Numerical Modeling of Recycled and Normal Aggregate CFRP-Strengthened Concrete-Filled Steel Columns Subjected to Lateral Impact

Acknowledgments

Notation

C_ij (d)

degradation matrix;

D/t

tube external diameter-to-wall thickness ratio;

d_c

compression damage parameter of concrete;

d_fc

compression damage variable of fiber;

d_ft

tension damage variable of fiber;

d_mc

compression damage variable of matrix;

d_mt

tension damage variable of matrix;

d_t

tension damage parameter of concrete;

E_cc

Young's modulus of confined concrete;

E₁₁

Young's modulus of CFRP along axis “1”;

E₂₂

Young's modulus of CFRP along axis “2”;

E₃₃

Young's modulus of CFRP along axis “3”;

$F_f^c$

fiber compression failure criterion;

$F_f^t$

fiber tension failure criterion;

$F_m^c$

matrix compression failure criterion;

$F_m^t$

matrix tension failure criterion;

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

cylinder compressive strength of concrete;

f_cc

cylinder compressive strength of confined concrete;

f_ck

cylinder compressive strength of unconfined concrete;

f_l

lateral stress;

f_t

maximum tensile strength of concrete;

f_y

yield strength of steel;

G₁₂

shear modulus of CFRP in plane 1–2;

G₁₃

shear modulus of CFRP in plane 1–3;

G₂₃

shear modulus of CFRP in plane 2–3;

k₁, k₂

constants;

L/D

tube length to its external diameter ratio;

S₁₂

shear strength of CFRP in plane 1–2;

w_c

crack width;

w_ccr

critical crack width;

X_1c

compressive strength of CFRP along axis “1”;

X_1t

tensile strength of CFRP along axis “1”;

X_2c

compressive strength of CFRP along axis “2”;

X_2t

tensile strength of CFRP along axis “2”;

ɛ_cc

strain corresponding to f_cc;

ɛ_ck

strain corresponding to f_ck;

ɛ_ij

strain matrix;

σ_ij

stress matrix;

${\tilde{\sigma }}_{11}$

effective stress along axis “1”;

${\tilde{\sigma }}_{22}$

effective stress along axis “2”;

${\tilde{\sigma }}_{12}$

effective stress in plane 1–2; and

ζ

shear stress contribution.

References