2019 Volume 75 Issue 2 Pages 80-94
Deployable reinforcement cage using PC strands as longitudinal reinforcement has been developed in order to improve construction of bored cast-in-place concrete piles in narrow space or small overhead clearance. Different from the similar construction method of bored cast-in-place pile using strands that has been invested previously, in this research, as pre-grouted PC strands were adopted, the construction of PC pile has been made possible. The cyclic loading tests of normal reinforced concrete (RC) pile, strand RC pile and strand prestressed concrete (PC) pile were performed to investigate flexure behaviors and examine applicability of the existing design method on skeleton curves. The results show that the strand RC and PC piles had higher yield displacement and smaller energy absorption than those of the normal RC pile. It is found that the strength and deformation properties of the strand RC and PC piles can be evaluated by the existing design standard which is based on Bernoulli-Euler theory. Besides, since the reinforcement ratio of the longitudinal strands becomes smaller when high tensile strands are use, the minimum required ratio of the longitudinal strands is also examined in this paper.
