• Title, Summary, Keyword: 변위

Search Result 6,092, Processing Time 0.164 seconds

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
    • /
    • v.13 no.3
    • /
    • pp.286-295
    • /
    • 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.

A study on the application of the critical strain concept by using the displacements occurring before excavation in tunneling (터널 선행변위를 활용한 한계변형률 개념의 적용 연구)

  • Park, Si-Hyun
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.10 no.4
    • /
    • pp.337-347
    • /
    • 2008
  • Critical strain is a new material property of the ground. Critical strain concept which was established in tunnel engineering can be applied to deformation limits in the ground due to tunneling by using the measured displacement at the tunnel construction site. In this study, quantitative evaluations for the tunnel stability are conducted by analysing the displacement results obtained at the construction field. Especially, critical stain concept was reviewed from a total displacement point of view using the displacements occurring before excavation. As a results, the variation characteristics of the tunnel stability are presented on the critical strain diagram with or without the preceeding displacements.

  • PDF

Performance Comparison of Traffic-Dependent Displacement Estimation Model of Gwangan Bridge by Improvement Technique (개선 기법에 따른 광안대교의 교통량 의존 변위 추정 모델 성능 비교)

  • Kim, Soo-Yong;Shin, Sung-Woo;Park, Ji-Hyun
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.23 no.4
    • /
    • pp.120-130
    • /
    • 2019
  • In this study, based on the correlation between traffic volume data and vertical displacement data developed in previous research using the bridge maintenance big data of 2006, the vertical displacement estimation model using the traffic volume data of Gwangan Bridge for 10 years A comparison of the performance of the developed model with the current applicability is presented. The present applicability of the developed model is analyzed that the estimated displacement is similar to the actual displacement and that the displacement estimation performance of the model based on the structured regression analysis and the principal component analysis is not significantly different from each other. In conclusion, the vertical displacement estimation model using the traffic volume data developed by this study can be effectively used for the analysis of the behavior according to the traffic load of Gwangan Bridge.

Measurement of Absolute Displacement-Amplitude of Ultrasonic Wave Using Piezo-Electric Detection Method (압전형 수신 기법을 이용한 초음파 절대변위진폭 측정)

  • Park, Seong-Hyun;Kim, Jongbeom;Jhang, Kyung-Young
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.37 no.1
    • /
    • pp.7-12
    • /
    • 2017
  • A nonlinear ultrasonic parameter is defined by the ratio of displacement amplitude of the fundamental frequency component to that of the second-order harmonic frequency component. In this study, the ultrasonic displacement amplitude of an SUS316 specimen was measured via a piezo-electric-based method to identify the validity of piezo-electric detection method. For comparison, the ultrasonic displacement was also determined via a laser-based Fabry-Pérot interferometer. The experimental results for both measurements were in good agreement. Additionally, the stability of the repeated test results from the piezo-electric method exceeded that of the laser-interferometric method. This result indicated that the piezo-electric detection method can be utilized to measure a nonlinear ultrasonic parameter due to its excellent stability although it involves a complicated process.

Displacement Based Seismic Performance Improved Design of RC Column Retrofitted Steel Jacket (변위기반 설계법에 의한 RC 기둥의 Steel Jacket 보강 내진성능개선 설계법)

  • Jung, In-Kju;Cho, Chang-Geun;Park, Soon-Eung
    • Journal of the Korean Association for Spatial Structures
    • /
    • v.10 no.4
    • /
    • pp.49-57
    • /
    • 2010
  • This study is the research appling the representative Displacement-Based Design which is the basic concept of Direct Displacement Based Design proposed by Chopra and Goel to original Reinforced Concrete structure and determining the thickness of retrofit Steel Jacket about the Maximum design ground acceleration, and developing the more improved Algorithm as well as program by the Retrofit Design method and Nonlinear analysis by the Performance design method before and after reinforcement appling the determined retrofit thickness. To predict the target displacement of retrofitted columns, a nonlinear analysis model of reinforced concrete columns has been developed to be based on the nonlinear fiber cross-sectional and segmental analysis model, and the seismic displacement level of retrofitted columns is estimated by two procedures, the direct displacement-based design method and the displacement coefficient method. In examples of seismic retrofit design, the current seismic improved design method gives good results in improvements of displacement levels and displacement ductilities of retrofitted columns.

  • PDF

Determination of Optimal Locations for Measuring Displacements to Adjust Cable Tension Forces of Cable-Stayed Bridges (사장교 시공 중 케이블 장력 보정을 위한 최적 변위계측 위치 결정)

  • Shin, Soobong;Lee, Jung-Yong;Kim, Jae-Cheon;Jung, Kil-Je
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.13 no.2
    • /
    • pp.129-136
    • /
    • 2009
  • The paper presents an algorithm of selecting optimal locations for measuring displacements(OLD) to adjust cable tension forces during the construction of cable-stayed bridges. The rank for optimal locations can be determined from the effective independence distribution vectors(EIDV) that are computed from the Fisher Information Matrices(FIM) formulated with the displacement sensitivities. To examine the efficiency and reliability of the proposed algorithm for determining OLD, a simulation study on a cable-stayed bridge has been carried out. The results using FIM formulated with displacements are compared with those using FIM with displacement sensitivities through the simulation study. The effects of measurement noise and error in cable length on the adjustment of cable tension forces are evaluated statistically by applying the Monte Carlo scheme.

Improvement of Medical Ultrasound Strain Image Using Lateral Motion Compensation (측방향 움직임 보상을 이용한 초음파 의료용 변형률 영상의 화질개선)

  • Park, Myung-Ki;Kwon, Sung-Jae;Jeong, Mok-Kun
    • The Journal of the Acoustical Society of Korea
    • /
    • v.30 no.5
    • /
    • pp.239-248
    • /
    • 2011
  • In order to improve the quality of strain images in medical ultrasound imaging, displacements need to be accurately estimated. In this paper, in order to apply one-dimensional displacement estimation methods to two-dimensional motion estimation, the axial and lateral displacements are separately estimated. In order to estimate lateral displacements, one-dimensional signals aligned in the lateral direction are converted to analytic signals, which are then crosscorrelated. Strain images are produced by first compensating two-dimensional displacements for lateral motion with lateral motion displacement estimates obtained from the proposed lateral displacement estimation algorithm and then estimating axial displacements. Both phantom and human data experiments show that the proposed method provides better signal-to-noise ratio and contrast-to-noise ratio characteristics than a conventional strain imaging method that utilizes axial displacement estimates only.

Effect of the Incident Optical Spot Size Upon the Quadrant Photodetector on the Optical Displacement Detection Sensitivity (4분할 광 검출기 상의 광점 크기가 변위 측정감도에 미치는 영향)

  • Lee, Eun-Joong;Lee, Jin-Woo;Kouh, Tae-Joon
    • Journal of the Korean Magnetics Society
    • /
    • v.18 no.2
    • /
    • pp.71-74
    • /
    • 2008
  • In this paper, we have measured the effect of the optical spot size, incident upon the quadrant photodetector, on the optical displacement sensitivity of the optical beam deflection technique. We have built an optical displacement detection system based on the optical beam deflection method using 3 mW He-Ne laser and measured the displacement sensitivity with changing the optical spot size on the quadrant photodetector. We have also calculated the changes in the optical displacement sensitivity as a function of the incident laser spot size by modeling a circular optical spot with constant laser intensity. Our experimental and theoretical studies show that the optical displacement sensitivity increases with the decrease in the optical spot size. This suggests that in the design of the optical motion detection systems with sub-nanometer sensitivity, the displacement sensitivity can be optimized by reducing the size of the incident optical spot on the detector.

Development of Resizing Techniques for Drift Designs of High-rise Buildings subjected to Lateral and Vertical Loads (횡하중과 연직하중을 받는 고층건물의 변위설계를 위한 재분배기법 개발)

  • 서지현;박효선
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.17 no.1
    • /
    • pp.49-58
    • /
    • 2004
  • Drift design of a high-rise building is a governing factor in the determination of structural weights and lateral resisting systems. However, high-rise buildings are composed of tens of thousands of structural member, designer can not know which members are active to lateral drift control and how much they contribute to lateral drifts. Resizing technique was proved to be a practical method for drift design of high-rise buildings. However, no resizing algorithm has been considered the effect of vertical loads in drift designs. Thus, in this paper, a resizing algorithm has been developed for drift designs of high-rise buildings subjected to both lateral and vertical loads. The drift design model has been applied to drift designs of two high-rise building examples.

Development of Performance-Based Seismic Design of RC Column Retrofitted By FRP Jacket using Direct Displacement-Based Design (직접변위기반설계법에 의한 철근콘크리트 기둥의 FRP 피복보강 내진성능설계법의 개발)

  • Cho, Chang-Geun
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.11 no.2
    • /
    • pp.105-113
    • /
    • 2007
  • In the current research, an algorithm of performance-based seismic retrofit design of reinforced concrete columns using FRP jacket has been proposed. For exact prediction of the nonlinear flexural analysis or FRP composite RC members, multiaxial constitutive laws of concrete and composite materials have been presented. For seismic retrofit design, an algorithm of direct displacement-based design method (DDM) proposed by Chopra and Goel (2001) has been newly applied to determine the design thickness of FRP jacket in seismic retrofit of reinforced concrete columns. To compare with the displacement coefficient method (DCM), the DDM gives an accurate prediction of the target displacement in highly nonlinear region, since the DCM uses the elastic stiffness before reaching the yield load as the effective stiffness but the DDM uses the secant stiffness.