• Title/Summary/Keyword: Steel Bridge

Search Result 1,676, Processing Time 0.023 seconds

A Study on the Dynamic Response of Highway Bridges by 4-Axles Single Truck (4축 단일차량에 의한 도로교의 동적응답에 관한 연구)

  • Chung, Tae-Ju
    • Journal of Korean Society of Steel Construction
    • /
    • v.23 no.3
    • /
    • pp.397-404
    • /
    • 2011
  • In this paper, a research for the dynamic wheel loads of a 3D vehicle model, which relates to a tire-enveloping model, is carried out. A single truck with four axles is modeled as a 10-D.O.F. vehicle by modeling both contact length of tires and pitching of tandem spring axles. The dynamic equations of the vehicle are obtained using the Lagrange's equation, the solution of the equations is calculated by Newmark-${\beta}$ method. The validity of the developed 3D vehicle model is demonstrated by comparing results obtained from the proposed method with those from experimental data. The maximum impact factors of tire force are evaluated according to the various step bumps on which a 24-ton dump truck is running.

Parametric Study on Curved Tub Girders for Varying Radii of Curvature (곡선 개구제형 거더의 곡률에 따른 매개변수 해석연구)

  • Kim, Jong-Min;Han, Taek-Hee;Choi, Jun-Ho;Choi, Byung-Ho;Kang, Young-Jong
    • Journal of Korean Society of Steel Construction
    • /
    • v.24 no.2
    • /
    • pp.175-188
    • /
    • 2012
  • A parametric study for varying the radii of curvature is performed with a curved tub girder bridge having three continuous spans. The bracing forces of top lateral bracings from the results of numerical equations are compared to those of 3-dimensional finite element analyses. New modifying factors applicable in computing the nominal member forces of top lateral bracings were suggested. The numerical equations were derived based on one girder system, and it is shown that the numerical equations exhibit some errors compared with 3D FEA results. The main reason for this phenomenon lies on the number of girders. The twin girder system has an external cross-beam between inner and outer girder. It also has larger lateral stiffness than the single girder system. Finally, the distributions by the torsion, bending, distortion, and lateral loading of the top lateral bracing forces were presented in this paper.

Effect of Cross Beams on Live Load Distribution in Rolled H-beam Bridges (압연형강(H형강) 거더교의 가로보가 활하중 횡분배에 미치는 영향)

  • Yoon, Dong Yong;Eun, Sung Woon
    • Journal of Korean Society of Steel Construction
    • /
    • v.18 no.5
    • /
    • pp.535-542
    • /
    • 2006
  • In this study, the effects of cross beams on the lateral distribution of live loads in composite rolled H-beam girder bridges, were investigated through three-dimensional finite element analysis. The parameters considered in this study were the inertial moment ratio between the main girder and the cross beam, the presence of the cross beam, and the number of cross beams. The live load lateral distribution factors were investigated through finite element analysis and the customary grid method. The results show that there was no difference between the bridge models with and without a cross beam. The cross beam of the beam and frame types also showed almost the same live load lateral distribution factors. However, the finite element analysis showed that the concrete slab deck plays a major role in the lateral distribution of a live load, and consequently, the effect of the cross beam is not so insignificant that it can be neglected.

Design of longitudinal prestress of precast decks in twin-girder continuous composite bridges (2거더 연속강합성 교량의 프리캐스트 바닥판 종방향 프리스트레스 설계)

  • Shim, Chang Su;Kim, Hyun Ho;Ha, Tae Yul;Jeon, Seung Min
    • Journal of Korean Society of Steel Construction
    • /
    • v.18 no.5
    • /
    • pp.633-642
    • /
    • 2006
  • Serviceability design is required to control the cracking at the joint of precast decks with longitudinal prestress in continuous composite bridges. Details of twin-girder bridges are especially complex not only due to their main reinforcements and transverse prestresses for the design of long-span concrete slabs, but also due to the shear pockets for obtaining the composite action. This paper suggests the design guidelines for the magnitude of the effective prestress and for the selection of filling materials and their requirements that would allow for the use of precast decks for twin-girder continuous composite bridges. The necessary initial prestress was also evaluated through long-term behavior analysis. From the analysis, existing design examples were revised and their effectiveness was estimated. When a filling material with a bonding strength higher than the requirement is used in the region of a high negative moment, a uniform configuration of the longitudinal prestressing steels along thewhole span length of continuous composite bridges can be achieved, which would result in the simplification of the details and the reduction of the construction costs.

A Simple Method of Obtaining Exact Values of the Natural Frequencies of Vibration for Some Composite Laminated Structures with Various Boundary Condition (다양한 경계조건을 갖는 복합적층판의 간편한 고유진동수 해석방법)

  • Won, Chi Moon
    • Journal of Korean Society of Steel Construction
    • /
    • v.14 no.1
    • /
    • pp.23-29
    • /
    • 2002
  • Many of the bridge systems, including the girders and cross-beams, and concrete decks behave as the special orthotropic plates. Such systems with boundary conditions other than Navier or Levy solution types, or with irregular cross sections, analytical solution is very difficult to obtain. Numerical method for eigenvalue problems are also very much involved in seeking such a solution. A method of calculating the natural frequency corresponding to the first mode of vibration of beam and tower structures with irregular cross-sections was developed and reported by Kim in 1974. Recently, this method was extended to two dimensional problems including composite laminates, and has been applied to composite plates with shear deformation effects. In this paper, application of this method to the specially orthotropic laminated plates with various boundary condition is accomplished and the result of analysis is presented.

The Fatigue Evaluation of Structural Steel Members under Variable-Amplitude Loading (변동하중을 받는 강구조부재의 피로거동 해석)

  • Chang, Dong Il;Kwak, Jong Hyun;Bak, Yong Gol
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.8 no.2
    • /
    • pp.167-175
    • /
    • 1988
  • The principle objective of this study is to evaluate the fatigue behavior of structural steel components of highway bridges subjected to service stresses. The main aspects of this investigation are; 1) a measurement and statistical analysis of service stress cycles observed in highway bridge. 2) fatigue tests under equivalent constant-amplitude(CA) loading and simulated variable-amplitude(VA) loading 3) a evaluation of the fatigue behavior under VA-loading by eqivalent root mean cube (RMC) stress range. Theoretically, the RMC model is adequate in evaluation of fatigue behavior under VA-loading, because the regression coefficient (m) of crack growth rate is 3 approximately. The result of fatigue test shows that the RMC model is fitter than the current RMS model in fatigue evaluation under VA-loading. The interaction effects and sequence effects under VA-loading affect little fatigue life of structural components. As the transition rate of stress ranges is higher, the crack growth rate is higher.

  • PDF

A Study on the Expection of the Stress to the Stiffness Variation of Members on Truss Railway Bridge (부재의 강성변화에 따른 강철도 트러스 교량의 발생응력 예측에 관한 연구)

  • Cho, Sun Kyu
    • Journal of Korean Society of Steel Construction
    • /
    • v.9 no.4 s.33
    • /
    • pp.535-541
    • /
    • 1997
  • It is proper that the load distribution and the actual stress of members is analyzed by field measurement in estimating to the behavior of truss railway bridges, but those procedures are very difficult. So, the studies for the deduction of the stress, using the indirect data which are able to get from the research and investigation without field measurement, are needed. In this study, to investigate quantitically the variation of the stress of members, the stresses are obtained from the simulation which is considered the the reduction of the section area and the stiffness due to the corrosion and the degree of the stress ratio and the distribution is calculated. As the results, the stress of truss members is almost lineary increased to the decreasing of the area and the lower chord is greatly affected. And the increasing of the stress is predicted by the superposition to the results of the amount of that in each members.

  • PDF

A Study of Seismic Resistant Design for Base-Isolated Bridges(I) (지진에 대비한 기초분리 교량의 설계법에 관한 연구(I))

  • Lee, Sang Soo
    • Journal of Korean Society of Steel Construction
    • /
    • v.9 no.4 s.33
    • /
    • pp.625-635
    • /
    • 1997
  • The base isolation technique and its benefits in reducing the transmitted earthquake energy into a structure have gained increasing recognition during the last two decades. Unfortunately, the current available design procedures, especially for base-isolated bridges, seem inadequate and too restrictive. As a result, practical design procedure still relies upon a series of deterministic time history analyses. In this study, the evaluation of the possibility of the normal mode method to predict the nonlinear seismic responses of base isolated bridges has been performed. The applicability has been examined through the numerical approach with isolator's elastic or plastic states of the base isolated bridges. Numerical results show that the 1st. mode period and the various responses are varied with the state but are conversed. And, the result show that the normal mode method is applicable to predict the seismic responses and to design the babe isolated bridge. Various analysis method to bridges with bilinearized hysteresis isolator and various pier heights are evalulated.

  • PDF

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
    • /
    • v.9 no.4 s.33
    • /
    • pp.501-513
    • /
    • 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.

  • PDF

Evaluation of Wake Galloping for Inclined Parallel Cables by Two-Dimensional Wind Testes Tests (2차원 풍동실험을 통한 평행 경사 실린더의 웨이크 갤로핑 평가)

  • Kim, Sun-Joong;Kim, Ho-Kyung;Lee, Sang-Hoon
    • Journal of Korean Society of Steel Construction
    • /
    • v.23 no.6
    • /
    • pp.763-775
    • /
    • 2011
  • The wake galloping phenomenon is evaluated for two cylinders via two-dimensional wind tunnel tests. The two cylinders are deployed parallel to the inclination of the vertical plane, which simulates the inclined stay cables of a cable-stayed bridge. The upstream and downstream displacements of the cylinder are observed with varying center distances between the two cylinders. The effect of structural damping on the mitigation of wake galloping is also investigated. The amplitude of the vibration is very sensitive to center distance between the two cylinders. The maximum amplitudes exceededthe allowable limit of the design guidelines for small center distances of less than or equal to six times the diameter of the cylinder. The overall results conformedto the conventional design practice for the wake galloping of parallel cables. It was found, however, that the increase in the damping was not effective in reducing the amplitude of the vibration in the wake galloping phenomenon.