A COMPARATIVE STUDY ON COMPRESSIVE BEHAVIOR OF H.S. STEEL VS. FRP CONFINED CONCRETE

This paper presents the results of an experimental and analytical study on application of “high strength steel strapping” technique and comparing it with FRP for retrofit of concrete columns. Various parameters were found to influence the compressive strength and ductility of confined concrete, including confinement mechanical volumetric ratio, number of confinement layers, strength of plain concrete and ductility of confining material. Among these parameters, the latter was found to play the most important role in determining the ultimate strain and post peak behavior of concrete. Axial compressive tests were performed on smallscale circular or square section concrete columns. Three different materials were applied for confining concrete specimens, including CFRP jacket, brittle highstrength steel strips and ductile steel strip. Test Results showed significant increase in strength and ductility of columns due to active confinement by metal strips. CFRP confined concrete also showed enhanced behavior. A database of results of compressive tests on concrete confined with various materials was collected from the literature. An analytical model was proposed based on results of this study and the collected database to determine the strength and ultimate strain of confined concrete. The proposed model takes the confinement ductility into account and shows good agreement with the experimental results.

Keywords:

concrete , confinement , FRP , steel strip , ultimate strain