• Structural Engineering and Mechanics
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• 제85권3호
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• pp.407-417
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• 2023

Precast assembled bridge piers with hybrid connection (PASP) use both tendons and socket connections. To study the seismic performance of PASP, a full-scale in-situ test was performed based on an actual bridge project. The elastic-plastic fiber model of PASP was established using finite element software, and numerical analyses were performed to study the influence of prestress degree and socket depth on the PASP seismic performance. The results show that the typical failure mode of PASP under horizontal load is bending failure dominated by concrete cracking at the joint between the column and cushion cap. The cracking of the pier concrete and opening of joints depend on the prestress degree and socket depth. The prestressing tendons and socket connection can provide enough ductility, strength, restoration capability, and bending strength under small horizontal displacements. Although the bearing capacity and post yield stiffness of the pier can be improved to some extent by increasing the prestressing force, ductility is reduced, and residual deformation is increased. Overall, there are reasonable minimum socket depths to ensure the reliability of the socket connection.

• 콘크리트학회논문집
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• 제19권1호
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• pp.11-18
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• 2007

댐 안전성 평가를 위한 내진성능평가는 지속적으로 실시하였으나, 댐에서 취약부로 알려진 여수로 피어부에 대한 거동 분석에 대한 연구는 거의 이루어지지 않았다. 실제 지진발생시 여수로 피어가 국부 손상을 받기에 취약한 부분으로 추정되어 본 연구에서 댐의 내진성능 평가를 위한 기초 실험으로서 정적 시험을 수행하였다. 본 연구에서는 댐의 여수로 피어부에 대한 축소된 철근콘크리트 모형을 통한 강도모델을 구성하여 정적 모형 시험을 실시하고, 시험 결과의 분석, 구조해석을 통한 실제 구조물의 거동 및 균열하중, 극한하중에 대한 분석을 실시하였다. 대상 시험체에 대한 모형 시험 결과와 수치해석 결과는 서로 다른 파괴 거동을 나타내어 파괴하중이 서로 다르게 추정되었으나, 모형 시험체의 파괴 거동을 고려하는 경우에는 정적 시험과 해석을 통하여 실제 구조물의 균열 발생 하중과 극한하중을 추정할 수 있는 것으로 사료된다.

• Structural Engineering and Mechanics
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• 제72권6호
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• pp.675-687
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• 2019

As the bridges are an integral part of the transportation network, their function as one of the most important vital arteries during an earthquake is fundamental. In a design point of view, the bridges piers, and in particular the wall piers, are considered as effective structural elements in the seismic response of bridge structures due to their cantilever performance. Owing to reduced seismic load during design procedure, the response of these structural components should be ductile. This ductile behavior has a direct and decisive correlation to the development of plastic hinge region at the base of the wall pier. Several international seismic design codes and guidelines have suggested special detailing to assure ductile response in this region. In this paper, the parameters which affect the length of plastic hinge region in the reinforced concrete bridge with wall piers were examined and the sensitivity of these parameters was evaluated on the length of the plastic hinge region. Sensitivity analysis was accomplished by independently variable parameters with one standard deviation away from their means. For this aim, the Monte Carlo simulation, tornado diagram analysis, and first order second moment method were used to determine the uncertainties associated with analysis parameters. The results showed that, among the considered design variables, the aspect ratio of the pier wall (length to width ratio) and axial load level were the most important design parameters in the plastic hinge region, while the yield strength of transverse reinforcements had the least effect on determining the length of this region.

• 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.

• Computers and Concrete
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• 제31권1호
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• pp.33-52
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• 2023

This paper proposes and validates the extension of two models, previously formulated for the evaluation of the shear strength of reinforced concrete members with un-corroded reinforcements, to the case of beams with corroded stirrups. These extended models are based on the plasticity theory (this model has been proposed in the past by one of the authors) and on the simplified modified compression field theory. The response of these models is compared with that of the compression chord capacity model, which has recently been embedded with modifications that simulate the effects of steel corrosion. These latter modifications are first discussed and then introduced into the other two models. An existing database of slender and non-slender beams tested in laboratory by other researchers is revised and improved. Finally, all the considered models are applied to the selected specimens and a comparison is drawn between the shear strength resulting from the considered models and the shear strength resulting from the laboratory tests. The effects of corrosion on some important parameters of the ultimate shear response of the reinforced concrete beams are also discussed.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
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• pp.381-388
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• 2000

The steel piers and the concrete-filled steel piers, in spite of reasonable strength, high ductility, small section, and fast construction, have not been considered as the alternatives to the RC piers even in the highly populated urban area where aseismic safety, limited space and fast construction are indispensably required. In this paper, a steel pier and 4 box type concrete-filled steel piers were tested with the quasi-static cyclic loading to estimate the ductility and the strength. Additional devices such as base rib, turn-buckle, and anchor bolted added at the to increase the ductility with minimum additional cost. The result showed that the concrete filled-in steel piers had higher energy absorbtion and strength than steel piers had, but also showed that slight overlooking in the design and fabrication could lead to the abrupt fracture just after small local buckling at the bottom.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.485-488
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• 2004

Steel encased composite columns have been used for buildings and piers of bridges. Since column section for pier is relatively larger than that of building columns, economical steel ratio need to be investigated for the required performance. Composite action between concrete and embedded steel sections can be obtained by bonding and friction. However, the behavior. of the column depends on the load introduction mechanism. Compression can be applied to concrete section, steel section and composite section. In this paper, experiments on shear strength of the steel encased composite column were performed to study the effect of confinement by transverse reinforcements, mechanical interlock by holes, and shear connectors. Shear strength obtained from the tests showed considerably higher than the design value. Confinement, mechanical interlock and stud connectors increased the shear strength and these values can be used effectively to obtain composite action of SRC columns.

• 한국전산구조공학회논문집
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• 제33권5호
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• pp.319-329
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• 2020

현재 우리나라에서 운영 중인 교량 중 30년 이상 된 교량이 전체의 약 11%를 차지할 정도로 노후교량의 수가 증가하고 있다. 따라서 교량의 노후화에 따른 영향을 고려한 내진성능 평가방법의 개발이 필요하다고 볼 수 있다. 예제 교량으로는 포트받침, 탄성고무받침과 납-고무받침을 가진 3가지의 강합성 상자형 거더교를 선정하고, opensees 프로그램을 사용하여 구조해석모델을 작성하였다. 본 연구에서는 교량의 노후도를 교각의 주철근과 띠철근의 부식에 의한 면적의 감소로 반영하였다. 교각의 노후화 정도로는 5%, 10%, 25%, 50%의 4가지 조건을 사용하였다. 입력지진으로는 근거리 지진과 원거리 지진을 각각 40개씩 사용하였으며, 노후화 정도에 따른 예제교량의 교각에 대한 최대변위와 최대 전단력 응답을 구하여 비교하였다. 노후도가 증가할수록 힘-변위 관계에서 교각의 강도 저하가 발생함을 알 수 있으며, 이로 인하여 교각의 변위응답이 증가함을 알 수 있다. 교각의 노후도에 따른 변위응답과 전단저항능력의 영향을 분석하기 위하여 변위비(D_ratio)와 전단력비(F_ratio)를 정의하여 평가하였다. 예제교량의 고유주기가 길어질수록 노후도에 따른 변위비(D_ratio)의 증가가 크게 나타남을 알 수 있으며, 전단력비(F_ratio)의 감소 경향은 작게 나타남을 알 수 있다.

• 콘크리트학회논문집
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• 제17권4호
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• pp.603-611
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• 2005

본 연구에서는 합리적인 내진설계기준의 정립을 위하여 철근콘크리트 교각의 내진성능에 영향을 미치는 주요 인자에 대하여 분석하였다. 주요 각국의 내진규정에서 내진성능을 발휘하기 위한 심부구속철근량을 규정함에 있어 다양한 요소들을 고려하고 있다. 하지만, 이러한 요소들이 합리적으로 고려되었는가에 대해서는 의문이 남는다. 따라서 본 연구에서 국내의 도로교설계기준, Eurocode 8 part2, NZS 3101, ATC-32 등의 설계기준을 비교분석하고, 기존 실험 연구 결과와 비교 분석하여 합리적인 영향인자들을 제안하고자 하였다. 연구결과에 따르면 원형 철근콘크리트 교각의 내진성능에 가장 지배적인 영향인자는 축하중비인 것으로 조사되었다. 따라서 심부구속철근비 산정식에 축하중비의 영향을 전혀 고려하고 있지 않는 현행 도로교설계기준에 축하중비를 도입해야 한다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.949-954
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• 2003

In this paper, simplified modeling approach describing the hysteretic behavior of reinforced concrete columns is discussed. The inelastic response of a reinforced concrete column or pier subjected to cyclic deformation reversals or earthquake ground motion is evaluated by use of lumped hysteretic representation. For this purpose, the hystertic model under axial force variation is developed and implemented into a nonlinear finite element analysis program. The analytical predictions obtained with the new formulation are compared with test results and reveal accuracy and applicability in terms of strength and stiffness. In addition, comparison between results with and without axial force variation stresses the importance of the proposed approach.