PSI - Issue 64

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Cevdet Enes Cukaci et al. / Procedia Structural Integrity 64 (2024) 531–538 Cukaci and Soyoz / Structural Integrity Procedia 00 (2024) 000 – 000 Cukaci and Soyoz / Structural Integrity Procedia 00 (2024) 000 – 000 Cukaci and Soyoz / Structural Integrity Procedia 00 (2024) 000 – 000

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Fig. 3 Vision-based modal identification algorithm. Fig. 3 Vision-based modal identification algorithm. Fig. 3 Vision-based modal identification algorithm.

Fig. 4 illustrates how the dynamic response of the cables is measured through a vision-based system, which indirectly estimates cable tension using vibration method. Videos are first converted into successive JPG images. The first image is determined as reference. ROI window is established in the reference frame considering potential cable deformations. The control point and the ROI's dimensions on the cable's HDPE sheathing are manually selected within the video, focusing on the cable's midpoint to accurately capture its dynamic behavior. To enhance the resolution, a second-order polynomial function refines the accuracy at the pixel level. Displacement is then calculated by comparing each point's pixel location to the reference point. By correlating pixel size to the actual structural dimensions, these measurements can be converted from pixel units to real-world distances. The ROI maintains a consistent position and size across all frames, allowing for the continuous assessment of the cable's dynamic response. From these measurements, PSDs are calculated. The peaks of these PSDs reflecting the cable's natural frequencies and its physical characteristics are used to estimate cable tension with the vibration method. These cable tensions are then validated by comparing the cable tensions from the bridge's existing monitoring system, demonstrating their reliability (Kim et al., 2023). Fig. 4 illustrates how the dynamic response of the cables is measured through a vision-based system, which indirectly estimates cable tension using vibration method. Videos are first converted into successive JPG images. The first image is determined as reference. ROI window is established in the reference frame considering potential cable deformations. The control point and the ROI's dimensions on the cable's HDPE sheathing are manually selected within the video, focusing on the cable's midpoint to accurately capture its dynamic behavior. To enhance the resolution, a second-order polynomial function refines the accuracy at the pixel level. Displacement is then calculated by comparing each point's pixel location to the reference point. By correlating pixel size to the actual structural dimensions, these measurements can be converted from pixel units to real-world distances. The ROI maintains a consistent position and size across all frames, allowing for the continuous assessment of the cable's dynamic response. From these measurements, PSDs are calculated. The peaks of these PSDs reflecting the cable's natural frequencies and its physical characteristics are used to estimate cable tension with the vibration method. These cable tensions are then validated by comparing the cable tensions from the bridge's existing monitoring system, demonstrating their reliability (Kim et al., 2023). Fig. 4 illustrates how the dynamic response of the cables is measured through a vision-based system, which indirectly estimates cable tension using vibration method. Videos are first converted into successive JPG images. The first image is determined as reference. ROI window is established in the reference frame considering potential cable deformations. The control point and the ROI's dimensions on the cable's HDPE sheathing are manually selected within the video, focusing on the cable's midpoint to accurately capture its dynamic behavior. To enhance the resolution, a second-order polynomial function refines the accuracy at the pixel level. Displacement is then calculated by comparing each point's pixel location to the reference point. By correlating pixel size to the actual structural dimensions, these measurements can be converted from pixel units to real-world distances. The ROI maintains a consistent position and size across all frames, allowing for the continuous assessment of the cable's dynamic response. From these measurements, PSDs are calculated. The peaks of these PSDs reflecting the cable's natural frequencies and its physical characteristics are used to estimate cable tension with the vibration method. These cable tensions are then validated by comparing the cable tensions from the bridge's existing monitoring system, demonstrating their reliability (Kim et al., 2023).

Fig. 4 Summary of algorithm. Fig. 4 Summary of algorithm. Fig. 4 Summary of algorithm.

4. Definition of the Komurhan Cable-stayed Bridge and monitoring system The bridge is different from the typical cable-stayed bridges in the world with its single inverted Y-shaped pylon and single span. It is 660 meters long and 168.5 meters high. The structure is composed of an approach viaduct, the main span, and a back span anchorage block, measuring 100, 380, and 180 meters long respectively. On each side of the pylon, there are 21 cables. The general overview and longitudinal section with the cable arrangement of the bridge are illustrated in Fig. 5 (Yüksel Project Inc. Wiecon Co. Doğus and Gülsan Co., 2012) . 4. Definition of the Komurhan Cable-stayed Bridge and monitoring system The bridge is different from the typical cable-stayed bridges in the world with its single inverted Y-shaped pylon and single span. It is 660 meters long and 168.5 meters high. The structure is composed of an approach viaduct, the main span, and a back span anchorage block, measuring 100, 380, and 180 meters long respectively. On each side of the pylon, there are 21 cables. The general overview and longitudinal section with the cable arrangement of the bridge are illustrated in Fig. 5 (Yüksel Project Inc. Wiecon Co. Doğus and Gülsan Co., 2012) . 4. Definition of the Komurhan Cable-stayed Bridge and monitoring system The bridge is different from the typical cable-stayed bridges in the world with its single inverted Y-shaped pylon and single span. It is 660 meters long and 168.5 meters high. The structure is composed of an approach viaduct, the main span, and a back span anchorage block, measuring 100, 380, and 180 meters long respectively. On each side of the pylon, there are 21 cables. The general overview and longitudinal section with the cable arrangement of the bridge are illustrated in Fig. 5 (Yüksel Project Inc. Wiecon Co. Doğus and Gülsan Co., 2012) .

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Fig. 5 (a) general view; (b) longitudinal view of the Komurhan Cable-stayed Bridge. Fig. 5 (a) general view; (b) longitudinal view of the Komurhan Cable-stayed Bridge. Fig. 5 (a) general view; (b) longitudinal view of the Komurhan Cable-stayed Bridge.