Design of a one-way slab - Reinforced Concrete with FRP Bars: Mechanics and Design - page 219

Check_BarSpacing3 = “OK”

The area of FRP reinforcement is

b

2

A: = ⋅ A0.39in = ⋅

f3 f_bar

s

f_bar3

The FRP reinforcement ratio (Equation 8-2 of ACI 440.1R-06) is

A
bd

f3
f3

ρ= ⋅ : = 0.00467

f3

Design flexural strength: Equation (8-3) of ACI 440.1R-06 is

β ⋅ ′

f
f

E ⋅ε

c f cu

ρ= :0.85 ⋅ = 0.00748

fb3 1

E ⋅ε + f

fu f cu fu

The effective concrete compressive strain at failure as a function of the
neutral axis depth, x, is

ε

cu

yif ρ≥ρ

f3 fb3

x

( )

ε x, y: =

c3

ε

fu

dx xif

⋅ ρ <ρ

f3 fb3

−

f3

The effective tensile strain in the FRP reinforcement as a function of the
neutral axis depth, x, is

ερ<ρ if

fu f3 fb3

()

ε x: =

ε

f3

( )

cu

min ⋅ dx, −ε if ρ≥ρ

f3 fu f3 fb3

x

The compressive force in the concrete as a function of the neutral axis
depth, x, is

( )

σ⋅ ε

x, y

c3

2. "

c

ε

x

∫

() =⋅

c0

Cx:b psidy

c3

2

( )

ε x, y

0in

c3

1 +

ε

c0