EXPERIMENTAL STUDY OF CONCRETE-FILLED PULTRUDED GFRP SHORT COLUMNS STRENGTHENED WITH CFRP SHEETS

In order to study the influence of carbon fiber reinforced ploymer (CFRP) sheets on the mechanical properties of concrete-filled glass fiber reinforced ploymer (GFRP) short columns strengthened with CFRP sheets, the experimental research on the design parameters of CFRP sheets layers and concrete strength grades was carried out. The failure modes, ultimate bearing capacity, load-displacement curves and load-strain curves of the specimens were obtained. The ultimate bearing capacity, ductility and stiffness of the pultruded GFRP tubes concrete short columns were analyzed. The results showed that the ultimate bearing capacity of the pultruded GFRP tubes concrete short column was obviously improved after CFRP sheets reinforcement. When the layers of the reinforced CFRP sheet were 3, the average ultimate bearing capacity of the specimens increased by 116.93%, and the failure modes of the specimens were changed from brittle failure to ductile failure with the increase of CFRP layer. When the specimen failed, the side wall cracking damage gradually turned to the end damage, and the ductility was improved. Keeping the wall-thickness (t) of the pultruded GFRP tube at 5 mm, when the aspect ratio (H/B) of the pultruded GFRP tube was 2.25 and the aspect ratio (B/t) was 20, the overall deformation capacity of the specimens with the concrete strength grade C30 had better deformation capacity and the ultimate bearing capacity which was significantly higher than the concrete strength grades C20 and C40.