PROFIS Design Guide: US-EN Summer 2021 | Page 177

PROFIS ENGINEERING REPORT SHEAR LOAD

Concrete Breakout Failure Mode
Variables e c , V
Variables ACI 318-14 Chapter 17 Provision Comments for PROFIS Engineering
e c , V
17.5.2.5 The modification factor for anchor groups loaded eccentrically in shear , ψ ec , V , shall be calculated as ψ ec , V
= but ψ ec , V shall not be taken greater than 1.0 .
1
1 + 2e ́V
3c a1
( 17.5.2.5 )
If the loading on an anchor group is such that only some anchors are loaded in shear in the same direction , only those anchors that are loaded in shear in the same direction shall be considered when determining the eccentricity e ́V for use in Eq . ( 17.5.2.5 ) and for the calculation of V cbg according to Eq . ( 17.5.2.1b ).
e ́V is an ACI 318 parameter to define shear eccentricity . PROFIS Engineering designates this parameter “ e c , V
”. The value for e ́V corresponds the distance of a resultant shear load from the centroid of anchors that are loaded in shear . Shear eccentricity is used to calculate the ACI 318 modification factor for shear eccentricity ( ψ ec , V
). PROFIS Engineering calculations for shear eccentricity are as follows :
• Calculate a resultant shear load acting on the anchors
• Calculate the distance ( e ́V ) between this load and the centroid of the anchors loaded in shear
• Calculate the modification factor for shear eccentricity ( ψ e , V
)
If a torsion moment acts on the anchorage , the direction of the shear load acting on individual anchors will vary . Below is an illustration showing how PROFIS Engineering accounts for shear eccentricity when a torsion moment acts on the anchorage .
V s
= ( V 2 , x ) 2 + ( V 4 , x
) 2 V y = ( V 3 , y
) 2 + ( V 4 , y ) 2 ➞ V ua , g
= ( V x ) 2 + ( V y
) 2 tan -1 θ =
V x
➞
ecv =
s
V y
2
( sin θ )
Reference the Variables section of the PROFIS Engineering report for more information on the parameter c a1
.
Reference the Calculations section of the PROFIS Engineering report for more information on the parameter ψ ec , V
.
177 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions