1.0 TENSION
1.1 Bond Failure Mode
Calculations A Na0
Calculations ACI 318-19 Chapter 17 Provision Comments for PROFIS Engineering
A Na0
( 2c Na
) 2
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 . where
A Na0
= ( 2c Na ) 2 ( 17.6.5.1.2a ) c Na
= 10d a т uncr ( 17 . 6 . 5 . 1 . 2b ) 1100
Example of a bond strength table in an ICC-ES evaluation report ( ESR ) showing characteristic bond stress values ( т k , uncr
) that could be used to calculate c Na for a given anchor diameter ( d a
) using
Eq . ( 17.6.5.1.2b ).
A Na0 is a modification factor that accounts for the area of influence assumed to develop in concrete , with respect to bond failure , when a tension load is applied to a single adhesive anchor without the influence of any fixed edges . A Na0 is calculated with the parameter “ c Na
”, which is defined in ACI 318-19 Chapter 2 as the “ projected distance from the center of an anchor shaft on one side of the anchor required to develop the full bond strength of a single adhesive anchor ”.
c Na is a calculated value , and is calculated per ACI 318-19 Equation ( 17.6.5.1.2b ). The geometry for A Na0 is defined by a projected distance of c Na from the anchor , on either side of the anchor , in both the x and y directions . The calculated value for A Na0 is always equal to ( 2c Na ) 2 , and c Na is always calculated per Equation ( 17.6.5.1.2b ) when designing with the anchoring-to-concrete provisions of ACI 318-19 .
The figure below illustrates how A Na0 is calculated .
ICC-ES ESR-3187 Table 14
DESIGN INFORMATION Symbol Units
Nominal Rod Diameter ( in ). 3 / 8 1 / 2 5 / 8 3 / 4 7 / 8 1 1-1 / 4
Minimum Embedment h ef , min in 2-3 / 8 2-3 / 4 3-1 / 8 3-1 / 2 3-1 / 2 4 5 ( mm ) ( 60 ) ( 70 ) ( 79 ) ( 89 ) ( 89 ) ( 102 ) ( 127 )
Maximum Embedment h ef , max in 7-1 / 2 10 12-1 / 2 15 17-1 / 5 20 25 ( mm ) ( 191 ) ( 254 ) ( 318 ) ( 381 ) ( 445 ) ( 508 ) ( 635 )
Temperature Range A
Temperature Range B
Temperature Range C
Characteristic bond strength psi 1045 1135 1170 1260 1290 1325 1380 in cracked concrete т k , cr ( Mpa ) ( 7.2 ) ( 7.8 ) ( 8.1 ) ( 8.7 ) ( 8.9 ) ( 9.1 ) ( 9.5 )
Characteristic bond strength psi 2220 2220 2220 2220 2220 2220 2220 in uncracked concrete т k , uncr ( Mpa ) ( 15.3 ) ( 15.3 ) ( 15.3 ) ( 15.3 ) ( 15.3 ) ( 15.3 ) ( 15.3 )
Characteristic bond strength psi 1045 1135 1170 1260 1290 1325 1380 in cracked concrete т k , cr ( Mpa ) ( 7.20 ) ( 7.80 ) ( 8.00 ) ( 8.67 ) ( 9.00 ) ( 9.00 ) ( 9.50 )
Characteristic bond strength psi 2220 2220 2220 2220 2220 2220 2220 in uncracked concrete т k , uncr ( Mpa ) ( 15.3 ) ( 15.3 ) ( 15.3 ) ( 15.3 ) ( 15.3 ) ( 15.3 ) ( 15.3 )
Characteristic bond strength psi 855 930 960 1035 1055 1085 1130 in cracked concrete т k , cr ( Mpa ) ( 5.9 ) ( 6.4 ) ( 6.6 ) ( 7.1 ) ( 7.3 ) ( 7.5 ) ( 7.8 )
Characteristic bond strength psi 1820 1820 1820 1820 1820 1820 1820 in uncracked concrete т k , uncr ( Mpa ) ( 12.6 ) ( 12.6 ) ( 12.6 ) ( 12.6 ) ( 12.6 ) ( 12.6 ) ( 12.6 )
A Nc0
= ( c Na + c Na
) ( c Na + c Na
)
= ( 2.0c Na
) 2
Reference the Equations and Calculations section of the PROFIS Engineering report for more information on c Na
.
Reference the Equations section of the PROFIS Engineering report for more information on A Na0
.
33 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-19 Provisions