Modal identification and finite element model updating of guangzhou new TV tower

Abstract

Structural health monitoring (SHM) is a novel field of research in civil engineering. It emerges from the needs to assess the safety and interiority of civil infrastructure, prolong the service life, and prevent catastrophic failure of the structure. The damage of the structure is inferred by comparing the modal properties identified from the measurement with those obtained from the baseline finite element (FE) model. FE model updating aims to increase the accuracy and reliability of the FE model, which is essential for the success of diagnostic and prognostic of the structure. This thesis analyzed the monitoring data on Guangzhou New TV Tower of 610m tall, which was furnished as an international benchmark problem by the Hong Kong Polytechnic University. Modal properties of the tower were successfully identified using frequency domain decomposition and stochastic subspace identification methods. A fair agreement the modal properties between the measurement and FE model was found, although still raised a need to update the FE model. A numerical simulation and FE model updating using real measurement data were performed. The results showed that the model updating process significantly reduced the differences between the modal properties of the updated FE model and the measurement. Some critical issues in FE model updating were attempted to consider: the choice of grouping, the random noise effect of the measurement, and the over-fitting problem of the updating parameters. Regularization term provides the parameters with smaller changes without scarifying the accuracy in the modal properties, which is more feasible to the real condition of the tower.