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

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 )

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