Real-time seismic vulnerability assessment of a high rise RC building using field monitoring data

In the framework of EU funded REAKT project (http://www.reaktproject.eu/) we evaluate the “realtime” seismic vulnerability of one of the main buildings of the most important hospital in Thessaloniki (AHEPA) using field monitoring data. The target building is an eight-storey RC structure composed by two units connected through a structural joint. The assessment of the dynamic characteristics is performed using ambient noise measurements recorded by a temporary seismic network installed inside the structure. System identification methods, namely the Frequency Domain decomposition and the Stochastic Subspace identification, are applied to perform operational modal analysis and extract the natural frequencies and mode shapes of the structural system. The modal identification results are used to update and better constrain the “initial” finite element model of the building, which is based on the available design and construction documentation plans. For both initial and updated finite element models, three-dimensional incremental dynamic analysis is performed to evaluate the actual seismic performance of the hospital building. Fragility curves are derived in terms of outcropping peak ground acceleration (PGA) for the immediate occupancy (IO) and collapse prevention (CP) limit states for the initial “as built” model and for the real structures as it is nowdays.