Design of a one-way slab - Reinforced Concrete with FRP Bars: Mechanics and Design - page 197

The recommended slab thickness can be selected as t slabACI := max(t end ,t int )
= 12∙in. It has to be noted that these values are only a starting point for the
design. In this example, a different thickness is selected:

t slab := 8 in.

6.3.2 Concrete properties
The following concrete properties are considered for the design:

f ′ c := 5000 psi Compressive strength

ε cu := 0.003 Ultimate compressive strain

ρ := 145 lbf
ft

3

Density

c

1.5

ρ
⋅

⋅

c

E =33psi

0.5

f Compressive modulus of elasticity

′ c c

− 3

lbf ft

E c = 4074∙ksi Computed as indicated in ACI 318-11

f =7.5 ⋅ fpsi ′ ⋅ Concrete tensile strength

r c

f r = 530∙psi Computed as indicated in ACI 318-11

The stress-block factor, β 1 , is computed as indicated in ACI 318-11:

0.85 if f=4000 psi ′ = 0.8

c

f
1000 psi

′ c

β :=

1.05 − 0.05 ⋅ if 4000 psi<f ′ < 8000 psi

1

c

0.65 otherwise

6.3.3 Analytical approximations of
concrete compressive stress-strain
curve—Todeschini's model

Concrete Compressive Stress-strain Curve

4000

2000

0

0 0.001 0.002 0.003

Strain, in./in.