Structural Detailing of Reinforcement for Economy - Simplified Design of Reinforced Concrete Buildings - page 240

8.4.3 Development of Hooked Bars in Tension

The ACI provides the following equation for development length in tension for bars ending with standard hook:

⎛ ⎞

0.02f y ψ e
λ ʹ

dh = ⎜ ⎟ d b

f c

⎝ ⎠

The values for ψ e and λ are as defined before.

For normal weight concrete with › = 4000 psi and uncoated reinforcing bars with f y = 60,000 psi the development
length ˜ dh = 19 d b . Table 8-2 lists the development length ˜ dh for different bar sizes and concrete strengths.

Table 8-2 Minimum Development Lengths ˜ dh for Grade 60 Bars with Standard End Hooks (in.)*

˜ dh

˜ dh

2 " min.
cover

d b

d b

A s f y

A s f y

4d b
5d b

#3 through #8
#9, #10, #11

4d b or
2.5" min.

Standard 90° hook

Standard 180° hook

*Values based on normal weight concrete.