PART 4 SHEAR LOAD
Pryout Failure Mode ( Pryout Bond )
Equation A Na0
Equation 318-14 Chapter 17 Provision Comments for PROFIS Engineering
A Na0
= ( 2c Na
) 2
17.4.5.1 …….. A Na0 is the projected influence area of a single anchor with an edge distance equal to or greater than c Na
: where
and constant 1100 carries the unit of lb / in 2 .
A Na0
= ( 2c Na ) 2 ( 17.4.5.1c ) c Na
= 10d a т uncr 17 . 4 . 5 . 1d 1100
When calculating the nominal concrete pryout strength in shear ( V cp or V cpg
), the parameter A Na0 is a modification factor that accounts for the area of influence assumed to develop in concrete when a shear load applied to a single anchor without the influence of any fixed edges creates a prying ( i . e . tension ) action on the anchor . A Na0 is calculated with the parameter “ c Na
”, which is defined in ACI 318-14 Chapter 2 as the “ projected distance from center of an anchor shaft on one side of the anchor required to develop the full bond strength of a single adhesive anchor ”. The geometry for A Na0 is defined by a projected distance of c Na from the anchor in the x and y directions . The figure below illustrates how A Na0 is calculated .
17.4.5.1 The nominal bond strength in tension , N a of a single adhesive anchor or N ag of a group of adhesive anchors , shall not exceed : ( a ) For a single adhesive anchor
( b ) For a group of adhesive anchors
N a
= A Na ψ ed , Na ψ cp , Na
N ba
( 17.4.5.1a )
A Na0
N ag
= A Na ψ ec , Na ψ ed , Na ψ cp , Na
N ba
( 17.4.5.1b )
A Na0
………………………………………………………
A Na0
= ( c Na + c Na
) ( c Na + c Na
)
= ( 2.0 c Na
) 2
Reference the Calculations section of the PROFIS Engineering report for more information on c Na and A Na0
.
211 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions