Compressive Behavior of Predamaged Concrete Cylinders Repaired with Jute and Basalt FRP Composites: A Comparative Study

Acknowledgments

Notation

b

width of rectangular section;

D

diameter of the equivalent circular of rectangular section;

d_c,c

compressive damage evolution parameter of concrete;

E_co, E_c, E_c,d

initial elastic modulus of the plain concrete, FRP-jacketed intact, and predamaged concrete, respectively;

E_en

strain energy;

E_frp(ɛ_h,rup)

secant tensile modulus of FRP jackets at ɛ_h,rup;

E_frp,1, E_frp,2

elastic modulus of the initial stage and second stage of FRP, respectively;

E₂, E_2,d

modulus of the linear second portion of the stress–strain curve of FRP-jacketed intact and predamaged concrete, respectively;

$f_{co}^{\mathrm{\prime }}$, $f_{cc}^{\mathrm{\prime }}$, $f_{cc,d}^{\mathrm{\prime }}$

compressive strength of the plain concrete, FRP-jacketed intact, and predamaged concrete, respectively;

f_frp

ultimate tensile strength of FRP;

f_l

lateral FRP confining pressure;

f_lf

lateral FRP confining pressure considering the FRP strain reduction factor;

f₀, f_0,d

Y-intercept of the linear second portion of the stress–strain curve of FRP-jacketed intact and predamaged concrete, respectively;

h

height of rectangular section;

k_ɛ

FRP strain reduction factor;

k₁, k₂

confinement-related effectiveness coefficient and strain enhancement coefficient for FRP-jacketed concrete, respectively;

k₃, m, n, q

fitting coefficients;

n_frp

number of FRP layers;

R

corner radius for rectangular section;

t_frp

thickness of a single FRP layer;

α_c

descending path parameter of the compressive stress–strain curve of concrete;

ɛ

a certain strain value on the compressive stress–strain curve of the plain concrete;

ɛ_c

axial compressive strain of FRP-jacketed concrete;

ɛ_co, ɛ_cc, ɛ_cc,d

strains corresponding to $f_{co}^{\mathrm{\prime }}$, $f_{cc}^{\mathrm{\prime }}$, $f_{cc,d}^{\mathrm{\prime }}$, respectively;

ɛ_h,rup

FRP hoop rupture strain;

ɛ_l

lateral strain;

ɛ_pre

unloading strain of the plain concrete in the preloading compression test, corresponding to the predefined predamage stress;

ɛ_t, ɛ_t,d

strain at the transition point between the first parabolic portion and the linear second portion of the stress–strain curve of FRP-jacketed intact and predamaged concrete, respectively;

ɛ_u,frp

ultimate tensile strain of FRP obtained from the flat coupon test; and

σ_l

confining pressure provided by FRP composites at a given strain ɛ_l.

References