2019 Volume 17 Issue 8 Pages 474-488
Damage of PC tendons in a prestressed concrete structure need to be detected before such damage accumulates to cause a serious failure. That, however, is quite a difficult task because the PC tendons are invisible from outside and the damage location cannot be known beforehand. Phase space analysis based on vibration data is a novel method for damage detection. An earlier study by the authors demonstrated that Change of Phase Space Topology (CPST) was effective in identifying the existence of PC tendon damage. However, CPST from impact hammer test, which is a more practical method, did not show a trend as obvious as that of the free vibration test. As it is known that PC tendon damage affects several modes of vibrations and that the hammer can be used for excitation to the higher modes, it may be possible to improve the capability of impact hammer test by considering CPST separately in different frequency ranges. As in the previous study, the current study conducted experiments on PC tendon damage, but with an increased number of accelerometers for constructing mode shapes and investigated CPST further in different frequency ranges. The results still revealed that CPST was more sensitive to damage than the parameters from modal-based analysis. CPST in different frequency ranges can improve results from impact hammer test and has the capability to identify roughly the damage locations.