This is a parameter used in anchor reinforcement shear breakout
resistance check.
When using hor. tie bar to resist shear breakout, at nodes where
hook is located the tie bar cannot develop full yield strength.
The following two assumptions are made for the anchor
reinforcement shear resistance calculation.
1. Use the pullout resistance in tension of a single hooked bolt as
per ACI318-11 D.5.3.5 Eq. (D-15) as the max force can be
developed at hook Th
2. Assume 50% of hor. tie bars can develop full yield strength Tr ,
the rest 50% can only develop pullout resistance at hook Th
If user agrees with above assumptions, user can select 50% hor.
tie bars develop full yield strength option, as a result of this
option more hor. tie bar (more legs, bigger bar diameter) may be
required to provide adequate shear breakout resistance.
There are cases where the hook reduction is not applicable.
For example, when the hor. hair pin is used and adequate
development length is provided at both side of breakout line, user
can select 100% hor. tie bars develop full yield strength
option in these cases.
