• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3A
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• pp.287-295
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• 2010

The main purpose of this study is to investigate the static behavior of spliced prestressed concrete girder with bending moment connector and lateral prestressing. Four (4) spliced girders and one (1) monolithic girder had been fabricated and tested to compare their static behaviors. Same geometry and materials are used to fabricate these spliced and monolithic girders. A monolithic girder and one (1) spliced girder without lateral bending connector are used as control specimens to estimate the performance of three (3) spliced girders with lateral bending connector. Deflections at the middle of girders have been measured for evaluation. Also, strains of the concrete at the middle of span and connection points have been measured. It was found from the result that laterally strengthened spliced girders showed improved ultimate strength but less stiffness compared to the monolithic girder at the ultimate state. Laterally strengthened spliced girder also showed improved strength as well as improved stiffness compared to the spliced girder without lateral strengthening.

• Journal of the Korea Concrete Institute
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• v.27 no.4
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• pp.377-385
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• 2015

The span-lengthening of PSC I girder has increased the risk of lateral instability of the girder with the increases in the aspect ratio and self-weight of the girder. Recently, collapses of PSC I girder during construction raise the necessity of evaluating the lateral instability of the girder. Thus, the present study evaluated the lateral behavior and instability of PSC I girders under wind load, regarded as one of the main causes of the roll-over collapse during construction. Lateral instability of the girder is mainly dependent on the length of the girder and the stiffness of the support. The analysis results of this study showed the decrease in the critical wind load and the increase in the critical deformation and angle of the girder, leading to the lateral instability of the girder. Finally, this study proposed analytical equations that can predict the critical amount of wind load and lateral deformation of the girder, which would provide quantitative management values to maintain lateral stability of PSC I girder during construction.

• Journal of the Korea Concrete Institute
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• v.19 no.4
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• pp.433-439
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• 2007

The main objective of the paper is to investigate the static behavior of a prestressed concrete (PSC) girder that has been spliced with precast box segments. A 20 m long full-scale spliced PSC girder is fabricated and tested to compare its static performance against a monolithic girder. The monolithic girder has the same geometric and material properties with respect to the spliced girder. This includes infernal strain, deflections, neutral axis position, and crack patterns for both girders. The test also consists of monitoring relative displacements occurring across the joints. Both the horizontal displacement (gap) and vertical displacement (sliding) are measured throughout the loading procedure. All results have been compared to those obtained from the monolithic girder. It has been demonstrated that the spliced girder offers close behavior with respect to the monolithic girder up to the crack load. Both girders exhibits ductile flexural failure rather than abrupt shear failure at joints.

• Journal of Korean Society of Steel Construction
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• v.17 no.5 s.78
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• pp.637-648
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• 2005

Innovative prestressed steel plate girders were presented in this study. Hot-rolled H beams were loaded first, then relatively high-strengthsteel plates were welded on the top and bottom flanges of preloaded H beams. Finally, high prestressed plate (HiPP) girder was manufactured by simply releasing prestresses of rolled beams. To verify prestress distributions induced in this girder, the experimental study was conducted and some guidelines to manufacture these girders effectively were addressed. In addition, methods to determine the allowable bending stress of HiPP girders and to check welding stresses were addressed for design of temporary bridges. The efficiency and effectiveness of the present girder were demonstrated through design examples of temporary bridges adapting the prestress-induced girder or the plate girder of the same section without prestresses. As a result, it has been found to be possible that the span length of HiPP girders for temporary bridges is longer than that of girders without prestresses.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.6
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• pp.617-625
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• 2021

The problems associated with the continuous method of a domestically improved prestressed concrete (PSC) girder and the bending moment of a continuous tendon were studied. Based on the results, a continuous tendon model was proposed that can resist the negative bending moment of an intergirder. This model lowers the anchorage of the continuous tendon as far as possible under the girder, and extends the tendon section arranged under the girder. This method reduces the PS's bending moment in the middle of the span, but maximizes it in the intergirder. This continuous tendon model can offer a suitable method for continuity before manufacturing a composite, which requires a higher design bending moment in the intergirder than in the middle of the span.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3A
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• pp.235-249
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• 2011

A new form of I-type PSC bridge girder, which has hole in the web, is proposed in this paper. Three different concepts were combined and implemented in the design. First of all, a girder was precast at a manufacturing plant as divided pieces and assembled at the construction site using post-tensioning method, and the construction period at the site will be reduced dramatically. In this way, the quality of concrete can be assured at the manufacturing factory and concrete curing can be well controlled, and the spliced girder segments can be moved to the construction site without a transportation problem. Secondly, a numerous number of holes was made in the web of the girder. This reduces the self-weight of the girder. But more important thing related to the holes is that about half of the total anchorages can be moved from the girder ends into individual holes. The magnitude of negative moment developed at girder ends will be reduced. Also, since the longitudinal compressive stresses are reduced at ends, thick end diaphragm is not necessary. Thirdly, Prestressing force was introduced into the member through multiple stages. This concept of multi-stage prestressing method overcomes the prestressing force limit restrained by the allowable stresses at each loading stage, and maximizes the magnitude of applicable prestressing force. It makes the girder longer and shallower. Two 50 meter long full scale girders were fabricated and tested. One of them was non-spliced, or monolithic girder, made as one piece from the beginning, and the other one was assembled using post-tensioning method from five pieces of segments. It was found from the result that monolithic and spliced girder show similar load-deflection relationships and crack patterns. Girders satisfied specific girder design specification in flexural strength, deflection, and live load deflection control limit. Both spliced and monolithic holed web post-tensioned girders can be used to achieve span lengths of more than 50m with the girder height of 2 m.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.3
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• pp.290-297
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• 2017

The flexural behavior tests of UHPC segmental U-girder and composite U-girder which has 160MPa compressive strength and 15.4m length were carried out. The test variables are volume fraction of steel fibers and slab over the U-girder. Each U-girder has longitudinal re-bars in web and lower flange. PS tendons which has 2 of 15.2mm diameter in upper flange and PS tendons which has 7 of 15.2mm diameter in lower flange were arranged and prestressed at onetime in U-girder connection stage. Enough strong prestressing force which applied to U-girder due to ultra high performance concrete strength can withstand the self weight and dead load in U-girder stage. By comparison with the brittle behavior of U-girder, composite U-girder showed the stable and ductile behavior. After the construction of slab over U-girder, flexural load capacity of composite U-girder can bear the design load in final construction stage with only one time prestressing operation which already carried out in U-girder stage. This simple prestressing method due to the ultra high strength concrete have the advantage in construction step and cost. The shear key which has narrow space has the strong composite connection between ultra high strength concrete U-girder and high strength concrete slab didn't show any slip and opening right before failure load.

• Journal of the Korea Concrete Institute
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• v.17 no.2 s.86
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• pp.229-236
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• 2005

To cope with increasing requirements of cost reduction, labor saving, and rapid construction, the purpose of this study is to investigate the structural behavior of PSC monolithic and spliced girders. Three tests were conducted on reduced-scale girder specimens having same type. This paper presents the result of experimental studies on the load-deflection behavior in which different joint and amount of tendon as major variables were investigated. The first one used a monolithic girder was arranged with three tendons. The second one used a spliced girder was joined with three tendons after producing five segments. And the third girder was produced in same conditions with the second girder and arranged with additional tendons. The experimental results show the difference of behavior between monolithic and spliced girders.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.5
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• pp.99-106
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• 2007

To satisfy with the increased requirements of cost reduction, labor saving, and rapid construction, the purpose of this study is to investigate the structural behavior of PSC monolithic and spliced girders. Three tests were conducted on small-scale girder specimens. This paper presents the result of experimental studies in terms of the load-deflection behavior. Different joint type and tendon amount were investigated as major variables. The monolithic girder was arranged with three tendons. The spliced girder consisted of five segments connected by three tendons. In addition, five-segmented girders connected by more than three tendons were built to examine the effect of the tendon amount. The experimental results show the difference of behavior between monolithic and spliced girders. Moreover, nonlinear finite element method analysis was utilized to verify the experimental result.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.352-355
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• 2010

본 논문에서는 내부 및 외부 긴장재로 보강된 PSC 거더의 가속도 응답 특성을 이용한 구조건전성 모니터링을 위해 실험 및 수치해석 결과를 비교 분석하는 연구를 수행하였다. 첫 번째로, 내부 및 외부 긴장재로 보강된 모형 PSC 거더를 제작하였다. 두 번째로, 모형 PSC 거더의 형상, 재료 및 경계조건과 긴장재의 배치를 고려하여 초기 유한요소모델을 설계하였다. 세 번째로, 다수의 내부 및 외부 긴장력 조건하의 모형 PSC 거더에 대한 동특성 추출 실험 및 수치해석을 수행하였다. 마지막으로, 실험결과와 수치해석 결과를 비교 분석하여 가속도 응답 특성을 이용한 내부 및 외부 긴장재로 보강된 PSC 거더의 구조건전성 모니터링에 대한 적용성을 검토하였다.