Efficiency of double helix rectangular continuous transverse reinforcement (RCTR) for RC column

Abstract

The continuity of transverse reinforcement for RC columns ensures ductile behavior and provides confinement and shear resistance. A previous study showed that rectangular continuous transverse reinforcement (RTCR) had increased the average strength of columns. However, the study concluded that the configuration of RTCR exhibited a high tendency of catastrophic unsymmetrical failure and premature buckling. This study proposed a double helix rectangular continuous transverse reinforcement (DHRTCR) and cyclic triangular transverse reinforcement (CTTR) configuration to be embodied in the design. Specifically, examine the increase in compressive strength, resistance to buckling failure, and steel consumption. The compressive strength is calculated theoretically and investigated using Universal Testing Machine (UTM) per ASTM C39. The buckling and steel consumption was determined using a digital vernier calliper and calculation of gross volumetric ratio, respectively. The result of the study showed that DHRTCR exhibited a 5.22% increase in compressive strength with a 1.080% average volumetric ratio. The CTTR decreased by 4.09% in compressive strength with an average 1.153% average volumetric ratio. In the mid-height intersecting point of the double loop of DHRTCR, the critical region occurs. The CTTR was critical at a distance creating two ties symmetrically placed at each other. The confinement and compressibility had significantly been affected by reinforcement spacing (lesser spacing leads to minimal buckling of longitudinal bars). Lastly, in larger-scale applications, such as slender columns, DHRTCR will consume lesser steel reinforcement due to the absence of hooks.