The BGA pile prediction competition was won by John Gammon. Below he outlines the method behind his winning entry.
John Gannon of York-based geotechnical consultant Byland Engineering has won the British Geotechnical Association's pile prediction competition.
The BGA received 16 entries for the competition, held to coincide with this year's annual conference on 9 June. Entrants were asked to predict pile head deflections at working load and one-and-a-half times working load for a 450mm diameter low headroom CFA pile and a 600mm diameter CFA pile.
Predictions were compared with measured deflections and the one closest to the real answers (based on the cumulative error) won.
Gannon used Fleming's method as the basis of his prediction (see box), with results of 1mm and 2mm settlement for the 450mm pile and 3mm and 7mm settlement for the 600mm pile.
Actual deflections were 0.99mm and 1.84mm for the 450mm pile and 3.77mm and 8.52mm for the 600mm pile. b