Proposed Development Length Equations for GFRP Bars in Flexural Reinforced Concrete Members

Data Availability Statement

Notation

A_b

cross-sectional area of the bar (mm²);

A_tr

area of transverse reinforcement (mm²);

a

shear span length (mm);

c

concrete cover to the center of the bar (mm);

d_b

diameter of reinforcing bars (mm);

d_c

bottom concrete cover thickness (mm);

d_cs

concrete cover thickness measured to the center of reinforcement (mm);

d_c,side

side concrete cover thickness (mm);

E_FRP

elastic modulus of GFRP bars (MPa);

E_s

elastic modulus of steel bars (MPa);

F

applied load from the actuator (N);

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

concrete compressive strength (MPa);

f_cr

concrete cracking strength (MPa);

f_f

design stress in GFRP reinforcement in tension (MPa);

f_fr

developed stress in the GFRP bars (MPa);

f_frpu

ultimate stress of the bar (MPa);

f_fu

design tensile strength of FRP reinforcement (MPa);

f_y

specified yield strength of steel reinforcing bars (MPa);

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

square root of the specified compressive strength of concrete;

j

lever arm from the center of the compression block to the center of tension reinforcement (mm);

K_tr

transverse reinforcement index;

k₁

bar location factor;

k₂

concrete density factor;

k₃

bar size factor;

k₄

bar fiber factor;

k₅

bar surface profile factor;

l_d

development length (mm);

l_e

embedded length of the reinforcing bar (mm);

l_e−exp.

experimental embedded length of the reinforcing bar and the same as l_e (mm);

l_e−theo.

theoretical embedded length that corresponds to the maximum experimental stress in the GFRP bar at failure (mm);

n

number of bars developed or spliced along the potential splitting failure plane;

s

spacing of transverse reinforcing bars (mm);

T

failure load monitored in beams at bond failure (N);

u

average bond stress (MPa);

α

coefficient accounts for the bar location; and

τ

average bond stress (MPa).

References