To reduce the crack width of concrete beams reinforced with glass-fiber reinforced polymer(GFRP) bars

this paper proposes a new type construction measure for FRP bars which is fabricated by inserting the GFRP bars into the metal corrugated pipe and filling the interspace with high strength cement-base grouting materials.The internal high-strength cement-based grouting material has good bonding performance with GFRP bars and participates in the pulling

while the external metal bellows can restrain the expansion of internal cohesive cracks and strengthen the bonding effect with concrete. Therefore

the crack width of concrete beams reinforced with GFRP bars is reduced. To verify the feasibility

a monotonic loading flexural test was carried out on six beams reinforced with steel bars

extruded GFRP bars

and the new type GFRP bars

respectively.The effects of longitudinal bars on the crack distribution

average crack spacing

and crack width were investigated. The experimental results show that the new type construction measure can reduce the crack width of beams in the serviceability limit state and delay the appearance of the cracks along the bars compared with general extruded GFRP bars.Besides

the beams treated with the new type construction measure met the code requirement of the maximum crack width of 0.5mm

while the ordinary concrete beams reinforced with GFRP bars did not. The failure modes of beams reinforced with GFRP bars began with concrete crush in compressive zone

and the final destruction were the rupture of longitudinal FRP bars. The flexural capacity of beams reinforced with GFRP bars was higher than that of RC beams and expressed the good deformability before final destruction

in which the average deflection span ratio approximately reached 1/56.