Large Rupture Strain FRP-Confined Concrete Columns of Different Sizes: Experiments and Stress–Strain Models

Data Availability Statement

Notation

B

empirical coefficient in size effect law;

b

cross-sectional side length;

C

intercept of the second branch of the tensile stress–strain curve on the stress axis;

D

cross-sectional diameter;

D_eq

equivalent diameter of a noncircular section;

D₀

the other empirical coefficient in size effect law;

d_a

maximum aggregate size;

E_co

elastic modulus of concrete;

E_frp1

elastic modulus of the first branch in the tensile stress–strain curve;

E_frp2

elastic modulus of the second branch;

Expe.

experimental result;

$f_{cf}^{\mathrm{\prime }}$

final axial stress of confined concrete;

$f_{cf}^{\mathrm{\prime }}/f_{co,s}^{\mathrm{\prime }}$

final strength enhancement ratio;

$f_{co}^{\mathrm{\prime }}$

standard cylindrical compressive strength of unconfined concrete;

$f_{co,s}^{\mathrm{\prime }}$

compressive strength of unconfined concrete considering the size effect;

$f_{cu}^{\mathrm{\prime }}$

ultimate axial stress of confined concrete considering the size effect;

$f_{cu,150}^{\mathrm{\prime }}$

ultimate strength of FRP-confined concrete with a diameter/side length of 150 mm;

$f_{cu}^{\mathrm{\prime }}/f_{co,s}^{\mathrm{\prime }}$

ultimate strength enhancement ratio;

f_frp

tensile strength of fibers;

f_l

lateral confining pressure;

f_lf

confining stress of final condition;

f_lu,a

confining stress of ultimate condition;

H

height of specimen;

k₁

strength enhancement coefficient;

k₂

strain enhancement coefficient;

k_ɛ

strain reduction coefficient of FRP;

r_c

corner radius;

t_frp

total nominal thickness of FRP fibers;

Theo.

theoretical result;

β

size effect weakening factor;

ɛ_c

axial strain of confined concrete;

ɛ_cf

final axial strain corresponding to $f_{cf}^{\mathrm{\prime }}$;

ɛ_cf/ɛ_co,s

final axial strain enhancement ratio;

ɛ_co

axial strain corresponding to $f_{co}^{\mathrm{\prime }}$;

ɛ_co,s

axial strain corresponding to $f_{co,s}^{\mathrm{\prime }}$;

ɛ_cu

ultimate axial strain corresponding to $f_{cu}^{\mathrm{\prime }}$;

ɛ_cu/ɛ_co,s

ultimate axial strain enhancement ratio;

ɛ_cu,150

ultimate axial strain corresponding to $f_{cu,150}^{\mathrm{\prime }}$;

ɛ_f

tensile strain of fibers;

ɛ_frp

ultimate elongation of fibers;

ɛ_frp0

strain at the intersection of the first branch and the second branch;

ɛ_h,f

FRP final hoop strain;

ɛ_h,rup

FRP hoop rupture strain;

ɛ_hc,f

FRP average final hoop strain of corners;

ɛ_hc,rup

FRP average hoop rupture strain of corners;

ɛ_hm,f

FRP average final hoop strain of midsection flat sides;

ɛ_hm,rup

FRP average hoop rupture strain of the midsection flat sides;

ɛ_l

FRP lateral strain;

σ_c

axial stress of confined concrete;

σ_f

tensile stress of fibers;

σ_Nu

nominal stress;

ρ_f

FRP volume ratio;

ω

residual error; and

2r_c/D_eq

corner radius ratio.

References