OasisLMS

Abstract:

Test pile programs, with both dynamic and static load tests, are often specified for large or complex pile foundation projects.  These programs provide valuable information that allow for optimization of the foundation.  However, they have high costs and require a significant time commitment.  A successful test pile program is customized with respect to the expected outcomes, and there are many considerations to enhance the test pile program.

The first step is to determine whether there is a need or benefit to a test pile program.  Following that, the appropriate quantities of static and dynamic test piles should be determined.  Dynamic testing is the quicker and more economical testing option, and should be relied on in advance of static load test piles.  Indicator or reaction piles should be dynamically tested before the static test piles.  This allows for a targeted final penetration and/or driving resistance for the static piles. Also, static test piles must be installed with the highest consideration of location and alignment tolerances.  Piles that have shifted, rotated, or have a batter will lead to issues during static load testing.

 Test piles should be installed with a goal of geotechnical failure during static load testing.  A pile that fails at less than the required capacity provides more information than a pile that cannot achieve the full geotechnical capacity.

Multiple restrikes may be specified but should only do so with consideration of the outcome.  Restrikes must be performed at a time interval as close to the interval between installation and static load testing, in order to obtain correlation between the two test methods.  One short restrike interval and one “long term” interval will often provide a setup profile.  Any additional restrikes should serve a specific purpose.  Restrikes only provide a benefit when the pile can be fully mobilized, which may require larger hammers or drop weight systems for restrikes.

The author’s intent is to provide an overview of the steps that should be considered for a successful test pile program, as well as pitfalls to avoid and extraneous testing to eliminate.  Data from test pile programs will be used to support the overview.