Use of Modal Flexibility for Damage Detection and Condition Assessment: Case Studies and Demonstrations on Large Structures

Displacement coefficients and profiles are presented as promising kernel condition and damage indices along with real-life examples. It is shown that dynamic tests, which do not require stationary reference measurement locations, can also be used to generate data for the computation of modal flexibility. Modal flexibility can then be employed to obtain the displacement profiles. It is also shown that the modal flexibility can be obtained from the frequency response function measurements of the structures. Problems such as environmental effects on measured data and limitations such as incomplete dynamic measurements, spatial and temporal truncation effects are commonly faced in damage detection and condition assessment of real structures. Possible approaches to mitigate these obstacles are discussed. The level of variation and the uncertainty that may be expected when displacement coefficients are extracted from real civil infrastructure systems are also presented. The methods are demonstrated on two real-life bridges and the findings are validated by independent test results.