Experimental study of CFRP-confined reinforced concrete masonry columns tested under concentric and eccentric loading

Using Carbon Fiber Reinforced Polymers (CFRP) jackets to confine existing concrete masonry columns for capacity and ductility enhancement has been approved in axial compression applications. Considering that the majority of columns in practice are loaded under a combination of axial compression load and bending moment, experimental work for testing reinforced concrete masonry columns confined by CFRP jackets under eccentric loading is needed. This paper presents the results of testing 28 half-scale fully grouted reinforced concrete masonry columns under different concentric, eccentric loading conditions and variations in CFRP jacketing. The ability of CFRP jackets to improve the structural performance is evaluated. Axial force-bending moment interaction diagrams of confined reinforced concrete masonry columns are compared against the unconfined masonry columns to quantify the enhancement in strength and moment. The results indicate that increasing the CFRP jacket thickness enhanced the performance of masonry columns regarding axial strain and strength; however, there was a noticeable reduction in strength gain under strain gradient condition upon increasing the eccentricity level. Also, axial force-bending moment interaction diagrams of confined masonry columns showed an increase in the load and the moment capacity compared to that of unconfined masonry columns.