Cable tension estimation of cable-stayed bridge using vision- based monitoring system

Abstract

In this study, it is aimed to estimate the cable tensions of the New Kömürhan Cable-stayed Bridge using a vision-based monitoring system. The number of structures where cables are used as main load carrying members is increasing with the development of material properties, analysis, and construction processes. Structural Health Monitoring (SHM) is necessary to ensure operational and structural safety and integrity. The estimation of the cable tensions is one of the most important factors in early detection of deterioration and damage. Fatigue damage caused by cyclic traffic and wind loads, corrosion due to environmental factors, and sudden earthquake loads cause a decrease in cable tensions, which affects the overall performance of the structure. In this study, cable tensions were determined using the lift-off test and the vibration response under seismic events recorded by existing acceleration sensors on the bridge. The image processing technique was developed through experiments, two of which were conducted in the laboratory and two in the field. Then, cable tensions were estimated by vision-based methods using video. In the first two methods, only 8 of 42 cables are continuously monitored; on the other hand, all cable tensions were estimated with the vision- based monitoring system and gave consistent results compared to 8 cables. In the last part of the study, Finite Element Model (FEM) of the bridge was developed and verified by comparing cable tensions obtained from FEM and measurements. Additionally, pylon and deck frequencies of verified FEM match with those obtained from vibration records.