1.0 TENSION
1.1 Bond Failure Mode
Variables h ef
Variables ACI 318-19 Chapter 17 Provision Comments for PROFIS Engineering
h ef
17.6.5 . 2.1 Basic bond strength of a single adhesive anchor in tension in cracked concrete , N ba , shall be calculated by Eq . ( 17.6.5.2.1 )
N ba
= λ a т cr πd a h ef
( 17.6.5.2.1 )
Example of a table in an ICC-ES evaluation report ( ESR ) showing effective embedment depth values ( h ef , min and h ef , max
) for threaded rod elements used with an adhesive anchor system .
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 )
Reduction for Seismic Tension α N , seis - 0.88 1.0 1.0 1.0 1.0 0.97 1.0
The parameter N ba corresponds to a calculated bond strength for a single adhesive anchor element without any fixed edge or spacing influences . Calculation of N ba is predicated on the characteristic bond stress of the adhesive product ( т cr or т uncr ), the anchor element geometry ( πd a and h ef ), and a modification factor for lightweight concrete ( λ a
). Adhesive anchor systems tested per the ICC-ES acceptance criteria AC308 can also include an additional seismic modification factor ( α N , seis
). when calculating N ba . h ef is defined as the “ effective embedment depth of an anchor ”. This parameter corresponds to the embedded portion of the anchor that is “ effective ” in transferring tension load from the anchor into the concrete . ACI 318-19 Equation ( 17.6.5.2.1 ) includes h ef for calculating N ba
.
Testing per the ICC-ES acceptance criteria AC308 and the ACI test standard ACI 355.4 is used to derive product-specific data that is used in ACI 318 bond strength calculations for an adhesive anchor system . Data derived from this testing , as well as some of the parameters used to develop this data , are provided in an ICC-ES evaluation report ( ESR ). The minimum effective embedment depth ( h ef , min
) derived from this testing is specific to the anchor element ( e . g . threaded rod , rebar , internally threaded insert ), and to the adhesive product . AC308 limits the maximum effective embedment depth ( h ef , max
) for adhesive anchor systems to a value of 20 times the anchor diameter ( 20d a
). For post-installed adhesive anchors , PROFIS Engineering permits users to input h ef values that are within the embedment depth range given in the ESR for a specific anchor element , diameter , and adhesive product .
post-installed adhesive anchor
h ef , min
≤ h ef ≤ h ef , max where h ef , min and h ef , max
(= 20d a
) are given in the anchor ESR
23 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-19 Provisions