Assessment of Diagonal Macrocrack-Induced Debonding Mechanisms in FRP-Strengthened RC Beams

Acknowledgments

Notation

D

damage factor in Mode I, Mode II, and mixed-mode conditions;

D₂

weakening factor of the rebar–concrete interface;

f

friction coefficient;

F_t

tensile strength of the interface;

$F_t^r$

relative tensile strength of the interface;

G_I

fracture energy in the Mode I condition;

G_II

fracture energy in the Mode II condition;

$G_{\mathrm{I}}^r$

energy release rate in the normal direction;

$G_{\mathrm{II}}^r$

energy release rate in the tangential direction;

h_rib

height of the rib;

k_n

interface stiffness in the normal direction;

P_max

peak load value during the loading process;

T_f

friction stresses in the tangential direction;

T_fmax

maximum friction stress;

δ

total relative displacement;

δ₀

total relative displacement at the onset of interfacial softening in the mixed-mode condition;

δ_f

total relative displacement at the onset of interfacial failure in the mixed-mode condition

δ_n

displacement in the normal direction;

δ_n0

normal displacement at the onset of interfacial softening in the Mode I condition;

δ_nf

normal displacement at the onset of interfacial failure in the Mode I condition;

${\delta }_{n0}^r$

relative normal displacement at the onset of interfacial softening in the mixed-mode condition;

${\delta }_{nf}^r$

relative normal displacement at the onset of interfacial failure in the mixed-mode condition;

δ_s

total displacement in the tangential direction;

δ_s0

tangential displacement at the onset of interfacial softening in the Mode II/III condition;

δ_sf

tangential displacement at the onset of interfacial failure in the Mode II/III condition;

${\delta }_{s0}^r$

relative tangential displacement at the onset of interfacial softening in the mixed-mode condition;

${\delta }_s^{\mathrm{slide}}$

tangential sliding displacement that has been generated during the loading process;

${\delta }_{sf}^r$

relative tangential displacement at the onset of interfacial failure in the mixed-mode condition;

θ

peeling angle;

λ

constant parameter in the parabola criterion;

σ

normal stress;

τ

shear stress;

τ₀

shear strength;

${\tau }_0^r$

relative shear strength;

τ_max

bond strength of the rebar–concrete interface; and

τ_res

residual strength of the rebar–concrete interface.

References