• 한국강구조학회 논문집
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• 제23권1호
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• pp.61-72
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• 2011

본 연구에서는 일체식교대 강교량 거더-교대 연결부의 강체거동 및 균열저항성능의 향상을 위한 구조상세를 제시하고 그에 따른 연결부의 거동을 실험적으로 평가하였다. 거더-교대 연결부의 강체거동 및 균열저항성능을 향상시키기 위하여 전단연결재 및 tie bar를 적용한 연결부를 제시하였으며, 제시된 연결부 실험체와 기존 시공경험에 의해 설계된 연결부 실험체의 하중재하실험을 통하여 연결부의 성능 및 거동 특성을 검토하였다. 하중재하실험 결과, 모든 강 거더-교대 연결부 실험체들은 목표 설계하중 및 항복하중 이하에서 충분한 강성 및 균열저항 성능을 보여 강 거더-교대 연결부로 적용 가능하다. 하지만 실험체의 초기 강성, 균열의 진전형상 측면, 하중-변형률 측면에서 전단연결재와 tie bar가 적용된 강 거더-교대 연결부가 기존에 적용되어 왔던 강 거더-교대 연결부에 비하여 구조적으로 우수한 것으로 판단된다.

• 콘크리트학회논문집
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• 제24권3호
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• pp.249-258
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• 2012

교대 일체식 교량과 강합성 라멘교는 유지보수의 주된 원인이 되는 신축이음 및 받침이 생략되어 유지관리 및 구조적인 장점을 얻을 수 있는 교량 형식이다. 하지만, 통상적으로 거더를 교대에 매립하는 형태로 시공되는 접합부는 시공상세가 복잡하고 접합부의 시공상세를 간략화하여 시공효율을 향상시킨 새로운 교량 형식을 제안하였다. 제안된 형식의 교량은 PS 강봉에 긴장력을 도입하여 강재로 제작된 거더와 교대를 일체화하는 형태의 교량이다. 이 연구에서는 PS 강봉으로 일체화된 접합부의 피로 성능을 평가하기 위하여 접합부에 대한 유한요소해석 및 피로실험을 실시하였다. 유한요소해석 결과, 제안된 교량의 접합부는 기본적으로 피로에 의한 손상의 가능성이 매우 낮은 것으로 나타났으며, 피로시험 결과로부터 2,000,000회의 피로반복하중이 재하된 상태에서도 접합부의 일체화 성능을 유지하고 있는 것을 확인할 수 있었다.

• Structural Monitoring and Maintenance
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• 제6권2호
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• pp.85-101
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• 2019

The effects of foundation scour depth and riverbed condition on the natural frequencies of a typical cross-river integral abutment bridge have been studied. The conventional operational modal analysis technique has been employed in order to extract the modal properties of the bridge and the results have been used in the Finite Element (FE) model updating procedure. Two tests have been carried out in two different levels of water and wet condition of the riverbed. In the first test, the riverbed was in dry condition for two subsequent years and the level of water was 10 meter lower than the natural riverbed. In the second test, the river was opened to water flow from the upstream dam and the level of water was 2 meter higher than the natural riverbed. The results of these two tests have also been used in order to find to what extend the presence of water flow in the river and saturation of the surrounding soil affect the bridge natural frequencies. Finally, the updated FE model of the bridge has been applied in a series of parametric analyses incorporating the effect of piles' relative scour depth on the bridge natural frequency of the first four vibration modes.

• Earthquakes and Structures
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• 제16권1호
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• pp.11-28
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• 2019

This article investigates the response of Integral Abutment Bridges (IAB) when subjected to a sequence of seasonal thermal loading of the deck followed by ground seismic shaking in the longitudinal direction. Particular emphasis is placed on the effect of pre-seismic thermal Soil-Structure Interaction (SSI) on the seismic performance of the IAB, as well as on the ability of various backfills configurations, to minimize the unfavorable SSI effects. A series of two-dimensional numerical analyses were performed for this purpose, on a complete backfill-integral bridge-foundation soil system, subjected to seasonal cyclic thermal loading of the deck, followed by ground seismic shaking, employing ABAQUS. Various backfill configurations were investigated, including conventional dense cohesionless backfills, mechanically stabilized backfills and backfills isolated by means of compressive inclusions. The responses of the investigated configurations, in terms of backfill deformations and earth pressures, and bridge resultants and displacements, were compared with each other, as well as with relevant predictions from analyses, where the pre-seismic thermal SSI effects were neglected. The effects of pre-seismic thermal SSI on the seismic response of the coupled IAB-soil system were more evident in cases of conventional backfills, while they were almost negligible in case of IAB with mechanically stabilized backfills and isolated abutments. Along these lines, reasonable assumptions should be made in the seismic analysis of IAB with conventional sand backfills, to account for pre-seismic thermal SSI effects. On the contrary, the analysis of the SSI effects, caused by thermal and seismic loading, can be disaggregated in cases of IAB with isolated backfills.

• 복합신소재구조학회 논문집
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• 제5권2호
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• pp.21-26
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• 2014

This paper introduces general concepts of jointless bridges and field construction case of semi-integral bridge with psc girder integrating end-diaphragm. The expansion joints need to satisfy thermal and safety conditions of bridges. General bridges with joints have some problems, which are frequently replacement cycle time from mechanical damage or unstable movement, maintenance cost and more. To solve these problems, Integral Abutment Bridges(IAB) have been applied overseas in the 1930s. In Korea, first IAB was constructed in the early 2000s and precast IAB systems was invented and applied lately. Kyungshin overpass bridge in Incheon is the Semi-IAB constructed, the span length is 2@35=70m and the width is 13.9m. The original plan was to use general joint bridge but design field changed with expectations for advanced economic estimation and maintenance. This changed method of B.I.B bridge construction provided not only workability, construction cost but also safety improvement at the same time.

• Steel and Composite Structures
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• 제34권1호
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• pp.35-51
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• 2020

Integral abutment bridges (IABs) are those bridges without expansion joints. A single row of steel H-piles (SHPs) is commonly used at the thin and stub abutments of IABs to form a flexible support system at the bridge ends to accommodate thermal-induced displacement of the bridge. Consequently, as the IAB expands and contracts due to temperature variations, the SHPs supporting the abutments are subjected to cyclic lateral (longitudinal) displacements, which may eventually lead to low-cycle fatigue (LCF) failure of the piles. In this paper, the potential of using finite element (FE) modeling techniques to estimate the LCF life of SHPs commonly used in IABs is investigated. For this purpose, first, experimental tests are conducted on several SHP specimens to determine their LCF life under thermal-induced cyclic flexural strains. In the experimental tests, the specimens are subjected to longitudinal displacements (or flexural strain cycles) with various amplitudes in the absence and presence of a typical axial load. Next, nonlinear FE models of the tested SHP specimens are developed using the computer program ANSYS to investigate the possibility of using such numerical models to predict the LCF life of SHPs commonly used in IABs. The comparison of FE analysis results with the experimental test results revealed that the FE analysis results are in close agreement with the experimental test results. Thus, FE modeling techniques similar to that used in this research study may be used to predict the LCF life of SHP commonly used in IABs.

• 콘크리트학회지
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• 제10권3호
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• pp.53-61
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• 1998

• 한국구조물진단유지관리공학회 논문집
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• 제22권1호
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• pp.123-128
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• 2018

기존 거더 형식의 교량이나 슬래브 교량에서는 신축이음장치, 받침, 역T형 교대 및 별도의 접속슬래브 구조를 이루는 시스템으로 이루어져 있다. 이러한 시스템은 신축이음부의 빈번한 파손으로 인한 비용증가, 모멘트 재분배가 낮은 구조로 인한 내구성 감소 등의 문제가 있다. 상기의 문제를 개선하기 위해 일체식 및 반일체식 복합 교량을 제안하고 구조해석을 통해 안전성을 검토하였다. 검토결과 단면강성은 작지만 접속슬래브와 본체 구조가 연속 강결된 다연속 프레임 구조계 형성과 상부구조의 경간과 단면강성의 균형으로 인하여 모멘트재분배와 힘전달이 확실하게 이루어져 기존교량에 비해 구조안전성 높은 구조임을 확인하였다.

• Steel and Composite Structures
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• 제26권2호
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• pp.227-239
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• 2018

Integral abutment bridges (IABs) have no joint across the length of bridge and are therefore also known as jointless bridges. IABs have many advantages, such as structural integrity, efficiency, and stability. More importantly, IABs have proven to be have both low maintenance and construction costs. However, due to the restraints at both ends of the girder due to the absence of a gap (joint), special design considerations are required. For example, while replacing the deck slabs to extend the service life of the IAB, the buckling strength of the steel girder without a deck slab could be much smaller than the case with deck slab in place. With no deck slab, the addition of thermal expansion in the steel girders generates passive earth pressure from the abutment and if the applied axial force is greater than the buckling strength of the steel girders, buckling failure can occur. In this study, numerical simulations were performed to estimate the buckling strength of typical steel girders in IABs. The effects of girder length, the width of flange and thickness of flange, imperfection due to fabrication and construction errors on the buckling strengths of multiple and single girders in IABs are studied. The effect of girder spacing, span length ratio (for a three span girder) and self-weight effects on the buckling strength are also studied. For estimation of the reaction force of the abutment generated by the passive earth pressure of the soil, BA 42/96 (2003), PennDOT DM4 (2015) and the LTI proposed equations (2009) were used and the results obtained are compared with the buckling strength of the steel girders. Using the selected design equations and the results obtained from the numerical analysis, equations for preventing the buckling failure of steel girders during deck replacement for maintenance are presented.

• 한국지반공학회논문집
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• 제19권6호
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• pp.127-149
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• 2003

본 교량은 교축방향에 대해 사각 60도인 90m 3경간 연속 완전 일체식 교대교량이다. 이 교량의 상부슬래브 콘크리트 타설후, 7일간의 콘크리트 양생에 따른 H말뚝의 수평거동을 알아보기 위하여, H말뚝 축방향으로 매설형 경사계와 변형률계를 설치하여 계측을 실시하였다. 이때 계측 결과를 수화열 및 건조수축 전용프로그램인 HACOM의 해석결과와 H말뚝의 횡방향 비선형 p-y 모델해석 거동에 비교하였다. 그 결과에 의하면, 실측한 H말뚝의 수평변위는 상부슬래브 콘크리트가 양생함에 따라 발생하는 수화열과 건조수축에 영향을 받았고, 그 크기는 각각 2.2mm, 1.4mm이었다. 말뚝 축방항 수평변위의 변곡점은 교대 기초저면에서 1.3m 위치에서 발생하였다. 이는 이 교량의 교대말뚝은 말뚝머리 고정조건으로 거동하는 것이 아니라 이와 매우 유사한 거동을 보였다. 그리고 실측한 말뚝의 휨응력 거동은 말뚝머리 회전구속과 같은 거동을 보이지 않고, 연직방향의 하중전이와 같은 거동을 나타내었다. 또한 교대말뚝의 비선형 p-y 모델해석으로 구한 최대휨응력 증분량의 크기는 약 300(kgf/$\textrm{km}^2$)이었고, 교대말뚝의 계측기 부착위치와는 무관하게 실측한 값보다 약 2배 크게 발생하였다. 그리고 말뚝의 비선형 p-y 모델해석에서 말뚝의 수평하중, 최대수평 변위, 최대휨응력, 최대휨모멘트는 콘크리트 양생시간에 따라 모두 선형적인 거동을 보였다.