• Title/Summary/Keyword: moving load

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A Study on the Behavior Character of Roadbed in High-Speed Railway Slab Tract (고속전철 슬레브궤도에서의 노반거동 특성에 관한 연구)

  • 조용권;이성혁;황선근
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.11a
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    • pp.319-326
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    • 2000
  • It is investigated character of the dynamic behavior at over excavation zone of roadbed using crushed stone instead of lean concrete. It is considered that behavior of roadbed using PENTAGON-3D and Baber's equation. Typical load of sine wave type using impact factor is compared to moving load system to examine relationship in using PENTAGON-3D case. Variations of this paper are material properties of roadbed, train velocity, subgrade bearing capacity. Using variations, safety of roadbed is estimated by dynamic behavior character.

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A Study on the Bending and Torsional Behaviors of Cable-Stayed Bridges under a Concentrated Moving Load (집중 이동하중을 받는 사장교의 휨 및 비틈 거동에 관한 연구)

  • Chang, Sung Pil;Yhim, Sung Soon;Chu, Seok Beom
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.9 no.3
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    • pp.1-12
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    • 1989
  • The nonlinearity of a cable-stayed bridge results from the large displacement of main girder due to a long span, the catenary action of cables and the flexural stiffness reduced by large axial forces. The dynamic behaviour of a cable-stayed bridge plays an important role in determining its safety. Especially, when the eccentrically moving load is applied to a cable-stayed bridge, the torsional vibration and vertical vibration are coupled and moreover the variation of cable tensions shows important dynamic characteristics. This dissertation presents a theoretical study and a finite element procedure for analysis of a cable-stayed bridge under a eccentrically moving load. Attention is focused on the dynamic behaviours such as dynamic increments of cable tensions and nodal displacements, with the variety of velocities and eccentricities of moving load. It is found that a moving load with eccentricity can have significant effects upon the responses; the torsion of bridge deck and the increments of cable tensions, according to the present results in this study.

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Influence of initial stresses on the critical velocity of the moving load acting in the interior of the hollow cylinder surrounded by an infinite elastic medium

  • Akbarov, Surkay D.;Mehdiyev, Mahir A.
    • Structural Engineering and Mechanics
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    • v.66 no.1
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    • pp.45-59
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    • 2018
  • The bi-material elastic system consisting of the pre-stressed hollow cylinder and pre-stresses surrounding infinite elastic medium is considered and it is assumed that the mentioned initial stresses in this system are caused with the compressing or stretching uniformly distributed normal forces acting at infinity in the direction which is parallel to the cylinder's axis. Moreover, it is assumed that on the internal surface of the cylinder the ring load which moves with constant velocity acts and within these frameworks it is required to determine the influence of the aforementioned initial stresses on the critical velocity of the moving load. The corresponding investigations are carried out within the framework of the so-called three-dimensional linearized theory of elastic waves in initially stresses bodies and the axisymmetric stress-strain state case is considered. The "moving coordinate system" method is used and the Fourier transform is employed for solution to the formulated mathematical problem and Fourier transformation of the sought values are determined analytically. However, the originals of those are determined numerically with the use of the Sommerfeld contour method. The critical velocity is determined from the criterion, according to which, the magnitudes of the absolute values of the stresses and displacements caused with the moving load approaches an infinity. Numerical results on the influence of the initial stresses on the critical velocity and interface normal and shear stresses are presented and discussed. In particular, it is established that the initial stretching (compressing) of the constituents of the system under consideration causes a decrease (an increase) in the values of the critical velocity.

Dynamic characteristics of a simple beam subjected to prebending moments and moving loads with constant velocity (이동하중이 일정속도로 작용하는 단순보에서 prebending moment에 의한 동적특성)

  • 강진선;김찬묵
    • Journal of the korean Society of Automotive Engineers
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    • v.3 no.1
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    • pp.54-60
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    • 1981
  • This paper presents the dynamic behaviour of a simple beam subjected to moving loads and prebending moments. The velocity of the moving loads is assumed constant, and the prebending moment is assumed to be M. The fundamental equation of motion of the beam is derived from the principle of virtual works and solved by using Duhamel's Integral. In this paper we found that the dimensionless deflection at the middle of beam was related with prebending moment(M), velocity(V) and magnitude of the moving load(F) ; that is y/y$_{0}$=1/1-.betha.$^{2}$-.pi.M/Fl The faster the velocity becomes, the deeper the maximum deflection becomes. And the maximum deflection at the middle of beam was occurred after the moving load passed the midpoint of beam.

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Experimental Verification of Damage Identification Method using Moving load Response (이동하중응답을 이용한 손상인식기법의 실험적 검증)

  • Choi, Sang-Hyun;Kim, Dae-Hyork
    • Proceedings of the KSR Conference
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    • 2009.05a
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    • pp.552-559
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    • 2009
  • Most damage identification methods for structural health monitoring developed to date utilize modal domain responses which require postprocessing and inevitably contain errors in transforming the domain of responses. In this paper, the feasibility of a damage identification method based on dynamics responses from moving loads is experimentally verified. The experiment is performed via applying periodic and non-periodic moving loads to a steel beam and acceleration and displacement responses of the beam is measured. The moving loads is applied using steel balls and the damage of a structure is simulated by saw-cutting the beam. The damage identification results using the measured responses show that the moving load response based damage identification method successfully identify all damages in the beam.

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Vehicle Load Effects on Slab of Parking Garage Structure (주차장 구조물 슬래브의 차량하중영향에 관한 연구)

  • 곽효경;송종영
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1997.04a
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    • pp.131-138
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    • 1997
  • The equivalent vehicle load factors which can consider the concentrated wheel load effect in slab design of parking garage structure are proposed. Based on the standard vehicle with total weight of 2.4 ton which is designed through the investigation of small to medium vehicle produced in Korea and the review of numerous foreign design codes for parking garage structure, the effects of moving vehicle loads on slab are analyzed using the finite element method. Besides. the relationships between the equivalent load factors and the sectional dimensions are established by regression analysis. The calculation of design forces can be easily accomplished without taking sophisticated numerical analysis for the moving vehicle load as the results obtained to the distributed load are multiplied by the proposed load factors in practice.

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Evaluation of Applicability of Sliding Carriage on the Membrane Retractable Roof under Vertical and Horizontal Load Considering the Inner Holder with Various Section Characteristics (다양한 단면성질의 Inner Holder를 고려한 연성 개폐식 Sliding Carriage의 수직 및 수평하중에 대한 적용성 평가)

  • Hwang, Kyung-Ju
    • Journal of Korean Association for Spatial Structures
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    • v.22 no.1
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    • pp.67-73
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    • 2022
  • Middle size of membrane retractable roof is under 25m span which consists of various moving systems. Sliding carriage is the system that leads the membrane to parking place, transferring the load from the membrane to structural cable. When membrane moves roof, thus, structural behavior of sliding carriage, which may contain various shapes with friction coefficients, should be investigated by vertical load as well as horizontal load. Nummerical simulation of sliding carriage prototypes, in this research, were performed by incrementation of vertical load and horizontal load as well. Consequently, this paper evaluated proper shapes of inner holder of Sliding carriage and evaluated the effective contact area of inner hold.

Bending Moment Characteristics of Flexibly Supported Infinite Beam Subjected to an Axial Force and a Moving Load (이동하중(移動荷重)과 축하중(軸荷重)이 작용(作用)하는 유연(柔軟)한 기초(基礎)위에 지지(支持)된 무한(無限)보의 휨모멘트 특성(特性))

  • Hong, Dong Pyo;Kim, Kwang Sic
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.2 no.3
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    • pp.15-22
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    • 1982
  • This paper presents analytic bending moment solution and resonance diagrams for a uniform beam of infinite length subjected to anaxial force and moving transverse load. Solutions are obtained that are time invariant in a coordinate system moving with the load velocity. The supporting foundation includes damping effects. The influences of the axial force, damping coefficient and load velocity on the beam response are studied. The limiting case of no damping and critial damping are also investigated. The profiles of the mement of the beam is shown graphically for several values of the load speed, the axial force and damping parameters.

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Evaluation of Dynamic Stability for Structural Bar Reinforced Precast and Prestressed Retaining Wall for Moving Train Load (이동열차하중에 대한 강봉으로 보강된 프리캐스트 프리스트레스트 옹벽의 동적 안정성 평가)

  • Lee, Il Wha;Um, Ju Hwan;Lee, Kang Myung;Keum, Chang Jun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.5
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    • pp.190-198
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    • 2011
  • The precast production has many advantages by fast construction period, labor-saving and high quality. In recent years, the application of the precast product has been increased in the earth retaining wall field. This paper presents the results of the numerical analysis that was carried out to evaluate the dynamic stability of precast and prestressed earth retaining wall under moving train load. The two-dimensional FEM analysis was used to the numerical analyses. The train load to act on trackbed is combined by the real measured roughness phase angle and quasi-static load. The dynamic stability is analysed by the displacement, acceleration and stress under moving train load at each specified location. The results of the analysis show that the precast and prestressed retaining wall has very stable capability for the railway.

Dynamic response of FG porous nanobeams subjected thermal and magnetic fields under moving load

  • Esen, Ismail;Alazwari, Mashhour A.;Eltaher, Mohamed A;Abdelrahman, Alaa A.
    • Steel and Composite Structures
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    • v.42 no.6
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    • pp.805-826
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    • 2022
  • The free and live load-forced vibration behaviour of porous functionally graded (PFG) higher order nanobeams in the thermal and magnetic fields is investigated comprehensively through this work in the framework of nonlocal strain gradient theory (NLSGT). The porosity effects on the dynamic behaviour of FG nanobeams is investigated using four different porosity distribution models. These models are exploited; uniform, symmetrical, condensed upward, and condensed downward distributions. The material characteristics gradation in the thickness direction is estimated using the power-law. The magnetic field effect is incorporated using Maxwell's equations. The third order shear deformation beam theory is adopted to incorporate the shear deformation effect. The Hamilton principle is adopted to derive the coupled thermomagnetic dynamic equations of motion of the whole system and the associated boundary conditions. Navier method is used to derive the analytical solution of the governing equations. The developed methodology is verified and compared with the available results in the literature and good agreement is observed. Parametric studies are conducted to show effects of porosity parameter; porosity distribution, temperature rise, magnetic field intensity, material gradation index, non-classical parameters, and the applied moving load velocity on the vibration behavior of nanobeams. It has been showed that all the analyzed conditions have significant effects on the dynamic behavior of the nanobeams. Additionally, it has been observed that the negative effects of moving load, porosity and thermal load on the nanobeam dynamics can be reduced by the effect of the force induced from the directed magnetic field or can be kept within certain desired design limits by controlling the intensity of the magnetic field.