• Title, Summary, Keyword: 변위

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Evaluation of inelastic performance of moment resisting steel frames designed by resizing algorithms (재분배 기법 적용에 따른 모멘트 저항골조의 비선형 특성 평가)

  • Seo, Ji Hyun;Kwon, Bong kwon;Park, Hyo Seon
    • Journal of Korean Society of Steel Construction
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    • v.18 no.3
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    • pp.361-371
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    • 2006
  • In recent years, to overcome drawbacks related to the aplicati on of classical structural optimization algorithms, various drift design methods based on factores of member displacement participation factors have been developed to size members if they satisfy stiffness criteria. In particular, a resizing algorithm based on dynamic displacement participation factors from the response spectrum analysis has been applied in the drift design of steel structures subjec ted to seismic lateral forces. In this aproach, active members are selected for displacement control based on the displacement participation fa ve members may be taken out and added to the active members for the drift control. The resizing algorithm can be practically and effectively applied to drift design of high-rise buildings however, the inelastic behavior o f the resizing algorithm has not ben evaluated yet. To develop the resizing algorithm considering the performance of nonlinearity as well a s elastic stifness, the evaluation model of resizing algorithm s is developed and aplied to the examples of moment-resisting steel frame, which is one of the simplest structural systems. The inelastic behavior of moment-resisting steel frame designed by the resizing algorithm is also discussed.

Estimation of Structural Displacements for Cantilever Beam Using Mode Shapes and Accelerometers Under Free Vibration (모드 형상과 가속도계를 이용한 자유 진동하는 외팔보의 변위 추정)

  • Kim, Kyung Jong;Lee, Yong Hwan;Lee, Kyu Beom;Lee, Cheol Soon;Cho, Jin Yeon;Kim, Jeong Ho
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.45 no.5
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    • pp.376-385
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    • 2017
  • In this paper, a method for the estimation of structural displacements using structure's mode shapes and accelerations is suggested to reduce the disadvantages of acceleration time integration method. Acceleration time integration method requires accurate information on initial conditions, and errors caused by noise can be accumulated during time integration. To avoid these problems, the method for the estimation of structural displacements based on mode superposition method is developed and two vibration experiments for cantilever beam are conducted to verify this method. Static displacements and dynamic displacements of beam structure are estimated using measured accelerations from experiments and mode shapes of cantilever beam, and they are compared with measured displacements using laser displacement sensor. From these results, the validity and usefulness of this method are verified.

Drift Design Method of High-rise Buildings Considering Design Variable Linking Strategy and Load Combinations (부재 그룹과 하중 조합을 고려한 고층건물 변위조절 설계법)

  • Seo, Ji-Hyun;Park, Hyo-Seon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.19 no.4
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    • pp.357-367
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    • 2006
  • Drift design methods using resizing algorithms have been presented as a practical drift design method since the resizing algorithms proposed easily find drift contribution of each member, called member displacement participation factor, to lateral drift to be designed without calculation of sensitivity coefficient or re-analysis. Weight of material to be redistributed for minimization of the lateral drift is determined according to the member displacement participation factors. However, resizing algorithms based on energy theorem must consider loading conditions because they have different displacement contribution according to different loading conditions. Furthermore, to improve practicality of resizing algorithms, structural member grouping is required in application of resizing algorithms to drift control of high-rise buildings. In this study, three resizing algorithms on considering load condition and structural member grouping are developed and applied to drift design of a 20-story steel-frame shear-wall structure and a 50-story frame shear-wall system with outriggers.

Inter-story Drift Design Method to Improve the Seismic Performance for Steel Moment Frames (철골모멘트골조의 내진성능향상을 위한 층간변위조절기법)

  • Choi, Se-Woon;Park, Hyo-Seon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.24 no.6
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    • pp.707-714
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    • 2011
  • The inter-story drift ratio is used to evaluate the damage of buildings by the earthquake. This is known that as the inter-story drift ratio decreases, the seismic damage decreases. Although to reduce the inter-story drift ratio is the important issue in the seismic design, no practical inter-story drift design method has bean developed. This study presents an optimal inter-story drift design method to improve the seismic performance of the steel moment frames using the resizing algorithm. The objective function of the proposed method is to minimize the differences of the inter-story drift ratios so that the inter-story drift ratios of the building could be distributed evenly and be reduced. Because this method redesigns the sectional properties of structural members base on the displacement participation factor calculated by the unit-load method, this can improve the seismic performance of the structure without the iterative structural analysis. The efficiency of this algorithm was demonstrated by the application to steel moment frames.

Development of Drift Design Method for High-rise Buildings Considering Characteristics of Member Forces (부재력 특성을 고려한 설계변수를 사용한 고층건물 변위조절설계법 개발)

  • 서지현;박효선
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.17 no.2
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    • pp.215-222
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    • 2004
  • Drift design methods using resizing techniques have been presented as a practical drift control methods of high-rise buildings. Most drift design methods using the resizing techniques have adopted the cross-sectional area as the design variables for all structural members in a structure. However, the cross-sectional area is not always governing sectional property for the structural members, but the governing sectional property of each member is dependent on the characteristics of member forces. In this paper, a drift design method using the sectional property related to the governing displacement participation factor as the design variable of each member is presented and applied to the drift design of 20-story steel frame-shear wall system. It can be noted from example test that drift design method considering member characteristics shows similar or somewhat better results in the view point of structural weights and the accuracy of displacement estimation.

Direct Control of Displacement Using Displacement and Resistance Force Contribution Factor (변위 및 내력기여도계수를 이용한 정량적 변위 제어)

  • Kim, Young-Min;Kim, Chee-Kyeong
    • Journal of the Korean Association for Spatial Structures
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    • v.5 no.3
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    • pp.91-100
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    • 2005
  • The paper presents a direct method for the diplacement control and stiffness redesign using displacement and response force contribution factors. At first, these two kinds of factors are derived and the relationship between them is examined. An equation to evaluate the change of displacement according to the change of each member stiffness is proposed. For the statically determinate structures, the proposed equation gives the exact solution with no approximation. But it has some error in case of statically indeterminate structures because the redistribution of response forces is neglected in the equation. However, the equation may be very useful even for statically indeterminate structures because it provides the relationship between the member stiffness and the global displacement. The proposed method is expected to be useful for the displacement control of large space or hi-rise building structures where the stiffness design governs the design result.

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Development of Displacement Estimation Technique for Bridges Located under Poor Measurement Circumstances (계측이 어려운 환경에 가설된 교량의 변위 추정 기술 개발)

  • Jeon, Junchang;Lee, Heehyun
    • Journal of the Korean Society for Railway
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    • v.19 no.6
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    • pp.755-764
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    • 2016
  • In this paper, to verify the field application of a displacement estimation technique based on the relationship between displacement and strain, static and dynamic field load test are performed on three-span continuous real bridge structures. The superstructure types of the test bridges are IPC girder highway bridge and steel box girder AGT bridge. LVDTs and strain gauges are attached to them; then, the responses due to test vehicle are measured. To obtain the displacement-strain relationship of the test bridges, the bridges are modeled as grillage system with 6 DOFs for the purpose of structural analyses. Static and dynamic displacements, which are estimated using both the calculated displacement-strain relationship and the measured strain signal, agree well with the values measured by LVDT. This study demonstrates that the displacement estimation technique using the strain signal can be effectively applied to the displacement measurement of bridge structures that cross rivers/roads/railways or have high clearance.

Prediction of Preceding Crown Settlement Using Longitudinal Displacement Measured on Tunnel Face in Fault Zone (단층대가 분포하는 터널에서 굴진면 수평변위를 이용한 선행 천단변위 분석)

  • Yun, Hyun-Seok;Do, Kyung-Ryang;Seo, Yong-Seok
    • The Journal of Engineering Geology
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    • v.27 no.1
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    • pp.81-90
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    • 2017
  • Preceding displacements in tunnel are difficult to predict since the measurements of displacements after excavation can not be performed immediately. In the present study, The longitudinal displacements which can be measured immediately after excavation are used to predict the crown settlements occurring before excavation only if fault is located at the tunnel crown. Three-dimensional finite element analysis was conducted using 28 numerical models with various fault attitudes to analyze the correlation between the longitudinal displacements on tunnel face and preceding crown settlements. The results, $L_{face}/C$ ratio show 2~12% in the drives with dip models and 2~13% in the drives against dip models individually. In addition, each model has a certain $L_{face}/C$ ratio. The result of the regression analysis show that the coefficient of determination is over 0.8 in most models. Therefore, crown settlements occurring before excavation can be predicted by analyzing the longitudinal displacements occurring on tunnel faces.

Displacement Analysis of Structures using RTK-GPS/Accelerometer Integration Methods (RTK-GPS와 가속도계 통합계산을 통한 구조물의 변위 해석)

  • Hwang, Jin-Sang;Yun, Hong-Sic;Lee, Dong-Ha;Hong, Sung-Nam;Suh, Yong-Cheol
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.29 no.6
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    • pp.583-591
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    • 2011
  • Accurate observation results of dynamic displacements are essential to the protection of civil structures. In this study, we evaluated the optimal methods of the RTK/GPS Accelerometer integration through comparison and analysis of several experiments results. Two methods will be used to calculate the dynamic displacements from the results of the acceleration data as well as two integration methods for measuring the dynamic, static, and quasi-static displacements by incorporating the displacement results from the RTK-GPS and Accelerometer. By using a Cantilever Beam and LVDT measurement, we were able to ensure that the different displacement comparisons would be reliable and accurate. As a results from experiments, the accelerometer processing method applied by use of accelerometers data was filtering with the double integral using FIR band-pass filter which is most optimal for assessing the dynamic displacements. Also, the integrated method using extracting substitution displacements is suitable for measuring synthetically the dynamic static and quasi-static displacements of civil structures with RTK-GPS and accelerometer.

Image Segment-Based Stereo Matching for Improving Boundary Accuracy (경계영역 정확도 향상을 위한 영상분할 기반 스테레오 매칭)

  • Mun, Ji-Hun;Ho, Yo-Sung
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • pp.63-66
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    • 2015
  • 3차원 영상을 생성하기 위해 스테레오 매칭을 통해 깊이 정보를 획득한다. 이때 발생하는 경계영역과 텍스처가 부족한 부분의 깊이정보 부정확성 문제를 해결하기 위해 영상 분할 기반 스테레오 매칭 방법을 제안한다. 일반적으로 사용하는 윈도우 기반 스테레오 매칭 결과를 기반으로 분할된 영상 내에서 최적의 변위 값을 재 할당함으로서 깊이정보의 정확성을 향상시킬 수 있다. Mean-shift는 참조 영상에서 화소 간 평균값 차이가 최대가 되는 영역들을 반복적으로 찾는다. 유사한 평균값을 갖는 영역들을 기반으로 영상을 분할하는 것을 Mean-shift를 이용한 영상분할 이라고 한다. 분할된 영상은 각 영역을 대표하는 패치 구조를 가지고 있어 참조 영상에 포함되어있는 잡음에 강인한 특성을 지닌다. 스테레오 매칭을 통해 화소별로 변위 값을 할당해주는 대신, 분할된 영상을 이용하여 각 분할 영역에 동일한 변위 값을 할당한다. 분할된 영상에 동일한 변위 정보를 할당할 경우 객체와 배경의 경계영역에서 잘못된 변위 값이 할당되는 경우가 발생한다. 이러한 경계 영역의 변위정보 부정확성을 보완하기 위해 화소의 기울기 항을 비용 값 계산 과정에 추가하여 단점을 보완한다. 최종 비용 값 계산을 통해 획득한 초기 변위 지도에 중간 값 필터를 적용하여 분류된 영역에 동일한 변위 값을 할당한다. 제안한 방법을 적용하여 경계영역의 정확도가 향상된 최종 변위 지도를 획득한다.

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