Seismic Behavior of RC Columns Strengthened with Textile-Reinforced Ultrahigh-Toughness Cementitious Composite Jackets

Data Availability Statement

Acknowledgments

Notation

A

specimen cross-sectional area, mm²;

A_f

area of the carbon fiber bundle of the textile, mm²;

A_n

area of the effectively confined core concrete, mm²;

a

shear-span length of the columns, mm;

b

width of the columns, mm;

d_b

diameter of the rebar, mm;

E_c

elastic modulus of concrete, GPa;

E_cu

cumulative energy dissipation, kN/mm;

E_el

elastic deformation energy at different displacements, kN/mm;

E_hy

hysteresis energy dissipation (area covered in one hysteresis loop), kN/mm;

E_sec

secant modulus of stirrup-confined concrete at the peak point, kN/mm;

f_U

tensile strength of the UHTCC, MPa;

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

peak compression stress of the concrete, MPa;

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

compressive strength of the concrete confined by stirrups, MPa;

$f_{c,s-T}^{\mathrm{\prime }}$

compressive strength of the concrete confined by combined TRM and stirrups, MPa;

f_el,s

effective confining stress provided by the stirrups, MPa;

f_u

ultimate tensile strength of the reinforcement, MPa;

f_y

yielding strength of the reinforcement, MPa;

$f_{0c}^{\mathrm{\prime }}$

compressive strength of the unconfined concrete, MPa;

H₀

effective height of the columns, mm;

h

cross-sectional height of the columns, mm;

h_i

vertical distances of the LVDTs to the top surface of the base beam, i = 1, 2, mm;

K_i

secant stiffness at each displacement step, kN/mm;

k

descending slope of the postpeak branch of the Concrete01 model, MPa;

k₀

confining stress coefficient correlated with the concrete strength;

k₁

fiber bridging improvement coefficient for short fibers used in the jacket matrix;

k₂

confinement coefficient provided by the stirrups;

k₃

confining interaction coefficient of the stirrup and TRU jackets;

l_i

horizontal distances between two LVDTs at the height of h₁ or h₂, i = 1, 2, mm;

l_p

height of the plastic hinge zone of the RC columns, mm;

n

number of textile layers;

n_b

number of fiber bundles per textile layer in the TRU plates;

P_p

peak load of the columns, kN;

P_u

ultimate load of the columns, kN;

P_y

yielding load of the columns, kN;

r

compression modulus factor of the concrete;

r_c

radius of the rounded corners of the columns, mm;

S_u

rebar slip at the bar ultimate strength, mm;

S_y

rebar slip at the column–base beam interface at yield stress, mm;

s

mesh spacing of adjacent weft threads in the textiles, mm;

T_TRU

tensile capacity of the TRU overlays, kN;

t_U

thickness of the jackets, mm;

α

parameter used in the local bond-slip relation;

γ

drift ratio of the columns, %;

δ_i

displacement measured using an LVDT at the height of h₁ or h₂, i = 1, 2, 3, 4, mm;

+P_i

positive peak loads of the first hysteresis loop at displacement step (i), kN;

−P_i

negative peak loads of the first hysteresis loop at displacement step (i), kN;

Δ_p

lateral displacement at the peak load, mm;

Δ_u

lateral displacement at the ultimate load, mm;

Δ_y

lateral displacement at the yielding load, mm;

+Δ_i

positive displacements at the peak points for displacement step (i), mm;

−Δ_i

negative displacements at the peak points for displacement step (i), mm;

ɛ_c

compressive strain;

ɛ_cc

strain at the peak compressive stress of the stirrup-confined concrete;

ɛ_cp

strain at the peak compressive stress of concrete;

ɛ_c,s-T

strain at the peak compressive stress of the concrete confined by TRM and stirrups;

ɛ_cu

ultimate compression strain of the unconfined concrete;

ɛ_cu,c

ultimate compression strain of the stirrup-confined concrete;

ɛ_cu,s-T

ultimate compressive strain of the concrete confined by TRM and stirrups;

ɛ_cu0

ultimate compressive strain of the unconfined concrete;

ɛ_c0

strain at the peak compressive stress of the unconfined concrete;

ɛ_su

tensile strain at fracture of the transverse reinforcing bar;

ɛ_0.85

strain at the compressive stress of 85% of peak stress;

${\epsilon }_p^{\mathrm{\prime }}$

strain at the initial drop point of the compressive stress;

ξ_eq

equivalent viscous damping coefficient;

η_U

ratio of the confinement by UHTCC to the confinement by TRU jackets;

θ_i

tested rotation obtained from one pair of LVDTs, i = 1, 2, degrees;

θ_s

slip rotation, degrees;

μ_Δ

ductility index;

ρ_f

volumetric ratio of lateral CFRP bundles in the textile to the confined concrete;

ρ_v

volumetric stirrup ratio;

σ_c

compressive stress, MPa;

σ_cu,c

ultimate compression stress of the stirrup-confined concrete, MPa;

σ_f

effective tensile strength of the carbon-fiber bundles in the textiles, MPa;

σ_fe

effective tensile strength of the carbon-fiber bundles in the textile, MPa; and

φ

curvature of the cross section in the plastic hinge region.

References