Effects of measuring techniques on the accuracy of estimating cable tension in a cable-stay bridge

Nowadays, many methods have been employed to estimate the cable tension in a cable-stayed bridge. In these methods, the non-destructive test has a widespread application thanks to its feasibility and effectiveness. The vibration-based approach determines the cable tension based on natural frequency. In fact, there are many factors that can influence the tension values. Some of them are derived from objective factors, others from subjective factors. In this paper, a subjective issue, so-called measurement technique, is studied. A cable, without fillings between the HDPE duct and strands, is the main object of this study. In the first step, some scenarios related to the placement of sensors are conducted. The former considers the tension between different positions of sensors, directly and indirectly contact conditions with strands, under the ambient and pulling-rope excitation. The latter takes into account the directions, out-of-plane and in-plane, of sensor placement on the strands or HPDE duct. In the next step, the relationship between the force and frequency is utilized to identify the mean tension of the cable. In the finally step, results of cable tension estimation are compared with the real-time monitoring and finite element (FE) simulation. From the comparison, the effects of measuring technique in situ are discussed in the conclusion