Experimental Studies on Seismic Behavior of Steel Pile-to-Pile-Cap Connections

To investigate the seismic behavior of bridge pile-to-pile-cap connections, five full-scale H-shaped steel pile-to-pile-cap connection subassemblies representing a portion of a typical bridge pile foundation were tested. Two of the full-scale subassembly specimens were subjected to a vertical cyclic load simulating axial forces in a pile caused by footing overturning during an earthquake attack. Two others were loaded with cyclic lateral force and constant vertical load. One specimen was tested under proportionally varied vertical and horizontal forces. It was found that, although it was designed as a pinned connection following the current design standard, the pile-to-pile-cap connection can sustain a significant amount of moment. Localized brittle failure was observed in the vicinity of the pile-to-pile-cap connection, as the results of unexpected moment resistance. Test results also showed that the anchorage details using two V-shape bars could not develop the full-design ultimate tensile capacity. Analytical methods are developed and found adequate to evaluate the strength of the pile-to-pile-cap connection.