• Title/Summary/Keyword: Moment influence line

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A Solution of the Influence Line of continuous beams with Variable cross Section (변단면 연속보의 영향선 해법)

  • 장병순
    • Journal of the Korean Professional Engineers Association
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    • v.16 no.4
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    • pp.4-14
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    • 1983
  • when one is designing a continuous bridge with variable cross sections, it is very troublesome to integrate explicitly load terms and various factor under consideration so that it has different moment of inertia at each cross section. In this paper to obtain the influence line of a arbitary-span continuous beam with variable cross sections, the value of some particular function due to a load at any point can be carried out by numerical integration instead of definite integral. The ordinate of the influence line equals the product of the magnitude of the final moment at each support due to unit moment at any support and the load terms due to unit load, measured at the point of application of the load. It is concluded that this method can be easily used to design continuous bridges with arbitary cross sections.

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Influence Line of Three- span Continuous Curved Box-Girder Bridge using Elastic Equation (탄성방정식을 이용한 3경간 연속곡선교의 영향선에 관한 연구)

  • 장병순;장준환;김수정
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.14 no.4
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    • pp.423-434
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    • 2001
  • In this paper, a three-span continuous box girder is analysed by using elastic equation based on energy method, concerning the behaviour with the effects of bending and pure torsional moment. The statically indeterminate forces of a three-span continuous curved box girder are calculated by applying the principle of least work to this elastic equation. The influence line of shear force, bending moment, pure torsion, displacement and angle of rotation due to unit vortical load and unit torque for curved box girder are obtained. The internal forces of the curved box girder which the actual load is applied can be calculated using the influence line obtained from this study.

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Adjusting Equation Method (or Relaxation Equation Method) and its Application to the Influence Line Analysis of Continuous Beams (조정방정식법(調整方程式法)(혹은 이완방정식법(弛緩方程式法))과 연속량(連續梁)에의 응용(應用))

  • Cho, Hyun Yung;Kim, Mi Ock
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.14 no.3
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    • pp.487-493
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    • 1994
  • Moment distribution procedure in the elastic analysis of rigid frames can be easily expressed with the adjusting moment equations(or relaxation equations) by using the concept of total adjusting moment at each joint after infinite cycles of moment distribution. Adjusting moment equations are a set of simultaneous equations from which the total adjusting moments at each joints after infinite cycles of physical relaxation can be determined. The form of simultaneous equations is a kind of relaxation equations and can be easily solved by the hand calculators. A unique and simplified procedure for the influence line analysis of a continuous beam is presented as an application of the method.

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A Comparative Study on Influence Line of Curved I-Girder Grid Bridge with Constant Cross Section and Variable Cross Section (등·변단면 I-형 곡선격자형교의 영향선에 관한 비교연구)

  • Chang, Byung Soon;Seo, Sang Geun;Ryoo, Eun Yeol;Yun, Jeung Seup
    • Journal of Korean Society of Steel Construction
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    • v.10 no.4 s.37
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    • pp.615-627
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    • 1998
  • In order to determine the maximum shear force, the maximum bending moment, the maximum pure torsion. the maximum warping torsion, and the maximum bimoment for the curved girder grid bridges, it is important to find the location of live load applied to the curved girder grid bridges, so that the influence line can be estimated. The fundamental differential equation concerning the behaviour with warping effects for the curved girder is developed by Vlasov. In this paper, the influence line of shear force, bending moment, pure torsion, warping torsion, and bimoment due to unit vertical load and unit torsional moment for curved I-girder grid bridges with variable and constant cross section are obtained by using the finite difference method and compared with respectively.

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A Study on Influence Line of Curved I-Girder Grid Bridge with Constant Cross Section (등단면 I-형 곡선 격자형교의 영향선에 관한 연구)

  • Chang, Byung Soon;Ryoo, Eun Yeol;Joo, Jae Hwan
    • Journal of Korean Society of Steel Construction
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    • v.9 no.4 s.33
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    • pp.501-513
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    • 1997
  • The general behavior of curved girder including the warping effects is formulated by series of differential equations postulated by Vlasov. In order to determine the maximum shear force, the maximum bending moment, the maximum pure torsion, the maximum warping torsion, and the maximum bimoment for the curved girder grid bridges, it is important to find the location of live load applied to the curved girder grid bridges, so that the influence line can be estimated. In this paper, the influence line of shear force, bending moment, pure torsion, warping torsion, and bimoment due to unit vertical load and unit torsional moment for curved I-girder grid bridges are obtained by using the finite difference method.

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A Study on the Approximate Analysis of the Bending Moment for the Three-Span Continuous Curved Girder Bridges with Constant Cross Section (등단면 3경간 연속 곡선격자형교의 휨모멘트 근사해석에 관한 연구)

  • Chang, Byung Soon;Seo, Sang Geun;Cha, Ki Hyuk
    • Journal of Korean Society of Steel Construction
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    • v.11 no.2 s.39
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    • pp.131-142
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    • 1999
  • The general behavior of the curved girder including the warping effects can be presented as the series of differential equations developed by Vlasov. Generally, bending moment is the most important factor for engineer to decide the section of the girder. In order to accommodate easiness of the structural analysis for the curved girder bridge, this paper suggest the ratios of bending moment of curved gilder to that of straight girder. These ratios are presented by an approximate formula setting central angle ${\theta}(L/R)$ as a variable. The approximate formula of the maximum bending moment ratios and influence lines of all stress resultants can be used to design the three-span curved girder bridges.

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Sensitivity-based BWIM System Using Dynamic Strain Responses of Bridge Deck Plate (교량바닥판의 동적 변형률 응답을 이용한 민감도 기반 BWIM 시스템)

  • Kim, Byeong-Hwa;Park, Min-Seok;Yeo, Keum-Soo;Kim, Soo-Jin
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.7
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    • pp.620-628
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    • 2010
  • Using the responses of deck plate, a new bridge weigh-in-motion system has been introduced. The approach includes not only a systematic algorithm for the extraction of moment influence sequence but also a sensitivity-based system identification technique. The algorithm indentifies the influence sequence, the axle loads, and axle location of moving vehicles on a bridge, simultaneously. The accuracy and practicability of the algorithm have been examined experimentally for a folded deck plate on Yongjong Grand suspension bridge. It turns out that the two-dimensional effects of the behavior of deck plate should be considered for further accuracy improvement.

Development of Moving Force Identification Algorithm Using Moment Influence Lines at Multiple-Axes and Density Estimation Function (다축모멘트 영향선과 밀도추정함수를 사용한 이동하중식별 알고리듬의 개발)

  • Jeong, Ji-Weon;Shin, Soobong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.6
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    • pp.87-94
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    • 2006
  • Estimating moving vehicle loads is important in modeling design loads for bridge design and construction. The paper proposes a moving force identification algorithm using moment influence lines measured at multi-axes. Density estimation function was applied to estimate more than two wheel loads when estimated load values fluctuated severely. The algorithm has been examined through simulation studies on a simple-span plate-girder bridge. Influences of measurement noise and error in velocity on the identification results were investigated in the simulation study. Also, laboratory experiments were carried out to examine the algorithm. The load identification capability was dependent on the type and speed of moving loads, but the developed algorithm could identify loads within 10% error in maximum.

Immediate influence of application of Kinesio Taping on forward head posture (키네시오테이핑 적용이 앞쪽머리자세에 미치는 즉시적 영향)

  • Kim, Eun-Ja;Kim, Dae-hun
    • The Journal of the Convergence on Culture Technology
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    • v.4 no.4
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    • pp.101-105
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    • 2018
  • The purpose of this study was to evaluate the effect of Kinesio Taping on the forward head posture before application and immediately after application. We measured 18 students college students in Kangwon province by using Exbody's equipment before applying kinesio taping and immediately after application, we measured plumb line, CVA and PCMT. The results of this study were statistically significant (p <.05) as compared to before Kinesio Taping application for both Plumb Line, CVA, and PCMT immediately after application of Kinesio Taping. Therefore, it was confirmed that the effect of improving the head posture from the moment of Kinesio taping application.

Effects of the earth fissure on the seismic response characteristics of a nearby metro station

  • Jiang Chang;Yahong Deng;Huandong Mu
    • Earthquakes and Structures
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    • v.24 no.1
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    • pp.53-64
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    • 2023
  • Earth fissures with several kilometers will inevitably approach or cross the metro line, significantly threatening the safety of the underground structure in the earth fissure site. However, the influence of the earth fissure site's amplification effect on the metro station's dynamic response is still unclear. A representative earth fissure in Xi'an was taken as an example to establish a numerical model of a metro station in the earth fissure site. The dynamic response characteristics of the metro stations at different distances from the earth fissure under various seismic waves were calculated. The results show that the existence of the earth fissure significantly amplifies the dynamic response of the nearby underground structures. The responses of the axial force, shear force, bending moment, normal stress, horizontal displacement, inter-story drift, and relative slip of the metro station were all amplified within a specific influence range. The amplification effect increases with the seismic wave intensity. The amplification effect caused by the earth fissure has relatively weak impacts on the axial shear, shear force, bending movement, normal stress, and horizontal movement; slightly larger impacts on the inter-story drift and acceleration; and a significant impact on the relative slip. The influence ranges of the axial force and normal stress are approximately 20 m. The influence ranges of the acceleration and inter-story drift can reach 30 m. Therefore, the seismic fortification level of the underground structure in the earth fissure site needs to be improved.