• Earthquakes and Structures
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• 제26권5호
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• pp.401-416
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• 2024

Long-span structures, such as bridges, can experience different seismic excitations at the supports due to spatially variability of ground motion. Regarding current bridge designing codes, it is just EC 2008 that suggested some regulations to consider it and in the other codes almost ignored while based on some previous studies it is found that the effect of mentioned issue could not be neglected. The current study aimed to perform a comprehensive study about the effect of spatially varying ground motions on the dynamic response of a reinforced concrete bridge under asynchronous input motions considering soil-structure interactions. The correlated ground motions were generated by an introduced method that contains all spatially varying components, and imposed on the supports of the finite element model under different load scenarios. Then the obtained results from uniform and non-uniform excitations were compared to each other. In addition, the effect of soil-structure interactions involved and the corresponding results compared to the previous results. Also, to better understand the seismic response of the bridge, the responses caused by pseudo-static components decompose from the total response. Finally, an incremental dynamic analysis was performed to survey the non-linear behavior of the bridge under assumed load scenarios. The outcomes revealed that the local site condition plays an important role and strongly amplifies the responses. Furthermore, it was found that a combination of wave-passage and strong incoherency severely affected the responses of the structure. Moreover, it has been found that the pseudo-static component's contribution increase with increasing incoherent parameters. In addition, regarding the soil condition was considered for the studied bridge, it was found that a combination of spatially varying ground motions and soil-structure interactions effects could make a very destructive scenarios like, pounding and unseating.

• 조명전기설비학회논문지
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• 제20권6호
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• pp.1-8
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• 2006

본 연구는 휘도측정장비인 CS-100과 ProMetric 1400을 활용하여 조망점의 변화에 따른 교량 경관조명의 휘도를 분석한 것이다. 이를 위하여 경관조명이 적용된 한강의 교량4개를 교량형태별로 선정하고 조망유형에 따라 한강둔치에서 바라본 조망(투시뷰), 교량주변 건물에서 바라본 조망(건물뷰), 그리고 교량 위 주행자가 바라본 조망(주행뷰) 등 3가지로 분류하였다. 연구대상의 주변하늘, 강물표면, 상부구조물, 상판측면 그리고 교각에 대한 휘도분포를 측정하였다. 분석결과, 광진교와 동호대교는 투시뷰의 휘도가 높게 나타났으며, 올림픽대교와 동작대교는 건물뷰의 휘도가 높게 나타났다. 따라서 거더교와 같이 상부구조물이 없는 교량에서는 투시뷰가, 사장교 및 아치교와 같이 상부 구조물이 있는 교량에서는 건물뷰가 경관조명의 특성을 크게 반영하는 휘도분포가 강하게 나타났다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.444-446
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• 2007

This paper presents a ZVS (Zero Voltage Switching) half-bridge converter of simple structure. The operational principle of the proposed converter is explained, briefly. It is shown through that the experimental results the proposed converter operates excellently as a high efficiency converter. As the proposed converter utilizes the transformer leakage inductor as the resonant inductor, its structure is simplified.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 춘계 학술발표회논문집
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• pp.415-421
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• 2003

With the increasing possibility of earthquake occurrence, seismic safety of bridges has become one of the most important social issues in Korea. In this study, a nonlinear earthquake response analysis is carried out for a real bridge by incorporating soil-structure interaction and pier nonlinearity. The material nonlinearity of the bridge pier is realized by utilizing SAP2000 whereas the soil-structure interaction is analized in time domain by adapting KIESSI. The numerical results are compared to those of the models without considering the effects.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2814-2820
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• 2011

Railway bridge, contact of vehicle needs to design considering the running safety about the running train load of the railway bridge, ride comfort and dynamic safety. Also, upper structure of the railway bridge has to satisfy design standard about moving load(train). So, the railway bridge has to satisfy the requirement for vertical acceleration of the bridge deck, vertical displacement of the bridge and face distortion, which is suggested railway design standard in Korea(2011.5.). In this study, it was investigated and evaluated to the running safety about the running train load of the railway bridge, ride comfort and dynamic safety with railway design standard for steel composite(Steel Box Girder) railway bridge considering KTX, freight train and standard train load.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.157-160
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• 2007

The dynamic behavior of a steel bridge crossed by the Korean High Speed Train(KHST) has been investigated experimentally and numerically. The bridge is a 2-girder simply supported steel bridge which has 40m of span length. A set of experimental tests were performed during operation of KHST, and 13 accelerometers and 6 LVDTs were utilized for measurement of dynamic responses. Numerical analyses considering bridge-structure interaction were performed for validation of experimental results. Since structural type and dynamic characteristics of the bridge differ from those of the representative concrete box bridge, dynamic behavior of the concerning steel bridge shows differences, but dynamic performances are all satisfying specification requirements.

• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.810-819
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• 2007

Usually the status of a bridge is determined by its structural capability and material strength. Consequently a lot of researchers have studied the failure, the fatigue, and the deterioration of the structure in terms of the structural function of a bridge. However, the overall performance of a bridge may be affected simply by the damage of one of its components. Therefore this study utilized a systematic classification and statistical analysis based on the existing bridge inspection data collected in Taiwan to reach the following goals: (1) assess the performance distribution and deterioration rate for bearing and expansion joint of bridge; (2) find out the right time to do the preventive and essential maintenance for the component of bridge with an empirical method, and to decide what time and which component of a bridge will receive preventive maintenance or regular maintenance.

• Journal of Power Electronics
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• 제17권5호
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• pp.1256-1267
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• 2017

A fault tolerant structure and its corresponding control strategy for electromagnetic stirring power supplies are proposed in this paper. The topology structure of the electromagnetic stirring power supply contains two-stages. The fore-stage is the PWM rectifier. The back-stage is the fault tolerant inverter, which is a two-phase three-bridge orthogonal inverter circuit while operating normally. When the power switch devices in the inverter are faulty, the structure of the inverter is reconfigured. The two-phase half bridge inverter circuit is constructed with the remaining power switch devices and DC-link capacitors to keep the system operating after cutting the faulty power switch devices from the system. The corresponding control strategy is proposed to let the system work under both normal and fault conditions. The reliability of the system is improved and the requirement of the electromagnetic stirring process is met. Finally, simulation and experimental results verify the feasibility of the proposed fault tolerant structure and corresponding control strategy.

• 한국공간구조학회논문집
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• 제14권2호
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• pp.69-78
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• 2014

The purpose of this study is to increase applicability of high strength steel, HSA800 to the structure. Selected study of structure is to consider high strength steel, and following parts, 1) Tensile member with no consider of buckling, 2) Truss existing both tension and compression members with small slenderness ratio. This studied structure is included tension column hang on to the upper bridge truss. The structure element quantity with apply HSA800 instead of SM570 is reduced about 38.9% of tension column and 29.7% of bridge truss. In addition, the number of element's division is reduced about two sections due to reduction of self weight that the crane is able to lift up. This improves to reduce erection sequence and construction period which can save about a month. All connections are reviewed as welding and bolt. Also, the cost of welding is reduced about 41.3% due to apply HSA800. In conclusion, applying HSA800 to the hanging structure aggressively can secure economic and constructability.

• 한국안전학회지
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• 제28권5호
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• pp.41-48
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• 2013

This paper is intended to provide the background information and justification for Korean highway bridge design code(limit state design)(2012). Limit state design method calculates reliability index and probability of failure through the analysis of the reliability of the experimental database. It has become possible to perform the economical and consistent design by evaluating the safety of a structure quantitatively. In this paper, we used the design specifications of RC slab bridge of superstructure form of Road Design Manual in Part 5 bridge built in highway bridge. This study conducted structural analysis using the method of frame structure theory, design and analysis of bridge by limit state design method, the design code including various standards and Load model applied Korean highway bridge design code limit state design(KHBDC;2012). As a result, it analyzed the effect of safety through comparison. Showing effect of improvement the safety factor and comparing the value of the result, it is determined to be capable of economical design and safety. Furthermore, limit state design method was able to determine many redundant force of cross-section compared with existing design method. It is determined that it can reduce the overall amount because of the reduction of the cross-section and girder depth.