01-0006 Experimental Investigation and Retrofit of Steel Pile Foundations and Pile Bents Under Cyclic Lateral Loadings A.A. Shama, J.B. Mander, B.B. Blabac and S.S. Chen 2001 University at Buffalo 262 PB2002-107950 35 This research investigated the performance and retrofit of bridge pile-to-cap connections that are representative of construction in the eastern and central United States. Both the seismic vulnerability of existing pile cap connections, where the embedment depth of the pile inside the cap beam is small and the seismic design requirements for strong cap beam-to-pile connections for new construction and retrofit of existing structures are considered. Two simplified theoretical concepts were developed to predict the connection behavior under different lateral and axial load patterns. These concepts were then compared to rigorous finite element analysis that validated the simplified limit theories. On the basis of these theories, design guidelines and retrofit strategies for these connections were proposed. Seismic performances. Pile-to-cap connections. Steel pile foundations. Steel pile bents. Fatigue life models. Bridges.