Design of a one-way slab - Reinforced Concrete with FRP Bars: Mechanics and Design - page 216

c: a

f1
1

= = 1.233 inf2 ⋅ .

f2

β

The nominal moment capacity is

⋅

a
2

f2

M: =⋅ Af d =17ftkip ⋅⋅

nACI_2 f2 f2 f2

The concrete crushing failure mode is less brittle than the one due to
FRP rupture. The ϕ-factor is computed according to Equation (8-7) of
ACI 440.1R-06:

0.55if ρ≤ρ φ = 0.55

f2 fb2 bACI_ 2

+ ⋅ ρ
ρ

f2

φ : = 0.30 0.25 if ρ<ρ< 1.4 ⋅ρ

bACI_2 fb2 f 2

fb 2

fb2

0.65otherwise

The design flexural strength equation is computed per Equation (8-1) of
ACI 440.1R-06:

ϕ bACI _ 2 ·M nACI _ 2 = 9·kip·ft

( )

“OK”if φ ⋅ MMM5kipft ≥ = ⋅ ⋅

bACI_ 2 nACI_2 u2 u2

Check_FlexureACI_2 : =

“Not good”otherwise

Check_FlexureACI_2 = “OK”

Development of positive moment reinforcement: The development
length, l d , for straight bars can be calculated using Equation (11-3) of ACI
440.1R-06. Minimum between cover to bar center and half of the center-
to-center bar spacing is

, s + φ

f_bar

C:minc =

f_bar2

=⋅ 1in .

b2 c

2 2

The bar location modification factor for bottom reinforcement is

α Pos := 1