• Structural Engineering and Mechanics
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• v.40 no.5
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• pp.719-743
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• 2011

A hybrid damage monitoring scheme using parallel acceleration-impedance approaches is proposed to detect girder damage and support damage in steel plate-girder bridges which are under ambient train-induced excitations. The hybrid scheme consists of three phases: global and local damage monitoring in parallel manner, damage occurrence alarming and local damage identification, and detailed damage estimation. In the first phase, damage occurrence in a structure is globally monitored by changes in vibration features and, at the same moment, damage occurrence in local critical members is monitored by changes in impedance features. In the second phase, the occurrence of damage is alarmed and the type of damage is locally identified by recognizing patterns of vibration and impedance features. In the final phase, the location and severity of the locally identified damage are estimated by using modal strain energy-based damage index methods. The feasibility of the proposed scheme is evaluated on a steel plate-girder bridge model which was experimentally tested under model train-induced excitations. Acceleration responses and electro-mechanical impedance signatures were measured for several damage scenarios of girder damage and support damage.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.240-245
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• 2005

There has been a strong demand on more economic and lower depth girder bridges for short and medium span range, PRECOM, which is a new type steel-concrete composite girder, has been developed to realize a more economic bridge system with a lower depth girder. In the PRECOM girder bridge, a steel plate girder is simply supported and then concrete form is hung to girder. Thus, the self-weight of the concrete is loaded to the steel girder. To increase the resistance of concrete in the lower casing against tensile stress, compressive force is introduced by prestressed tendon To evaluate the manufacturability and performances of the completed bridge, four 15-m girders and a bridge specimen with two 20m girders wvere constructed. The camber during the construction and introduction of an appropriate compressive force was evaluated. Dynamic data were obtained through the modal testing of the completed girders. Static loading test was also conducted to examine cracks and evaluate the decrease in stiffness and failure behavior under extreme conditions.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.486-489
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• 2006

This paper presents a newly proposed object-oriented finite element framework and its applications on dynamic analysis of plate girder bridge. The developed framework supports various types of finite elements, materials, constraints, loads, and solution methods. One major feature different from other object-oriented finite element programs is that static model and dynamic state can be easily read from or written to a file. In addition, the framework supports efficient DOF pattern handling for a node connecting elements with different DOF patterns, new multi-point constraint handling, and various scripting languages for easy use of the library. In order to show the applicability to dynamic analysis, dynamic moving load analysis on plate girder bridge is performed.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1450-1459
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• 2007

Line type rigid bearings for Open-Steel-Plate-Girder railway bridges have several problem in service, and they are unstable structurally. Thus, spherical bearings having advanced maintenance capability and device to resistance up-lift are developed and replace the existing ones. A experiment of maintenance for a new placed spherical bearings under real Open-Steel-Plate-Girder bridge is conducted and their good maintenance performance is proved. The dynamic behavior of the bridge is measured and analyzed for the two cases of the existing and replacing bearings. Therefore, the effect of the new spherical bearings on the railway bridge is assessed.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.803-808
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• 2007

LCCA module enabling to estimate LCC and analyze time-variant reliability index of a plate girder bridge was developed. The developed module was based on the designed data structure following the standardized methodology of ISO/STEP, LCCA module consisted of LCC estimation module, which is composed of six sub modules according to the cost category, and reliability index analysis module, which is composed of time-variant corrosion sub module, time-variant live load sub module, and element reliability analysis sub module, The effectiveness of the developed LCCA module was verified by estimating LCC and analyzing time-variant reliability index of a plate girder bridge on the basis of the constructed test database.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.558-564
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• 2006

When vehicles pass the connection between the bridge and earthwork, the difference of both sections' stiffness produces an increasing wheelload. As a consequence, it results in the excessive vibration of vehicles and the damage of bearing system. In general, steel plate girder railway bridges without ballast track have larger stiffness than the bridge with ballast, and produces larger impulse on the bridge superstructure. Thus, it is necessary to reduce the differences of both stiffness. This study presents parametric studies on the behavior of plate girder bridges and their tracks by means of various stiffnesses and the length of approach zone. The results of numerical study showed that the smaller the stiffness of both sides and the longer the length of approach zone, the variation of wheelload becomes smaller. Hence, it gives less burden into the plate girder bridges and their tracks. It is expected that the results of parametric study can be used as a preliminary data for the determination of economical length on the approach zone and the stiffness of both sides.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.1
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• pp.135-142
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• 2008

This study is concerned with the optimum design of LB-Deck plate girder bridge. The optimizing problems of the composite bridge are formulated with objective functions and constraints. The objective functions are formulated as the total cost of the concrete deck and steel girder construction and the constraints are derived by criteria with respect to the Korean Highway bridge design. The optimizing algorithm using SUMT for optimum design of the Simple span, 2-Span, 3-span LB-deck plate and general RC-steel composite girder bridges (L=60m) which act live load(DB24). And their optimum numerical results are compares and analyzed to examine the possibility of optimization, the application and convergency of this optimizing algorithm.

• Smart Structures and Systems
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• v.31 no.1
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• pp.29-43
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• 2023

This study investigates the possibility of damage detection of a real bridge by means of a modal parameter-based finite element (FE) model update. Field moving vehicle experiments were conducted on an actual steel plate girder bridge. In the damage experiment, cracks were applied to the bridge to simulate damage states. A fast Bayesian FFT method was employed to identify and quantify uncertainties of the modal parameters then these modal parameters were used in the Bayesian model update. Material properties and boundary conditions are taken as uncertainties and updated in the model update process. Observations showed that although some differences existed in the results obtained from different model classes, the discrepancy between modal parameters of the FE model and those experimentally obtained was reduced after the model update process, and the updated parameters in the numerical model were indeed affected by the damage. The importance of boundary conditions in the model updating process is also observed. The capability of the MCMC model update method for application to the actual bridge structure is assessed, and the limitation of FE model update in damage detection of bridges using only modal parameters is observed.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1569-1576
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• 2011

To install heavy structures in the railway bridges, crane methods or launching methods using temporary structure have been applied. These methods are uneconomical because working yard is required, temporary cut of rail system, etc. In this study, various construction methods has been developed which are suitable to the filed conditions. In the case of simple span structure like plate girder bridges, the girder is loaded to troy system at the working yard and then transferred to the working place. To lift and lower the girder system, a new transfer system was developed. Different methods each for simple span bridge girder and long span girder were developed and detailed work procedures were proposed. Using these methods, the heavy structures can be installed with simple and safe work procedures and the construction cost and duration can be reduced.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.401-410
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• 2007

Form the application of long rail system the non-ballast steel plate bridges, fatigue strength increase and rail noise reduction can be expected. This is mainly form the reduction of the rail impact at the rail joint locations which already made to behave together from welds. In the high speed rail, application of long rail system is essential because without long rail system, the required serviceability level can not be achieved. But even with this long rail systems, the thermal expansion from the girder can not be absorbed in the normal bearing systems, and these expansion cause between girder and rail. Also unexpected rail buckling and fracture through rail thermal tension may happen. It was found through numerical analysis and field measurement that these problems can be avoided by semi-fixed bearing system. In this study, the benefits of non-ballast plate bridge through long rail system, especially at the point of girder stability, girder stiffness increase and bearing maintenance will be reviewed.