Blind Prediction Competition Co-organization with TC212, ISSMGE-PPT Presentation

PPT Presentation

Pdf Summary

The ISSMGE TC212 blind prediction competition assessed predictions of the lateral-load response of two 21 m-long, 2 m-diameter piles: one impact-driven and one vibro-driven. Participants were evaluated on initial lateral stiffness, loads at displacements equal to 2% and 7.5% of pile diameter, maximum axial strain and its depth, and report quality.<br /><br />Ten predictions were submitted by 26 participants from nine countries. Approaches varied widely: teams used different soil-property estimates, including CPT, laboratory and in-situ data; analyses ranged from 1D p–y methods to 3D finite-element models; and some incorporated pile-installation effects while others did not.<br /><br />Predicted load–displacement behaviour varied substantially. The spread among predictions was especially large for initial stiffness and load at 2% diameter displacement. Measured results showed initial stiffnesses of 71 MN/m for the impact-driven pile and 63 MN/m for the vibro-driven pile. Most reports were clearly presented, but prediction accuracy differed considerably.<br /><br />The competition highlights persistent uncertainty in predicting the lateral response of piles. Choices about soil parameters, constitutive models, analysis methods and engineering adjustments can produce markedly different results, so agreement with observed behaviour may sometimes be coincidental rather than evidence of reliable prediction. The presentation concludes that better research and predictive tools are still needed.

Keywords

ISSMGE

TC212

blind prediction

lateral-load response

pile behavior

impact-driven pile

vibro-driven pile

lateral stiffness

load-displacement

finite element analysis