• Structural Engineering and Mechanics
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• 제50권4호
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• pp.419-439
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• 2014

In this study, the structural performance of a seven span masonry arch bridge was evaluated. Investigations were performed on Aspendos (Belkis) Masonry Arch Bridge which was located on road of Aspendos Acropolis City in Antalya, Turkey. The old bridge was constructed in the early of fourth century AD, but it was exposed to the earthquakes in this region and the overloading by the river water. The old bridge was severely damaged and collapsed by probably an earthquake many years ago and a new bridge was then reconstructed on the remains of this old bridge by Seljuk in the 13th century. The bridge has also been affected from overflowing especially in the spring of each year, so some protective measures should be taken for this monumental bridge. Therefore, the structural performance under these loading has to be known. For this purpose, an initial finite element model was developed for the bridge and it was calibrated according to ambient vibration test results. After that, it was analyzed for different load cases such as dead, live, earthquake and overflow. Three load combinations were taken into account by deriving from these load cases. The displacements and the stresses for these combination cases were attained and compared with each other. The structural performance of Aspendos Masonry Arch Bridge was determined by considering the demand-capacity ratio for the tensile stress of the mortar used in Aspendos Masonry Arch Bridge. After these investigations, some concluding remarks and offers were presented at the end of this study.

• Structural Engineering and Mechanics
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• 제46권3호
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• pp.353-370
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• 2013

This paper presents a new method to study the impact factor of an old bridge based on the model updating technique. Using the genetic algorithm (GA) by minimizing an objective function of the residuals between the measured and predicted responses, the bridge and vehicle coupled vibration models were updated. Based on the displacement relationship and the interaction force relationship at the contact patches, the vehicle-bridge coupled system can be established by combining the equations of motion of both the bridge and vehicles. The simulated results show that the present method can simulate precisely the response of the tested bridge; compared with the other bridge codes, the impact factor specified by the bridge code of AASHTO (LRFD) is the most conservative one, and the value of Chinese highway bridge design code (CHBDC) is the lowest; for the large majority of old bridges whose road surface conditions have deteriorated, calculating the impact factor with the bridge codes cannot ensure the reliable results.

• Computers and Concrete
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• 제32권4호
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• pp.411-423
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• 2023

The rapid development of road transport has increased the number of bridges that require widening. A critical issue in the construction of bridge widening is the influence of vibrations of the old bridge on the casting of wet joint concrete between the old and new bridges owing to the running traffic. Typically, the bridge is closed to traffic during the pouring of wet joint concrete, which negatively affects the existing transportation network. In this study, a newly developed microscopic traffic load modeling approach and the vehicle-bridge interaction theory are incorporated to develop a refined numerical framework for the analysis of random traffic-bridge coupled dynamics. This framework was used to investigate traffic-induced vibrations at the wet joint of a widened bridge. Based on an experimental study on the vibration resistance of wet joint concrete, traffic control strategies were proposed to ensure the construction performance of cast-in-site wet joint concrete under random traffic without interruption. The results show that the vibration displacement and frequency of the old bridge, estimated by the proposed framework, were comparable with those obtained from field measurements. Based on the target peak particle velocity and vibration amplitude of the wet joint concrete, it was found that traffic control measures, such as limiting vehicle gross weight and limiting traffic volume by closing an additional traffic lane, could ensure the construction performance of the wet joint concrete.

• 콘크리트학회지
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• 제10권6호
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• pp.291-301
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• 1998

본 논문은 공용년수가 오래되어 노후화된 철근콘크리트 교량의 파괴가지의 거동에 예측하기 위한 비선형 파괴해석 모델링 기법이 개발에 관한 연구이다. 본 논문에서는 비선형파괴해석을 위해철근부식으로 인하여 철근주변 콘크리트의 열화를 고려한 인장경화모델을 제안하였으며 교량의 노후화된 지점조건을 고려할 수 있는 지점 모델링 기법을 제안하였다. 제안된 모델을 사용하여 반복하중을 받는 노후화된 철근콘크리트 T형 교량이 파괴될 때까지의 2차원 및 3차원 파괴해석을 수행하였으며 파괴시험으로부터 분석된 교량의 파괴거동과 비교하였다. 해석결과와 실험결과의 비교로부터 본 논문의 모델링기법이 노후화된 교량의 파괴해석에 유용하게 사용될 수 있으며 노후화된 지점조건의 모델링이 교량의 강도평가에 매우 큰 영향을 주는 것을 규명하였다.

• Coupled systems mechanics
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• 제10권1호
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• pp.1-19
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• 2021

Composite nature of the masonry structures in general causes complex and non-linear behaviour, especially in intense vibration conditions. The presence of different types and forms of structural elements and different materials is a major problem for the analysis of these type of structures. For this reason, the analysis of the behaviour of masonry structures requires a combination of experimental tests and non-linear mathematical modelling. The famous UNESCO Heritage Old Bridge in Mostar was selected as an example for the analysis of the global behaviour of reinforced stone arch masonry bridges. As part of the experimental research, a model of the Old Bridge was constructed in a scale of 1:9 and tested on a shaking table platform for different levels of seismic excitation. Non-linear mathematical modelling was performed using a combined finite-discrete element method (FDEM), including the effect of connection elements. The paper presents the horizontal displacement of the top of the arch and the failure mechanism of the Old Bridge model for the experimental and the numerical phase, as well as the comparison of the results. This research provided a clearer insight into the global behaviour of stone arch masonry structures reinforced with steel clamps and steel dowels, which is significant for the structures classified as world cultural heritage.

• 콘크리트학회지
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• 제22권1호
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• pp.59-64
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• 2010

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.655-658
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• 1999

An experimental investigation on the ruined RC bridge with 30 years old has been conducted to estimate the durabilities. The ruined RC bridge estimated in this study was located at Kyung-Bu Express Way. First, concrete strength and durability characteristics such as concrete resistivity, chloride content were estimated. Second, it was to test reinforcing corrosion embedded in slab of bridge. And, third, tensile strength and yield strength of reinforcing bar corroded and not corroded were estimated. This bridge inspection provides the most common cause of defects and deterioration and the results of this inspections give more specific information than those of laboratory inspections do.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2006년 추계학술발표대회 개요집
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• pp.277-279
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• 2006

Due to the numerous environmental factors, cracks and corrosion are frequently occured especially in old steel bridge, which deteriorate the structural integrity; thus bring about the problems of structural safety of the steel bridge. Therefore, repair and reinforcement are required for the damaged structure. the replacement repair welding method is spotlighted for its brilliant features, i.e. it can be achieved without incurring traffic dislocation. the method cuts the damaged parts and replaces them with new steel plate by welding under live loads. However, the mechanical behavior of the welded joints under cyclic loads due to the traffic which passes along bridge is not clarified. In this paper, the fatigue strength of the replacement repair welded joints was investigated in order to improve reliability in the repair welded joints of old steel bridge.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1050-1055
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• 2007

In the case of a rail road bridge extension work, especially single track to double track, the foundation of new substructure which supports the extended part of superstructure could be interfered by the exist foundation of an old bridge. When these two foundations are jointed to prevent such fatal effects of the structure as unequal subsidence of soil foundations, it is important to prove the structural behaviour of the joining surfaces between new foundation and old foundation. 3-Dimensional Finite Element Analysis Method have been studied for the solutions of the structural behaviour of the foundations. In this analysis, 'Contact Element' which allows the sliding of each adjoining member is used for the joint of the boundary surface of the old and new pier foundations. Furthermore, Material Nonlinear Behaviour Analysis also supports the accuracy of the result in this study because the foundations consist of concrete main bodies and reinforced steel bars. These detailed analyses secure the verification of the structural safety of the foundations in the extension work more firmly.

• 대한기관식도과학회:학술대회논문집
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• 대한기관식도과학회 1977년도 제11차 학술대회연제 순서 및 초록
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• pp.4.3-4
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• 1977

1946년 Metz가 impedance audiometry를 처음 임상적으로 응용한이래 많은 연구가 계속되고 있다. Brooks는 4세 부터 11씨 소아 1053명에 대한 electroacoustic impedance bridge의 결과를 보고하였고, J. Jerger는 6세이상 소아 398에 대한 impedance audiometry의 결과를 보고하였으며, Cooper 등은 소아 539명에 대한 conventional audiometry technic과 impedance audiometry와의 정확도를 비교 발표하였다. 우리나라에서는 1974년 서울대학교 이비인후과에서 처음으로 madsen impedance bridge를 도입하였고 다음으로 본원에서 1976년 teledyne impedance를 사용하여 1976년 9월 학동기 아동(7세부터 14세) 1023명에 대한 결과를 보고하였고 이번에는 1세부터 6세까지의 유소아 110명에 대한 impedance audiometry의 결과를 문헌고찰과 함께 보고하는 바이다.