Case Study: Lateral Pile Testing for Seismic Design in Unexpected Soil Conditions

This paper documents unplanned lateral pile tests that were performed in support of the recent replacement of Pier 8 at Naval Base San Diego. Lateral design of the pier was governed by seismic loading. Design parameters were initially based upon the results of a soil exploration program provided with the request for proposal (RFP), with the intent that the recommendations for vertical capacity would be confirmed by the results of a test-pile program. However, these results were unexpected, indicating soils with significantly lower capacity than anticipated. Although it was determined that the required vertical capacity was achievable, a significant degree of uncertainty in the lateral performance of the pier remained. In order to address these concerns, a lateral-load-testing program for the existing test piles was developed. The methodology, results, and design application of the lateral testing is presented in this paper, providing a reference for other design professionals encountering similar challenges.