Evaluation by Hybrid Simulation of Earthquake-Damaged RC Walls Repaired for In-Plane Bending with Single-Sided CFRP Sheets

Acknowledgments

Notation

A_e

effective shear wall area, taken as 80% of the total shear wall area (mm²);

A_h

area of one leg of the transverse reinforcement (mm²);

b_w

thickness of the wall (mm);

c

cohesive stress (MPa);

D′

core dimension from center-to-center of the peripheral hoops (mm);

DOFs

degrees of freedom;

d

distance from extreme fiber in comparison with centroid of tensile force (mm);

E_c

concrete modulus of elasticity (MPa);

E_f

tensile modulus of elasticity of the CFRP (MPa);

E_s

modulus of elasticity of steel (MPa);

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

28-day concrete compressive strength (MPa);

f_F,flexure

ultimate tensile strength of CFRP composites in flexure (MPa);

f_F,shear

ultimate tensile strength of CFRP composites in shear (MPa);

f_fu

ultimate tensile strength of CFRP composites (MPa);

f_y

steel yield stress of the vertical steel reinforcement (MPa);

f_yh

yield stress of the horizontal steel reinforcement (MPa);

h_w

height of the wall (mm);

l_w

length of the wall (mm);

M_r

moment resistance without CFRP reinforcement (kN-m);

M_r,FRP

moment resistance with CFRP reinforcement (kN-m);

M_u

ultimate moment (kN-m);

M_y

yield moment (kN-m);

m

number of faces reinforced with CFRP;

n

number of legs of horizontal steel reinforcement;

n_F

number of layers of CFRP reinforcement;

P_f

factored axial load;

r_o

outer radius of the steel tube anchor (mm);

s

spacing between horizontal steel reinforcing bars (mm);

S_A

area scale factor for similitude;

S_E

modulus of elasticity scale factor for similitude;

S_F

force scale factor for similitude;

S_L

length scale factor for similitude;

S_M

moment scale factor for similitude;

S_M

reinforcement ratio scale factor for similitude;

t_f

thickness of a single sheet of FRP laminate in the defined state (mm);

V_F

CFRP reinforcement contribution to diagonal tension shear strength (kN);

V_c

concrete contribution to diagonal tension shear strength (kN);

V_r

total diagonal tension shear strength without CFRP sheets (kN);

V_r,FRP

total diagonal tension shear strength with CFRP reinforcement (kN);

V_s

steel reinforcement contribution to diagonal tension shear strength (kN);

V_u

equivalent ultimate force (kN), taken as M_u/h_w;

V_y

equivalent yield force (kN), taken as M_y/h_w;

α_F

orientation angle of the fibers with respect to the longitudinal axis;

Δ_res

residual drift (%);

Δ_u

ultimate displacement (mm);

Δ_y

equivalent yield displacement (mm);

ɛ_c

concrete strain at maximum compressive stress (mm/mm);

ɛ_F

strain in the horizontal CFRP layers (mm/mm);

ɛ_Fmax

maximum strain in the vertical CFRP layers (mm/mm);

ɛ_fu

ultimate strain in the FRP reinforcement (mm/mm);

ɛ_r

steel rupture strain (mm/mm);

ɛ_sh

steel strain hardening strain (mm/mm);

ɛ_u

concrete strain at 15% drop from maximum compressive stress (mm/mm);

ɛ_y

yield strain for steel reinforcement (mm/mm);

θ_y

yield rotation (rad);

θ_u

ultimate rotation (rad);

κ_v

bond reduction coefficient for the horizontal CFRP reinforcement;

λ

factor accounting for lightweight concrete;

μ

coefficient of friction;

μ_Δ

displacement ductility ratio (mm/mm);

μ_θ

rotational ductility ratio (rad/rad);

ρ_h

horizontal steel reinforcement ratio (%); and

ρ_v

vertical steel reinforcement ratio (%).

References