High strain drop weight dynamic load testing is an effective tool when evaluating the construction quality and axial capacity of offshore drilled deep foundations. This is a result of the complexity and cost of the alternative conventional static load tests. Drop weight systems can be designed for project specific needs, providing sufficient energy to mobilize the required resistance while permitting ease in transporting the device. Test shafts/piles can be instrumented and analyzed using the same dynamic testing techniques used for driven pile foundations. A case study is presented where drop weight dynamic load tests were utilized for offshore drilled shaft foundations. The project includes the design, construction, and quality control for a cement unloading pier at the Tema port in Ghana, Africa. The foundations are unique, consisting of 0.8m outer diameter steel pipes embedded in 1.0m rock-socketed drilled shafts. Three dynamic load tests to failure and six load verification tests were performed offshore. The load verification tests were carried out due to construction difficulties and/or complex subsurface conditions. The piles' integrity and mobilized resistances were assessed using the signal matching analysis software CAPWAP. The underlying assumptions in the one-dimensional wave equation formulation on which CAPWAP is based are violated in these complex cases. Finite element analyses were therefore performed using the PLAXIS 2D software in order to examine the validity of the one-dimensional wave equation application under such conditions. This paper briefly describes the project, the associated difficulties, the unique foundations, example load tests and their analyses, as well as some initial processing in examining the validity of the one-dimensional wave equation analyses under the tested conditions.
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