AS 2159-2009 requires that piles are designed to satisfy the inequality that resistance is greater than applied load at both the Ultimate Limit State (ULS) and the Serviceability Limit State (SLS). It is clear that, especially for rock socketed piles, the SLS may control, and this was acknowledged back in 1998 by Pells et al who gave values for end bearing pressure at the SLS that were 5 to 10 times lower than the end bearing pressures for ULS, when the loads would typically be only 1.3 to 1.5 times less. Thus, it is important to be able to predict pile performance.
Examples will be given from international experience, where pile load testing to provide the necessary data is far more common, and also from the Gateway Upgrade. In addition reference will be made to Pile Prediction events, which are “games” played by some geotechnical engineers, to predict the performance of piles during a static load test, before the test has been carried out, based on provided geotechnical data.
I have been involved in one in Edmonton, Canada in 2011, another in Santa Cruz, Bolivia in 2013, one in Santa Catarina, Brazil in June 2015, and a second one in Santa Cruz, Bolivia also in June 2015, and a third one planned for Santa Cruz, Bolivia in February 2017. The results will be presented and discussed.
About Stephen Buttling
Stephen Buttling graduated from Imperial College and studied for a PhD at Bristol University. On his way from the UK to Australia he stopped off in Hong Kong, Singapore and Thailand, building underground railways, elevated highways, ports and harbours, airports, and hydro-electric plant, eventually arriving here in 2006. He is now a Principal at National Geotechnical Consulting, a new consultancy which offers specialist advice in relation to piling, deep excavations and ground improvement. Having spent time with Hyder as Regional Functional Head of Geotechnics, Piling Contractors as National Technical Manager, and GHD as a Senior Principal Geotechnical Engineer, he launched out on his own at NGC in July 2015.
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