Lateral response of single and groups of fixed head piles

Being a fundamental part of the family of soil-structure interaction (SSI) engineering problems, soil-piled foundation-structure interaction constitutes an important part of everyday practice in civil, structural, and geotechnical engineering. While the behavior of the system under gravity conditions are rather well consolidated, estimation of ultimate lateral capacity is still often disregarded. As a current state of practice, there are already well-developed complete methodologies based on p-y curves that are able to predict with a good accuracy the whole response of single piles (e.g. Naggar and Bentley, 2000). Furthermore, p-y curves approach is already implemented into various design guidelines (e.g. ASCE Guidelines, 1984). The group effects on each pile (taking into account of “shadowing effects”) in piled foundations are traditionally represented by p-multipliers (e.g. Brown et al., 1988). In this thesis, first a numerical campaign of laterally loaded pile groups with fixed head conditions, and hybrid model is presented. By means of commercial code FLAC3D (continuum model) and SeismoStruct2018 (p-y curve approach model), responses of single piles as well as the foundations are thoroughly studied and verified by considering a variety of different geometrical and constitutive parameters. As the outcome, a compilation of foundation group efficiency factors is assembled based on the results of the numerical analyses. Then, a simple-to-apply design method in the estimation of foundation group efficiency factor is proposed, which is based on the extension of classical Broms method. Comparisons of foundation group efficiency factors computed through theoretical and numerical means show reasonably close agreement. Finally, a worked example regarding the application of the proposed simplified method is implemented in a spreadsheet.