• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.549-555
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• 2023

Jacking force loss management inside the PSC Box girder of a common high-speed railway is a very important feature in girder performance, and requires detailed management during the maintenance of the girder. This study aimed to analyze the timing of re-tension prediction of PSC Box girder based on the reduction level of the packing force inside the girder and the results of the tension loss measured without the train load test. As a result of predicting the timing of re-tension according to the level of tension reduction of the PSC Box Girder, the Jacking Force Loss curve was gently analyzed before the structure reached 17 years after confirmed completion, and 17 years later, it was found that the jacking force loss curve progressed rapidly. The results confirmed that the tension of the structure decreases with the service life increase, but considerably decreases as the structure ages. Therefore, more data and research on tension loss of facilities over 20 years are much required.

• Journal of Korean Society of Disaster and Security
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• v.16 no.3
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• pp.17-26
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• 2023

Prestressed Concrete (PSC) girders are divided into pre- and post-tension types as prestressing method, and I- and U-type as cross-sectional shape. There are both advantages and disadvantages depending on each prestressing method and cross-sectional shape, and each method is applied to bridge construction sites. In this study, a new girder design was attempted to develop that overcomes its shortcomings by using the pretension method and U-type cross sectional shape. Its structural performance was verified in this study. Pretension type girders are mainly manufactured in factories because they require a reaction arm and related facilities, and have the disadvantage of being limited in weight and span length for road transportation. In addition, in the case of the U-type cross-section, structural stability is very reliable during construction against overturning, but its own weight is relatively large comparing to I-type, and the post-tension method is mainly applied after on-site production. In this study, a PSC girder manufacturing method using the field pretension was proposed and a span length of 40 m real-scale test specimen was manufactured and verified its structural performance.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.235-244
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• 2021

This study analyzes the applicability of limit state design method on bridge evaluation by considering the experiment of the existing bridge. The test strength of the member is obtained from the PSC beam bridge experiment. The test strength is compared with the calculated strength obtained from the statistical characteristics of material test strength and the two values are almost the same. The response modification factor and dynamic impact factor are obtained from the vehicle loading test. The rating factor is calculated by applying limit state design method as well as current evaluation method and the results are compared. The reliability index of the test bridge is calculated by using the statistical properties of the member strength obtained from material test and simulation. When the statistical properties of the PSC beam tested in this study are applied, the reliability index with a larger value was obtained than the reliability index obtained with the statistical properties of the design code.

• Journal of Korean Society of Steel Construction
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• v.18 no.6
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• pp.793-804
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• 2006

Various PSC and steel-concrete composite railway bridges are being developed for short-medium spans with structural and economic efficiency. According to the design concept, the prestressed composite girder bridge has the advantages of being lightweight and having low girder depth, with the capacity for long spans. However, the dynamic behavior under a passing train is one of the critical issues concerning these railway bridges designed with more flexibility. Therefore, it is very important to evaluate the modal parameters before performing dynamic analyses. In this paper, real-scale prestressed composite girders were fabricated as a test model and modal testing was carried out to evaluate modal parameters including natural frequency and modal damping ratio. During the modal testing, a digitally controlled vibration exciter as well as an impact hammer was applied to obtain frequency-response functions, and the modal parameters were also evaluated after the fracture of test models. With application of reliable properties from modal tests, the estimation of dynamic performances of prestressed composite girder railway bridges can be obtained from various parametric studies on dynamic behavior under the passage of a moving train.

• Journal of the Korea Concrete Institute
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• v.20 no.2
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• pp.231-237
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• 2008

This study was performed to evaluate joint behavior of prestressed concrete(PSC)-steel mixed girders through the flexural test of 14 beams according to embedded length, amount of reinforcing steel, stud arrangement, and prestressing force. All test beams were failed by turns of desertion of reinforcing steel, stud, and steel plate. From test results, prestressing force was more effective on performance of connection than stud arrangement and reinforcing steel. And the spacing of stud is also more effective than embedding length. This paper also presented 3D nonlinear analysis considering the slip of composite section as well as the static load tests of PSC-steel mixed girders. According to the slip modulus, the nonlinear analysis showed that the behavior of hybrid girders could be divided into three parts as full-composite, partial-composite and non-composite. However, the experimental results showed that the PSC-steel hybrid girders with shear connectors took the part of partial composite action in ultimate load stage. In addition, it was founded that stud shear connectors and welded reinforcements were contributed to improve the ultimate strength of hybrid girders for about 20%.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.2
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• pp.151-157
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• 2019

Concrete bridge constructed in metropolitan cities has different superstructure members like slabs and girders, and their carbonation depths vary with different design strengths and local environmental conditions. In this paper, 54 concrete cores were obtained from prestressed concrete girders and the related tests were performed for compressive strength and carbonation depth measurement. Referred to the specified compressive strength of 24MPa for slab and 35MPa for I-type girder, the strengths from cores were evaluated to 82% and 73% of design grade, respectively. For carbonation depth, the slab member showed 30.6mm of average with 32.9% of COV(Coefficient of Variation) and I-type girder showed 16.7~17.0mm with 22.8~33.6 of COV. The I-type girder has much lower carbonation depth and COV compared to slab member, however it has higher COV than column structures.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.39-40
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• 2009

This study is for development the anchorage that for development and practicality a holed precast prestressed concrete girder for forming an I-type Prestressed concrete girder bridge, in which at least one hole is formed in a body portion of the I-type Prestressed concrete girder.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.3
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• pp.127-134
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• 2008

The response of a bridge can be influenced by span length, bridge's surface condition, vehicle's weight, and vehicle's velocity. It is difficult to predict accurate behavior of a bridge. In the current standard of specifications, such dynamic effect is defined by impact factor and prescribed to consider live load as to increase design load by means of multiplying this value by live load. However, it is not well understood because the Impact factor method differs from every country. Dynamic, static and pseudo-staitic field loading tests on PSC-I girder bridges were carried out to find out the dynamic property of the bridge. This paper is aimed to figure out actual dynamic property of the bridge by using field loading test. An empirical method based on impact factor is widely used and also argued. Displacement and strain response measured from the tests was compared with one from the empirical method. The former seems to be reasonable since it can consider actual response of a bridge through field tests.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.625-630
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• 2002

PSC box girder is widely used in a domestic bridge and overpass, etc., therefore, the design and construction technique for the PSC box girder is developing day by day. Even if it were so, however, the design for anchorage zone in PSC box girder has depended on common sense and empirical results. And it is the current situation that the designer has difficulty due to inadequacy of provisions in the domestic design code and lack of understanding for behavior of anchorage zone. Besides, the design based on Leonhardt's method is being done in general, but the design may be various even for the same structure because of the difference in a way of applying. In this paper, therefore, anchorage zone in PSC box girder bridge is analyzed and designed by using strut-tie model. Adequacy for the application of strut-tie model is verified by comparison with the way used in current design practice, and this study presents that strut-tie model can be a rational and an economical design than current design methods.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.528-531
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• 2004

Nowadays, many of PSC bridges has constructed because high performance and long span bridge is required. Therefore, it is required that the evaluation of PSC bridges which retain various structure performance. In this study, nonlinear FEM analysis was performed with two parameter, concrete compressive strength and effective prestress force which is dominant factor for evaluating structural behavior of PSC bridge. Concrete compressive strength was adapted between 30Mpa and 100Mpa and effective prestress force was used the value which is considered effective rate for time-dependant effect. In the result of this study, it was showed that concrete compressive strength and effective prestress force is important factor for evaluating structural behavior of PSC bridge.