Health assessment of structures exposed to seismic excitations

The health assessment of existing infrastructure just after an earthquake is a very important but challenging task. Even engineered structures can suffer significant damage(s) due to seismic excitations. To ensure public safety and to maintain the economic activities of the surrounding communities, structural health needs to be assessed promptly following an earthquake. Two novel structural health assessment procedures are under development at the University of Arizona. They are known as the modified iterative least-squares with unknown input (MILS-UI) and generalized iterative least-squares extended Kalman filter with unknown input (GILS-EKF-UI) techniques. These procedures are finite-element based time domain system identification (SI) techniques, which are capable of identifying structures at the element level by using only the dynamic response information. These procedures have been extensively verified by using the numerically simulated and laboratory measured response information, as obtained for the defect-free and defective frames under sinusoidal and impulsive excitations. The health assessment of the same defect-free and defective frames by using the numerically simulated response information under seismic excitations is presented here.