• Title/Summary/Keyword: Maximum displacement

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Seismic Performance Evaluation of Multi-Span Bridges using CSM and modified DCM (역량스펙트럼 방법과 수정변위계수법을 이용한 다경간 교량의 내진성능 평가)

  • Nam, Wang-Hyun;Song, Jong-Keol;Chung, Yeong-Hwa
    • Journal of Industrial Technology
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    • v.26 no.B
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    • pp.119-126
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    • 2006
  • Capacity spectrum method(CSM) of ATC-40(1996) and displacement coefficient method(DCM)of FEMA-273(1997) are applied to evaluate the seismic performance of bridges. In this study, equivalent response is obtained from nonlinear static analysis for the 3spans continues bridge and nonlinear maximum displacement response is calculated using CSM and DCM. Nonlinear maximum displacement response of DCM is larger than this of CSM. It is method that DCM can evaluate target displacement and ductility of structural to be easy and simple, but tend to overestimate the maximum displacement response. Therefore, this method is mainly used at preparation design level to evaluate the structural response. It is not desirable to evaluate the seismic performance using DCM.

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The Stability of Excavated Soft Ground Supported by Sheet-pile Walls (강널말뚝 흙막이벽으로 시공된 굴착연약지반의 안정성)

  • Hong Won-Pyo;Kim Dong-Uk;Song Young-Suk
    • Journal of the Korean Geotechnical Society
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    • v.21 no.1
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    • pp.5-14
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    • 2005
  • Based on the field measuring data obtained from excavation sections in Inchon International Airport project, the relationships between the horizontal displacement of sheet-pile walls and the deformations of soft ground around the excavation were investigated. The horizontal displacements of walls according to supporting method occur, and the displacements were found to become larger in the order of anchors, anchors with struts, and struts. The depths of maximum horizontal displacement are varied with supporting systems. If the stability number shows lower than ${\pi}$, the maximum horizontal displacement and the velocity of maximum horizontal displacement are respectively developed less than $1\%$ of excavation depth and 1mm/day. When the stability number shows lower than ${\pi}+2$, the maximum horizontal displacement and the velocity are respectively developed less than $2.5\%$ of excavation depth and 2mm/day. Also, when the stability number shows more than ${\pi}+2$, the maximum horizontal displacement and the velocity rapidly increase. Also, the maximum horizontal displacement is found to increase rapidly when N value is less than 10. The maximum horizontal displacement increases with decreasing the factor of safety against basal heave (Terzaghi, 1943), and the maximum horizontal displacement is found to increase rapidly when the factor of safety against basal heave is greater than 2.0. This value can be proposed as the criterion for the factor of safety against basal heave in Korea.

Centrifuge Modeling on the Deformation Modes of Dredged Clay Slope (준설 점토사면의 변형양상에 관한 원심모델링)

  • Ahn, Kwangkuk;Kim, Jeongyeol;Zheng, Zhaodian;Lee, Cheokeun
    • Journal of the Korean GEO-environmental Society
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    • v.8 no.2
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    • pp.19-27
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    • 2007
  • In this study, the centrifugal tests were performed with varying the angle of slope such as 1:3, 1:2.5, and 1:2 in order to analyze the deformation and failure type of dredged clay slope for a short term. The displacement mode, displacement vector and the variation of pore pressure with the different slope angle were measured. As a results, even though the displacement in the slope after 4 months were developed in the case of 1:3 for the dredged slope, there are little problems to obtain the stability of dredged slope because the original construction section maintains. Also, in the case of 1:2.5 after 4 months the local slope failure occurred and in the case of 1:2 after 2 months the circle failure starting from the point of the tensile crack occurred. After reviewing the results, the maximum vertical displacement occurred at the crest of slope and maximum horizontal displacement was about double of maximum vertical displacement.

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A Study on Behavior of the Earth Retaining Structure by Field Measurement and Numerical Analysis (현장계측과 수치해석에 의한 흙막이구조물의 거동 비교분석)

  • Wo, Jongtae
    • Journal of the Society of Disaster Information
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    • v.13 no.3
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    • pp.286-295
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    • 2017
  • In this study, it is compared various coefficients of subgrade reaction for application of numerical analysis based on measured data by using various theories and empirical formula. The ratio of the maximum and minimum value is 6.80 at the top of wall but it is 1.06 at the maximum displacement point depends on change of calculated coefficient of subgrade reaction. The data of displacement were generally similar considering an increment of a coefficient of subgrade reaction. And the results of comparison of the displacement at the maximum displacement point by numerical analysis and measured data show similar displacement shape.

Characteristic Analysis of Displacement Behavior of Hollow Rollers with Cross Sectional Area Profiles (중공롤러의 절단면 형상변화에 따른 변형거동 특성해석)

  • Chung, Joon Ki;Kim, Chung Kyun
    • Journal of the Korean Institute of Gas
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    • v.19 no.4
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    • pp.55-61
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    • 2015
  • In this paper, the displacement behavior characteristic of hollow rollers with various cross sectional area profiles and circular plate for load supporting capacity increment has been presented using a finite element method. The FEM results present that the hollow roller with X-shaped or Y-shaped columns between outer tube, middle tube and inner tube reduces a maximum displacement at the middle length of hollow rollers. And the circular plate, which is inserted at the middle of the hollow roller, is very useful to reduce the maximum displacement of hollow rollers with the plate thickness of 30~40mm. This paper presents the weight vs the maximum displacement ratio in which is represented for the optimized design as a function of a hollow roller total weight. The FEM analyzed results recommend the design model 4, 5 and 6 of hollow rollers for decreasing the ratio of maximum displacement and total weight of hollow rollers.

The Behavior of Sheet Piling Walls supported by Anchors in Soft Ground (연약지반에 설치된 앵커지지 강널말뚝 흙막이벽의 거동)

  • 홍원표;송영석;김동욱
    • Journal of the Korean Geotechnical Society
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    • v.20 no.4
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    • pp.65-74
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    • 2004
  • Based on the field measuring data obtained from seven excavation sections in Inchon International Airport Project, the horizontal displacement of sheet piling walls supported by anchors and the lateral earth pressure acting on sheet piling walls was investigated in soft ground. The proposed diagram of lateral earth pressure is a rectangular form, and the maximum earth pressure corresponds to $0.6\gamma H$. The maximum earth pressure is similar to the empirical earth pressure proposed by NAVFAC(1982). The quantitative safe criterion of sheet piling walls with struts is established from the relationships between increasing velocity of maximum horizontal displacement and stability number in excavated ground. If the velocity of maximum horizontal displacement shows lower than 1mm per day, the sheet piling walls exist under stable state. When the velocity of maximum horizontal displacement becomes more than 1mm and less than 2mm per day, excavation works should be observed with caution. Also, when the velocity of maximum horizontal displacement becomes more than 2mm per day, appropriate remediations and reinforcements are applied to sheet piling walls.

An Analytical Study on the Change of System Supports according to the Brace Installation (가새 설치 여부에 따른 시스템 동바리 거동변화에 대한 해석적 연구)

  • Oh, Byoung-Han;Choi, Byong J.
    • Journal of the Korean Society of Safety
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    • v.33 no.2
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    • pp.104-111
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    • 2018
  • System supports are widely used in concrete construction due to the convenience and structural safety at the point of both installation and dismantling. However, there were frequent collapses in the construction sites due to the absence of both structural review and brace installations. Therefore, this paper examines the importance of braces in the system supports. In order to examine the importance of the brace, four types of braces were considered: 100% braces, 50% braces, 25% braces, and without braces. The maximum displacement of the 100% braced model was 0.97 mm, the 50% braced model was 1.13 mm, the 25% braced model was 1.16 mm and the non-braced model was 24.3 mm, respectively. Compared to the model with the without-braces, the model with 100% of the braces installed has a displacement of 4.0%, the model with 50% of the braces showed a displacement of 4.7%, and the model with 25% of the braces appeared to be a displacement of 4.8%. That is, the installation of the braces is effective in reducing the maximum displacement of the system supports and is effective in reducing the maximum displacement with only small number of braces installed.

Displacement Measuring Method using Terrestrial LiDAR for Safety and Serviceability Monitoring of Steel Beams (지상 LiDAR를 이용한 철골보의 안전 및 사용성 모니터링을 위한 변위 계측기법)

  • Lee Hong-Min;Park Hyo-Seon;Lee Im-Pyeong
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2005.04a
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    • pp.190-197
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    • 2005
  • To monitor the safety and serviceability of a structures, structural responses including displacements due to various design and unexpected loadings must be measured. The maximum displacement and its distributions of a structure can be used as a direct assessment index on its stiffness. For this reason, there have been diversely studied on measuring of the maximum displacement of a structure. However, there is no practical method for measuring displacement of a structure. Therefore, in this paper, new displacement measuring method is developed and accuracy of LiDAR is examined in detail for development of a new method for measuring displacement of a structure.

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A Study on the Displacement Measuring Method of High-rise Buildingas using LiDAR (라이다를 이용한 고층 건물의 변위 계측 기법에 관한 연구)

  • Lee Hong-Min;Park Hyo-Seon
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.151-158
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    • 2006
  • Structural health monitoring is concerned with the safety and serviceability of the users of structures, especially for the case of building structures and infrastructures. When considering the safety of a structure, the maximum stress in a member due to live load, earthquake, wind, or other unexpected loadings must be checked not to exceed the stress specified in a code. It will not fail at yield, excessively large displacements will deteriorate the serviceability of a structure. To guarantee the safety and serviceability of structures, the maximum displacement in a structures must be monitored because actual displacement is a direct assessment index on its stiffness. However, no practical method has been reported to monitor the displacement, especially for the case of displacement of high-rise buildings because of not to easy accessive. In this paper, it is studied displacement measuring method of high-rise buildings using LiDAR The method is evaluated by analyzing accuracy of measured displacements for existing building.

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Numerical Analysis of Tunnelling-Induced Ground Movements (터널굴착으로 발생한 지반거동에 대한 수치해석적 분석)

  • Son, Moo-Rak;Yun, Jong-Cheol
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.396-403
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    • 2009
  • Numerical analysis has been performed to estimate maximum settlement and maximum horizontal displacement due to tunnel excavation varying ground condition, tunnel depth and diameter, and construction condition (volume loss at excavation face). The maximum surface settlement from the numerical analysis has been compared with the maximum settlement at tunnel crown considering ground condition, tunnel depth and diameter, and construction condition, and it has been also compared with the maximum horizontal displacement. The results from the numerical analysis have been compared with field measurements to confirm the applicability and validity of the results and by this comparison it is believed that the numerical results in this study can be utilized practically in analyzing the ground movements due to tunnel excavation.

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