Post-seismic Structural Health Monitoring of a Column Subjected to Near Source Ground Motions

This study reports on the results acquired from shaking table tests of a column subjected to progressively increasing amplitudes of seismic motions recorded during the Northridge earthquake. Scope of the investigation includes application and evaluation of deterministic structural health monitoring methods to assess the post-seismic conditions following application of the various amplitudes of earthquake motions. Results from this study demonstrate the applicability of specially designed surface-adhered fiber optic sensors for detecting the formation and the progression of cracks subjected to reverse dynamic loads, as well as application of various SHM techniques for evaluation of damage. The range of damage identification methods evaluated comprises of simple frequency and damping analysis of the column under free vibrations, and modal analysis techniques including curvature mode shapes. The concept of strain mode shape analysis, which was previously established for dynamic analysis of structures, is also introduced here for damage identification. Evaluation of the SHM techniques involves efficiency in terms of the number of sensors required to investigate the progression of damage, and resolution in terms of damage identification both in terms of location as well as the state of the damage.