It is very important to determine eigen-values before and after certain extreme events that may cause damage accumulation such as earthquake, blasts, mining or seismic tests on research models. Unique experiment design and shake table testing was performed to investigate seismic performance of a 3D RC building model with infill walls and advanced protection with polyurethane-based joints and fiber polymer reinforced light and emergency jackets. For the purpose of a wider experimental activities three methods for determination of the dynamic characteristics were used during multiple successive shake table tests following a dynamic pushover approach and are presented in detail. They are Inertance function through impact hammer tests, standard Fourier transformation of measured acceleration time history and digital image correlation. The expected differences in the results are related to the type and intensity of excitation used, the involvement of materials with different mechanical and physical properties and with different rate and extend of damage accumulation, as well as local or global measurements. Yet, all methods lead to reliable results when a consistent methodology is being used, that takes into account locality or globality of measurements, leaving a choice for the most suitable depending on the site conditions. The presented inertance function method manifested its high efficiency in analysis of dynamic properties of large-scale structures and in monitoring of their changes caused by damage and repair process. It offers quite wide range of useful information, does not require very expensive equipment and its transportation cost is negligible. This method seems to be a proper diagnostic tool for simple experimental modal analysis of real structures and their structural elements, where detection of changes in structural condition and in dynamic properties is required, also as a non-destructive testing and monitoring method. The Digital image correlation proved to be a promising non-contact tool, strongly supporting the conventional instrumentation of shake table testing, while the Fourier transformation was used as a benchmark method yielding the most reliable results.
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