• 한국철도학회논문집
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• 제8권5호
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• pp.439-443
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• 2005

The biggest challenge bridge agencies face is the maintenance of bridges, keeping them safe and serviceable, with limited funds. To maintain the bridges effectively, there is and urgent need to predict their remaining life from a system reliability viewpoint. In this paper, a model using lifetime functions to evaluate the overall system probability of survival of a rail road bridge is proposed. In this model, the rail load bridge is modeled as a system. Using the model, the lifetime of the rail road bridge is predicted.

• Earthquakes and Structures
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• 제6권5호
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• pp.495-514
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• 2014

The performance of passive control system for the seismic protection of a multi-tower cable-stayed bridge with the application of partially longitudinal constraint system is investigated. The seismic responses of the Jiashao Bridge, a six-tower cable-stayed bridge using the partially longitudinal constraint system are studied under real earthquake ground motions. The effects of the passive control devices including the viscous fluid dampers and elastic cables on the seismic responses of the bridge are examined by taking different values of parameters of the devices. Further, the optimization design principle of passive control system using viscous fluid dampers is presented to determine the optimized parameters of the viscous fluid dampers. The results of the investigations show that the control objective of the multi-tower cable-stayed bridge with the partially longitudinal constraint system is to reduce the base shears and moments of bridge towers longitudinally restricted with the bridge deck. The viscous fluid dampers are found to be more effective than elastic cables in controlling the seismic responses. The optimized parameters for the viscous fluid dampers are determined following the principle that the peak displacement at the end of bridge deck reaches to the maximum value, which can yield maximum reductions in the base shears and moments of bridge towers longitudinally restricted with the bridge deck, with slight increases in the base shears and moments of bridge towers longitudinally unrestricted with the bridge deck.

• Structural Engineering and Mechanics
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• 제63권6호
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• pp.799-808
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• 2017

Failure of a redundant long-span bridge is often described by innumerable failure modes, which make the structural system reliability analysis become a computationally intractable work. In this paper, an innovative procedure is proposed to efficiently identify the dominant failure modes and quantify the structural reliability for a long-span bridge system. The procedure is programmed by ANSYS and MATLAB. Considering the correlation between failure paths, a new branch and bound operation criteria is applied to the traditional stage critical strength branch and bound algorithm. Computational effort can be saved by ignoring the redundant failure paths as early as possible. The reliability of dominant failure mode is computed by FORM, since the limit state function of failure mode can be expressed by the final stage critical strength. PNET method and FORM for system are suggested to be the suitable calculation method for the bridge system reliability. By applying the procedure to a CFST arch bridge, the proposed method is demonstrated suitable to the system reliability analysis for long-span bridge structure.

• Wind and Structures
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• 제31권5호
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• pp.393-402
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• 2020

Long-span bridges with high flexibility and low structural damping are very susceptible to the vortex-induced vibration (VIV), which causes extremely negative impacts on the ride comfort of vehicles running on the bridges. To assess the ride comfort of vehicles running on the long-span bridges subjected to VIV, a coupled wind-vehicle-bridge system applicable to the VIV case is firstly developed in this paper. In this system, the equations of motion of the vehicles and the bridge subjected to VIV are established and coupled through the vehicle-bridge interaction. Based on the dynamic responses of the vehicles obtained by solving the coupled system, the ride comfort of the vehicles can be evaluated using the method given in ISO 2631-1. At last, the proposed framework is applied to several case studies, where a long-span suspension bridge and two types of vehicles are taken into account. The effects of vehicle speed, vehicle type, road roughness and vehicle number on the ride comfort are investigated.

• 해양환경안전학회지
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• 제11권1호
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• pp.17-22
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• 2005

선박의 항해 계기들의 기술이 발전됨에 따라 많은 장비들이 개발되고 있으나 여전히 인간과실에 의한 해양 사고는 지속적으로 발생하고 있는 현실에서, 인간과실에 의한 사고를 감소시키기 위하여 선교의 항해 계기들은 인간공학적적으로 배치, 설계되었는지가 많은 관심의 대상이 되고 있다 선교 내 여러 계기들의 알람장치는 선교 근무자에게 그 알람 장치가 주고자 하는 정보를 가능한 빨리 인식하고 정확한 정보를 전달할 수 있도록 설계되어야 하며, 국제적으로 인간공학적 선교를 위한 알람장치(Bridge Alarm Management System : BAMS)의 필요성이 논의 되고 있으나 아직 실질적인 설계방법 등에 대해서는 논의가 이루어지고 있지 않다. 따라서 본 논문에서는 선박의 여러 설비 중 선교의 알람장치에 관한 인간공학적 개념의 설계에 대하여 알아보고 현재 개발, 운용 중인 인간공학적 통합선교시스템(Integrated Bridge System :IBS)의 선교통합알람장치(Ergonomic Integrated Bridge Alarm Management System : EIBAMS)에 관한 개념적인 설계를 제안하고자 한다.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2005년도 춘계학술발표회
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• pp.1-6
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• 2005

선박의 항해 계기들의 기술이 발전됨에 따라 많은 장비들이 개발되고 있으나 여전히 인적과실에 의한 사고는 줄어들고 있지 않다. 이에 인적과실에 의한 사고를 줄이기 위하여 선교의 항해 계기들은 인간공학적적으로 배치, 설계되었는지가 관심의 대상이 되고 있다. 선교내에서의 여러 계기 중 알람장치는 선교 근무자에게 그 알람 장치가 주고자 하는 정보를 가능한 빨리 인식하고 정확한 정보를 전달할 수 있도록 설계되어야 하며, 국제적으로 인간공학적 선교를 위한 알람장치(Bridge Alarm Management System : BAMS)의 필요성이 논의 되고 있으나 아직 실질적인 설계방법 등에 대해서는 논의가 이루어지고 있지 않다. 따라서 본 논문에서는 선박의 여러 설비 중 선교의 알람장치에 관한 인간공학적 개념의 설계에 대하여 알아보고 현재 개발, 운용중인 인간공학적 통합선교시스템(Integrated Bridge System : IBS)의 선교통합알람장치(Ergonomic Integrated Bridge Alarm Management System : EIBAMS)에 관한 개념적인 설계를 제안하고자 한다.

• Computers and Concrete
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• 제3권1호
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• pp.29-42
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• 2006

In this study, a novel education system for inspection of concrete bridges is presented. The new education approach uses virtual reality (VR) and three-dimensional computer graphics (3DCG) in training engineers to become bridge inspection specialists. The slow time-dependent deterioration of concrete bridges can be reproduced on the computer screen in any chosen time frame, thus providing the trainees with illustrative and educative insight into the deterioration problem. In the proposed VR/3DCG approach a three-dimensional model of concrete bridge, including surfaces, viewpoints and walkthrough paths is created. With the help of this virtual bridge model, an experienced bridge inspection specialist teaches the different deterioration phenomena of concrete bridges to the trainees. The new system was tested, and the inspection results from the case bridge showed that in comparison with the traditional Japanese bridge inspection education system, the new system gives better results. In addition to the improvement of quality of bridge inspections, the new VR/3DCG system-based education brings along some other, more intangible benefits.

• Wind and Structures
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• 제13권5호
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• pp.471-485
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• 2010

In comparison with the common two-tower suspension bridge, due to the lack of effective longitudinal restraint of the center tower, the three-tower suspension bridge becomes a structural system with greater flexibility, and more susceptible to the wind action. By taking a three-tower suspension bridge-the Taizhou Bridge over the Yangtze River with two main spans of 1080 m as example, effects of structural parameters including the cable sag to span ratio, the side to main span ratio, the deck's dead load, the deck's bearing system, longitudinal structural form of the center tower and the cable system on the aerodynamic stability of the bridge are investigated numerically by 3D nonlinear aerodynamic stability analysis, the favorable structural system of three-tower suspension bridge with good wind stability is discussed. The results show that good aerodynamic stability can be obtained for three-tower suspension bridge as the cable sag to span ratio is assumed ranging from 1/10 to 1/11, the central buckle are provided between main cables and the deck at midpoint of main spans, the longitudinal bending stiffness of the center tower is strengthened, and the spatial cable system or double cable system is employed.

• Structural Engineering and Mechanics
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• 제69권2호
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• pp.177-191
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• 2019

The local topography has a significant effect on the characteristics of seismic ground motion. This paper investigates the influence of topographic effects on the seismic response of a train-bridge system. A 3-D finite element model with local absorbing boundary conditions is established for the local site. The time histories of seismic ground motion are converted into equivalent loads on the artificial boundary, to obtain the seismic input at the bridge supports. The analysis of the train-bridge system subjected to multi-support seismic excitations is performed, by applying the displacement time histories of the seismic ground motion to the bridge supports. In a case study considering a bridge with a span of 466 m crossing a valley, the seismic response of the train-bridge system is analyzed. The results show that the local topography and the incident angle of seismic waves have a significant effect on the seismic response of the train-bridge system. Leaving these effects out of consideration may lead to unsafe analysis results.

• Structural Engineering and Mechanics
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• 제52권1호
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• pp.51-73
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• 2014

A three-dimensional finite element model for the Jiashao Bridge, the longest multi-span cable-stayed bridge in the world, is established using the commercial software package ANSYS. Dynamic characteristics of the bridge are analyzed and the effects of structural system measures including the rigid hinge, auxiliary piers and longitudinal constraints between the girders and side towers on the dynamic properties including modal frequency, mode shape and effective mass are studied by referring to the Jiashao Bridge. The analysis results reveal that: (i) the installation of the rigid hinge significantly reduces the modal frequency of the first symmetric lateral bending mode of bridge deck. Moreover, the rigid hinge significantly changes the mode shape and effective mass of the first symmetric torsional mode of bridge deck; (ii) the layout of the auxiliary piers in the side-spans has a limited effect on changing the modal frequencies, mode shapes and effective masses of global vibration modes; (iii) the employment of the longitudinal constraints significantly increases the modal frequencies of the vertical bending modes and lateral bending modes of bridge deck and have significant effects on changing the mode shapes of vertical bending modes and lateral bending modes of bridge deck. Moreover, the effective mass of the first anti-symmetric vertical bending of bridge deck in the longitudinal direction of the fully floating system is significantly larger than that of the partially constrained system and fully constrained system. The results obtained indicate that the structural system measures of the multi-span cable-stayed bridge have a great effect on the dynamic properties, which deserves special attention for seismic design and wind-resistant design of the multi-span cable-stayed bridge.