Effects of bonding in short-span rectangular concrete filled GFRP tubes

Flexural performance of concrete-filled tubes is highly dependent on the composite action between the concrete core and encasing tube. This study investigates the performance of short-span concrete-filled rectangular glass fiber reinforced polymer (GFRP) tubes with different levels of bonding between the concrete core and GFRP tube. The bonding configurations include (1) no bonding, (2) bonding of the webs, (3) bonding of the flanges, and (4) bonding of the webs and flanges. The study includes both experimental and finite element analysis results for each configuration. Comparing the performance of each configuration showed a two fold increase in stiffness and strength as a result of bonding between the concrete core and GFRP tube. Furthermore it was concluded that bonding of the flanges was most critical with web bonding providing only a slight increase in performance.