Design of a T-beam - Reinforced Concrete with FRP Bars: Mechanics and Design - page 268

Equation (8-3) of ACI 440.1R-06 is

β ⋅ ′

f
f

E ⋅ε

c f cu

ρ :0.85 = ⋅ = 0.0126

1

fb2

E ⋅ε + f

fu f cu fu

The selected reinforcement ratio is smaller than the ratio corresponding
to the balanced conditions, as shown:

ρ
ρ

fb2

= 1.779

f_des2

Because the reinforcement is to be placed on two levels, an even number
of FRP bars is selected:

N bar2 := 8

The total area of FRP reinforcement is

A f2 := N bar2 ·A f_bar = 6.283·in. 2

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

A
A

f2

ρ : = = 0.00822

f2

c2

FRP bar spacing: The clear bar spacing is

bN − ⋅ φ−−

−

c in

w bar2 f_bar c

s : = =⋅ inf20_

f20_clear

N1

bar2

The minimum required bar spacing is

S f_min2 := max(1·in, ϕ f_bar ) = 1·in.

“OK” if s > s

f20_ clear f_min2

Check_BarSpacing2 : =

“Too many bars” therwise

Check_BarSpacing = “Too many bars”

TwoManyBars := ✓ □Check Box

The flexural FRP reinforcement is placed in two layers: