The impact factor of general road bridges is typically calculated according to Korea Highway Design Code(KHDC) or Design Guidelines For Cable-Supported Bridges in Korea. Above design codes define the impact factor as the function of span length or effective span length. But calculated impadt factors from this function are different to the measured values of long-span bridges such as cable-stayed bridge, suspension bridge. There are several methods to estimate the impact factor of cable supported bridges. In this study, the impact factor of cable-stayed bridges is estimated from dynamic load tests and compared to calculated values from the various design codes.
This study presents a technical overview of snow and ice accretion on cable-stayed bridges and suspension bridges. Specially, it focuses on measures against snow or ice falling into bridge decks. Many different types of de-icing and anti-icing are discussed in this paper.
In this study, measured data of cable-supported bridge’s thermal expansion and contraction were analyzed. To evaluate structural behaviors by temperature variations, measured data were compared with theoretical values by correlation analysis between thermal movements and temperatures. Additionally, the cumulative displacements were analyzed. Through the analysis of the results, the evaluation methods of cable-supported bridge's thermal expansion and contraction is suggested.
Since cable members are the major structural components in cable bridges, they should be properly inspected for surface damage as well as inside defects such as corrosion and/or breakage of wires. In this study, only the vision-based surface damage detection system based on image processing techniques is addressed. The damage detection programs are consist of real-time and post processing detection programs. The proposed damage detection programs were verified through laboratory tests on many types of cables.
This study presents a technical overview of inspection practices on cable-stayed bridges and suspension bridges in service. Specially, it focuses on special inspections, which are regularly scheduled or unscheduled inspections, contrary to those used in general bridges. Conceptual improvements of special inspections are discussed.
상관관계가 높은 복합열화의 완벽한 개별예측모델의 개발은 매우 어려운 문제로, 본 논문에서는 현수교 시스템의 미래열화와 유지 예산을 예측하기 위하여, 10년간의 유지 데이터가 주어진 매개변수(파손지표와 사용성)의 사후 확률 밀도함수를 찾기 위해 베이지언 추론을 적용하였다. 마르코프 연쇄 몬테카를로법을 이용하여 매개변수의 사후 분포를 조사하였다. 감소한 사용성의 모의위험예측은 사전분포와 연간유지 업무에서 업데이트한 데이터의 가능성에 따라 작성한 사후 분포이다. 기존의 선형 예측 모델과 비교하면, 제안된 2차 모델은 교량부품의 사용성, 위험요소, 그리고 유지 예산의 측정 데이터에 대하여 매우 개선된 수렴성과 근접성을 제공한다. 따라서 제안된 2차 추계학적 회귀 모델을 기반으로 복잡한 사회간접설비의 미래 성능과 유지관리예산을 예측하고 제어할 수 있는 기회를 제공할 것으로 기대한다.
In this paper, we propose a cable climbing robot which can climb up and down the cables in the bridges. The robot mechanism consists of three parts: a wheel based driving mechanism, adhesion mechanism, and safe landing mechanism. The wheel based driving mechanism is driven by tooth clutches and motors. The adhesion mechanism plays the role of maintaining adhesion force by a combination of pantograph, ball screw, and springs even when the power is lost. The safe landing mechanism is developed for guaranteeing the safety of the robot during operations on cables. It can make the robot fall down with reduced speed by dissipating the gravitational forces. The robot mechanism is designed and manufactured for validating its effectiveness.