• Proceedings of the KSR Conference
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• 2011.10a
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• pp.800-806
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• 2011

Thermal expansion which occurs at the high speed rail joint is proportional to the free length from the point of fixity. This thermal expansion behaves similar to free expansion because the girder longitudinal stiffness is much larger than longitudinal resistance of rail pads. But the longitudinal displacement in the long rail is nominal because the longitudinal support condition of the girder is normally MFM(movable-fix-movable) system. Due to these girder expansion characteristics, there is longitudinal relative displacement at the rail pad and rail fastener spring which connects rail and girder. If the relative displacement between rail and girder is beyond the elastic limit for the rail pad, rail fastener system shall be applied using sliding fastener to prevent rail pad damage and fastener separation resulting from slip. On the other hand, train vertical vibration and tilting can occur due to the lack of fastener vertical force if the sliding fastener is applied at the girder joint. In the high speed rail bridge, vibration can occur due to the spring stiffness of the elastomeric bearing, also both vertical downward and upward displacement can occur. The elastomeric bearing vertical movement can cause rail displacement and finally the stability of the ballast is reduced because the gravel movement is induced.

• Structural Engineering and Mechanics
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• v.61 no.6
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• pp.795-806
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• 2017

According to the characteristics of continuous beam bridges, the relative displacement is too large to collision or even girder falling under earthquakes. A device named Cable-sliding Modular Expansion Joints(CMEJs) that can control the relative displacement and avoid collision under different ground motions is proposed. Working principle and mechanical model is described. This paper design the CMEJs, establish the restoring force model, verify the force model of this device by the pseudo-static tests, and describe and analyze results of the tests, and then based on a triple continuous beam bridge that has different heights of piers, a 3D model with or without CMEJs were established under Conventional System (CS) and Seismic Isolation System (SIS). The results show that this device can control the relative displacement and avoid collisions. The combination of isolation technology and CMEJs can be more effective to achieve both functions, but it need to take measures to prevent girder falling due to the displacement between pier and beam under large earthquakes.

• Earthquakes and Structures
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• v.16 no.6
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• pp.641-654
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• 2019

This paper investigates the seismic response of a typical non-navigable continuous girder bridge isolated with friction sliding bearings of the Hong Kong-Zhuhai-Macao link projects in China. The effectiveness of the friction pendulum system (FPS) and accuracy of the numerical model were evaluated by a 1/20 scaled bridge model using shaking table tests. Based on the hysteretic properties of friction pendulum system (FPS), double concave friction pendulum (DCFP), and triple friction pendulum system (TFPS), seismic response analyses of isolated bridges with the three sliding-type bearings are systematically carried out considering soil-pile interaction under offshore soft clay conditions. The fast nonlinear analysis (FNA) method and response spectrum are employed to investigate the seismic response of isolated offshore bridge structures. The numerical results show that the implementation of the three sliding-type bearings effectively reduce the base shear and bending moment of the reinforced concrete pier, at the cost of increasing the absolute displacement of the bridge superstructure. Furthermore, the TFPS and DCFP bearings show better isolation effect than FPS bearing for the example continuous girder bridge.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.1-7
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• 2020

Although the temperature load is an important load among the various loads affecting the behaviors of general rahmen-type temporary bridges (GRTB), no study of the thermal load has been carried out. In the case of GRTB, horizontal displacement should be free, and the generated internal force should be minimized to reduce stress due to a temperature load. Sliding girder type bridge (SGTB) allows the axial deformation due to thermal load, and decreases the axial stress and delivers bending stress. This study examined the temperature behavior of an SGTB. Structural analysis was carried out for four types of spans (eq, 10, 20, 30, and 40m) and three types of pier heights (eq, 2, 4, and 6m) along with the GRTB. The applied loads were a fixed vertical load and an axial temperature load. The friction coefficient was 0.4, which is a representative value of a steel girder. Consequently, the stress of the SGTB increased with increasing span length, regardless of the temperature load. The stress of the GRTB increased with increasing temperature and span length. Compared to the GRTB, the stress of the SGTB decreased by 20% to 50% at the center of the girder and by 50% to 90% at the bottom of the pier. This could secure the structural efficiency compared to the GRTB with the same specifications.

• Journal of the Korea Concrete Institute
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• v.19 no.4
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• pp.433-439
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• 2007

The main objective of the paper is to investigate the static behavior of a prestressed concrete (PSC) girder that has been spliced with precast box segments. A 20 m long full-scale spliced PSC girder is fabricated and tested to compare its static performance against a monolithic girder. The monolithic girder has the same geometric and material properties with respect to the spliced girder. This includes infernal strain, deflections, neutral axis position, and crack patterns for both girders. The test also consists of monitoring relative displacements occurring across the joints. Both the horizontal displacement (gap) and vertical displacement (sliding) are measured throughout the loading procedure. All results have been compared to those obtained from the monolithic girder. It has been demonstrated that the spliced girder offers close behavior with respect to the monolithic girder up to the crack load. Both girders exhibits ductile flexural failure rather than abrupt shear failure at joints.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.2
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• pp.169-177
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• 2016

Sliding slab track system, which consists of low friction sliding layer between track slab and bridge deck, is recently devised to reduce track-bridge interaction effect of continuously welded rail(CWR) without applying special devices such as rail expansion joint(REJ). In this study, a series of track-bridge interaction analyses of a long-span bridge with sliding slab track and REJ are performed respectively and the results are compared. The bridge model includes PSC box girder bridge with 9 continuous spans, and steel-concrete composite girder bridge with 2 continuous spans. The total length of the bridge model is 1,205m, and the maximum spacing between the two fixed supports is 825m. Analyses results showed that the sliding slab track system is highly effective on interaction reduction since lower rail additional axial stress is resulted than REJ application. Additionally, horizontal reaction forces in fixed supports were also reduced compared to the results of REJ application. However, higher slab axial forces were developed in the sliding slab track due to the temperature load. Therefore, track slab section of the sliding slab track system should be carefully designed against slab axial forces.

• Structural Engineering and Mechanics
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• v.59 no.3
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• pp.387-401
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• 2016

This paper takes a half-through steel truss arch bridge as an example. A seismic analysis is conducted with nonlinear finite element method. Contrast models are established to discuss the effect of simplified method for main girder on the accuracy of the result. The influence of seismic wave direction and wave-passage on seismic behaviors are analysed as well as the superstructure and arch ring interaction which is mostly related with the supported bearings and wind resistant springs. In the end, the application of cable-sliding aseismic devices is discussed to put forward a layout principle. The main conclusions include: (1) The seismic response isn't too distinctive with the simplified method of main girder. Generally speaking, the grillage method is recommended. (2) Under seismic input from different directions, arch foot is usually the mostly dangerous section. (3) Vertical wave input and horizontal wave-passage greatly influence the seismic responses of arch ring, significantly increasing that of midspan. (4) The superstructure interaction has an obvious impact on the seismic performance. Half-through arch bridges with long spandrel columns fixed has a less response than those with short ones fixed. And a large stiffness of wind resistant spring makes the the seismic responses of arch ring larger. (5) A good isolation effectiveness for half-through arch bridge can be achieved by a reasonable arrangement of CSFABs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1469-1476
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• 2015

The bridges take a significant part of entire route in Korea railway, because 70% of Korean territory is covered with mountains. For this reason, span enlargement of railway bridges is more advantageous to increase economic efficiency on the bridge design. However there are many limitations such as additional axial force of the rail, excessive displacement due to track-bridge interaction. In this study, track-bridge interaction analysis was conducted considering the sliding layer which was installed between the track and girder. From the numerical analysis results, the behavior of track-bridge interaction was investigated according to the installation method of sliding layer. Finally, a guideline for development of track-bridge structure system to reduce the track-bridge interaction was proposed.

• Proceedings of the Korea Contents Association Conference
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• 2006.05a
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• pp.448-451
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• 2006

Currently the bolt joint defect occurs from the steel bridge which is in the process of using but that investigation about each kind defect is lacking state. Research to see consequently the high strength bolt joint sliding conduct bring the model it used a structural analysis program LUSAS numerical analysis execution and a plan for Steel Box Girder Bridge copying full-size H-Beam and plan pretensioned bolt force 100%. 75%, 50% and 25% pretensioned force it acted in standard. And a hold an examination, against the sliding loads which it follows in the pretensioned force it will analysis.

• Proceedings of the Korea Contents Association Conference
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• 2006.05a
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• pp.541-544
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• 2006

Currently the bolt joint defect occurs from the steel bridge which is in the process of using but that investigation about each kind defect is lacking state. Research to see consequently the high strength bolt joint sliding conduct bring the model it used a structural analysis program LUSAS numerical analysis execution and a plan for Steel Box Girder Bridge copying full-size H-Beam and plan pretensioned bolt force 100%. 75%, 50% and 25% pretensioned force it acted in standard. And a hold an examination, against the sliding loads which it follows in the pretensioned force it will analysis.