αd and βd are the strain-dependent parameter and stress-dependent parameter under the design limit state, respectively.

αu and βu are the strain-dependent parameter and stress-dependent parameter under the ultimate limit state, respectively.

εcd and fcd are the concrete compressive strain and stress under the design limit state, respectively.

εfd and ffd are the tensile strain and stress of the GFRP bar under the design limit state, respectively.

εcu and fcu are the concrete compressive strain and stress under the ultimate limit state, respectively.

εfl and ffl are the tensile strain and stress of the GFRP bar under the ultimate limit state, respectively.

xcd is the height of the concrete compression zone under the design limit state.

xcu is the height of the concrete compression zone under the ultimate limit state.

εfu is the ultimate tensile strain of the GFRP bar.

ffu is the ultimate tensile strength of the GFRP bar.

Ef is the modulus of elasticity in tension of the GFRP bar.

fc is the concrete strength.

ρfb is the balanced reinforcement ratio.

ρf is the longitudinal reinforcement ratio of the tensile GFRP bar in test specimens.

ρd is the longitudinal reinforcement ratio of the tensile GFRP bar under the design limit state.

Wd,ex is the experimental value of the maximum flexure crack width.

Pd,ex is the experimental value of the applied load under the design limit state.

Md,ex is the experimental bending moment under the design limit state.

Md,th is the theoretical bending moment under the design limit state.

Wu,ex is the experimental value of the maximum flexure crack width under the ultimate limit state.

Pu,ex is the applied load under the ultimate limit state.

Mu,ex is the experimental bending moment under the ultimate limit state.

Mu,th is the theoretical bending moment under the ultimate limit state.

b is the width of the beam section.

h is the height of the beam section.

h0f is the effective height of the beam section.