• Journal of the Korea Academia-Industrial cooperation Society
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• 제17권2호
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• pp.220-226
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• 2016

Because MS(Multi-Strand) cables consist of many strands, a jacking force is applied to each strand one by one for cable construction. All strands should have an equal tensile force when the last one is wedged. This is the core technology for MS iso-tensioning. In this study, a new MS cable iso-tensioning system was developed for controlling and jacking the high-strength strands, with an ultimate tensile strength of 2,200MPa, for a stay cable of extra-dosed/cable-stayed bridges. The newly developed iso-tensioning system consists of electrical resistance load cells, hydraulic jacking devices, hydraulic pumps, and integrated controllers. Moreover, it is embedded with an algorithm that can control and predict the variations in tensile forces of the Master and Slave strands in real time. Actual experiments were carried out to verify the function and performance of the newly developed system. This system was applied successfully to the stay cable construction of 2nd Tae-in extra-dosed bridge in Gwangyang.

• Journal of Korean Society of Steel Construction
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• 제19권5호
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• pp.435-454
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• 2007

In this study, we demonstrated the characteristics of the near-fault ground motion thatwas not considered in the domestic seismic design code and how the effect of the near-fault ground motion affects the response of cable-stayed bridges. Afterselecting the actual measurement records of the typical near- and far-fault ground motion, the characteristics of ground motion is analyzed using the elastic and inelastic response spectrum. Analyzing the response regarding the earthquake's characteristics on cable-stayed bridges by the typical three-type cable-stayed bridges and the actual cable-stayed bridge, the characteristics of responses about main members are compared and analyzed. Moreover,reliability analysis is accomplished using the results of the seismic response analysis, and the seismic safety of the cable-stayed bridges is evaluated quantitatively as a reliability index and probability of failure. According to the results of the response spectrum, the earthquake response analysis and the reliability analysis, because the effect of the near fault ground motion against the response of cable-stayed bridges is different from the effect of the existing far-fault ground motion, it should be considered as an important factor when designing cable-stayed bridges.

• Journal of the Korean Society of Industry Convergence
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• 제25권5호
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• pp.773-782
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• 2022

Estimation of cable tension through proper measurements is one of the essential tasks in evaluating the safety of cable structures. In this paper, a study on cable tension estimation using the built-in accelerometer and camera in a smartphone was conducted. For the experimental study, visual displacement measurement using a smartphone camera and acceleration measurement using a built-in accelerometer were performed in the cable-stayed bridge model. The estimated natural frequencies and transformed tensions from these measurements were compared with the theoretical values and results from the normal visual displacement method. Through comparison, it can be seen that the error between the method using the smartphone and the normal visual displacement is sufficiently small to be acceptable. It has also been shown that those errors are much smaller than the difference between the values calculated by the theoretical model. These results show that the deviation according to the type of measurement method is not large and it is rather important to use an appropriate mathematical model. In conclusion, in the case of cable tension estimation, it can be said that the visual displacement measurement and acceleration using a smartphone can be a sufficiently applicable method, just like the normal visual displacement method. It is also noteworthy that the smartphone accelerometer has a larger magnitude error and has more limitations such as high-frequency sampling instability compared to the visual displacement method, but shows almost the same performance as the visual displacement method in this cable tension estimation.

• Journal of the Korea institute for structural maintenance and inspection
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• 제13권2호통권54호
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• pp.129-136
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• 2009

The paper presents an algorithm of selecting optimal locations for measuring displacements(OLD) to adjust cable tension forces during the construction of cable-stayed bridges. The rank for optimal locations can be determined from the effective independence distribution vectors(EIDV) that are computed from the Fisher Information Matrices(FIM) formulated with the displacement sensitivities. To examine the efficiency and reliability of the proposed algorithm for determining OLD, a simulation study on a cable-stayed bridge has been carried out. The results using FIM formulated with displacements are compared with those using FIM with displacement sensitivities through the simulation study. The effects of measurement noise and error in cable length on the adjustment of cable tension forces are evaluated statistically by applying the Monte Carlo scheme.

• Structural Engineering and Mechanics
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• 제59권3호
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• pp.387-401
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• 2016

This paper takes a half-through steel truss arch bridge as an example. A seismic analysis is conducted with nonlinear finite element method. Contrast models are established to discuss the effect of simplified method for main girder on the accuracy of the result. The influence of seismic wave direction and wave-passage on seismic behaviors are analysed as well as the superstructure and arch ring interaction which is mostly related with the supported bearings and wind resistant springs. In the end, the application of cable-sliding aseismic devices is discussed to put forward a layout principle. The main conclusions include: (1) The seismic response isn't too distinctive with the simplified method of main girder. Generally speaking, the grillage method is recommended. (2) Under seismic input from different directions, arch foot is usually the mostly dangerous section. (3) Vertical wave input and horizontal wave-passage greatly influence the seismic responses of arch ring, significantly increasing that of midspan. (4) The superstructure interaction has an obvious impact on the seismic performance. Half-through arch bridges with long spandrel columns fixed has a less response than those with short ones fixed. And a large stiffness of wind resistant spring makes the the seismic responses of arch ring larger. (5) A good isolation effectiveness for half-through arch bridge can be achieved by a reasonable arrangement of CSFABs.

• Computational Structural Engineering
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• 제27권2호
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• pp.55-59
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• 2014

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.394-395
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• 2009

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2010년도 추계학술대회 논문집
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• pp.138-139
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• 2010

• Magazine of the Korea Institute for Structural Maintenance and Inspection
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• 제17권3호
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• pp.6-17
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• 2013

• Magazine of the Korea Concrete Institute
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• 제18권1호
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• pp.62-70
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• 2006