Confinement Effect of Soil on Plastic Hinge Length in Extended Pileshafts

Abstract:

Based on the calibrated numerical modeling method, a finite element (FE) model of the extended pileshaft used in a simply supported bridge was developed. Then some FE models of extended pileshafts embedded in sands varying different relative densities were established to study the confinement effect of soil on ① the displacement ductile capacity; ② the curvature distribution along the shafts and ③ the equivalent plastic hinge length of piles. The study indicates that confinement effect of soil can enhance the maximum sectional curvature of extended pileshafts at failure significantly, increase both the lateral strength of piles and the displacement ductility factor, and lead to noticeable decrease of the plastic region length and the equivalent plastic hinge length of piles. The equivalent plastic hinge length of piles has a remarkable drop with the increase of the displacement ductility factor.

Key words:extended pileshafts; performancebased seismic design; equivalent plastic hinge length; confinement effect of soil