• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.3
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• pp.77-86
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• 2004

The retrofit priority of existing and retrofitted bridges is examined and compared to determine effectively the seismic retrofit method of bridges. For the retrofit prioritization of bridges a quantitative procedure is proposed firstly based on seismic damage probabilities and total failure cost due to the damage of seismic vulnerable components. Using the proposed procedure, the retrofit priority of four typical girder-type bridges is determined. In addition, the ranking indices of bridges retrofitted by steel jackets and cable restrainers are revaluated for comparing with the results of existing bridges. Application of retrofitting method can considerably decreases damage possibilities of retrofitted components but may increases those of adjacent vulnerable components. Therefore, the seismic retrofitting effects based on the global motions of existing and retrofitted bridges should be examined to determine efficiently the retrofitting method. For evaluating the retrofitting effects the ranking indices obtained from the proposed procedure is found to be utilized effectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.742-752
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• 2017

The bridge type of steel concrete composite rahmen or pre-flex has been applied where a lower depth girder is required due to vertical clearance restrictions caused by the crossing of rivers and roads. On the other hand, because these types are not only complicated to manufacture and construct, but also expensive, void slab bridges may be an alternative. In this study, prefabricated PSC-I shape girder was used to make a void slab and all procedures for bridge development, such as analysis, design, fabrication, and real-scale test, were included in the scope of research. The results of this study will provide sufficient background data to be applied to the field and the structural safety has been verified through experiments.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1370-1378
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• 2007

High speed railway bridge is affected on safety of bridge by dynamic amplification effect, when dynamic response of bridge is equal to effect cycle load for rolling stock axle according to high speed operation train. And excessive deformation of structure has negative effect on operation safety of train and comfort of passenger due to fluctuation of wheel load by torsion of track etc. and decrease of contact force on vehicle wheel-rail. To ensure the safety of track and train operation safety, it is have to perform the study on resonance and deformation of structure. That criteria and requirement of railway bridge is limitation of vertical acceleration on deck for dynamic behavior of structure, contact of vehicle wheel and rail, limitation of face distortion and rotation angle of end deck, and limitation of vertical displacement by train. Unlike KYEONGBU High Speed Railway, New constructed HONAM High Speed Railway have to applied the new requirement for dynamic behavior safety according to change of condition which is type of ballast (slab ballast), interval of track, and actual rolling stock load. Therefore, in this paper, it was conformed the dynamic characteristic due to parameter, which related with above mentioned criteria, for steel composite bridges.

• Journal of Korean Society of Steel Construction
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• v.9 no.3 s.32
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• pp.431-440
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• 1997

The paper describes a theoretical model for the prediction of bridge temperatures from meteorological data measured at bridge site and local meteorological center together with existing finite element heat transfer theory and solar radiation transfer theory to determine the time dependent temperature distribution of bridge. In this analytical model, the most adequate equation for the calculation of solar radiation on the bridge surface, which is dominant in day time is described based on the results of several experimental studies for the solar energy. The validity of this model is tested against field data obtained from long term experimental program on Sadang Viaduct in Seoul. Also, this paper describes the linear correlation between design variables and meteorological data to establish analytical criteria for the prediction of the average temperature, which are responsible for the longitudinal deformation of the bridges and of the vertical differential temperature profiles. which are responsible for the bending deformations from the long term experimental results.

• Journal of Korean Society of Steel Construction
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• v.10 no.2 s.35
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• pp.263-277
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• 1998

Recently, it is frequently reported that fatigue damages of deck slabs and floor systems of highway bridges occur under the conditions of increasing weight and traffic of heavy vehicles. These troubles are affected by dynamic wheel load of heavy vehicles running on roadway surface roughness with bump at expansion joint. It is required that this kind of traffic-induced vibration of highway bridges must be analyzed by using three-dimensional models of bridge and vehicle. In this study, the three-dimensional dynamic analysis is carried out, and dynamic responses of deck slab and wheel loads of moving vehicle are estimated according to different vehicle speeds and bump heights. Analytical responses of bridge deck slab are compared with experimental ones which were measured at Umeda entrance bridge of Hanshin Expressway in Osaka.

• Journal of Korean Society of Steel Construction
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• v.19 no.2
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• pp.147-160
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• 2007

In this paper, we described the aeroelastic full-bridge model tests that were conducted to investigate the effect of alternative temporary stabilizing measures for thecable-stayed bridge during construction to ensure aerodynamic stability in the event of a typhoon or similar disasters. The effect of alternative temporary stabilizing measures was investigated through various configurations on two cable-stayed bridges with a main span of 475 m and 230 m, respectively. To investigate the bridge's aerodynamic behaviour and dynamic wind force during construction, the deflections at the end of the cantilever, the accelerations atthe top of the pylon and the moments at the lower part of the pylon were measured. As the result, the system with two sets of vertical cables per cantilever seemed to be the overall most effective solution, but the system with single vertical cable may also work. The combined system using the caisson support and vertical cables and the system with two sets of inclined cables per cantilever on the same anchor block may also be a solution. The inclined cables from the caisson to the girder were effective for some early stages of erecting the deck.

• Journal of Korean Society of Steel Construction
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• v.15 no.2
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• pp.125-135
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• 2003

A 3-dimensional model of curved steel box girder bridges without diaphragm was presented. This model yielded results that were consistent with those of the parameter analysis using the BEF and Ritz methods. Se veralmodels with diaphragms were analyzed to estimate the appropriate diaphragm spacing. In case of 50m span, models A-10, A-20, A-30, B-10, B-20, and B-30 were found to have 5(8.3m), 7(6.25m), 8(5.5m), 4(10m), 6(7.1m), and 7(6.25m) diaphragms, respectively. In addition, a formula that presents the ratio of distortional stress to bending stresswas created from the results of the 3-dimensional FEM model analysis.

• Journal of Korean Society of Steel Construction
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• v.22 no.5
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• pp.465-475
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• 2010

In the horizontally curved bridges, girders are subjected to the combined action of vertical bending and torsion due to their curvatures without any eccentric loads. As subjected to bending and torsion, the ultimate strength of steel/concrete composite box girders are limited by the diagonal tensile stress in the deck concrete induced by the St. Venant torsion. To determine the ultimate strength of composite box girders in bending and torsion and their interactions, this study conducted a 3-dimensional FEA and classical strength of materials investigation. Using ABAQUS, the FEA fully utilized advanced nonlinear analysis techniques simulating material/geometrical nonlinearity and post-cracking behaviors. The ultimate strength from numerical data were compared with theoretically derived values. Concurrent compressive stresses in the concrete deck improve the shear-resisting capacity of concrete, thereby resulting in an increased torsional resistance of the composite box girder in positive bending. The proposed interaction equation is very simple yet it provides a rational lower bound in determining the ultimate strength of concrete/steel composite box girders.

• Composites Research
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• v.24 no.5
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• pp.29-33
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• 2011

The application of high performance materials for the deck can represent a fair alternative to reduce the weight of the deck and improve the econimic efficiency of the bridge even if high performance materials are costly. In UHPC(Ultra High Performance Concrete) bridges, it is necessary to verify that exiting headed stud can be used to transfer longitudinal shear forces across the steel-concrete interface. In this paper, the push-out tests are performed to analisys the composite behavior between UHPC bridge deck and steel girder. The ultimate strength of test specimens is proportional to the diameter of headed studs in push-out test for static loading. Test results show that the shear strength of headed stud is improved for the case of normal concrete bridge decks.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.423-431
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• 2013

The k-factor method has been widely used in design of steel-concrete composite bridges to determine indeterminate stresses. The accuracy of k-factor method is examined by a comparative analysis with the equivalent load method in a continuous 2-span composite bridge. To improve the accuracy, the direction of creep stress has to be modified and the variety of section must be considered. This paper suggests j-factor method which can improve the accuracy of k-factor method with simple modification.