Design of a one-way slab - Reinforced Concrete with FRP Bars: Mechanics and Design - page 223

Tension lap splice: The recommended development length of FRP tension
lap splices is 1.3 l d (Section 11.4 of ACI 440.1R-06). The minimum recom-
mended tension lap splice development length is
1.3 l d = 33.8⋅in.
A tension lap splice development length of 34 in. is considered and
implemented.
Embedment length: Because this is a case of negative reinforcement, it
has to be checked if adequate moment capacity can be achieved at the end
of the embedment length. The maximum available length for embedment is
equal to half the length of the adjacent span:
l emb3 := 0.25⋅l 2 = 60⋅in.
The developable tensile stress is calculated per Equation (11-3) of ACI
440.1R-06. Minimum between cover to bar center and half of the center-
to-center bar spacing is

=⋅

+ φ , s

f_bar f _bar3

C:minc = 1in . c

b3

2 2

Bar location modification factor for top reinforcement but less than 12
in. of concrete below it is

α Neg3 := 1.0
Required stress in the FRP is

f ffr3 := E f ·ε f3 (c u3 ) = 80·ksi

The developable tensile stress (ACI 440.1R-06 Equation 11-3 is

fpsi ′ ⋅

1 C 1

c

emb3 b3 emb3

f f ⋅ 13.6 ⋅ φ + φ ⋅ φ + 340 ≥ f

fu fu

α

Neg3 f_bar f_bar f_bar

f : =

ffd13

fpsi

′ ⋅ 1 C 1 c

emb3 b3 emb3

⋅ 13.6 ⋅ φ + φ ⋅ φ + 340 otherwise

α

Neg3 f_bar f_bar f_bar

f ffd13 = 80⋅ksi

“Bar ultimate strength”iff ≥ f

fd11 fr1

CheckFailure3 : =

“Bond strength”otherwise

CheckFailure3 = “Bond strength”

The cross section of interest is not a bond critical section and adequate
moment capacity can be achieved.