Behavior of Large-Scale Concrete Columns Wrapped with CFRP and SFRP Sheets

Circumferential wrapping of fiber-reinforced polymer (FRP) sheets is one of the most common applications for repair and rehabilitation of large-scale columns. Common types of fibers used for wrapping are carbon FRP (CFRP), glass FRP (GFRP), and aramid FRP (AFRP). Recently, steel FRP (SFRP) has been introduced as a new class of composites for strengthening applications. Up to now, there has been no experimental data available on the behavior of large-scale columns wrapped with SFRP sheets. Thus, in this paper, the behavior of nonreinforced and reinforced large-scale columns (300 x 1; 200 mm) wrapped with CFRP and SFRP sheets is examined and compared with that of unwrapped columns. The experimental results include stress-strain behavior, ultimate stress, ultimate strain, dilation, and ductility of large-scale columns. This study presents the first ever insight into the strain variation of large-scale circular columns wrapped with CFRP and SFRP sheets using the digital image correlation technique (DICT). This technique is a photogrammetric technique that allows capturing strains from the surface of FRP-confined concrete. Results from DICT were used to analyze the strain efficiency of the SFRP sheets. Results indicate that the overall performance of the SFRP-wrapped concrete columns is superior to that of the CFRP-wrapped concrete columns. DOI: 10.1061/(ASCE)CC.1943-5614.0000278. (C) 2012 American Society of Civil Engineers.