Experimental study of effect of arrangement of GFRP bars on tensile behaviour of concrete elements

Abstract

Despite the simplicity of tensile test layouts of reinforced concrete prisms, interpretation of their results may be inadequate. Typically, a tie-test provides measurements of average deformations of the reinforcing bar and the concrete surface. However, the experimental output often contradicts the general assumption of the equivalence of mean strains of the reinforcement and concrete. This experimental study deals with the effect of arrangement of GFRP bars on tensile behavior of concrete elements. A specific equipment for anchorage of multiple bars of various materials has been designed and produced for the tension tests. A general target of the setup is to secure uniform distribution of the applied tension to the bars. The study is based on test results of 16 concrete specimens with different distribution of GFRP bars. The number and diameter of the bars are varying from 4 to 16 and from 6 mm to 16 mm, respectively. Five corresponding specimens with steel reinforcement were used for the reference. The tensile behaviour analysis is based on the average strains of reinforcement and concrete surface. Bond properties of GFRP bars as well as the effect of variation of the diameter-to-reinforcement ratio (Ø/p) were also examined.