Postearthquake Analysis of a Piled Foundation: Fid-Bau Portal

Postearthquake Analysis of a Piled Foundation

Castelli, Francesco / Maugeri, Michele

Abstract

On December 13, 1990, a moderate earthquake ( $M_{L} = 5.4$ and MKS intensity equal to VII) struck the southern part of eastern Sicily causing intense damage in some localized areas and the loss of 19 human lives. At Augusta, which has soft-soil conditions, amplification phenomena were observed, and RC frame buildings based on piles were severely damaged. Because seismic regulations were not enforced in the area during construction, the buildings were designed only for static loads. An investigation was conducted on the superstructures, soil, and piled foundations for evaluating the potential to repair and retrofit these buildings. The site has been subjected to extensive soil investigations. Loading tests on single piles and a three-pile group were conducted to test the integrity of the piles after the seismic event. To simulate the behavior of piles subjected to both inertial and kinematic effects resulting from the earthquake, a pseudostatic pushover analysis was carried out. Seismic loading was evaluated by a deterministic approach based on accelerograms measured during the earthquake. Because the load-bearing capacity of the existing foundation was insufficient to resist the design seismic loading, retrofitting of the piled foundation required the enlargement of the foundation and new bored piles.