Abstract:
In the Pacific Northwest, piles for bridges in mountainous terrain are often required to have a minimum embedment for lateral resistance due to high seismic demands and scour protection purposes. Due to the presence of cobbles and boulders, piles often need to be advanced by drilling followed by impact driving to avoid early refusal. Open-ended steel pipe piles in granular soils often fail to plug during such installation. This can result in excessively long piles to achieve the termination criteria and corresponding required geotechnical resistance. Plugging of piles can be induced using either an internal diaphragm plate or a concrete plug of limited length. This paper will review the results of high-strain dynamic testing (HSDT) completed on piles with concrete plugs along with a discussion on the challenges related to signal matching. The paper will attempt to provide general, yet preliminary, guidance on the construction, dynamic testing and signal matching. Finally, the paper will also include a discussion on the benefits of plotting multiple measured signals on top of each other (“stacking”) to evaluate and compare the quality of the measured signals and the performance of the piles before and following installation of the concrete plug.