Estimation of Installation Torque and Axial Ultimate Capacity of Screw Piles in Tropical Soils Using SPT Data-PPT Presentation

PPT Presentation

Pdf Summary

The study evaluates a method for estimating screw-pile installation torque and axial ultimate capacity in tropical soils using standard penetration test (SPT) data. It extends the Yanez and Renosto (2019) approach to account for differences between lateritic and non-lateritic soils, whose properties can affect torque substantially.<br /><br />The method combines corrected SPT blow counts, soil-specific resistance estimates, pile geometry, and torque–capacity relationships. It was assessed using seven screw-pile case studies in Brazil, with installation records and tension load tests. Lateritic soils were found to have higher shear stiffness and installation torque, attributed to their cemented structure. The analysis applied a laterization factor of 3 and derived a torque correlation factor, Kt, of approximately 19.7 m⁻¹. Predicted capacities showed good agreement with measured and extrapolated load-test results.<br /><br />The authors conclude that torque-based design can be a practical and consistent tool for screw piles in tropical soils when local soil behaviour is recognized and the method is appropriately calibrated. Explicitly accounting for lateritic conditions can improve capacity estimates and support safer decisions about installation equipment, pile geometry, and design margins. The findings are based on a limited set of Brazilian case studies, so broader validation may be needed for other sites and soil conditions.

Keywords

screw-pile installation

installation torque

axial ultimate capacity

tropical soils

SPT data

lateritic soils

soil resistance

pile geometry

torque correlation factor

Brazil case studies