PROFIS Design Guide: US-EN Summer 2021 | Page 24

PROFIS ENGINEERING REPORT TENSION LOAD

Bond Failure Mode
Variables c a , min
Variables ACI 318-14 Chapter 17 Provision Comments for PROFIS Engineering
c a , min
17.4.5.1 …….. A Na is the projected influence area of a single adhesive anchor or group of adhesive anchors that shall be approximated as a rectilinear area that projects outward a distance c Na from the centerline of the adhesive anchor , or in the case of a group of adhesive anchors , from a line through a row of adjacent adhesive anchors ……..
17.4.5.1 …….. A Na0 is the projected influence area of a single adhesive anchor with an edge distance equal to or greater than c Na
.
A Na0
= ( 2c Na
) 2 ( 17.4.5.1c )
17.4.5.4 The modification factor for edge effects for single adhesive anchors or adhesive anchor groups loaded in tension , ψ ed , Na
, shall be calculated as If c a , min
≥ c Na , then ψ ed , Na
= 1.0 ( 17.4.5.4a )
If c a , min < c Na
, then ψ ed , Na = 0.7 + 0.3 c a , min ( 17 . 4 . 5 . 4b )
c Na c a , min is defined as the “ minimum distance from the center of an anchor shaft to the edge of concrete .” When one or more fixed edges are modeled in PROFIS Engineering , the report will show the smallest fixed edge as “ c a , min
” in the
Variables section .
Excerpted ACI 318-14 anchoring-to-concrete provisions and equations that include c a , min for calculating bond strength in tension are shown to the left . Reference the parameters A Na and A Na0 in the Equations section of the PROFIS Engineering report for more information on the following parameters :
c a1
: Distance from the center of an anchor shaft to the edge of concrete in one direction ( e . g . the x + direction ). For tension calculations , c a1 is the smallest fixed edge distance c a2
: Distance from the center of an anchor shaft to the edge of concrete in a direction perpendicular to c a1
( e . g . the y + direction )
Reference the parameters ψ ed , Na and ψ cp , Na in the Equations and Calculations sections of the PROFIS Engineering report for more information on how c a , min is used to calculate these parameters .
17.4.5.5 The modification factor for adhesive anchors designed for uncracked concrete in accordance with 17.4.5 . 2 without supplementary reinforcement to control splitting , ψ cp , Na
, shall be calculated as : If c a , min
≥ c ac , then ψ cp , Na
= 1.0 ( 17.4.5.5a )
If c a , min < c ac
, then ψ cp , Na = c
a , min
( 17.4.5.5b )
c ac
but ψ cp , Na determined from Eq . ( 17.4.5.5b ) shall not be taken less than c Na
/ c ac , where the critical distance cac is defined in 17.7.6 . For all other cases , ψ cp , Na shall be taken as 1.0 .
24 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions