ISSPEA 2019: 1st International Symposium on Screw Piles for Energy Applications

Abstract

This volume forms the proceedings of the 1st International Symposium on Screw Piles for Energy Applications (ISSPEA), held at the University of Dundee, 27-28 th May, 2019. This conference is the first such event organised at the University of Dundee and was originally designed to be a small event to disseminate the findings of the EPSRC sponsored Supergen WindHub Grand Challenges project: Screw piles for wind energy foundation systems. The impetus to expand the guest list and scope of this event came after discussion with Dr Alan Lutenegger of the University of Massachusetts Amherst who organised the successful 1st International Geotechnical Symposium on Helical Foundations. Unfortunately, the eagerly anticipated 2 nd symposium in this series did not occur as planned so it was decided to partially plug this gap in screw pile innovation reporting by expanding the scope and invitees of ISSPEA. This conference has been organised by the Geotechnical Engineering Research Group at the University of Dundee representing the Screw piles for wind energy foundation systems project partners with academic teams at Durham University and the University of Southampton. The first ISSPEA provides an excellent opportunity for academics, engineers, scientists, practitioners and students to present and exchange the latest developments, experience and findings in screw pile engineering for renewable energy applications. The proceedings contains 12 papers and 9 extended abstracts with the latter representing the presentations made at the event that were not supported by a full paper. The proceedings contain one invited keynote paper from Alan Lutenegger on the current state-of-understanding of the engineering behavior of screw piles and helical anchors. This paper presents an overview of historical applications of screw piles, with discussions on aspects of their design and behaviour which are both understood and in need of further research, using case studies as examples. Other papers in the proceedings look at a variety of topics including: installation requirements and effects; cyclic behaviour; advanced numerical modelling of screw piles, including the use of DEM and MPM to incorporate installation effects into the models; and screw piles used in industrial applications. It is hoped that this proceedings and symposium will lead to similar future meetings and serve as a useful indicator of the current state of innovation and deployment. It is also hoped the event and proceedings will act as the springboard for new lines of research and development and increased use of screw piles for a variety of applications. We are grateful to all the authors and reviewers for their efforts in the preparation of the papers. Finally, the Organisers would like to acknowledge the support and efforts of the Local Organising Committee, paper reviewers and the support of our industrial partners.

Effects of screw pile installation on installation requirements and in-service performance using the discrete element method

“…This is due to the value representing the interaction of a single spherical particle on the surface of the pile with, with the rotation of the particle being restricted in order to model the rolling resistance of the angular soil particle. The calibrated contact models were further validated, by modelling the pitch-matched installation of the O2VD screw pile from Davidson et al (2019). The O2VD screw pile is a dual helix screw pile, with an optimised central core (lower shaft has a smaller diameter than the upper shaft) and is drastically different to that of the straight shafted pile used for the previously described calibration purposes.…”

“…These are outlined in Table 1 (Sharif et al 2019a). The sand modelled in the simulations is based upon the properties of HST95, which is a medium to fine well-graded sand that is commonly used at the University of Dundee in physical modelling (Davidson et al 2019) and element testing. The particle size distribution (PSD) is the same as that of HST95 sand (see Table 1) and can be seen in Lauder (2010).…”

“…Applied vertical force or "crowd" is also not recorded therefore it is very difficult to investigate the effects of installation from current practice. Part of the motivation for investigating screw pile installation has been the development of silent offshore piling techniques for renewable energy deployment, and in particular as an alternative foundation type for offshore wind and floating future wind (Davidson et al 2019(Davidson et al , 2020. To achieve this, significant upscaling of typical onshore screw piles is required, resulting in quite different geometry.…”

“…To achieve this, significant upscaling of typical onshore screw piles is required, resulting in quite different geometry. Davidson et al (2019) showed that screw piles capable of supporting a typical four-legged offshore jacket structure would require significant installation torque to install (7MNm) and very high vertical compressive forces to achieve pitch-matched installation (23MN). As part of this work an insitu cone penetration test (CPT) method was developed to allow prediction of both installation torque and crowd for various geometries of screw piles with pitch-matched installation (Davidson et al, 2018(Davidson et al, , 2020.…”

Linking the installation response of screw piles to soil strength and ultimate capacity

“…The content of this paper was first presented at the 1st International Symposium on Screw Piles for Energy Applications in Dundee, Scotland on May 27-28, 2019, the proceedings of which include an extended abstract that reproduces a small portion of this work (Hambleton and Stanier 2019). This work could not have been completed without enabling financial support from the Australian Research Council (ARC) and the National Science Foundation (NSF), in particular through ARC award numbers CE110001009 and DE160100328 and NSF award number CMMI 1846817.…”