• 대한토목학회논문집
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• 제6권2호
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• pp.17-22
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• 1986

본 연구에서는 교량 구조물의 콘크리트덱에 시공시 생기는 건조수축과 크리프에서 오는 영향을 검토하였다. 본 연구에서는 4가지의 교량을 비교하였으며, 그 중 두 개의 직선복합 상자교량과 2개의 곡선상자교량을 (+)모멘트 지역과 (-)모멘트 지역프로 구분하여 위의 영향에서 오는 응력변화의 차이점을 검토하였다. 또한 변형율과 처짐에 미치는 영향도 검토하였다. 해석 방식 은 Vlasov의 미분방정식을 이용하였으며, 유한차분법(Finite Difference Method)을 사용하였다.

• 한국구조물진단유지관리공학회 논문집
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• 제21권6호
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• pp.196-205
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• 2017

프리캐스트 바닥판 공법은 바닥판간 이음부가 존재하며, 이음부의 연결성능에 따라 전체 교량 구조물의 성능이 좌우되므로 이음부의 연결성능 확보가 중요한 요소이다. 본 연구에서는 고강도 강섬유보강콘크리트(High Strength Fiber Reinforced Concrete, HSFRC)가 적용된 비대칭 요철형 이음단면을 갖는 연결형식을 제안하였으며, 이음부의 단면형태, 철근 겹침이음길이 및 겹침이음 형식에 따른 구조실험을 수행하여 제안된 연결형식의 휨 성능을 평가하였다. 실험결과, 이음부 상세에 관계없이 이음철근은 항복변형률 수준의 인장변형을 나타내었으며, 제안된 연결형식은 충분한 휨 저항성능을 확보하는 것으로 나타났다. 이러한 실험결과는, 현행 도로교설계기준의 최소 겹침이음길이에 대한 규정은 이음부 채움재로 HSFRC를 적용한 프리캐스트 바닥판 이음부에서는 보수적인 규정임을 알 수 있다. 따라서 이음부 채움재로 HSFRC를 사용함에 의해 철근 겹침이음 상세의 단순화 및 이음부 폭의 감소가 가능하며, 제안된 연결형식은 프리캐스트 바닥판 이음부에 효과적으로 적용 가능할 것으로 판단된다.

• 대한토목학회논문집
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• 제31권6A호
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• pp.417-424
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• 2011

본 연구에서는 60 m 급의 장경간 PSC 거더의 개발을 위하여 단면 개선부터 텐던 배치 형상까지 구조적인 성능뿐만 아니라 경제성과 시공성 등을 고려해가며 거더 개발에 관한 연구를 진행하였다. 단면 최적화를 통해 Bulb-T 형의 단면을 도출하였고 단면 평가를 통해 실제 설계 가능성을 평가하였다. 또한 텐던의 배치를 효율적으로 구성하여 사용하중에 대해 효과적으로 대처할 수 있도록 하였다. 실제 대상교량을 선정한 후 개발 거더를 적용해 유한요소해석을 수행한 결과, 모든 하중단계에서 설계 허용응력을 만족하였다. 또한 사용하중에 의해 발생하는 응력이 허용하중보다 작아 안전측 설계가 가능한 것으로 나타났다. 이를 바탕으로 실물 크기의 60 m 거더를 제작해 4점 실험을 실시한 결과 초기 균열이 사용하중의 2배 이상에서 발생하여, 실험 결과를 통해서도 충분한 구조적 성능을 입증하였다. 본 연구를 통해 개발된 Half-Decked PSC 형식의 60 m 거더는 단면개선과 효율적인 텐던 배치로 경간대비 매우 낮은 형고를 갖게 되었고, 구조적인 이점은 물론 경제성이나 시공성 등에서도 큰 장점을 가질 것으로 판단된다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.1171-1176
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• 2005

The latest technical development of steel plate girder railway bridge are developing in ways to maximize its durability of materials in use of high strength steel and efficiency of maintenance and management by the introduction of simplified and standardization ideas. In addition to this, it is also expected to reduce the cost of bridge construction and to simplify the process of bridge manufacturing. Referring to this, composite few plate girder railway bridge is highly recommendable that is very economical with the fine exterior. In this paper, it will analyse the variation of dynamic behavior of existing composite few plate girder railway bridge with ballast caused by modified Slab Track through interpretation of limited enzyme in order to obtain the existing data for improvement of Slab Track system from Ballast Track system. Consequently, it can help maximize economic efficiency and structural capability. As a results, although the natural frequency by modified Slab Track are decreased, it is hardly influencing on the safety of railway bridges. It is also evident in the case of slab deck with a reduced scale in comparison with Ballast Track. Therefore, it is expected to reduce the cost of a railway bridge plan. And, it can expect the synergistic effect of the ensure long term durability of bridge caused by decreased stresses of bottom flange due to reduced dead load. As a result, the analytical study are carried out to investigate the composite few plate girder railway bridge could be the optimal design method for the dynamic safety of a girder section.

• 한국강구조학회 논문집
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• 제24권6호
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• pp.613-625
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• 2012

철도교는 일반적으로 설계하중에 근접한 열차하중이 빈번하게 통과할 가능성이 있으므로, 초기설계단계부터 여러 구조상세에 대해 피로특성을 충분한 반영하는 것이 필요하다. 그럼에도 불구하고 철도교에 작용하는 축하중의 크기 및 배치 특성, 피로에 대한 부적절한 구조상세의 적용 등으로 인하여 강철도 플레이트거더교에서 부분적으로 피로균열이 보고되고 있다. 상부플랜지와 복부의 용접이음부에서의 피로균열의 주요 발생 원인의 하나는 침목을 지지하는 주거더와 열차하중이 작용되는 레일과의 중심간격 차이에 따른 열차하중의 편심작용에 의한 것이다. 이 연구에서는 공용중인 강철도 상로플레이트거더교를 대상으로 현장조사 및 현장계측, 일련의 구조해석을 실시하고, 대상교량의 구조거동 특성 및 피로균열의 발생 원인의 규명, 보수 보강(안)에 대하여 검토하였다.

• 복합신소재구조학회 논문집
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• 제2권2호
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• pp.20-25
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• 2011

본 논문에서는 2차원 콘크리트 슬래브 철도교량을 특별직교이방성 복합적층판 이론으로 해석하였다. 슬래브의 해석에 있어 단면의 기하학적, 물리적 특성이 중립면에서 휨-연계강성 $B_{ij}$ = 0 이고, $D_{16}=D_{26}=0$임을 고려하였다. 교량상판은 특별직교이방성 판으로 거동한다. 이러한 경계조건을 갖는 단면 혹은 불규칙한 단면을 갖는 시스템은 해석적 해를 구하기가 매우 어렵다. 이러한 문제에 대한 해석을 위해서 유한차분법이 이용되었다. 본 논문에서는 보 이론과 유한차분법이 해석을 위해 사용되었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.812-817
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• 2004

Recently drastic improvement of railway technology has been accompanied by the construction of very high-speed tracks. It should be noticed that Continuously Welded Rail(CWR) has played significant role in technical development of railway and that installation of CWR is now being scheduled on existing lines as well as newly-built lines. In general, interaction between CWR and bridge deck takes place on bridge section and additional axial force and displacement is to be developed owing to temperature and braking/acceleration forces. This interaction is known to be mainly governed by span organizations and arrangements of foot bearings. In common practice, movable bearing is stationed and designed on the assumption that it is not able to transfer the horizontal force of upper decks. However, it is well known that horizontal resistance is developed in movable bearings due to friction and that friction coefficient of movable bearing is ranged from 0.03 to 0.20 depending on the material of bearings and magnitude of reactions. Therefore, it is easily reasoned out that friction of movable bearing can influence the mutual behavior of CWR and bridge decks. Suggested in this study is to investigate the validity and efficiency of friction effect of movable bearings in controlling the axial force and displacement of CWR on continuous railway bridges.

• Advances in concrete construction
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• 제7권1호
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• pp.11-22
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• 2019

A comprehensive assessing approach for durability of reinforced concrete structures dealing with the corrosion process of rebar subjected to the attack of aggressive agent from environment was proposed in this paper. Corrosion of rebar was suggested in the form of combination of global corrosion and pitting. Firstly, for the purposed of considering the influence of rebar's radius, a type of Plane Corrosion Model (PCM) based on uniform corrosion of rebar was introduced. By means of FE simulation approach, global corrosion process of rebar regarding PCM and LCM (Linear Corrosion Model) was regressed and compared according to the data from Laboratoire $Mat{\acute{e}}riaux$ et $Durabilit{\acute{e}}$ des Constructions (LMDC). Secondly, pitting factor model of rebar in general descend law with corrosion degree was introduced in terms of existing experimental data. Finally, with the comprehensive numerical simulation, the durability of an existing arch bridge was studied in depth in deterministic way, including diffusion process and sectional strength of typical cross section of arch, crossbeam and deck slab. Evolution of structural capacity considering life-cycle rehabilitation strategy indicated the degradation law of durability of reinforced arch bridges.

• Steel and Composite Structures
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• 제26권2호
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• pp.197-211
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• 2018

The study presents the earthquake performance of the Bosphorus Bridge under multi-point earthquake excitation considering the spatially varying site-specific earthquake motions. The elaborate FE model of the bridge is firstly established depending on the new considerations of the used FEM software specifications, such as cable-sag effect, rigid link and gap elements. The modal analysis showed that singular modes of the deck and the tower were relatively effective in the dynamic behavior of the bridge due to higher total mass participation mass ratio of 80%. The parameters and requirements to be considered in simulation process are determined to generate the spatially varying site-specific ground motions. Total number of twelve simulated ground motions are defined for the multi-support earthquake analysis (Mp-sup). In order to easily implement multi-point earthquake excitation to the bridge, the practice-oriented procedure is summarized. The results demonstrated that the Mp-sup led to high increase in sectional forces of the critical components of the bridge, especially tower base section and tensile force of the main and back stay cables. A close relationship between the dynamic response and the behavior of the bridge under the Mp-sup was also obtained. Consequently, the outcomes from this study underscored the importance of the utilization of the multi-point earthquake analysis and the necessity of considering specifically generated earthquake motions for suspension bridges.

• Wind and Structures
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• 제6권6호
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• pp.451-470
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• 2003

The classical two-degree-of-freedom (2-d-o-f) "sectional model" is of common use to study the dynamics of suspension bridges. It takes into account the first pair of vertical and torsional modes of the bridge and describes well global oscillations caused by wind actions on the deck, yielding very useful information on the overall behaviour and the aerodynamic and aeroelastic response; however, it does not consider relative oscillations between main cables and deck. On the contrary, the 4-d-o-f model described in the two Parts of this paper includes longitudinal deformability of the hangers (assumed linear elastic in tension and unable to react in compression) and thus allows to take into account not only global oscillations, but also relative oscillations between main cables and deck. In particular, when the hangers go slack, large nonlinear oscillations are possible; if the hangers remain taut, the oscillations remain small and essentially linear: the latter behaviour has been the specific object of Part I (Sepe and Augusti 2001), while the present Part II investigates the nonlinear behaviour (coexisting large and/or small amplitude oscillations) under harmonic actions on the cables and/or on the deck, such as might be generated by vortex shedding. Because of the discontinuities and strong nonlinearity of the governing equations, the response has been investigated numerically. The results obtained for sample values of mechanical and forcing parameters seems to confirm that relative oscillations cannot a priori be excluded for very long span bridges under wind-induced loads, and they can stimulate a discussion on the actual possibility of such phenomena.