PROFIS Design Guide - AC 318-19 July 2022 | Page 24

1.1 Bond Failure Mode

Variables c _{a , min}

Variables ACI 318-19 Chapter 17 Provision Comments for PROFIS Engineering

c _{a , min}

17.6.5.1.1 …….. A _Na is the projected influence area of a single adhesive anchor or an adhesive anchor group that is approximated as a rectilinear area that projects outward a distance c _Na from the centerline of the adhesive anchor , or in the case of an adhesive anchor group , from a line through a row of adjacent adhesive anchors ……..

17.6.5.1.2 …….. A _Na0 is the projected influence area of a single adhesive anchor with an edge distance of at least c _Na

.

A _Na0

= ( 2c _Na

) ² ( 17.6.5.1.2a )

17.6.5.4.1 Modification factor for edge effects for single adhesive anchors or adhesive anchor groups in tension , ψ _{ed , 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 ) ca , 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 318-19 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

:

c _a2

: 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 .

distance from the center of an anchor shaft to the edge of concrete in a direction perpendicular to ca1 ( 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 .

( b ) If c _{a , min} < c _Na

, c a , min ( 17 . 6 . 5 . 4 . 1b ) then ψ _{ed , Na} = 0.7 + 0.3 c _Na

17.6.5.5.1 Modification factor for adhesive anchors designed for uncracked concrete in accordance with 17.6.5.1 without supplementary reinforcement to control splitting , ψ _{cp , Na}

, shall be determined by ( a ) or ( b ) where c _ac is defined in 17.9.5 .

( a ) If c _{a , min} ≥ c _ac

, then ψ _{cp , Na} = 1.0 ( 17.6.5.5.1a )

17.6.5.5.2 For all other cases , ψ _{cp , Na} shall be taken as 1.0 .

24 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-19 Provisions