• Proceedings of the Korea Concrete Institute Conference
• /
• 1995.04a
• /
• pp.385-390
• /
• 1995

In segmentally erected bridges, the structural systems are changed as the construction stages progress and redistribution of member forces occurs due to time dependent effects of concrete and relaxation of perstressing steel. Therefore, structural analysis is required at each construction stage. In this study, nonlinear analysis program of the segmentally erected prestressed concrete box girder bridges is developed to raise the efficiency in making input file for the main program and analysis of the results produced by the main program.

• Structural Engineering and Mechanics
• /
• v.41 no.1
• /
• pp.139-155
• /
• 2012

Structural health monitoring systems are often installed on bridges to provide assessments of the need for structural maintenance and repair. Damage or deterioration may be detected by observation of changes in bridge characteristics evaluated from measured structural responses. However, construction materials such as concrete and steel cables exhibit certain time-dependent behaviour, which also results in changes in structural characteristics. If these are not accounted for properly, false alarms may arise. This paper proposes a systematic and efficient method to study the time-dependent effects on the dynamic properties of cable-stayed bridges. After establishing the finite element model of a cable-stayed bridge taking into account geometric nonlinearities and time-dependent behaviour, long-term time-dependent analysis is carried out by time integration. Then the dynamic properties of the bridge after a certain period can be obtained. The effects of time-dependent behaviour of construction materials on the dynamic properties of typical cable-stayed bridges are investigated in detail.

• Proceedings of the KSR Conference
• /
• 2006.11b
• /
• pp.530-537
• /
• 2006

Recently, the railroad route plan is trying to minimize the damage of the local resident which is caused by railroad construction. For this reason, reducing the banking height of soil roadbed, lowering the bridge girder height of a solid intersection and a part of cross river, the through bridge type which can achieve a required span length must apply. The representative through bridges of railroad are arch bridges, truss bridges and plate girder bridges, the through plate girder bridge of variable section can apply that the span length of these bridges is about $30{\sim}50m$, namely, middle span length bridge types, and that can satisfy structural capacity and beauty of railroad at the same time. This paper introduces plan and design process of the Su-eo cheon bridge applied by a through plate girder bridge type of the Jinju-Gwangyang double track 6th construction ordered at Korea Rail network Authority in 2005.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1993.04a
• /
• pp.188-193
• /
• 1993

In widening of existing bridges, construction joints between old new parts of concrete slabs are subjected to repeated traffic loads during placing and curing of concrete. Therefore, the main focus of this paper is given to examine several construction methods of bridge widening. As a result, the occurrence of cracks in vibrating specimen is faster than non-vibrating one, but the difference between flexural strength and ultimate moment was negligible. Also, it shows the same result in other construction method, say direct and non-shrinkage joint specimen.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.10 no.1
• /
• pp.81-86
• /
• 1990

This study aims to systemize the developement of the domestic girder bridges, and to contribute to the future construction of our own bridges. Bridges are analyzed by grouping them in terms of construction time and structural component. The bridges, which were constructed during the first era of Goryeo-dynasty, have no distinction between main beams and stone deck. Form the latter era of Goryeo-dynasty, the structure of the bridges began to seperate into main beams and stone deck in order to enlarge the width and span length. The bridges, which were constructed during the Chosun-dynasty, were constructed using modulized material, and are considered to be built by structural design concept. Their construction materials became larger due to the development of transportation method. The superstructure of the old Korean bridges became more complicated in contrast to simplification of the substructures.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.05a
• /
• pp.524-527
• /
• 2004

Recently, precast concrete products have been increasingly used in the construction of bridges except for special bridges like long-span bridge due to their easy and high-quality construction. Specially the use of precast prestressed concrete hollow box slab bridges is also increased due to the merits in their construction. Thus, an experimental evaluation of flexural behavior of the precast PSC hollow box slab bridges and a development of effective analytical technique for the behavior are necessary. For the development, experimental study on the flexural behavior of the precast bridges up to ultimate states is needed. In this study, two full-scale precast PSC hollow box slab girders are manufactured and full-scale flexural failure tests of the girders subjected to cyclic loading are carried out. For the failure analysis of the girders, the so-called volume control method is applied to finite element analysis of the precast PSC hollow box slab girders discretized using multi-layered shell elements. The analytical results by the volume control method is verified by comparing with test results.

• Journal of the Korean Society for Advanced Composite Structures
• /
• v.6 no.3
• /
• pp.26-31
• /
• 2015

The domestic and foreign specifications presented the effective width based on flange length to width ratio only. The existing paper on the effective width grasped of the effect of span, load type and cross-section properties, but localized steel bridges. Recently, The studies are going on in progress for the application of fiber reinforced composite material in construction field. Therefore, it is required to optimum design that have a good grasp the deformation characteristic of the displacements and stresses distribution and predict variation of the effective width for serviceability loading. This research addresses the effective width of all composite material box girder bridges using the finite element method. The characteristics of the effective width of composite structures may vary according to several causes, e.g., change of fibers, aspect, etc. Parametric studies were conducted to determine the effective width on the stress elastic analysis of all composite materials box bridges, with interesting observations. The various results through numerical analysis will present an important document for construct all composite material bridges.

• Proceedings of the KSR Conference
• /
• 2007.11a
• /
• pp.1132-1140
• /
• 2007

As it recently appears that Life Cycle Cost Analysis may be considered as new methodology for economic valuation of infrastructure many researches have been made to assess LCC(Life Cycle Cost) of each facility based on a reasonable methods. In general, LCC is composed of construction cost and expected maintenance repair cost. And especially, maintenance repair cost must be estimated to enhance the reliability through systematic and reasonable methods. However in Korea, because high speed railway steel bridges are recently constructed no direct statistical data are available for the account of the maintenance cost and then their maintenance characteristics are not linear yet. Therefore, the approach proposed in the paper utilizes a theoretical determination and degradation of the corrosion and fatigue of the bridges based on Rahgozar et al.(2006)'s model on fatigue notch factor considering into the corrosion to incorporate the corrosion effect into the fatigue strength reduction model. And then, the corresponding probability of failure is calculated in terms of the reliability index using S-N curve to formulate the fatigue limit state. Therefore, this paper proposes the minimum Life Cycle Cost through optimum maintenance plan analysis of high-speed railway steel bridges under construction. Finally, this paper reviews the proposed model in oder to confirm the applicability and feasibility by appling it to high speed railway steel bridges under construction

• Journal of Korean Society of Steel Construction
• /
• v.13 no.4
• /
• pp.337-349
• /
• 2001

This study present an optimum deck and girder system design for minimizing the life-cycle cost (LCC) of orthotropic steel deck bridges. The problem of optimum LCC design of orthotropic steel deck bridges is formulated as that of minimization of the expected total LCC that consists of initial cost, maintenance cost, expected retrofit costs for strength, deflection, and fatigue. To demonstrate the effect of LCC optimum design of orthotropic steel deck bridges, the proposed optimum LCC design is compared with the conventional method for orthotropic steel deck bridges design. From the numerical investigations, it may be positively stated that the proposed optimum design procedure for orthotropic steel deck bridges based on the LCC will lead to more rational, economical and safer design.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1993.04a
• /
• pp.176-181
• /
• 1993

Recent increasing traffic volumes have made many bridges on highway be widened. Depending on the construction method of bridge widening, several undesirable problems have been arisen with the additional stresses resulting from de-staging of new bridge and the difference of the amount of creep and shrinkage between new and existing bridge. The main focus of this paper is given to investigate the variation of the adhesive strength of steel bar and construction joints of new and old concrete slab. The result shows that repeated vibration loadings was caused some bad effects on the construction joints between new and existing bridges.