PROFIS Design Guide - AC 318-19 July 2022 | Page 14

1.0 TENSION

1.1 Bond Failure Mode
Equations ψ ec , Na
Equations ACI 318-19 Chapter 17 Provision Comments for PROFIS Engineering
ψ ec , Na
=
1
1 + e ́N
c Na
≤ 1.0
17.6.5.3.1 Modification factor for adhesive anchor groups loaded eccentrically in tension , ψ ec , Na shall be calculated by Eq . ( 17.6.5.3.1 ).
ψ ec , Na
=
1
1 + e ́N
( 17.6.5.3.1 )
17.6.5.3.2 If the loading on an adhesive anchor group is such that only some of the adhesive anchors are in tension , only those adhesive anchors that are in tension shall be considered for determining the eccentricity e ́N in Eq . ( 17.6.5.3.1 ) and for the calculation of N ag according to Eq .
( 17.6.5.1b ).
c Na
17.6.5.3.3 If a load is eccentric about two orthogonal axes , ψ ec , Na shall be calculated for each axis individually , and the product of these factors shall be used as ψ ec , Na in Eq . ( 17.6.5.1b ).
ψ ec , Na is a modification factor that is used to account for a resultant tension load that is eccentric with respect to the centroid of anchors that are loaded in tension .
ψ ec , Na is only considered when calculating the nominal bond strength in tension for an anchor group ( N ag
).
Reference the Variables section of the PROFIS Engineering report for more information on the following parameters :
e c1 , N
: parameter for tension eccentricity with respect to the x direction
e c2 , N
: parameter for tension eccentricity with respect to the y direction
Reference the Calculations section of the PROFIS Engineering report for more information on the following parameters :
c Na
: projected distance from an adhesive anchor
ψ ec1 , N
: modification factor for tension eccentricit with respect to the x direction
ψ ec2 , N
: modification factor for tension eccentricity with respect to the y direction
Equations ψ ed , Na
Equations ACI 318-19 Chapter 17 Provision Comments for PROFIS Engineering
ψ ed , Na
= 0.7 + 0.3
c a , min ≤1 . 0
c Na
17.6.5.4.1 Modification factor for edge effects for single adhesive anchors or adhesive anchor groups in tension , ψ ec , Na
, shall be determined by ( a ) or ( b ) using the critical distance c Na as defined in Eq . ( 17.6.5.1.2b )
( a ) If c a , min > c Na
, then ψ ed , Na = 1.0 ( 17.6.5.4.1a )
( b ) If c a , min < c Na
, c a , min ( 17 . 6 . 5 . 4 . 1b )
ψ ec , Na is a modification factor that is used to account for fixed edge distances less than c Na
, where c Na corresponds to a projected distance from the center of the adhesive anchor element being modeled in PROFIS Engineering . The illustration below shows how the assumed area of influence ( A Na
) would be defined for an adhesive anchoring application being modeled with two fixed edges ( c a1 and c a2 ) that are both less than c Na , and with c a1 being less than c a2 . The smallest edge distance ( c a1 ) corresponds to the parameter c a , min
, and would be used to calculate the modification factor ψ ed , Na .
then ψ ed , Na = 0.7 + 0.3
c Na
ψ ed , Na
= 0.7 + 0.3 ( c a1 / c Na
)
Reference the Variables section of the PROFIS Engineering report for more information on the following parameter :
c a , min
: parameter for the smallest fixed edge being modeled .
Reference the Calculations section of the PROFIS Engineering report for more information on the following parameter :
c Na
: projected distance from an adhesive anchor .
14 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-19 Provisions