For suspension bridges, the super-structure is supported by main cables and hangers which carry the dead and live loads to the pylons and anchorages. Due to the fact that the difficultly of repair and strengthening for damaged cables, it is very important to find an efficient way of maintenance methods for cables. The corrosion is one of main causes for cable damages. The use of dehumidification system can be an alternative for this issue. Therefore, the authors have been evaluated for efficiency of the cable dehumidification system for main cables of suspension bridge. This study was initiated to develop an efficient and economical management strategy to operate the cable dehumidification system for suspension bridges built in South Korea.

This study is the National R&D project which has been carried out since 2016 with governmental support. The main objective of this study is to enhance technical and economical competitiveness on cable bridge through providing total solution for the major field issues in overseas market. In this paper, methodology and promotion strategy of the study are introduced and future research plan is also explained.

In this study, a vision-based monitoring system was applied to measure the dynamic characteristics of the stay cable. The image was acquired during the day to measure the dynamic characteristics of the stay cable and the image filter processing algorithm was applied to reduce the analytical noise of the image.

In this study, to verify the validity of the dynamic responses of cables with the image processing technique, the lift-off test and vibration method (Vision-based System) were used to measure the cable tensions, and the results were compared and analyzed.

In the case of a railway bridge where the ratio of live load to fixed load is relatively large, one of the main factors that dominate the bridge life is the fatigue phenomenon that occurs due to long-term accumulation by live load. Therefore, evaluating and constantly maintaining the fatigue life of cables in cable-supported bridges is an important item in ensuring the safety of bridges over their lifetime.

This paper introduces and summarizes damage cases of cable for cable supported bridges. The damage cases of similar bridge types may become an important database in the maintenance and management of cable supported bridges in the future. It will also be used as a base material for improving and developing the technology of inspection and maintenance of cable supported bridges.

Earthquake safety assessment software of the cable-stayed bridge using the seismic acceleration measurement date was developed. Various safety assessment indices for evaluation structural safety and serviceability of bridges are discussed. A systematic approach is proposed to process the raw data for generating appropriate safety assessment indicators. The software for structural state evaluation includes (i) format conversion of raw data, (ii) noise filtering, (iii) generation of assessment index, (iv) state evaluation. Determination of the limit state included in the condition evaluation step is discussed and an example of the graphic user interface of the software is shown.

Previous shape sensors including bend sensors and optic fiber based sensors are widely used in various applications including goniometer and surgical robots. But theses sensors have large nonlinearity, limited in the range of sensing curvature, and sometimes are expensive. This study suggests a new concept of bend sensor using cable-conduit which consists of the outer sheath and the inner wire. The outer sheath is made of helical coil whose length of the central line changes as the sheath bends. This length change of the central line can be measured with the length change of the inner cable. The modeling and the experimental results show that the output signal of the proposed sensor is linearly related with the bend angle of the sheath with root mean square error of 5.3% of 450° sensing range. Also the polynomial calibration of the sensor can decrease the root mean square error to 2.1% of the full sensing range.

In the case of a railway bridge where the ratio of live load to fixed load is relatively large, one of the main factors that dominate the bridge life is the fatigue phenomenon that occurs due to long-term accumulation by live load. Therefore, evaluating and constantly maintaining the fatigue life of cables in cable-supported bridges is an important item in ensuring the safety of bridges over their lifetime.

This paper introduces and summarizes damage cases of cable for cable supported bridges. The damage cases of similar bridge types may become an important database in the maintenance and management of cable supported bridges in the future. It will also be used as a base material for improving and developing the technology of inspection and maintenance of cable supported bridges.

Earthquake safety assessment software of the cable-stayed bridge using the seismic acceleration measurement date was developed. Various safety assessment indices for evaluation structural safety and serviceability of bridges are discussed. A systematic approach is proposed to process the raw data for generating appropriate safety assessment indicators. The software for structural state evaluation includes (i) format conversion of raw data, (ii) noise filtering, (iii) generation of assessment index, (iv) state evaluation. Determination of the limit state included in the condition evaluation step is discussed and an example of the graphic user interface of the software is shown.

In this research, experiment and simulation plans for evaluating the performance of the cables used for cable-stayed type bridges is presented. 27 cables are prepared where each of the cables are introduced with either corrosion or/and fatigue damage. Then the acquired data is analyzed with the vibration characteristics to evaluate the performance of the cables subjected to the two damage types.

This study was conducted to build an emergency action plan (EAP) for cable-supported bridges in South Korea. First, accidents happened on Cable-supported bridges were investigated and categorized based on the types. Second, accident scenarios were built-up regarding the types. Two bridges were selected for planning the emergency action following the accident scenarios. The emergency action plan established in this study could be used for the management of cable-supported bridges in the future.

A study performs estimation of fatigue safety that is considering cross-sectional loss of cable by applying foreign regulatory review. Because of steel cable-stayed bridge cable`s corrosion which is occurred after construction completion more than 30 years. Analysis result, all cable members secure fatigue safety considering cross-sectional loss of cable.

During maintenance, we closely examined the reinforced section where concrete has cracked at the time of cable installation. We confirmed that there has not been any sight of new cracks or growth of existing cracks. For the following year of Investigation, we plan to conduct close inspection of the reinforced section.

To monitor static and dynamic responses of bridges, an image-based monitoring system using networking Pan-Tilt-Zoom IP (Internet Protocol) cameras has been developed. Verification testing is carried out during the human-excited vibration test of the stay cables in a cable-stayed bridge. As well as identifying the natural frequencies of the stay cable, the reasonable damping ratios are successfully extracted from the acquired images.

This paper focuses on the vibration analysis of planar cable–driven parallel robots on their configurations. Despite of many advantages of the cable robots, elasticity of the cables may cause the vibration at the existence of external disturbance, resulting in deterioration of positioning accuracy. According to the vibration theory, having high first order natural frequency can prevent resonance with low frequency disturbance from the surrounding environment. A series of simulations showed that choosing frame / end-effector shape and cable connection method affects robots’ natural frequency. For the precise simulation, the cables are modeled as linear springs and axial vibration of cables is mainly considered. Aspect ratios of the frame and end-effector are defined as non-dimensional parameters while their areas are fixed. It was shown that vibration analysis guides to design a planar cable robot in terms of high capacity to reduce vibration.

본 연구는 현수교에 설치된 주케이블 제습시스템의 효율성에 대한 검증을 수행한 것으로서, 송기 시스템 본체, 주케이블 내부, 대기중에서 온도 및 습도 등의 데이터를 측정하여, 교량에 설치된 제습시 스템의 작동 유·무를 고려한 습도변화량 등을 분석하였다.