Flexural strength and ductility analysis of spirally reinforced prestressed concrete piles

Abstract

A method to analyze the flexural strength and ductility of prestressed concrete piles containing spiral reinforcement is presented. The method is based on moment-curvature analysis. Account is taken of the increase in flexural strength and ductility of the pile due to concrete confinement from the spirals. The method is applicable to all sections of the pile. In the end regions of the pile, allowance is made for the possibility that the stresses in the pretensioned strands may not have fully developed. Design tables and charts for the enhanced flexural strength, available ultimate curvature and curvature ductility factor are derived for prestressed concrete piles with 400 mm (15.7 in.) octagonal cross sections and with various spiral contents and axial load levels.