• Earthquakes and Structures
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• 제13권2호
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• pp.137-150
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• 2017

This paper focuses on the post-earthquake serviceability of steel arch bridges installed with three types of seismic dampers suffered mainshock-aftershock sequences. Two post-earthquake serviceability verification methods for the steel arch bridges are compared. The energy-absorbing properties of three types of seismic dampers, including the buckling restrained brace, the shear panel damper and the shape memory alloy damper, are investigated under major earthquakes. Repeated earthquakes are applied to the steel arch bridges to examine the influence of the aftershocks to the structures with and without dampers. The relative displacement is proposed for the horizontal transverse components in such complicated structures. Results indicate that the strain-based verification method is more conservative than the displacement-base verification method in evaluating the post-earthquake serviceability of structures and the seismic performance of the retrofitted structure is significantly improved.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.954-959
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• 2011

The intensity of train load in the railway bridges is relatively large and continues to repeat. Also, the speed of vehicles is very fast. For these reasons, analyses for dynamic response under train load are necessary in the railway bridges. In other words, the dynamic characteristics of steel-composite bridges under train loads should be investigated considering effects of dynamic responses such as vibrations, repeated displacements and acceleration of bridge members. Therefore, in this study, static and dynamic analyses for the steel box girder bridges and I-girder bridges are carried out. Based on analyses results, we investigated and compared dynamic response considering the impact factors of domestic and foreign design specifications.

• 한국강구조학회 논문집
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• 제15권4호통권65호
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• pp.341-358
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• 2003

본 논문에서는 강교의 실용적인 생애주기비용 (LCC) 최적설계를 위한 일반화된 정식화와 LCC 설계시스템 모델을 제안하였다. 강교 최적설계를 위한 LCC는 초기비용, 직접 복구 (rehabilitation) 비용과 인적 혹은 물적 손실비용의 직접비용, 도로이용자비용, 그리고 사회-경제 손실비용을 포함한 간접비용의 현재가치의 합으로 정식화하였다. 특히 본 논문에서는 교량이 속해 있는 도로의 네트워크를 고려한 도로이용자비용과 사회-경제 손실비용 산정을 위한 새로운 모델을 제안하였다. 본 연구에서 제안된 LCC 정식화 모델은 실제 강박스 거더교와 강상판형교의 LCC 최적설계 문제에 적용하였고, 다양한 경우에 대한 LCC의 효율성에 대해 비교 고찰하였다. LCC를 고려한 강교량의 최적설계는 설계시방서에 기초한 설계방법뿐만 아니라 초기비용 절감을 위한 최적설계 방법과 비교할 때 더욱 합리적이고, 경제적이며, 안전한 설계를 유도할 수 있으리라 판단된다.

• Steel and Composite Structures
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• 제33권4호
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• pp.537-550
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• 2019

Korea and Japan have done a lot of research on composite girders with corrugated steel webs and built many bridges with corrugated steel webs due to the significant advantages of this type of bridges. Considering the demanding on the calculation method of such types of bridges and lack of relevant reinforcement design method, this paper proposes the spatial grid analysis theory and tensile stress region method. First, the accuracy and applicability of spatial grid model in analyzing composite girders with corrugated steel webs was validated by the comparison with models using shell and solid elements. Then, in a real engineering practice, the reinforcement designs from tensile stress region method based on spatial grid model, design empirical method and specification method are compared. The results show that the tensile stress region reinforcement design method can realize the inplane and out-of-plane reinforcement design in the top and bottom slabs in bridges with corrugated steel webs. The economy and precision of reinforcement design using the tensile stress region method is emphasized. Therefore, the tensile stress region reinforcement design method based on the spatial grid model can provide a new direction for the refined design of composite box girder with corrugated steel webs.

• 한국구조물진단유지관리공학회 논문집
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• 제9권3호
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• pp.151-160
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• 2005

현재의 교량설계기준에서는 연속거더교량에 대한 활하중 분배계수 규정에 대해 명확한 언급이 되어있지 않다. 따라서 이 논문의 목적은 단순교에 사용되는 시방서 규정 활하중 분배계수가 연속거더교에도 적용이 가능한지를 유한요소해석에 의해 검증하는 것이다. 연속거더교에 대한 활하중 분배의 영향을 검증하기 위해 5개의 공용중인 연속교에 대한 유한요소해석을 실행하였으며 그 결과 연속교에서 정모멘트 구역과 부모멘트 구역에서 활하중의 분배 형태는 매우 비슷하다는 결론을 내릴 수 있었다. 또한 처짐값의 비교에서 얻어진 활하중의 분배와 변형율에 기본한 활하중의 분배 양상의 차이가 거의 없는 것으로 나타났다. 해석 결과 현재 사용되고 있는 설계기준의 활하중 분배에 대한 규정은 연속거더교에 대해 매우 보수적이라고 판단된다.

• 한국강구조학회 논문집
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• 제17권5호통권78호
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• pp.511-518
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• 2005

원곡선교의 거동은 일반적인 직선교보다 복잡하여 교량의 해석 및 설계와 시공에 있어서 많은 주의를 요한다. 곡선교의 설계에는 일반적인 구조해석 프로그램이나 전용 프로그램에 의한 격자 해석이 주로 이용되는데 이들 해석 프로그램의 결과와 실제 곡선 교량의 거동에 대한 정합성을 비교 검토한 연구는 국내에서 아직까지 이뤄지지 않았다. 본 연구에서는 두 개의 교량-단경간 교량과 3경간 연속교-을 대상으로 현장 계측 및 범용 구조해석 프로그램과 3차원 정밀 해석 프로그램을 이용한 해석을 실시하여 곡선교의 거동에 대한 연구와 현 설계 방법에 대한 검증을 실시하였다. 공정별 계측과 해석 결과는 서로 정량적인 차이를 보이고 있지만 정성적으로는 유사한 관계를 가지고 있었다. 플랜지의 횡 방향에 대한 응력의 변화가 관찰되었고, 격자 해석 모델이 3차원 정밀 해석 모델보다 보수 측의 해석 결과를 갖는 것으로 나타났다.

• Steel and Composite Structures
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• 제42권1호
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• pp.139-149
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• 2022

To simplify the design and reduce the construction cost of traditional multi-girder structural systems, twin I-girder structures are widely used in many countries in recent years. Due to the concern on post-fracture redundancy, however, twin girder bridges are currently classified as fracture critical structures in AASHTO specifications for highway bridges. To investigate the after-fracture behavior of such structures, a composite steel and concrete twin girder specimen was built and an artificial fracture through the web and the bottom flange was created on one main girder. The static loading test was performed to investigate its mechanical performance after a severe fracture occurred on the main girder. Applied load and vertical displacement curves, and the applied load versus strain relationships at key sections were measured. To investigate the load distribution and transfer capacities between two steel girders, the normal strain development on crossbeams was also measured during the loading test. In addition, both shear and normal strains of studs were also measured in the loading test to explore the behavior of shear connectors in such bridges. The functions and structural performance of structural members and possible load transfer paths after main girder fractures in such bridges were also discussed. The test results indicate in this study that a typical twin I-girder can resist a general fracture on one of its two main girders. The presented results can provide references for post-fracture performance and optimization for the design of twin I-girder bridges and similar structures.

• Steel and Composite Structures
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• 제21권5호
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• pp.1045-1067
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• 2016

Concrete bridges with corrugated steel webs and prestressed by both internal and external tendons have emerged as one of the promising bridge forms. In view of the different behaviour of components and the large shear deformation of webs with negligible flexural stiffness, the assumption that plane sections remain plane may no longer be valid, and therefore the classical Euler-Bernoulli and Timoshenko beam models may not be applicable. In the design of this type of bridges, both the ultimate load and ductility should be examined, which requires the estimation of full-range behaviour. An analytical sandwich beam model and its corresponding beam finite element model for geometric and material nonlinear analysis are developed for this type of bridges considering the diaphragm effects. Different rotations are assigned to the flanges and corrugated steel webs to describe the displacements. The model accounts for the interaction between the axial and flexural deformations of the beam, and uses the actual stress-strain curves of materials considering their stress path-dependence. With a nonlinear kinematical theory, complete description of the nonlinear interaction between the external tendons and the beam is obtained. The numerical model proposed is verified by experiments.

• 한국강구조학회 논문집
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• 제19권1호
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• pp.87-98
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• 2007

일반적으로 가교량은 주형와 강재교각이 강결 연결된 강재 라멘구조를 형성하고 있다. 강재 라멘구조의 경우, 작용하는 하중에 의해 축력 및 휨을 받는 부재/축력 및 휨을 동시에 받는 부재가 발생한다. 본 연구에서는 이러한 부재에 대해서 시스템 좌굴해석을 통하여 가교량 주요부재의 유효길이를 산정하고 이를 이용하여 안정성 해석을 수행한다. 이를 위하여 실제 설계/시공될 수 있는 가교의 6가지 유형을 선택하고, 고정하중, 온도하중 그리고, 활하중조합에 대한 3차원 좌굴설계를 실시한다. 결과적으로 6가지 가교에 대한 사례연구를 통하여 주형 및 교각부의 유효길이 산정법, 3차원 좌굴모드에 대한 고찰, 그리고 2차해석의 효용을 조사한다.

• Earthquakes and Structures
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• 제1권1호
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• pp.21-41
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• 2010

Multi-span steel-concrete composite (SCC) bridges are very sensitive to earthquake loading. Extensive damage may occur not only in the substructures (piers), which are expected to yield, but also in the other components (e.g., deck, abutments) involved in carrying the seismic loads. Current seismic codes allow the design of regular bridges by means of linear elastic analysis based on inelastic design spectra. In bridges with superstructure transverse motion restrained at the abutments, a dual load path behavior is observed. The sequential yielding of the piers can lead to a substantial change in the stiffness distribution. Thus, force distributions and displacement demand can significantly differ from linear elastic analysis predictions. The objectives of this study are assessing the influence of piers-deck stiffness ratio and of soil-structure interaction effects on the seismic behavior of continuous SCC bridges with dual load path, and evaluating the suitability of linear elastic analysis in predicting the actual seismic behavior of these bridges. Parametric analysis results are presented and discussed for a common bridge typology. The response dependence on the parameters is studied by nonlinear multi-record incremental dynamic analysis (IDA). Comparisons are made with linear time history analysis results. The results presented suggest that simplified linear elastic analysis based on inelastic design spectra could produce very inaccurate estimates of the structural behavior of SCC bridges with dual load path.