Assessment of Bond Strength of GFRP Bars Embedded in Fiber-Reinforced Cementitious Composites

Acknowledgments

Notation

A_f

cross-sectional area of the bar;

A_tr

area of transverse reinforcement normal to the plane of splitting through the bars;

A_tr

area of transverse reinforcement;

B

headed anchorage factor;

C

lesser of the cover to the center of the bar or one-half of the center-to-center spacing of the bars being developed;

d_b

bar diameter;

d_bo

reinforcement outer diameters;

d_cs

smallest of the distance from the closest concrete surface to the center of the bar being developed or two-thirds of the center to center spacing of the bars being developed;

E₀

elastic modulus of steel;

E_t

elastic modulus of transverse reinforcement;

$f_c^{\mathrm{\prime }}$

compressive strength of concrete;

f_bod

design bond strength of concrete;

f_CFRP

design tensile strengths in the CFRP bars;

f_F

tensile stress in the reinforcing bar;

f_GFRP

design tensile strengths in the GFRP bars;

f_tsp

splitting tensile strength of steel fiber-reinforced concrete;

f_u

rupture stress of the bar;

f_y

yield strength of transverse reinforcement;

K₁

bar location factor;

K₂

concrete density factor;

K₃

bar size factor;

K₄

bar fiber factor;

K₅

bar surface profile factor;

K_tr

transverse reinforcement index;

${\ell }_{\mathit{e}2}^{\mathrm{\prime }}$

additional straight part of the bar to the head;

ℓ_e

embedment length;

L_f

fiber length;

n

number of bars being developed along the plane of splitting;

S

coefficient for the reinforcement fiber and surface type;

V_f

volumetric fiber ratio;

τ_f

bond stress;

Δf_F

increase in the tensile stress;

α₂

modification factor for bond strength of FRP; and

Φ_f

fiber diameter.

References