• 한국강구조학회 논문집
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• 제12권4호통권47호
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• pp.407-416
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• 2000

본 연구는 실험적인 방법으로 이동하중을 받는 판형교의 동적 응답을 연구하였다. 판형교의 상부 슬래브는 판요소로, 거더는 보요소로 이상화였다. 이동하중과 판형교는 각각 소규모 차량모델과 교량모델로 제작하였다. 이동 하중을 받는 판형교의 동적 응답은 변형계, 변위계, 가속도계 및 변형도 측정기를 이용하여 측정하였고 측정한 자료로부터 얻은 최대동적응답을 유한요소법의 결과와 비교하였다. 실험적인 모형실험으로 판형교의 동적응답을 얻을 수 있음을 알 수 있다.

• Smart Structures and Systems
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• 제32권6호
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• pp.371-382
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• 2023

Box girder bridges are now widely used in bridge construction, and it is necessary to perform load rating regularly to evaluate the load capacity of box girder bridges. Load testing is a common measure for load rating. However, the bridge must be loaded by many trucks under different loading conditions, which is time-consuming and laborious. To solve this problem, this paper proposes a load rating method for box girder bridges based on rapid moving loads testing. The method includes three steps. First, the quasi-influence factors of the bridge are obtained by crossing the bridge with rapidly moving loads, and the structural modal parameters are simultaneously obtained from the dynamic data to supplement. Second, an objective function is constructed, consisting of the quasi-influence factors at several measurement points and structural modal parameters. The finite element model for load rating is then updated based on the Rosenbrock method. Third, on this basis, a load rating method is proposed using the updated model. The load rating method proposed in this paper can considerably reduce the time duration of traditional static load testing and effectively utilize the dynamic and static properties of box girder bridges to obtain an accurate finite element model. The load capacity obtained based on the updated model can avoid the inconsistency of the evaluation results for the different structural members using the adjustment factors specified in codes.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 추계학술대회 논문집
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• pp.369-370
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• 2007

• Coupled systems mechanics
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• 제7권4호
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• pp.485-507
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• 2018

The moving load causes the occurrence of vibrations in civil engineering structures such as bridges, railway lines, bridge cranes and others. A novel engineering method for separation of the variables in the differential equation of the elastic line of Bernoulli-Euler beam has been developed. The method can be utilized in engineering structures, leading to "a beam under moving load model" with generalized boundary conditions. This method has been implemented for analytical study of the dynamic response of the metal structure of a single girder bridge crane due to the telpher movement along the bridge girder. The modeled system includes: a crane bridge girder; a telpher, moving with a constant horizontal velocity; a load, elastically fixed to the telpher. The forced vibrations with their own frequencies and with a forced frequency, due to the telpher movement, have been analyzed. The loading resulting from the telpher uniform movement along the bridge girder is cyclical, which is a prerequisite for nucleation and propagation of fatigue cracks. The concept of "dynamic coefficient" has been introduced, which is defined as a ratio of the dynamic deflection of the bridge girder due to forced vibrations, to the static one. This ratio has been compared with the known from the literature empirical dynamic coefficient, which is due to the telpher track unevenness. The introduced dynamic coefficient shows larger values and has to be taken into account for engineering calculations of the bridge crane metal structure. In order to verify the degree of approximation, the obtained results have been compared with FEM outcomes. An additional comparison has been made with the exact solution, proposed by Timoshenko, for the case of simply supported beam subjected to a moving force. The comparisons show a good agreement.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1536-1541
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• 2011

Simple girder bridges are more economical than commonly used PSC box girder bridges in high-speed railway construction, if they secure the riding stability. In this study, the dynamic behavior and riding stability of the newly developed precast V-girder bridge are analyzed. The dynamic moving load analysis is used including two train load case : the KTX train and freight train.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.709-710
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• 2009

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1742-1749
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• 2011

The 3 way segmented Maglev switch is developed for the urban Maglev vehicle, which is scheduled to debut at the middle of 2013 in Incheon International Airport. The 3 way switch is composed of 3 moving girders, 4 fixed girders, driving units, moving units, clamping units and articulated angle relieving equipment etc. In this paper, the measured results on the interaction between vehicle and switch are discussed. The measured results are following; First, continuous moving test and natural frequency for girder and levitation rail. Second, levitation and lateral air gap of the bogies running on the curved switch. Third, noise of moving mechanical parts of the 3 way segmented switch. Forth, thermal displacement of the girder due to temperature change. With over the measured results, more reliability and stability of the 3 way segmented switch are secured.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 봄 학술발표회 논문집
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• pp.218-225
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• 1999

In order to completely automatize the moving load analysis for the three-dimensional frame model of the girder bridge, the efficient software technique is presented, which makes use of the signal among processes. If this software technique is used in automation, the separate algorithm is not needed for the transverse loading analysis, and the complete automatic moving load analysis algorithm can be easily developed. The program, which has the complete automatic moving load analysis function, has been developed with using this software technique, and has been verified by comparing the results with the one in the famous design book.

• 대한토목학회논문집
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• 제31권3A호
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• pp.163-172
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• 2011

CFTA 거더는 아치형상을 갖는 콘크리트 충전 강관구조이며 초기처짐 및 공용 중 응력제어를 위해 외부긴장재를 배치한 거더 형식이다. 본 연구에서는 차량진행에 따른 거더의 동적거동에 긴장재가 미치는 영향을 분석하였다. 이를 위해 유한요소 프로그램을 이용하여 거더 및 긴장재 등을 수치모델링하였으며 긴장재의 양과 긴장력을 다양한 값으로 변화시켰다. 차량하중은 도로교설계기준의 DB-24 하중을 고려하였으며 3축-2트랙으로 모델링하였다. 차량하중은 등가절점하중으로 적용시켰으며 차량하중의 이동은 차량통과 시간 및 절점수를 고려한 각 절점에서의 시간함수로 나타내었다. 차량속도는 40 km/hr에서 100 km/hr까지 20 km/hr씩 증가시켰다. 해석결과 긴장재의 긴장력 변화는 거더의 동적거동에 영향을 주지않았으며 초기처짐에만 영향을 주었다. 긴장재의 양에 따라서는 거더의 동적거동이 다르게 나타났으며 긴장재의 양이 적을수록 동적처짐은 증가하였다. 이를 바탕으로 거더의 동적증폭계수(DAF)를 산출하였으며 긴장재가 없는 경우에도 AASHTO LRFD와 도로교 표준시방서에서 정한 기준값보다 매우 작은 안정적인 거동을 보였다.

• Interaction and multiscale mechanics
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• 제4권4호
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• pp.273-289
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• 2011

The vibration response of the bridges under the moving vehicular load is of importance for engineers to estimate the serviceability of existing bridges and to design new bridges. This paper deals with the three dimensional vibration analysis of prestressed concrete bridges under moving vehicles. The prestressed bridges are modeled by four-node isoparametric flat shell elements with the transverse shearing deformation taken into account. The usual five degrees-of-freedom (DOFs) per node of the element are appended with a drilling DOF to accommodate the transformation of the local stiffness and mass matrices to the global coordinates. The vehicle is modeled as a single or two-DOF system. A single-span prestressed Tee beam and two-span prestressed box-girder bridge are studied as the two numerical examples. The effects of prestress forces on the natural frequencies and dynamic responses of the bridges are investigated.