New Flexible System of Transverse Reinforcement for RC Piers

Abstract

In this paper Polyacetal Fibre (PAF) is demonstrated as a new continuous system of shear reinforcement replacing major parts of dense steel tie. Five reinforced concrete piers were tested under reversed (or back and forth) cyclic loading to study the performance of the new material in withstanding the very high shear without premature rupture. A simple clamping system was developed, tested and successfully used to clamp the two extremities of the continuous PAF shear reinforcement. Rupture failure of the PAF at the bent-portions has been avoided. The desirable confinement is acquired with a network of inner and outer core concrete and consequently strength and ductility are enhanced. The effect of the confinement action of PAF continuous shear reinforcement is represented by the strain development in the PAF as a function of displacement level, average PAF strain and applied number of repeated cyclic displacement reversals. A generalized approximate formulation is suggested which shows good correlation with available data and boundary conditions.