• Journal of Korean Society of Steel Construction
• /
• v.18 no.1
• /
• pp.53-58
• /
• 2006

The aim of this paper is to verify the dynamics stability of the continuous PSC Box bridges on the high-speed Kyoung-bu railway when a high-sped train runs through it. An experimental study was carried out to investigate the dynamic behaviors of the PSC Box railway bridge, which had ben designed based on dynamic design criteria. As a result, it was determined that PSC Box railway bridges possess enough dynamics stability for use by high-speed trains. According to the result of a field test (dynamics measuring analysis) that was conducted, an application of the natural frequency of train speed and the adjustment of the bridge's span length will allow one to come up with a more economical and suitable bridge design. Furthermore, it was found that the continuous control of the bridge's dynamic behavior and the bridge's maintena nce require the recording of data. The results of this study are very important in evaluating the structural stability of high-speed line bridges.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2000.10a
• /
• pp.205-210
• /
• 2000

An optimum design algorithm of PSC box girder bridges using design sensitivity analysis is proposed in this paper. For the efficiency of the proposed algorithm, approximated reanalysis techniques using design sensitivity analysis are introduced. And also to save the numerical efforts, an efficient reanalysis technique through approximated structural responses is proposed. A design sensitivity analysis of structural response is executed by automatic differentiation(AD). The efficiency and robustness of the proposed algorithm, compared with conventional algorithm, is successfully demonstrated in the numerical example.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.23 no.6
• /
• pp.311-319
• /
• 2019

The number of aged bridges is increasing so that bridges over 30 years old account for about 11% of all bridges. Consequently, the development of a seismic performance evaluation method that considers the effects of ageing is essential for a seismic retrofitting process for improvement of the seismic safety of existing old bridges. Assessment of the damage situation of bridges after the recent earthquakes in Korea has been limited to the bearings, anchor, and concrete mortar on piers. The purpose of this study is to evaluate the seismic responses of PSC box girder bridges by considering the ageing effect of rubber bearings (RBs) and lead-rubber bearings (LRBs). The modification factor proposed by AASHTO is used to take into account the ageing effect in the bearings. PSC box girder bridges with RBs and LRBs were 3D modeled and analyzed with the OpenSEES program. In order to evaluate the ageing effect of RBs and LRBs, 40 near fault and 40 far field records were used as the input earthquakes. When considering the effect of ageing, the displacement responses and shear forces of bridge bearings (RBs and LRBs) were found to increase mostly under the analytical conditions. It was shown that the effect of ageing is greater in the case of RBs than in the case of LRBs.

• 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 Korea institute for structural maintenance and inspection
• /
• v.5 no.3
• /
• pp.191-201
• /
• 2001

In spite of the increasing construction of segmental PSC box girder bridges, the techniques associated with real-time monitoring, construction control and safety assessment during construction have been less developed compared with the construction techniques. Thus, the development of an integrated system including real-time measurement and monitoring, control and safety assessment system during construction is necessary fur more safe and precise construction of the bridges. This study presents a prototype integrated monitoring system for preventing abnormal behavior and accidents under construction stages, that consist of behavior control system for precise construction, reliability-based safety assessment system, and structural analysis. Also, a prototype software system is developed on the basis of the proposed model. It is successfully applied to the Sea-Hae Grand Bridge built by FCM. The integrated system model and software system can be utilized for the safe and precise construction of segmental PSC bridges during construction.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.20 no.3
• /
• pp.329-338
• /
• 2007

The PSC box bridge constructed of concrete, reinforcing bar and tendon is a complex structure that exhibits tension cracks, nonlinear behaviour of steel and time dependent behaviour of concrete. The frame element is commonly used for construction stage analysis PSC bridges. However, the frame element does not show sufficient information when in the curved PSC box bridges. For the case of curved PSC bridges, the deformations in the inner and outer web are different. In this case, different jacking forces are required in the inner and outer webs. However, it is impossible to calculate different jacking forces if we use the frame element for construction stage analysis. In order to overcome this problem, the use of the shell element is essential for a three-dimensional construction stage analysis of PSC bridges. In the following, the formulation of a Quasi-conforming shell element and its application of PSC box girder bridge analysis are presented.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2009.05a
• /
• pp.561-562
• /
• 2009

The needs for inspection automation for more systematic and efficient maintenance were gradually increased by several inspectors and researchers. With the robotic and digital image processing technologies, in this paper, new inspection automation system were introduced and tested in the real PSC box crack inspection procedures The configuration and scheme of robotic inspection and digital image processing algorithms were represented. The designed robotic sensors and image processing system were tested and the feasibility and possibility of the robot based automatic inspection were approved in the real PSC box bridges.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.5 no.2
• /
• pp.111-120
• /
• 2001

This paper aims at estimating instantaneous prestress losses by measuring the actual prestress forces in prestressed concrete (PSC) box girder bridges. Measurement were taken to study initial prestress losses such as friction losses and slip losses. A new strain gauge system was developed to measure strains in internal tendons. The system was installed on a total of 20 tendons in a PSC box girder bridges. The variation of prestress forces were monitored during prestressing tendon and after prestress transfer. The prestress losses are also calculated including friction losses and slip losses. The measured data were compared with the theoretical values. The result shows that the measured prestress forces agree well with the theoretical values. It is shown that prestress force of each strand in the same tendon is a bit different. This study also shows that prestress losses of continuity tendons during prestress transfer are significantly different each other, which results from the variety of buttress location and tendon profile. The present study provides realistic information on the estimation of actual prestress forces and losses in PSC box girder bridges.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.11 no.5
• /
• pp.197-211
• /
• 2007

The deteriorated PSC Beam bridge is necessary improved reinforcement method. In the study, it is proposed the box reinforcing method which could make the stiffness of the PSC Beam bridges increase more stably through the secondary composition effect of open type PSC Beam bridge's girder which is converted into the consolidation box type and the half panel is formed between the lower flange of the PSC Beam about the deteriorated PSC Beam bridge suffering the capacity decline. In case the proposed reinforcement method combine with the existed external prestressed method, the close analysis depending on the time is conducted by the construction stage because of searching the effect of reinforcement quantitatively. The reinforcement method of the box type which is proposed an efficiency improvement in objective in application case, by a reinforcement method after proposing the whole and bend sectional reinforcement method, against a each reinforcement method evaluated the upward camber which it follows in secondary composite effect and a member stress characteristics. Also, the structural safety of PSC Beam bridge is evaluated quantitatively by examining of rating factor through load carrying capacity evaluation.

• Journal of the Korean Society for Railway
• /
• v.15 no.2
• /
• pp.154-161
• /
• 2012

The damping ratio of railway bridge has become one of the most important issues in dynamic design and dynamic stability of railway bridge. In the present study, laboratory and field test were performed for railway bridges such as a twin I-shaped steel composite girder, PSC box, steel box, PSC, IPC, PRECOM, preflex. The damping ratio of railway bridge according to structure types was estimated by logarithmic decrement method. Therefore, magnitude, frequency and amplitude of load did not affect damping ratio of railway bridge. Also, damping ratio limit of steel composite and PSC bridges was evaluated in 1.0%.