Outdoor Test of a Prefabricated Column-Pile Cap-Pile System under Combined Vertical and Lateral Loads

An outdoor test was conducted on a prefabricated column-pile cap-pile system at a cohesive soil site. The half-scale test unit consisted of a precast bridge column, a precast pile cap, and eight steel piles. The components were connected utilizing socket connections that were preformed in the pile cap with corrugated steel pipes. To evaluate the system performance and the behavior of various connections, the test unit was subjected to combined vertical and lateral loads at service conditions as well as at conditions representing extreme events. The test unit remained undamaged under the loads representing the service conditions, and a plastic hinge was formed in the column under loading conditions representing a seismic event. The column connection and pile connections exhibited excellent behavior as they maintained fixity with the formation of a column plastic hinge. The outdoor test demonstrated that up to 40% of column top displacement was produced by foundation flexibility at the service conditions. The description of the outdoor test and key results are included in this paper.