Cyclic Stress–Strain Behavior and Model for FRP-Confined Engineered Cementitious Composite

Data Availability Statement

Notation

AAE

average absolute error;

C

tensile stress of the second part of the curve extending in the opposite direction to the stress axis (MPa);

D

diameter of specimen (mm);

E₂

slope of the second part of FRP-confined concrete (MPa);

$E_2^{*}$

slope of the third part of FRP-confined concrete (MPa);

E_frp1

elastic modulus of the first part of FRP (GPa);

E_frp2

elastic modulus of the second part of FRP (GPa);

E_re

slope of the first linear part of reloading path (MPa);

Expe.

experimental result;

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

standard concrete cylindrical compressive strength (MPa);

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

ultimate axial stress of FRP-confined concrete (MPa);

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

strength enhancement ratio;

f_l

lateral confining pressure (MPa);

f_lu,a

confinement stress of ultimate condition (MPa);

$f_{lu,a}^{\mathrm{\prime }}/f_{co}^{\mathrm{\prime }}$

confinement ratio;

f′_o2

stress at the intersection of the last linear part of the envelope curve and the axial stress axis (MPa);

H

height of specimen (mm);

k₁

strength enhancement coefficient;

k₂

strain enhancement coefficient;

k_ɛ

strain reduction factor of FRP;

M

mean;

n

number of cycles at each unloading point (n = 1, envelope cycle; n = 2, 3, 4…, internal cycle);

SD

standard deviation;

t_frp

total nominal thickness of FRP fibers (mm);

Theo.

theoretical result;

β_un,n

partial unloading factor of the nth cycle;

γ_re,n

partial reloading factor of the nth cycle;

ɛ_c

axial strain of confined concrete;

ɛ_co

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

ɛ_cu

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

ɛ_cu/ɛ_co

strain enhancement ratio;

ɛ_f

tensile strain of fibers;

ɛ_frp

ultimate elongation of fibers;

ɛ_frp0

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

ɛ_h,rup

FRP hoop rupture strain;

${\epsilon }_t$

axial strains of the first turning points;

${\epsilon }_t^{*}$

axial strains of the second turning points;

ɛ_pl/ɛ_un,env

plastic index;

ɛ_pl,n

plastic strain of the nth cycle;

ɛ_pl,n/ɛ_pl,n−1

plastic strain ratio;

ɛ_re,n

reloading strain of the nth cycle;

ɛ_ref,n

reference strain of the nth cycle;

ɛ_ret,env

envelope returning strain;

ɛ_un,env

envelope unloading strain;

ɛ_un,n

unloading strain of the nth cycle;

ϕ_n

stress deterioration ratio of the nth cycle;

σ_c

axial stress of confined concrete (MPa);

σ_f

tensile stress of fibers (MPa);

σ_new,n

new stress corresponding to reference strain for the reloading path of the nth cycle (MPa);

σ_re,n

reloading stress corresponding to ɛ_re,n (MPa);

σ_ref,n

reference stress of the nth cycle (MPa);

σ_ret,env

envelope returning stress (MPa);

σ_un,env

envelope unloading stress (MPa);

σ_un,n

unloading stress of the nth cycle (MPa);

ω_n

strain recovery ratio; and

ω_n,ful

strain recovery ratio when γ_re,n = 1.

References