bridges

  • Moyo, Pilate;Sibanda, Bongani;Beushausen, Hans
    • Structural Engineering and Mechanics
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    • 제42권1호
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    • pp.55-72
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    • 2012
  • Precast-cast insitu concrete bridge construction is widely practiced for small to medium span structures. These bridges consist of precast pre-stressed concrete beams of various cross-sections with a cast in-situ reinforced concrete slab. The connection between the beams and the slab is via shear links often included during the manufacturing process of the beams. This form of construction is attractive as it provides for standardisation, reduced formwork and construction time. The assessment of the integrity of shear connectors in existing bridges is a major challenge. A procedure for assessment of shear connectors based on vibration testing and finite element model updating is proposed. The technique is applied successfully to a scaled model bridge model and an existing bridge structure.

연속슬래브교량의 고유진동해석에 대한 수치모형 (Numerical Modeling of Reinforced Concrete Bridge Panels for Vibration Analysis)

  • 박제선;심도식;이정호;정경일
    • 산업기술연구
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    • 제17권
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    • pp.205-211
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    • 1997
  • The problem of deteriorated highway concrete slab is very serious all over the world. Before making any decision on repair work, reliable non-destructive evaluation is necessary. One of the dependable methods is to evaluate the in-situ stiffness of the slab by means of obtaining the natural frequency. By comparing the in-situ stiffness with the one obtained at the design stage, the degree of damage can be estimated rather accurately. In this paper, the numerical modeling of vibration analysis to three span continuous reinforced concrete bridge with elastic intermediate support is presented.

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지반 진동에 의한 주변침하 예측기법 사례 연구를 중심으로 (Prediction Technique of Vibration Induced Settlement -On the Basis of Case Studies)

  • 김동수;이진선
    • 한국지반공학회지:지반
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    • 제12권5호
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    • pp.103-116
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    • 1996
  • 교통하중이나 건설 작업에 의해 야기되는 지반진동은 인접구조물에 손상을 입힐 수 있으므로 중요하게 관리되어야 한다. 최근 문헌에 의하면 도심지에서 구조물 손상의 주요 원인은 진동파의 직접 전달에 의한 손상보다 지반다짐으로 야기되는 부등침하에 의한 것으로 알려져 있다. 덕 논문에서는 지반진동에 의한 주변침하 예측기 법을 사례 연구를 충심으로 소개하였다. 실험실에서 개발된 침하예측모델의 현장적용기법을 설명하였으며, 사례연구에서 계측된 침하량과 모델에서 예측된 침하량을 비교하였다. 모델에서 예측한 침하량은 실제침하량과 비교적 잘 일치하였다. 전형적인 도심지 상황에서 영향요소 연구를 수행하여 침하예민요소들을 살펴보고 현장에서의 신뢰성있는 진동 계측 및 평가 방법을 제안하였다. 이상의 연구를 통해 사직토 지반에서 진동에 의한 침하평가 및 예측을 위해 개발된 모델의 사용 가능성을 입증하였다.

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전달함수함성법을 이용한 선박구조변경시 고유진동수 추정에 관한 연구 (A study on natural frequency estimation of modified ship structure by using FRF synthesis method)

  • 김극수;최수현;조성재
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2006년도 춘계학술대회논문집
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    • pp.176-180
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    • 2006
  • When the vibration troubles occur on the ship structure during the sea trial, the rectification work is very restricted because of in-situ limitation. Usually, the finite element method is used to improve vibration characteristics of the structure, but it takes lots of time and effort in modeling the structure and adjusting the finite element model in order to consider appropriate boundary conditions of a complex ship structure. Therefore, experimental methods have been in general suggested to obtain proper countermeasures without time-consuming in modeling. In this paper, FRE(frequency response function) synthesis method is applied to estimate natural frequency of the modified ship structure, which is obtained from experimental and numerical methods.

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펌프-터빈에서 안내 베어링의 예압이 온도 및 축 진동에 미치는 영향 (Preload Effects on the Metal Temperature and Shaft Vibration in a Guide Bearing for Hydraulic Pump-Turbines)

  • 하현천;양승헌;최성필;김호종
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 1997년도 제26회 추계학술대회
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    • pp.123-128
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    • 1997
  • In-situ bearing metal temperature and shaft vibration are measured for an unload type and a preload type, m=0.87, of vertical guide bearing for hydraulic pump-turbines. Guide bearing is a tiltingpad type journal bearing consisting of eight pads whose diameter is 1,450 mm. Rotational speed is 450 rpm. Both the bearing metal temperature and the shaft vibration are very high in the unload type but are slight in the preload type, comparatively. The bearing metal temperature is decreased due to the increase of cooling effect by the increase of preload and the shaft vibration is decreased due to the increase of bearing stiffness. It is concluded that the preload effect of a guide bearing for hydraulic pump-turbines has a large influence on the bearing metal temperature and the shaft vibration.

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불균형 보상법을 이용한 능동 자기베어링 구동기의 동특성 규명 (Identification of Active Magnetic Bearing Actuator Using Unbalance Compensation Method)

  • 김철순;이종원
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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    • pp.261-266
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    • 1998
  • In this study, the in-situ parameter identification method for active magnetic bearing (AMB) actuator based on an open-loop balancing scheme is proposed. The scheme utilizes the relation between the compensating voltage and the known unbalance force. Main advantage of this method is that it is easy to use, yet it gives the actuator dynamics on the actual operating condition of an AMB system. The experimental results show that the proposed scheme compensates the known unbalance accurately and consequently identifies the actuator dynamics effectively.

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자동차 엔진오일 열화상태 in situ 측정용 전기용량 센서 (Capacitive Sensor for in situ Measurement of Deterioration of Car Engine Oil)

  • 이래덕;김한준;세메노프
    • 센서학회지
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    • 제10권4호
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    • pp.266-272
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    • 2001
  • 자동차 엔진오일의 열화상태를 직접 in situ로 측정할 수 있는 코일형 전기용량 센서를 개발하였다. 엔진 오일팬의 드레인 홀의 제한된 공간 속에서 10 pF 이상을 얻기 위하여 코일형으로 설계 제작되었다. 코일의 직경 및 권선 조건, 포머의 재질 및 구조, 차폐조건 등 안정된 전기용량 측정을 위한 설계 요구 조건을 컴퓨터 시뮬레이션과 실험적인 방법에 의해서 찾아내었다. 제작된 여러 개의 센서를 이용하여 동일한 조건의 사용오일 특성을 분석한 결과 0.25% 이내에서 일치하였다. 차량에 직접 장착하여 장기간 측정한 결과, 심한 진동과 온도 및 습도변화와 전자기적 잡음 등 열악한 차량의 조건에서도 매우 우수한 측정결과를 나타내었다.

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구조물 및 시설물 인접 구릉지의 암반굴착 발파설계 (Blast Design of Hilly Rock Excavation Adjacent to Structures and Facilities)

  • 류창하;선우춘;신희순;정소걸;최병희
    • 터널과지하공간
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    • 제4권1호
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    • pp.38-46
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    • 1994
  • This paper concerns the design of blasts adjacent to structures and facilities. In order to investigate the site characteristics, measurements of in-situ wave propagation and laboratory tests of rock cores taken from the boreholes were carried out. Effects of rock media and delay intervals on ground vibration levels were identified from over sixty measurements of three times of test blasts. For practical use in the field, an empirical propagation equation was derived so as to reflect the characteristics of rock media and delay effects. Safe limits of vibration level for structures were conservatively established based on various suggested criteria. Safe limits for facilities were adopted so that vibration levels induced by blasting should not exceed the allowable limits specified in the manufacturer's installation condition. Suggested were blast pattern and operation to enhance the rock fracturing and to reduce the ground vibration levels under the restricted conditions.

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