Reliability of non-destructive testing methods in the assessment of the strength of concrete columns reinforced with two layers of transverse confining stirrups: Empirical evidence

Abstract

Wide spread literature is available on the approach to assess the strength of Reinforced Concrete structures. However no attention has been made so far to study the similar potential when the RC columns are reinforced with double layer of transverse confining stirrups. An obvious reason could be that studies in double layered stirrups options are quite at their infancy. The authors took the advantage of their involvement in studying the axial compression behaviour in terms of strength and ductility of concrete columns reinforced with double layered transverse confining stirrups, applied the two non-destructive measures, viz., Rebound Hammer Test Method (RHTM) and Ultrasonic Pulse Velocity Test Technique (UPVTT), and destructive testing measure, viz., Compression Testing Method (CTM) on the specimens that they have developed in this study. The results have been subjected to regression techniques to build relevant equations for predictability. The present study attempts to explain the detailed procedures adopted within the frame work of the informed knowledge and had attempted to derive meaningful implications for the use of practitioners and academic fraternity. The findings of this paper drew attention to the superior impact of a combined non-destructive testing approach whereby RHTM and UPVTT have been merged in a fashion to yield better assessment of RC columns with double layers of transverse confining stirrups. The combined influence of RHTM and UPVTT clearly explain, greater characteristic compressive strength as one moves from a specimen with a Normal Strength Concrete (NSC) to a specimen with High Strength Concrete (HSC).