Strength Evaluation and Reveal the Reserved Strength of Confined RC Circular Column under Static Load

Abstract

Abstract

The strength of RC circular column is evaluated as per IS 456:2000 guideline and design charts of SP16. The secondary steel in the form of lateral ties or helical reinforcement is provided to suit the requirements of IS 456:2000 and IS 13920:2016. The secondary steel provides the confinement to the concrete and imparts ductility to the column. The strength of confined concrete is found more than the strength of 150 mm size concrete cube. This higher strength of confined concrete imparts higher strength to the RC column. Current design practice does not consider the higher strength of confined RC column and the excess strength remains unutilized throughout the life of the building structures. The enhanced strength is revealed using constitutive law as per Mander et al and the column strength is evaluated under static loading condition. To quantify the reserved strength, the enhanced strength in terms of  chart for confined RC circular column is plotted between the ‘offset curves’ of design charts provided by SP16. It is revealed that the enhanced strength of RC circular column reinforced with lateral ties remains within 5 to 15% for different confinement and it ranges between 19 and 29% of the strength as per IS 456:2000 for helically reinforced RC column. It is observed that the reserved strength; though not accounted for in design, is utilized by the stakeholders of building construction to their advantage.

Keywords: RC circular column,  interaction chart, confined concrete, reserved strength, offset curve

Cite this Article

Solanki DH, Londhe RS. Strength Evaluation and Reveal the Reserved Strength of Confined RC Circular Column under Static Load. Journal of Construction Engineering, Technology and Management. 2018; 8(1): 7–14p.