Shear behavior of fibrous concrete beams reinforced by GFRP

الملخص EN

The “glass fiber reinforced polymers (GFRP)” can be used to produce reinforcement bars that can be used as good alternatives for conventional steel reinforcement due to its reasonable strength / weight ratio and corrosion resistance.

the “fiber reinforced concrete (FRC)” is such kind of concrete that can be fabricated by the addition of steel fibers into concrete mix in order to enhance the mechanical potential and the consequent structural performance.

this study was presented to inspect the shear performance of fibrous concrete beams that reinforced by GFRP bars and stirrups.

the experimental program cast and test sixteen reinforced concrete beams.

fifteen beams were reinforced by GFRP stirrups and one beam was reinforced by steel stirrups as a reference beam.

the variables of this study comprised the amount of steel fibers, shear reinforcement ratio and concrete compressive strength, the beam was divided to five groups according to test parameters.

experimental results showed that increasing shear reinforcement ratio from 0.444% to 0.887% increases the failure load by 8, 9 and 11% for steel fiber content 0, 0.5 and 1%, respectively.

also results showed that increasing concrete compressive strength from 30 MPA to 70 MPA increases the failure load by 27, 40 and 42% for steel fiber content 0, 0.5 and 1%, respectively.

increasing steel fibers content from 0 to 1% increases the failure load by 8 to 18.9%.

the increases in concrete compressive strength from 30 to 70 MPA decrease the strain in GFRP stirrups between (60-125%), while the increase in shear reinforcement ratio from 0.444 to 0.887 decreases the strain in stirrups GFRP bars between (5-64%).

the increase in steel fibers content leads to decrease in concrete compressive strain between (71.5-301%).the increases in concrete compressive strength from 30 to 70 MPA decrease in concrete compressive strain between (25.8-269%).crack width were decreased by (32-108%) when the steel fibers content increased from 0 to 1% for all tested beams.

experimental results showed that increase steel fibers content and shear reinforcement ratio decrease the ultimate concrete compressive strain.

results showed that the ductility index by deformability approach decreases with the increase of the steel fibers content due to increase the moment and deflection at (εcu = 0.001).

the comparison of experimental and calculated ultimate shear load showed that the CSA and ISIS codes result were very conservative with safety factor reaching to 66%, the experimental results showed good agreement to the ACI and Tureyen while equation code results.