• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1464-1469
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• 2010

In this paper, the dynamic stability evaluation of special bridge for high speed railway under ground excitation is performed. The mass, damping, stiffness matrices of bridge are derived from the modal frequencies and mode shape vectors which can be obtained by commercial program. And the high speed train is modeled as multi-single d.o.f models for the sake of vehicle-bridge interaction analysis. In the vehicle-bridge interaction analysis, the vertical directional interaction is only considered. As a numerical example, the 3 span Extradosed bridge which is expected to be installed in Ho-Nam high speed railroad is considered. The analysis results show that the example bridge satisfies the criteria of dynamic stability.

• Journal of Korean Society of Disaster and Security
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• v.16 no.4
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• pp.129-136
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• 2023

A special offshore bridge with a high pylon has special structural features.Special offshore bridges have inspection blind spots that are difficult to visually inspect. To solve this problem, safety inspection methods using drones are being studied. In this study, image data of the pylon of a special offshore bridge was acquired using a drone. In addition, an artificial intelligence algorithm was developed to detect damage to the pylon surface. The AI algorithm utilized a deep learning network with different structures. The algorithm applied the stacking ensemble learning method to build a model that formed the ensemble and collect the results.

• Journal of Korean Society of Disaster and Security
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• v.15 no.4
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• pp.31-38
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• 2022

In the case of special bridges whose superstructure is supported by cables, there are many blind spots that are difficult to access without special equipment and personnel. As a result, there are difficulties in the safety inspection of special bridges. The purpose of this study is to review the inspection blind spots of cable-supported bridges such as cable-stayed bridges and suspension bridges, and to study ways to eliminate blind spots using drones. To this end, the cables, stiffened girder, and pylons of the cable-stayed bridge located in the sea were inspected using drones. Through this study, it was confirmed that external safety inspection of special bridges that are difficult for inspectors to access is possible using drones. In particular, drone inspection to check the external condition and damage of the pylon, which is a blind spot for inspection of special bridges, is a very effective safety inspection method.

• Journal of the Korean Society of Safety
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• v.25 no.5
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• pp.54-61
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• 2010

The additional axial force of CWR(continuous welded rail) is occurred by structure-track interaction, in reverse, fixed supports of structure are applied the large load by that. Ratio of load which transferred on support through the bridge superstructure with one-side REJ by acceleration and braking load are stated in High-Speed Rail Design Criteria(2005). On the other hand the horizontal forces of support delivered to the load due to thermal loads has been no report about the criteria. Therefore, this study was performed the review of the reaction and displacement on support by structure-track interaction in a special bridge(composite brdiges, 45+55+55+45=200m) with REJ acting on the temperature load. As a result, because fixed support of a special bridge or a continuous bridge with REJ under the temperature load which is constant load has been acted the large lateral load by structure-track interaction, when determining the fixed bearing capacity of structure should be reflected in the results to secure the safety of structures was confirmed.

• Structural Engineering and Mechanics
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• v.35 no.1
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• pp.37-52
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• 2010

Special-shape arch bridge for self-balance (SBSSAB) in Zhongshan City is a kind of new fashioned spatial combined arch bridge composed of inclined steel arch ribs, curved steel box girder and inclined suspenders, and the mechanical behavior of the SBSSAB is particularly complicated. The SBSSAB is aesthetic in appearance, and design of the SBSSAB is artful and particular. In order to roundly investigate the mechanical behavior of the SBSSAB, 3-D finite element models for spatial member and shell were established to analyze the mechanical properties of the SBSSAB using ANSYS. Finite element analyses were conducted under several main loading cases, moreover deformation and strain values for control section of the SBSSAB under several main loading cases were proposed. To ensure the safety and rationality for optimal design of the SBSSAB and also to verify the reliability of its design and calculation theories, the 1/10 scale model tests were carried out. The measured results include the load checking calculation, lane loading and crowd load, and dead load. A good agreement is achieved between the experimental and analytical results. Both experimental and analytical results have shown that the SBSSAB is in the elastic state under the planned test loads, which indicates that the SBSSAB has an adequate load-capacity. The calibrated finite-element model that reflects the as-built conditions can be used as a baseline for health monitoring and future maintenance of the SBSSAB.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1057-1064
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• 2004

For New In-Cheon Airport. South Approach Section of Young long Great Bridge is to be special concerned to CWR due to substructure was already constructed former railroad bridge design specification. So we applied maintenance free system and CWR (Continuous Welded Rail) by ZLR(Zero Longitudinal Restraint) at bridge expansion joint part. This thesis generally introduce for CWR by ZLR at South Approach Section of Young long Great Bridge.

• Structural Engineering and Mechanics
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• v.29 no.4
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• pp.381-390
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• 2008

This paper proposed a conceptual design of bascule bridge, which is a new kind of movable bridge with an aim of reducing the weight of superstructure. Compared with the traditional bascule bridge, the light bascule bridge chooses cable-stayed bridge with inclined pylon as its superstructure; therefore, the functions of balance-weight and structure will fuse into one. Otherwise, it adopts moving counterweight to adjust its center of gravity (CG) to open or close the bridge. In order to lighten the superstructure, it uses contact springs to auxiliary retract, and intelligent prestressing system (IPS) to control the main girder's deformation. Simultaneously the vibration control scheme of structure is discussed. Starting from establishing the mechanical model of bridge, this article tries to analyze the conditions that the design parameters of structure and attachments should satisfy to. After the design procedure was presented, an example was also adopted to explain the primary design process of this kind bridge.

• Structural Engineering and Mechanics
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• v.40 no.4
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• pp.471-488
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• 2011

The Ting Kau Bridge in Hong Kong is a cable-stayed bridge comprising two main spans and two side spans. The bridge deck is supported by three towers, an end pier and an abutment. Each of the three towers consists of a single reinforced concrete mast strengthened by transverse cables and struts. The bridge deck is supported by four inclined planes of cables emanating from anchorages at the tower tops. In view of the heavy traffic on the bridge, and threats from typhoons and earthquakes originated in areas nearby, the dynamic behaviour of long-span cable-supported bridges in the region is always an important consideration in their design. Baseline finite element models of various levels of sophistication have been built not only to match the bridge geometry and cable forces specified on the as-constructed drawings but also to be calibrated using the vibration measurement data captured by the Wind and Structural Health Monitoring System. This paper further describes the analysis of axle loading data, as well as the generation of random axle loads and simulation of vibrations of the bridge using the finite element models. Various factors affecting the vehicular loading on the bridge will also be examined.

• Structural Monitoring and Maintenance
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• v.9 no.1
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• pp.43-57
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• 2022

One of the instances which demand structural engineer's greatest attention and upgradation is the changing live load requirement in bridge design code. The challenge increases in developing countries as the pace of infrastructural growth is being catered by the respective country codes with bigger and heavier vehicles to be considered in the design. This paper presents the case study of India where Indian Roads Congress (IRC) codes in its revised version from 2014 to 2017 introduced massive Special vehicle (SV) around 40 m long and weighing 3850 kN to be considered in the design of road bridges. The code does not specify the minimum distance between successive special vehicles unlike other loading classes and hence the consequences of it form the motivation for this study. The effect of SV in comparison with Class 70R, Class AA, Class A, and Class B loading is studied based on the maximum bending moment with moving load applied in Autodesk Robot Structural Analysis. The spans considered in the analysis varied from 10 m to 1991 m corresponding to the span of Akashi Kaikyo Bridge (longest bridge span in the world). A total of 182 analyses for 7 types of vehicles (class B, class A, class 70R tracked, class 70R wheeled, class AA tracked, AA wheeled, and Special vehicle) on 26 different span lengths is carried out. The span corresponding to other vehicles which would equal the bending moment of a single SV is presented along with a comparison relative to Standard Uniformly Distributed Load. Further, the results are presented by introducing a new parameter named Intensity Factor which is proven to relate the effect of axle spacing of vehicle on the normalized bending moment developed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.845-856
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• 2020

This study proposes a bridge evaluation system for indivisible permit vehicles such as hydraulic cranes. The permit loads for the bridge evaluation are divided into three categories: routine permit loads, special permit 1 loads, and special permit 2 loads. Routine permit and special permit 1 vehicles are allowed to cross a bridge with normal traffic. For these two permits, the standard lane model in the Korean Highway Bridge Design Code was adopted to consider normal traffic in the same lane. Special permit 2 vehicles are assumed to cross a bridge without other traffic. Structural analyses of two prestressed-beam bridges and two steel box girder bridges were conducted for the proposed permit loads. The rating factors of the four bridges for all permit loads were calculated as sufficiently large values for the moment and shear force so that crossing the bridges can be permitted. A reliability assessment of the bridges was performed to identify the reliability levels for the permit vehicles. It was confirmed that the reliability level of the minimum required strength obtained by the load-resistance factors yields the target reliability index of the design code for the permit vehicles.