Effect of Surface Roughness on the Shaft Resistance of Displacement Model Piles in Sand

This paper presents the results of tensile load tests performed with instrumented model piles with different surface roughnesses jacked into sand samples in a half-circular calibration chamber with digital image correlation (DIC) capability. Digital images of the model piles and sand were taken during each test; processing of these images using the DIC technique yielded the soil displacement and strain fields in the sand. Data from local sensors and DIC show that an increase in the roughness of the shaft results in an increase in the average unit shaft resistance and in the displacements and strains in the soil next to the shaft of the pile. Guidance is provided for consideration of pile shaft surface roughness in the calculation of the tensile limit unit shaft resistance of jacked piles in sand. (c) 2017 American Society of Civil Engineers.