vibration-based tension force estimation of external post-tensioned tendons: experimental study

Tendon tension loss is one of the most important damages of pre-stressed, cable stayed and suspension bridges. in this experimental study, vibration based method have been implemented for tension estimation of mono-strand externallytendon. the test has been done in iiees structural laboratory. in order to identify the natural frequency of system, three methods have been used and their results were compared: 1) fast fourier transform (fft); 2) frequency domain decomposition (fdd) and 3) stochastic subspace identification (ssi) as output-only system identification methods. afterderivation of natural frequencies of vibration from output measurements, using numerical pre-determined formula of string theory is achieved and compared to the exact amounts of tension in tendon experiment setup. the obtained results show the ability of vibration based method to estimate tension loss of external tendons.