PROFIS ENGINEERING REPORT SHEAR LOAD
Concrete Breakout Failure Mode
Calculations ψ hV
Calculations 318-14 Chapter 17 Provision Comments for PROFIS Engineering
ψ hV
17.5.2.8 The modification factor for anchors located in a concrete member where h a < 1.5c a1
, ψ h , V , shall be calculated as ψ h , V
= but ψ h , V shall not be taken less than 1.0 .
1.5c a1 ( 17.5.2.8 )
h a ψ h , V is a modification factor that is used to account for a concrete member thickness h a that is less than a projected distance of 1.5c a1 down from the surface of the concrete . The parameter c a1 corresponds to the distance of an anchor , in the direction of the applied shear load , to the fixed edge for which concrete breakout in shear is being calculated . ψ h , V is always ≥ 1.0 per the provisions of
Section 17.5.2.8 . ACI anchoring-to-concrete provisions do not set a maximum limit on the value for
c a1
. Minimum edge distance values ( c min
) are given in ACI 318-14 Sections 17.7.2 , 17.7.3 and in post-installed anchor approvals .
PROFIS Engineering always uses a c a1
-value corresponding to the distance from the anchor row nearest the fixed edge where concrete breakout is assumed to occur unless AWS D1.1 headed studs are being modeled . AWS D1.1 headed studs are rigidly attached to a fixture so a c a1
-value corresponding to the distance from the anchor row farthest from the fixed edge where concrete breakout is assumed to occur can be used to model this type of anchor .
The figures below illustrate conditions for calculating ψ h , V . h a
> 1.5c a1 h a
< 1.5c a1 ψ h , V
= 1.0 ψ h , V =
1.5c a1
h a
Reference the Variables section of the PROFIS Engineering report for more information on the following parameters :
c a1
: Fixed edge distance in the direction of the applied shear load
h a
: Concrete thickness
Reference the Equations section of the PROFIS Engineering report for more information on ψ h , V
.
194 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions