ANALYSIS MODEL OF PILE-TO-PILE MECHANICAL CONNECTOR FOR SCREW PILES

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Screw piles consist of hollow steel pipe with one or more helical bearing plates welded to the pipe. They are installed by applying a downward force and a turning moment to the head of the pile, "twisting" the pile into the soil. Extensions to the original length of the pile are often needed to reach soil layers with sufficient load-bearing capacity. A common solution to pile extensions are welded connections. However, welding often entails an excessive amount of down-time during construction due to the required supervision of the welds by a specialist, making the process expensive. A new type of mechanical connector for use in pile extensions has been recently developed by Almita Piling Inc. The new connector represents a cost-effective alternative to welding, facilitating a rapid and efficient pile installation process. Almita Piling Inc. is interested in validating the design of the connector through a 3D finite-element analysis model. A robust, rigorous 3D model will be developed at the University of Alberta using state-of-the-art finite-element software. The model will be validated using experimental results from "in-air" tests conducted by Almita Piling Inc. The analysis model will be used to better understand the structural performance of the pile-to-pile connection, the load path through the coupler, the response of the mechanical connector under combined stresses, and to identify regions with high stress concentrations that potentially would lead to failure of the connector. Once validated, the model will be used to conduct a parametric analysis that includes studying the influence of different geometric details and material properties on the performance of the connector. Almita Piling Inc. will benefit from the analytical evidence generated in this study by showing that the connector performs as designed, and that it can be used safely for a wide range of pile sizes. Using the mechanical coupler instead of welded connections will be more cost-effective for Almita Piling Inc, allowing the company to offer its services more competitively, to reach new market areas, and to increase its business volume.