• Earthquakes and Structures
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• 제19권6호
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• pp.427-444
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• 2020

The performance of an isolated horizontally curved continuous bridge with High Damping Rubber (HDR) Bearings has been investigated under seismic loading conditions. The effectiveness of response controls of the bridge by HDR bearings for various aspects viz. variation in ground motion characteristics, multi-directional effect, level of earthquake shaking, varying incidence angle, have been determined. Three recorded ground motions, representative of historical earthquakes along with near-field, far-field and forward directivity effects, have been considered in the study. The efficacy of the bearings with bidirectional effect considering interaction behavior of bearing and pier has also been investigated. Modeling and analysis of the bridge have been done by finite element approach. Sensitivity studies of the bridge response with respect to design parameters of the bearings for the considered ground motions have been performed. The importance of the nonlinearity of HDR bearings along with crucial design parameters has been identified. It has been observed that the HDR bearings performed well in different variations of ground motions, especially for controlling torsional moment. However, the deck displacement has been found to be increased significantly in case of Turkey ground motions, considering forward directivity effect, which needs to be paid more attention from designer point of view.

• Smart Structures and Systems
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• 제31권6호
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• pp.585-599
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• 2023

Field monitoring techniques offer an attractive approach for understanding bridge behavior under in-service loads. However, the investigations on bridge behavior under high-speed train load using field monitoring data are limited. The focus of this study is to explore the structural behavior of an in-service long-span steel truss arch bridge based on field monitoring data. First, the natural frequencies of the structure, as well as the train driving frequencies, are extracted. Then, the train-induced bearing displacement and structural strain are explored to identify the effects of train loads and bearings. Subsequently, a sensitivity analysis is performed for the impact factor of strain responses with respect to the train speed, train weight, and temperature to identify the fundamental issues affecting these responses. Additionally, a similar sensitivity analysis is conducted for the peak acceleration. The results indicate that the friction force in bearings provides residual deformations when two consecutive trains are in opposite directions. In addition, the impact factor and peak acceleration are primarily affected by train speed, particularly near train speeds that result in the resonance of the bridge response. The results can provide additional insight into the behavior of the long-span steel truss bridges under in-service high-speed train loads.

• Earthquakes and Structures
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• 제27권1호
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• pp.69-82
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• 2024

In the conventional seismic design approach for a bridge pier, the function of the stopper, and shear key are to serve as mechanisms for unseating prevention devices that retain and transmit the lateral load to the pier under strong earthquakes. This frequently inflicts immense shear forces and bending moments concentrated at the plastic hinge zone. In this study, a shear panel damper plus gap (SPDG) is proposed as a low-cost alternative with high energy dissipation capacity to improve the seismic performance of the pier. Therefore, this study aimed to investigate the seismic performance of the pre-stressed concrete I girder (PCI-girder) bridge equipped with SPDG. The bridge structure was analyzed using nonlinear time history analysis with seven-scaled ground motion records using the guidelines of ASCE 7-10 standard. Consequently, the implementation of SPDG technology on the bridge system yielded a notable decrease in maximum displacement by 41.49% and a reduction in earthquake input energy by 51.05% in comparison to the traditional system. This indicates that the presence of SPDG was able to enhance the seismic performance of the existing conventional bridge structure, enabling an improvement from a collapse prevention (CP) level to an immediate occupancy (IO).

• 한국전산구조공학회논문집
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• 제33권6호
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• pp.411-417
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• 2020

Building Information Modeling(BIM)기술을 유지관리 단계에서 활용하기 위해서는 상당량의 유지관리 데이터와 BIM기반 정보모델 객체들이 연계되어 운용되어야 한다. 본 연구에서는 교량 점검데이터를 표현하기 위해 확장된 IFC기반의 BIM모델과 온톨로지를 연계하여 정보를 관리하는 방법을 제시하였다. 이를 위해 현재의 IFC버전은 교량 객체를 제대로 표현할 수 없기 때문에 교량을 위한 IFC엔티티를 확장하였으며, 확장된 IFC기반의 정보모델을 생성하는 방법을 제시하였다. 또한, 교량 점검데이터에 대한 기본 개념을 추출하고, 교량 점검데이터를 위한 온톨로지(Ontology)를 생성하였다. 추출된 기본 개념들은 제시된 온톨로지에서 시멘틱 웹의 트리플(Triple) 방식으로 관계를 형성되었다. 마지막으로, 생성된 IFC기반의 BIM모델은 제시된 온톨로지와의 통합을 위하여 시멘틱 데이터 형식으로 변환되었다. 확장된 IFC기반 BIM모델은 제시된 교량 점검데이터 관리를 위한 온톨로지와 통합되었고, 실제 교량 점검데이터를 기반으로 테스트모델을 생성하였다. SPARQL query를 통해 목적에 맞는 교량 점검데이터가 추출됨을 확인하여 실효성을 검증하였다.

• 대한토목학회논문집
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• 제34권2호
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• pp.437-446
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• 2014

현 논문에서는 전편 논문에서 제안한 3차원 격자요소를 활용하는 스트럿-타이 모델 방법의 타당성 및 효율성을 검증하기 위해 파괴실험이 수행된 13개의 슬래브-기둥 접합부 및 51개의 비틀림 보 등의 극한강도를 평가하였으며, 또한 3축 방향의 하중을 받는 교각코핑부에 대한 설계를 수행하였다. 현 연구의 방법에 의한 철근콘크리트 슬래브-기둥 접합부 및 비틀림 보의 극한강도 평가결과는 실험결과, ACI 318 설계기준을 비롯한 세계 주요설계기준, 그리고 몇몇 연구자의 방법에 의한 평가결과 등과 비교하여 현 연구방법의 타당성을 검증하였다. 교각코핑부의 설계결과는 ACI 318 설계기준의 단면법 및 AASHTO-LRFD의 스트럿-타이 모델 설계기준에 의한 설계결과와 비교하여 그 결과의 타당성을 검토하였다.

• 한국강구조학회 논문집
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• 제12권2호통권45호
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• pp.123-131
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• 2000

이 연구에서는 강박스 거더 교량의 연속 바닥판 타설에 따른 거동규명을 위해 시공중인 교량에 대한 현장실험과 해석을 수행하였다. 해석 및 실험 결과는 교축을 따라 교량의 거동이 크게 변하는 몇몇 점들에서 단명의 상, 하부 플랜지의 변형률로 나타내었으며 이를 통해 제안된 해석모델의 적합성을 검토하였다. 해석적 연구를 위해 사용한 모델은 단면해석의 경우 적층단면을 사용하였으며 요소 강성은 변위법과 3점 가우스 수치적분을 사용하여 구성하였다. 끝으로 해석결과와 실험결과를 비교, 검토하였다.

• International Journal of Railway
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• 제5권2호
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• pp.89-92
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• 2012

Effective notch stress, as an approach to evaluate the local stress at a notch (weld toe or root), is defined as the total stress assuming linear-elastic material behavior. This method can be effectively used to evaluate the fatigue performance of welded joints. In this study, finite element analysis results using the effective notch stress method were correlated with fatigue test results of rib-to-deck welded joints in a steel orthotropic bridge deck. Effective notch stress approach provided a good correlation with the crack pattern observed in the full-scale fatigue test. A higher effective notch stress at the critical weld toe than at the weld root was consistent with the dominant crack pattern observed at the weld toe during testing. The effective notch stress at the toe on the deck plate was about 80% higher than that on the rib; no cracks at the weld toe on the rib in the testing were observed. Maximum effective notch stress at the weld root occurred on the upper side of the root notch, which indicates that cracks are more likely to propagate into the deck plate, not into the weld metal. This is also consistent with the observed crack pattern in which the crack from the root propagated upward into the deck plate. No such crack pattern, propagating into the weld metal, was observed in the testing.

• Structural Engineering and Mechanics
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• 제39권2호
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• pp.187-206
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• 2011

This paper uses dynamic computer simulation techniques to develop and apply a multi-criteria procedure using non-destructive vibration-based parameters for damage assessment in truss bridges. In addition to changes in natural frequencies, this procedure incorporates two parameters, namely the modal flexibility and the modal strain energy. Using the numerically simulated modal data obtained through finite element analysis of the healthy and damaged bridge models, algorithms based on modal flexibility and modal strain energy changes before and after damage are obtained and used as the indices for the assessment of structural health state. The application of the two proposed parameters to truss-type structures is limited in the literature. The proposed multi-criteria based damage assessment procedure is therefore developed and applied to truss bridges. The application of the approach is demonstrated through numerical simulation studies of a single-span simply supported truss bridge with eight damage scenarios corresponding to different types of deck and truss damage. Results show that the proposed multi-criteria method is effective in damage assessment in this type of bridge superstructure.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.235-240
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• 2000

Although dapped-end beams are widely used in bridge and building structures, there are not any specific and reasonable design regulations on dapped-end beams. In this study, the validity of the suggested experimental and empirical design methods, conventional strut-tie model approach, and nonlinear strut-tie model approach is evaluated through the analysis of dapped-end beams tested to failure. The nonlinear strut-tie model approach proved to be the most suitable method for dapper-end beam design.

• 한국철도학회논문집
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• 제11권2호
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• pp.195-202
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• 2008

교량과 토공의 접속부은 궤도의 대표적인 취약구간으로서 교대배면의 부등침하로 인한 궤도틀림발생이 빈번하여 유지관리에 많은 어려움을 겪고 있는 구간 중의 하나이다. 콘크리트궤도부설구간의 경우에는 교대배면의 부등침하를 방지하기 위하여 접속슬래브 부설이 일반화되고 있는 추세이다. 이 경우, 접속슬래브를 지지하고 있는 노반의 침하로 인하여 접속슬래브에 경사처짐이 발생하게 되면 궤도도 경사처짐이 발생하게 된다. 이로 인해 이 구간을 통과하는 차량의 주행안정성과 승차감의 저하, 그리고 과도한 충격에 의한 궤도의 손상을 유발하게 되므로 접속슬래브의 단부에서의 침하를 제한할 필요가 있다. 따라서 본 연구에서는 콘크리트 궤도 부설 교량과 토공의 접속부에 부설되는 접속슬래브의 단부에서의 처짐한도를 알아보기 위하여 접속슬래브의 길이와 단부처짐량을 매개변수로 한 차량-궤도 상호작용 해석을 실시하여 차체가속도, 윤중변동률, 레일 저부응력, 그리고 체결구에 발생하는 상향압력을 조사하였으며, 수치해석결과와 각 검토항목별 허용한도와의 비교검토를 통하여 접속슬래브의 길이에 따른 단부처짐의 허용한도를 제시하였다.