Investigation of bond properties of glass fibre reinforced polymer (GFRP) bars in concrete under direct tension.

摘要

A study of existing research shows a need for an investigation of the bond properties of anchorage systems for GFRP bars including; straight, anchor heads and bends. The standard pullout test was modified to improve testing efficiency, accommodate bend tests, as well as reduce variability of concrete properties across specimens. Based on the results of the experimental work it was concluded that the surface profile of GFRP bars influences the post-peak phase of the bond stress-slip curve. It was also found that GFRP bars with anchor heads would still require a considerable embedment length to develop the bars’ full strength. Bend strengths of three GFRP manufacturers were determined to be between 58 and 80% of the strength of the straight portion of the same bar, while the development length of a two legged stirrup was found to be between five and ten times the bar diameter for all bar types.