Detection of infill wall damage due to earthquakes from vibration data

Vibration-based methodologies are nowadays gaining increasing application for the structural health monitoring and damage detection on buildings, especially damage due to earthquakes. A fast and efficient damage recognition on structural and non-structural components can support the decision-making process after exceptional events and may contribute to reduce troubles due to the inoccupancy of buildings. The paper offers insights on the usefulness of vibration data for the damage detection in infilled frame structures starting from the tracking of the stiffness and modal properties of an infilled laboratory steel-concrete composite mock-up subjected to vibration-based tests. The mock-up has been object of an extensive experimental campaign that involved both quasi-static cyclic and dynamic tests characterized by different level of excitation provided to the structure. Cyclic load tests are performed to simulate the effects of earthquakes by progressively increasing the imposed displacement to the cracking and then to the failure of infills. The dynamic tests are executed at the various steps to capture the effects of the infill damage on the global dynamic response triggered by excitations of different amplitudes. Results of dynamic and quasi-static tests are used to correlate the infill damage with the mechanical properties and the modal parameters of the mock-up, as well as with the vibration amplitude, providing information about the damage expected during low and moderate seismic events as a function of the registered dynamic response of the building by structural health monitoring systems.