• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.221-224
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• 2008

조립식 교각을 교량의 하부구조에 적용하는 다양한 기술들이 최근에 활발히 개발되고 있다. 이 논문에서는 프리스트레스를 필요로 하지 않는 형태의 프리캐스트 합성교각을 제안하였다. 낮은 강재비를 갖는 합성교각의 정적 및 내진성능 평가에 기반하여 교각 단면을 설계하고 기초부와의 연결상세는 교각 단면이 기초부로 일부 매입된 상태에서 볼트 연결로 설계하여 설계의 단순화를 도모하였다. 새롭게 제안된 프리캐스트 합성교각에 대한 구조적 성능을 검증하기 위해 준정적실험을 수행하였다. 실험을 통하여 정적 성능과 내진성능을 함께 평가하고 기존의 현장타설 합성교각의 거동과 비교를 수행하였다. 프리캐스트로 제작할 경우에 기초와 만나는 교각 끝단의 보강 상세가 요구되고 이와 관련한 상세 제안사항을 도출하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.121-124
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• 2008

교량 하부의 급속시공 기술은 교량 설계의 새로운 경향이다. 부착 강봉으로 프리스트레스를 도입하는 프리캐스트 교각 시스템을 제안한다. 이 논문에서는 부착 강봉으로 프리스트레스가 도입된 프리캐스트 원형 교각의 준정적 실험을 통해 내진 성능 평가를 하였다. 기둥의 세그먼트 연결부의 전단강도 보강을 위해 모르터로 충전된 원형강관을 사용하였다. 프리캐스트 교각의 변위연성도와 에너지 소산능력을 평가하였다. 제안된 프리캐스트 교각 시스템은 요구연성도보다 더 좋은 내진성능을 보였다. 실험적 연구를 바탕으로 경전철 교량의 하부구조를 설계하고, 설계 고려사항에 대해 검토하였다.

• 한국산학기술학회논문지
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• 제22권1호
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• pp.116-122
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• 2021

본 논문은 반복하중을 받는 원형 철근콘크리트 교각 외부에 강판 보강을 적용한 경우, 교각의 성능 향상도를 정량적으로 평가하였다. 범용 유한 요소해석프로그램인 ABAQUS의 다양한 3차원 요소를 적용하여 교각 구조물을 해석하였다. 비탄성, 비선형 해석 변수로는 강판 보강 높이와 교각 높이 비, 강판 보강 두께와 교각 지름 비를 적용하였다. 교각 하부는 고정단으로 고려하였으며, 하중은 교각 상단에 횡 방향 반복하중을 가력하였다. 하중-변위 곡선, 응력-변형률 곡선, 연성도, 에너지 흡수 능력을 고려하여 보강에 따른 교각의 내진 성능 향상도를 평가하였다. 강판으로 보강한 원형철근콘크리트 교각은 보강재로 인한 외부 콘크리트 구속 효과로 인해 기둥의 항복 하중과 극한하중이 평균 3.76배 증가하였고, 에너지 흡수능력은 최대 4배 증가하였다. 소성 힌지가 발생하는 교각 하부 부분만 보강하여도 연성도가 크게 향상되었으며 강판의 두께가 두꺼울수록 에너지 흡수 능력이 가장 큰 값을 나타내었다. 본 연구결과를 토대로 원형철근콘크리트 교각의 외부 강판 보강을 통하여 교각의 구조 성능을 향상시킬 수 있음을 정량적으로 확인할 수 있었다.

• Structural Engineering and Mechanics
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• 제85권4호
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• pp.563-571
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• 2023

Girdling underpinning joints are key areas of concern for the pier-cutting bridge-lifting process. In this study, five specimens of an underpinning joint were prepared by varying the cross-sectional shape of the respective column, the process used to treat the beam-column interface (BCI), and the casting process. These specimens were subsequently analyzed through static failure tests. The BCI was found to be the weakest area of the joint, and the specimens containing a BCI underwent punching shear failure. The top of the girdling beam (GB) was subjected to a circumferential tensile force during slippage failure. Compared to the specimens with a smooth BCI, the specimens subjected to chiseling exhibited more pronounced circumferential compression at the BCI, which in turn considerably increased the shear capacity of the BCI and the ductility of the structure. The GB for the specimens containing a column with a circular cross-section exhibited better shear mechanical properties than the GB of other specimens. The BCI in specimens containing a column with a circular cross-section was more ductile during failure than that in specimens containing a column with a square cross-section.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2002년도 춘계 학술발표회 논문집
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• pp.203-210
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• 2002

The past bridge design specifications of Korea didn't include 1imitation on the amount of lap splices in the plastic hinge zone of piers, and so do current specifications. But these specifications include just limitation on the minimal length of lap splices. Thus, a large majority of non-seismically designed bridge piers may have lap splices in plastic hinge zone. In this study, model pier was selected among existent bridge piers whose failure mode is complex shear-flexure mode. Full scaled RC pier models whose aspect ratio is about 2.67 were constructed and quasi static test according to the drift level history was implemented. From the test results, effect of the lap splices on the seismic performance of bridges piers was analyzed, and the seismic capacity of the model bridges was evaluated by capacity spectrum method.

• 한국BIM학회 논문집
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• 제8권1호
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• pp.15-23
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• 2018

Geometry control of precast members is the most important technology for modular construction. In this paper, image-based modeling and rendering (IBMR) technology was adopted for 3D modeling of precast elements. It is necessary to use match-casting method for precast post-tensioned column assembly. Preassembly using 3D models created by image processing can minimize construction error. Augmented reality devices are used to check the geometry of the segment. Laboratory-scale tests were performed. The proposed process has been applied to the real precast bridge pier segments.

• Smart Structures and Systems
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• 제14권4호
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• pp.501-516
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• 2014

The rocking pier system (RPS) allows the columns to rock on beam or foundation surfaces during the attacks of a strong earthquake. Literatures have proved that seismic energy dissipated by the RPS through the column impact is limited. To enhance the energy dissipation capacity of a RPS bridge substructure, frictional hinge dampers (FHDs) were installed and evaluated by shaking table tests. The supplemental FHDs consist of two brass plates sandwiched by three steel plates. The strategy of self-centering design is to isolate the seismic energy by RPS at the columns and then dissipate the energy by FHDs at the bridge deck. Component tests of FHD were first conducted to verify the friction coefficient and dynamic characteristic of the FHDs. In total, 32 shaking table tests were conducted to investigate parameters such as wave forms of the earthquake (El Centro 1940 and Kobe 1995) and normal forces applied on the friction dampers. An analytical model was also proposed to compare with the tested damping of the bridge sub-structure with or without FHDs.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 춘계 학술발표회논문집
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• pp.377-384
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• 2003

Recently, there are much concerns about new and innovative transverse materials which could be used instead of conventional transverse steel in reinforced concrete bridge piers. FRP materials could be substituted for conventional transverse steel because of their sufficient strength, light weight, easy fabrication, and useful applicability to any shapes of pier sections, such as rectangular or circular sections. The objective of this research is to evaluate the seismic performance of reinforced concrete bridge pier specimens with FRP transverse reinforcement by means of the Quasi-Static test. In the first task, test columns were made using FRP rope, but these specimens appeared to fail at low displacement ductility levels due to insufficient confinement of strand extension itself. Therefore, the second task was to evaluate the seismic performance of test specimens transversely confined with FRP band. Although FRP banded specimens showed lower seismic performance than the specimen with spiral reinforcing steel, it satisfied with the response modification factor, 3, required for the single column of Korea bridge roadway design code. It was concluded that FRP band could be efficiently substituted for conventional reinforcing steel.

• Earthquakes and Structures
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• 제16권4호
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• pp.391-399
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• 2019

Residual deformation of high-speed railway bridge piers is cumulative under repeated earthquakes, and influences the safety and ride comfort of high-speed trains. This paper investigates the effects of the peak ground acceleration, longitudinal reinforcement ratio, and axial compression ratio on the cumulative deformation through finite element analysis. A simply-supported beam bridge pier model is established using nonlinear beam-column elements in OpenSees, and validated against a shaking table test. Repeated earthquakes were input in the model. The results show that the cumulative deformation of the bridge piers under repeated earthquakes increases with the peak ground acceleration and the axial compression ratio, and decreases with the longitudinal reinforcement ratio.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2002년도 춘계 학술발표회 논문집
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• pp.211-219
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• 2002

This study is performed to investigate the behavior of multi-column piers and to evaluate the seismic performance. In this study, 3 types of scale model piers with 2-column are designed and tested by quasi-static load in both longitudinal and transverse directions. Each type of model consisting of 2 specimens has different reinforcement details in the lap splice of longitudinal bars and amount of transverse reinforcements. This paper reports that the ductility of the model in transverse direction is rather higher than in longitudinal direction because of formation of several plastic hinges and that the ultimate displacement and the energy absorbtion capacity are enhanced by using continuous longitudinal bars instead of lap-splice ones. And it is confirmed that relatively large amount of ductility can be achieved by providing sufficient lap-splice length and transverse reinforcements with end hook even if longitudinal bars are lap spliced in the base of pier.